module stb_truetype;

import std.math.rounding : floor, ceil;
import core.stdc.math    : pow, cos, acos;
import core.math         : sqrt, fabs;
import dlib.alloc        : malloc, free;
import core.stdc.string   : strlen, memset, memcpy;

// TODO: fix security issues
// =======================================================================
//
//    NO SECURITY GUARANTEE -- DO NOT USE THIS ON UNTRUSTED FONT FILES
//
// This library does no range checking of the offsets found in the file,
// meaning an attacker can use it to read arbitrary memory.
//
// =======================================================================

int ifloor(T)(T x) if(__traits(isFloating, T)) => cast(int)floor(x);
int iceil(T)(T x)  if(__traits(isFloating, T)) => cast(int)ceil(x);

struct stbtt__buf
{
	ubyte* data;
	int    cursor;
	int    size;
}

struct stbtt_bakedchar
{
	ushort x0, y0, x1, y1;
	float  xoff = 0.0, yoff = 0.0, xadvance = 0.0;
}

struct stbtt_aligned_quad
{
	float x0 = 0.0, y0 = 0.0, s0 = 0.0, t0 = 0.0;
	float x1 = 0.0, y1 = 0.0, s1 = 0.0, t1 = 0.0;
}

struct stbtt_packedchar
{
	ushort x0, y0, x1, y1;
	float  xoff  = 0.0, yoff  = 0.0, xadvance = 0.0;
	float  xoff2 = 0.0, yoff2 = 0.0;
}

struct stbtt_pack_range
{
	float             font_size = 0.0;
	int               first_unicode_codepoint_in_range;
	int*              array_of_unicode_codepoints;
	int               num_chars;
	stbtt_packedchar* chardata_for_range;
	ubyte             h_oversample, v_oversample;
}

T STBTT_POINT_SIZE(T)(T x) if(__traits(isNumeric, T)) => -x;

struct stbtt_pack_context 
{
  void*  user_allocator_context;
  void*  pack_info;
  int    width;
  int    height;
  int    stride_in_bytes;
  int    padding;
  int    skip_missing;
  uint   h_oversample, v_oversample;
  ubyte* pixels;
  void*  nodes;
}

struct stbtt_fontinfo
{
   ubyte* data;                       // pointer to .ttf file
   int    fontstart;                  // offset of start of font

   int numGlyphs;                     // number of glyphs, needed for range checking

   int loca,head,glyf,hhea,hmtx,kern,gpos,svg; // table locations as offset from start of .ttf
   int index_map;                     // a cmap mapping for our chosen character encoding
   int indexToLocFormat;              // format needed to map from glyph index to glyph

   stbtt__buf cff;                    // cff font data
   stbtt__buf charstrings;            // the charstring index
   stbtt__buf gsubrs;                 // global charstring subroutines index
   stbtt__buf subrs;                  // private charstring subroutines index
   stbtt__buf fontdicts;              // array of font dicts
   stbtt__buf fdselect;               // map from glyph to fontdict
}

struct stbtt_kerningentry
{
   int glyph1; // use stbtt_FindGlyphIndex
   int glyph2;
   int advance;
}

enum stbtt_curvetype : ubyte
{
	none,
	vmove,
	vline,
	vcurve,
	vcubic,
}

struct stbtt_vertex
{
	short x, y, cx, cy, cx1, cy1;
	ubyte type, padding;
}

private struct stbtt__bitmap
{
   int    w, h, stride;
   ubyte* pixels;
};

enum STBTT_MACSTYLE_DONTCARE   = 0;
enum STBTT_MACSTYLE_BOLD       = 1;
enum STBTT_MACSTYLE_ITALIC     = 2;
enum STBTT_MACSTYLE_UNDERSCORE = 4;
enum STBTT_MACSTYLE_NONE       = 8;   // <= not same as 0, this makes us check the bitfield is 0

enum STBTT_PLATFORM
{
	ID_UNICODE   = 0,
	ID_MAC       = 1,
	ID_ISO       = 2,
	ID_MICROSOFT = 3,
}

enum STBTT_UNICODE_EID
{
	UNICODE_1_0      = 0,
	UNICODE_1_1      = 1,
	ISO_10646        = 2,
	UNICODE_2_0_BMP  = 3,
	UNICODE_2_0_FULL = 4,
}

enum STBTT_MS_EID
{
	SYMBOL       = 0,
	UNICODE_BMP  = 1,
	SHIFTJIS     = 2,
	UNICODE_FULL = 10,
}

enum STBTT_MAC_EID
{
	ROMAN        = 0,
	JAPANESE     = 1,
	CHINESE_TRAD = 2,
	KOREAN       = 3,
	ARABIC       = 4,
	HEBREW       = 5,
	GREEK        = 6,
	RUSSIAN      = 7,
}

enum STBTT_MS_LANG
{
	ENGLISH  = 0x0409,
	CHINESE  = 0x0804,
	DUTCH    = 0x0413,
	FRENCH   = 0x040C,
	GERMAN   = 0x0407,
	HEBREW   = 0x040D,
	ITALIAN  = 0x0410,
	JAPANESE = 0x0411,
	KOREAN   = 0x0412,
	RUSSIAN  = 0x0419,
	SPANISH  = 0x0409,
	SWEDISH  = 0x041D,
}

enum STBTT_MAC_LANG
{
	ENGLISH            = 0,
	ARABIC             = 12,
	DUTCH              = 4,
	FRENCH             = 1,
	GERMAN             = 2,
	HEBREW             = 10,
	ITALIAN            = 3,
	JAPANESE           = 11,
	KOREAN             = 23,
	RUSSIAN            = 32,
	SPANISH            = 6,
	SWEDISH            = 5,
	CHINESE_SIMPLIFIED = 33,
	CHINESE_TRAD       = 19,
}

enum STBTT_MAX_OVERSAMPLE = 8;

static assert(STBTT_MAX_OVERSAMPLE <= 255);
static assert((STBTT_MAX_OVERSAMPLE & (STBTT_MAX_OVERSAMPLE-1)) == 0);

enum STBTT_RASTERIZER_VERSION = 2;

// returns number of contours
static stbtt__point *
stbtt_FlattenCurves(stbtt_vertex *vertices, int num_verts, float objspace_flatness, int **contour_lengths, int *num_contours)
{
   stbtt__point *points = null;
   int num_points = 0;

   float objspace_flatness_squared = objspace_flatness * objspace_flatness;
   int i,n=0,start=0, pass;

   // count how many "moves" there are to get the contour count
   for (i=0; i < num_verts; ++i)
      if (vertices[i].type == stbtt_curvetype.vmove)
         ++n;

   *num_contours = n;
   if (n == 0) return null;

   *contour_lengths = cast(int *)malloc(int.sizeof * n);

   if (*contour_lengths == null) {
      *num_contours = 0;
      return null;
   }

   // make two passes through the points so we don't need to realloc
   for (pass=0; pass < 2; ++pass) {
      float x=0,y=0;
      if (pass == 1) {
         points = cast(stbtt__point *)malloc(num_points * stbtt__point.sizeof);
         if (points == null) goto error;
      }
      num_points = 0;
      n= -1;
      for (i=0; i < num_verts; ++i) {
         switch (vertices[i].type) {
            case stbtt_curvetype.vmove:
               // start the next contour
               if (n >= 0)
                  (*contour_lengths)[n] = num_points - start;
               ++n;
               start = num_points;

               x = vertices[i].x, y = vertices[i].y;
               stbtt__add_point(points, num_points++, x,y);
               break;
            case stbtt_curvetype.vline:
               x = vertices[i].x, y = vertices[i].y;
               stbtt__add_point(points, num_points++, x, y);
               break;
            case stbtt_curvetype.vcurve:
               stbtt__tesselate_curve(points, &num_points, x,y,
                                        vertices[i].cx, vertices[i].cy,
                                        vertices[i].x,  vertices[i].y,
                                        objspace_flatness_squared, 0);
               x = vertices[i].x, y = vertices[i].y;
               break;
            case stbtt_curvetype.vcubic:
               stbtt__tesselate_cubic(points, &num_points, x,y,
                                        vertices[i].cx, vertices[i].cy,
                                        vertices[i].cx1, vertices[i].cy1,
                                        vertices[i].x,  vertices[i].y,
                                        objspace_flatness_squared, 0);
               x = vertices[i].x, y = vertices[i].y;
               break;
						default: break;
         }
      }
      (*contour_lengths)[n] = num_points - start;
   }

   return points;
error:
   free(points);
   free(*contour_lengths);
   *contour_lengths = null;
   *num_contours = 0;
   return null;
}

void 
stbtt_Rasterize(stbtt__bitmap *result, float flatness_in_pixels, stbtt_vertex *vertices, int num_verts, float scale_x, float scale_y, float shift_x, float shift_y, int x_off, int y_off, int invert)
{
   float scale            = scale_x > scale_y ? scale_y : scale_x;
   int winding_count      = 0;
   int *winding_lengths   = null;
   stbtt__point *windings = stbtt_FlattenCurves(vertices, num_verts, flatness_in_pixels / scale, &winding_lengths, &winding_count);
   if (windings) {
      stbtt__rasterize(result, windings, winding_lengths, winding_count, scale_x, scale_y, shift_x, shift_y, x_off, y_off, invert);
      free(winding_lengths);
      free(windings);
   }
}

void 
stbtt_FreeBitmap(ubyte *bitmap)
{
   free(bitmap);
}

ubyte *
stbtt_GetGlyphBitmapSubpixel(stbtt_fontinfo *info, float scale_x, float scale_y, float shift_x, float shift_y, int glyph, int *width, int *height, int *xoff, int *yoff)
{
   int ix0,iy0,ix1,iy1;
   stbtt__bitmap gbm;
   stbtt_vertex *vertices;
   int num_verts = stbtt_GetGlyphShape(info, glyph, &vertices);

   if (scale_x == 0) scale_x = scale_y;
   if (scale_y == 0) {
      if (scale_x == 0) {
         free(vertices);
         return null;
      }
      scale_y = scale_x;
   }

   stbtt_GetGlyphBitmapBoxSubpixel(info, glyph, scale_x, scale_y, shift_x, shift_y, &ix0,&iy0,&ix1,&iy1);

   // now we get the size
   gbm.w = (ix1 - ix0);
   gbm.h = (iy1 - iy0);
   gbm.pixels = null; // in case we error

   if (width ) *width  = gbm.w;
   if (height) *height = gbm.h;
   if (xoff  ) *xoff   = ix0;
   if (yoff  ) *yoff   = iy0;

   if (gbm.w && gbm.h) {
      gbm.pixels = cast(ubyte *)malloc(gbm.w * gbm.h);
      if (gbm.pixels) {
         gbm.stride = gbm.w;

         stbtt_Rasterize(&gbm, 0.35f, vertices, num_verts, scale_x, scale_y, shift_x, shift_y, ix0, iy0, 1);
      }
   }
   free(vertices);
   return gbm.pixels;
}

ubyte *
stbtt_GetGlyphBitmap(stbtt_fontinfo *info, float scale_x, float scale_y, int glyph, int *width, int *height, int *xoff, int *yoff)
{
   return stbtt_GetGlyphBitmapSubpixel(info, scale_x, scale_y, 0.0f, 0.0f, glyph, width, height, xoff, yoff);
}

void 
stbtt_MakeGlyphBitmapSubpixel(stbtt_fontinfo *info, ubyte *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, float shift_x, float shift_y, int glyph)
{

	int ix0,iy0;
	stbtt_vertex *vertices;
	int num_verts = stbtt_GetGlyphShape(info, glyph, &vertices);
	stbtt__bitmap gbm;

	stbtt_GetGlyphBitmapBoxSubpixel(info, glyph, scale_x, scale_y, shift_x, shift_y, &ix0, &iy0, null, null);
	gbm.pixels = output;
	gbm.w = out_w;
	gbm.h = out_h;
	gbm.stride = out_stride;

	if (gbm.w && gbm.h)
		stbtt_Rasterize(&gbm, 0.35f, vertices, num_verts, scale_x, scale_y, shift_x, shift_y, ix0,iy0, 1);

	free(vertices);
}
void 
stbtt_MakeGlyphBitmap(stbtt_fontinfo *info, ubyte *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, int glyph)
{
   stbtt_MakeGlyphBitmapSubpixel(info, output, out_w, out_h, out_stride, scale_x, scale_y, 0.0f,0.0f, glyph);
}

ubyte *
stbtt_GetCodepointBitmapSubpixel(stbtt_fontinfo *info, float scale_x, float scale_y, float shift_x, float shift_y, int codepoint, int *width, int *height, int *xoff, int *yoff)
{
	return stbtt_GetGlyphBitmapSubpixel(info, scale_x, scale_y,shift_x,shift_y, stbtt_FindGlyphIndex(info,codepoint), width,height,xoff,yoff);
}

void 
stbtt_MakeCodepointBitmapSubpixelPrefilter(stbtt_fontinfo *info, ubyte *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, float shift_x, float shift_y, int oversample_x, int oversample_y, float *sub_x, float *sub_y, int codepoint)
{
	stbtt_MakeGlyphBitmapSubpixelPrefilter(
		info, 
		output, 
		out_w, 
		out_h, 
		out_stride, 
		scale_x, 
		scale_y, 
		shift_x, 
		shift_y, 
		oversample_x, 
		oversample_y, 
		sub_x, 
		sub_y, 
		stbtt_FindGlyphIndex(info,codepoint)
	);
}

void 
stbtt_MakeCodepointBitmapSubpixel(stbtt_fontinfo *info, ubyte *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, float shift_x, float shift_y, int codepoint)
{
	stbtt_MakeGlyphBitmapSubpixel(info, output, out_w, out_h, out_stride, scale_x, scale_y, shift_x, shift_y, stbtt_FindGlyphIndex(info,codepoint));
}

ubyte *
stbtt_GetCodepointBitmap(stbtt_fontinfo *info, float scale_x, float scale_y, int codepoint, int *width, int *height, int *xoff, int *yoff)
{
	return stbtt_GetCodepointBitmapSubpixel(info, scale_x, scale_y, 0.0f,0.0f, codepoint, width,height,xoff,yoff);
}

void 
stbtt_MakeCodepointBitmap(stbtt_fontinfo *info, ubyte *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, int codepoint)
{
	stbtt_MakeCodepointBitmapSubpixel(info, output, out_w, out_h, out_stride, scale_x, scale_y, 0.0f,0.0f, codepoint);
}

void 
stbtt_GetBakedQuad(const stbtt_bakedchar *chardata, int pw, int ph, int char_index, float *xpos, float *ypos, stbtt_aligned_quad *q, int opengl_fillrule)
{
   float d3d_bias = opengl_fillrule ? 0 : -0.5f;
   float ipw = 1.0f / pw, iph = 1.0f / ph;
   const stbtt_bakedchar *b = chardata + char_index;
   int round_x = ifloor((*xpos + b.xoff) + 0.5f);
   int round_y = ifloor((*ypos + b.yoff) + 0.5f);

   q.x0 = round_x + d3d_bias;
   q.y0 = round_y + d3d_bias;
   q.x1 = round_x + b.x1 - b.x0 + d3d_bias;
   q.y1 = round_y + b.y1 - b.y0 + d3d_bias;

   q.s0 = b.x0 * ipw;
   q.t0 = b.y0 * iph;
   q.s1 = b.x1 * ipw;
   q.t1 = b.y1 * iph;

   *xpos += b.xadvance;
}


int 
stbtt_PackBegin(stbtt_pack_context *spc, ubyte *pixels, int pw, int ph, int stride_in_bytes, int padding, void *alloc_context)
{
   stbrp_context *context = cast(stbrp_context *)malloc(stbrp_context.sizeof);
   int            num_nodes = pw - padding;
   stbrp_node    *nodes   = cast(stbrp_node    *)malloc(stbrp_node.sizeof * num_nodes);

   if (context == null || nodes == null) {
      if (context != null) free(context);
      if (nodes   != null) free(nodes  );
      return 0;
   }

   spc.user_allocator_context = alloc_context;
   spc.width = pw;
   spc.height = ph;
   spc.pixels = pixels;
   spc.pack_info = context;
   spc.nodes = nodes;
   spc.padding = padding;
   spc.stride_in_bytes = stride_in_bytes != 0 ? stride_in_bytes : pw;
   spc.h_oversample = 1;
   spc.v_oversample = 1;
   spc.skip_missing = 0;

   stbrp_init_target(context, pw-padding, ph-padding, nodes, num_nodes);

   if (pixels)
      memset(pixels, 0, pw*ph); // background of 0 around pixels

   return 1;
}

void 
stbtt_PackEnd(stbtt_pack_context *spc)
{
   free(spc.nodes    );
   free(spc.pack_info);
}

void 
stbtt_PackSetOversampling(stbtt_pack_context *spc, uint h_oversample, uint v_oversample)
{
   assert(h_oversample <= STBTT_MAX_OVERSAMPLE);
   assert(v_oversample <= STBTT_MAX_OVERSAMPLE);
   if (h_oversample <= STBTT_MAX_OVERSAMPLE)
      spc.h_oversample = h_oversample;
   if (v_oversample <= STBTT_MAX_OVERSAMPLE)
      spc.v_oversample = v_oversample;
}

void 
stbtt_PackSetSkipMissingCodepoints(stbtt_pack_context *spc, int skip)
{
   spc.skip_missing = skip;
}

// rects array must be big enough to accommodate all characters in the given ranges
int 
stbtt_PackFontRangesGatherRects(stbtt_pack_context *spc, stbtt_fontinfo *info, stbtt_pack_range *ranges, int num_ranges, stbrp_rect *rects)
{
   int i,j,k;
   int missing_glyph_added = 0;

   k=0;
   for (i=0; i < num_ranges; ++i) {
      float fh = ranges[i].font_size;
      float scale = fh > 0 ? stbtt_ScaleForPixelHeight(info, fh) : stbtt_ScaleForMappingEmToPixels(info, -fh);
      ranges[i].h_oversample = cast(ubyte) spc.h_oversample;
      ranges[i].v_oversample = cast(ubyte) spc.v_oversample;
      for (j=0; j < ranges[i].num_chars; ++j) {
         int x0,y0,x1,y1;
         int codepoint = ranges[i].array_of_unicode_codepoints == null ? ranges[i].first_unicode_codepoint_in_range + j : ranges[i].array_of_unicode_codepoints[j];
         int glyph = stbtt_FindGlyphIndex(info, codepoint);
         if (glyph == 0 && (spc.skip_missing || missing_glyph_added)) {
            rects[k].w = rects[k].h = 0;
         } else {
            stbtt_GetGlyphBitmapBoxSubpixel(info,glyph,
                                            scale * spc.h_oversample,
                                            scale * spc.v_oversample,
                                            0,0,
                                            &x0,&y0,&x1,&y1);
            rects[k].w = (stbrp_coord) (x1-x0 + spc.padding + spc.h_oversample-1);
            rects[k].h = (stbrp_coord) (y1-y0 + spc.padding + spc.v_oversample-1);
            if (glyph == 0)
               missing_glyph_added = 1;
         }
         ++k;
      }
   }

   return k;
}

void 
stbtt_MakeGlyphBitmapSubpixelPrefilter(stbtt_fontinfo *info, ubyte *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, float shift_x, float shift_y, int prefilter_x, int prefilter_y, float *sub_x, float *sub_y, int glyph)
{
   stbtt_MakeGlyphBitmapSubpixel(info,
                                 output,
                                 out_w - (prefilter_x - 1),
                                 out_h - (prefilter_y - 1),
                                 out_stride,
                                 scale_x,
                                 scale_y,
                                 shift_x,
                                 shift_y,
                                 glyph);

   if (prefilter_x > 1)
      stbtt__h_prefilter(output, out_w, out_h, out_stride, prefilter_x);

   if (prefilter_y > 1)
      stbtt__v_prefilter(output, out_w, out_h, out_stride, prefilter_y);

   *sub_x = stbtt__oversample_shift(prefilter_x);
   *sub_y = stbtt__oversample_shift(prefilter_y);
}

// rects array must be big enough to accommodate all characters in the given ranges
int 
stbtt_PackFontRangesRenderIntoRects(stbtt_pack_context *spc, stbtt_fontinfo *info, stbtt_pack_range *ranges, int num_ranges, stbrp_rect *rects)
{
   int i,j,k, missing_glyph = -1, return_value = 1;

   // save current values
   int old_h_over = spc.h_oversample;
   int old_v_over = spc.v_oversample;

   k = 0;
   for (i=0; i < num_ranges; ++i) {
      float fh = ranges[i].font_size;
      float scale = fh > 0 ? stbtt_ScaleForPixelHeight(info, fh) : stbtt_ScaleForMappingEmToPixels(info, -fh);
      float recip_h,recip_v,sub_x,sub_y;
      spc.h_oversample = ranges[i].h_oversample;
      spc.v_oversample = ranges[i].v_oversample;
      recip_h = 1.0f / spc.h_oversample;
      recip_v = 1.0f / spc.v_oversample;
      sub_x = stbtt__oversample_shift(spc.h_oversample);
      sub_y = stbtt__oversample_shift(spc.v_oversample);
      for (j=0; j < ranges[i].num_chars; ++j) {
         stbrp_rect *r = &rects[k];
         if (r.was_packed && r.w != 0 && r.h != 0) {
            stbtt_packedchar *bc = &ranges[i].chardata_for_range[j];
            int advance, lsb, x0,y0,x1,y1;
            int codepoint = ranges[i].array_of_unicode_codepoints == null ? ranges[i].first_unicode_codepoint_in_range + j : ranges[i].array_of_unicode_codepoints[j];
            int glyph = stbtt_FindGlyphIndex(info, codepoint);
            stbrp_coord pad = cast(stbrp_coord) spc.padding;

            // pad on left and top
            r.x += pad;
            r.y += pad;
            r.w -= pad;
            r.h -= pad;
            stbtt_GetGlyphHMetrics(info, glyph, &advance, &lsb);
            stbtt_GetGlyphBitmapBox(info, glyph,
                                    scale * spc.h_oversample,
                                    scale * spc.v_oversample,
                                    &x0,&y0,&x1,&y1);
            stbtt_MakeGlyphBitmapSubpixel(info,
                                          spc.pixels + r.x + r.y*spc.stride_in_bytes,
                                          r.w - spc.h_oversample+1,
                                          r.h - spc.v_oversample+1,
                                          spc.stride_in_bytes,
                                          scale * spc.h_oversample,
                                          scale * spc.v_oversample,
                                          0,0,
                                          glyph);

            if (spc.h_oversample > 1)
               stbtt__h_prefilter(spc.pixels + r.x + r.y*spc.stride_in_bytes,
                                  r.w, r.h, spc.stride_in_bytes,
                                  spc.h_oversample);

            if (spc.v_oversample > 1)
               stbtt__v_prefilter(spc.pixels + r.x + r.y*spc.stride_in_bytes,
                                  r.w, r.h, spc.stride_in_bytes,
                                  spc.v_oversample);

            bc.x0       = cast(short)  r.x;
            bc.y0       = cast(short)  r.y;
            bc.x1       = cast(short) (r.x + r.w);
            bc.y1       = cast(short) (r.y + r.h);
            bc.xadvance =                scale * advance;
            bc.xoff     =       cast(float)  x0 * recip_h + sub_x;
            bc.yoff     =       cast(float)  y0 * recip_v + sub_y;
            bc.xoff2    =                (x0 + r.w) * recip_h + sub_x;
            bc.yoff2    =                (y0 + r.h) * recip_v + sub_y;

            if (glyph == 0)
               missing_glyph = j;
         } else if (spc.skip_missing) {
            return_value = 0;
         } else if (r.was_packed && r.w == 0 && r.h == 0 && missing_glyph >= 0) {
            ranges[i].chardata_for_range[j] = ranges[i].chardata_for_range[missing_glyph];
         } else {
            return_value = 0; // if any fail, report failure
         }

         ++k;
      }
   }

   // restore original values
   spc.h_oversample = old_h_over;
   spc.v_oversample = old_v_over;

   return return_value;
}

void 
stbtt_PackFontRangesPackRects(stbtt_pack_context *spc, stbrp_rect *rects, int num_rects)
{
   stbrp_pack_rects(cast(stbrp_context *) spc.pack_info, rects, num_rects);
}

int 
stbtt_PackFontRanges(stbtt_pack_context *spc, const ubyte *fontdata, int font_index, stbtt_pack_range *ranges, int num_ranges)
{
   stbtt_fontinfo info;
   int i,j,n, return_value = 1;
   //stbrp_context *context = (stbrp_context *) spc.pack_info;
   stbrp_rect    *rects;

   // flag all characters as NOT packed
   for (i=0; i < num_ranges; ++i)
      for (j=0; j < ranges[i].num_chars; ++j)
         ranges[i].chardata_for_range[j].x0 =
         ranges[i].chardata_for_range[j].y0 =
         ranges[i].chardata_for_range[j].x1 =
         ranges[i].chardata_for_range[j].y1 = 0;

   n = 0;
   for (i=0; i < num_ranges; ++i)
      n += ranges[i].num_chars;

   rects = cast(stbrp_rect *)malloc(stbrp_rect.sizeof * n);
   if (rects == null)
      return 0;

   stbtt_InitFont(&info, fontdata, stbtt_GetFontOffsetForIndex(fontdata,font_index));

   n = stbtt_PackFontRangesGatherRects(spc, &info, ranges, num_ranges, rects);

   stbtt_PackFontRangesPackRects(spc, rects, n);

   return_value = stbtt_PackFontRangesRenderIntoRects(spc, &info, ranges, num_ranges, rects);

   free(rects);
   return return_value;
}

int 
stbtt_PackFontRange(stbtt_pack_context *spc, const ubyte *fontdata, int font_index, float font_size,
            int first_unicode_codepoint_in_range, int num_chars_in_range, stbtt_packedchar *chardata_for_range)
{
   stbtt_pack_range range;
   range.first_unicode_codepoint_in_range = first_unicode_codepoint_in_range;
   range.array_of_unicode_codepoints = null;
   range.num_chars                   = num_chars_in_range;
   range.chardata_for_range          = chardata_for_range;
   range.font_size                   = font_size;
   return stbtt_PackFontRanges(spc, fontdata, font_index, &range, 1);
}

void 
stbtt_GetScaledFontVMetrics(const ubyte *fontdata, int index, float size, float *ascent, float *descent, float *lineGap)
{
   int i_ascent, i_descent, i_lineGap;
   float scale;
   stbtt_fontinfo info;
   stbtt_InitFont(&info, fontdata, stbtt_GetFontOffsetForIndex(fontdata, index));
   scale = size > 0 ? stbtt_ScaleForPixelHeight(&info, size) : stbtt_ScaleForMappingEmToPixels(&info, -size);
   stbtt_GetFontVMetrics(&info, &i_ascent, &i_descent, &i_lineGap);
   *ascent  = cast(float) i_ascent  * scale;
   *descent = cast(float) i_descent * scale;
   *lineGap = cast(float) i_lineGap * scale;
}

void 
stbtt_GetPackedQuad(const stbtt_packedchar *chardata, int pw, int ph, int char_index, float *xpos, float *ypos, stbtt_aligned_quad *q, int align_to_integer)
{
   float ipw = 1.0f / pw, iph = 1.0f / ph;
   const stbtt_packedchar *b = chardata + char_index;

   if (align_to_integer) {
      float x = cast(float) ifloor((*xpos + b.xoff) + 0.5f);
      float y = cast(float) ifloor((*ypos + b.yoff) + 0.5f);
      q.x0 = x;
      q.y0 = y;
      q.x1 = x + b.xoff2 - b.xoff;
      q.y1 = y + b.yoff2 - b.yoff;
   } else {
      q.x0 = *xpos + b.xoff;
      q.y0 = *ypos + b.yoff;
      q.x1 = *xpos + b.xoff2;
      q.y1 = *ypos + b.yoff2;
   }

   q.s0 = b.x0 * ipw;
   q.t0 = b.y0 * iph;
   q.s1 = b.x1 * ipw;
   q.t1 = b.y1 * iph;

   *xpos += b.xadvance;
}


ubyte * 
stbtt_GetGlyphSDF(stbtt_fontinfo *info, float scale, int glyph, int padding, ubyte onedge_value, float pixel_dist_scale, int *width, int *height, int *xoff, int *yoff)
{
   float scale_x = scale, scale_y = scale;
   int ix0,iy0,ix1,iy1;
   int w,h;
   ubyte *data;

   if (scale == 0) return null;

   stbtt_GetGlyphBitmapBoxSubpixel(info, glyph, scale, scale, 0.0f,0.0f, &ix0,&iy0,&ix1,&iy1);

   // if empty, return null
   if (ix0 == ix1 || iy0 == iy1)
      return null;

   ix0 -= padding;
   iy0 -= padding;
   ix1 += padding;
   iy1 += padding;

   w = (ix1 - ix0);
   h = (iy1 - iy0);

   if (width ) *width  = w;
   if (height) *height = h;
   if (xoff  ) *xoff   = ix0;
   if (yoff  ) *yoff   = iy0;

   // invert for y-downwards bitmaps
   scale_y = -scale_y;

   {
      // distance from singular values (in the same units as the pixel grid)
      const float eps = 1./1024, eps2 = eps*eps;
      int x,y,i,j;
      float *precompute;
      stbtt_vertex *verts;
      int num_verts = stbtt_GetGlyphShape(info, glyph, &verts);
      data = cast(ubyte *) malloc(w * h);
      precompute = cast(float *) malloc(num_verts * float.sizeof);

      for (i=0,j=num_verts-1; i < num_verts; j=i++) {
         if (verts[i].type == stbtt_curvetype.vline) {
            float x0 = verts[i].x*scale_x, y0 = verts[i].y*scale_y;
            float x1 = verts[j].x*scale_x, y1 = verts[j].y*scale_y;
            float dist = cast(float) sqrt((x1-x0)*(x1-x0) + (y1-y0)*(y1-y0));
            precompute[i] = (dist < eps) ? 0.0f : 1.0f / dist;
         } else if (verts[i].type == stbtt_curvetype.vcurve) {
            float x2 = verts[j].x *scale_x, y2 = verts[j].y *scale_y;
            float x1 = verts[i].cx*scale_x, y1 = verts[i].cy*scale_y;
            float x0 = verts[i].x *scale_x, y0 = verts[i].y *scale_y;
            float bx = x0 - 2*x1 + x2, by = y0 - 2*y1 + y2;
            float len2 = bx*bx + by*by;
            if (len2 >= eps2)
               precompute[i] = 1.0f / len2;
            else
               precompute[i] = 0.0f;
         } else
            precompute[i] = 0.0f;
      }

      for (y=iy0; y < iy1; ++y) {
         for (x=ix0; x < ix1; ++x) {
            float val = 0.0;
            float min_dist = 999999.0f;
            float sx = cast(float) x + 0.5f;
            float sy = cast(float) y + 0.5f;
            float x_gspace = (sx / scale_x);
            float y_gspace = (sy / scale_y);

            int winding = stbtt__compute_crossings_x(x_gspace, y_gspace, num_verts, verts); // @OPTIMIZE: this could just be a rasterization, but needs to be line vs. non-tesselated curves so a new path

            for (i=0; i < num_verts; ++i) {
               float x0 = verts[i].x*scale_x, y0 = verts[i].y*scale_y;

               if (verts[i].type == stbtt_curvetype.vline && precompute[i] != 0.0f) {
                  float x1 = verts[i-1].x*scale_x, y1 = verts[i-1].y*scale_y;

                  float dist,dist2 = (x0-sx)*(x0-sx) + (y0-sy)*(y0-sy);
                  if (dist2 < min_dist*min_dist)
                     min_dist = cast(float) sqrt(dist2);

                  // coarse culling against bbox
                  //if (sx > STBTT_min(x0,x1)-min_dist && sx < STBTT_max(x0,x1)+min_dist &&
                  //    sy > STBTT_min(y0,y1)-min_dist && sy < STBTT_max(y0,y1)+min_dist)
                  dist = cast(float) fabs((x1-x0)*(y0-sy) - (y1-y0)*(x0-sx)) * precompute[i];
                  assert(i != 0);
                  if (dist < min_dist) {
                     // check position along line
                     // x' = x0 + t*(x1-x0), y' = y0 + t*(y1-y0)
                     // minimize (x'-sx)*(x'-sx)+(y'-sy)*(y'-sy)
                     float dx = x1-x0, dy = y1-y0;
                     float px = x0-sx, py = y0-sy;
                     // minimize (px+t*dx)^2 + (py+t*dy)^2 = px*px + 2*px*dx*t + t^2*dx*dx + py*py + 2*py*dy*t + t^2*dy*dy
                     // derivative: 2*px*dx + 2*py*dy + (2*dx*dx+2*dy*dy)*t, set to 0 and solve
                     float t = -(px*dx + py*dy) / (dx*dx + dy*dy);
                     if (t >= 0.0f && t <= 1.0f)
                        min_dist = dist;
                  }
               } else if (verts[i].type == stbtt_curvetype.vcurve) {
                  float x2 = verts[i-1].x *scale_x, y2 = verts[i-1].y *scale_y;
                  float x1 = verts[i  ].cx*scale_x, y1 = verts[i  ].cy*scale_y;
                  float box_x0 = STBTT_min(STBTT_min(x0,x1),x2);
                  float box_y0 = STBTT_min(STBTT_min(y0,y1),y2);
                  float box_x1 = STBTT_max(STBTT_max(x0,x1),x2);
                  float box_y1 = STBTT_max(STBTT_max(y0,y1),y2);
                  // coarse culling against bbox to avoid computing cubic unnecessarily
                  if (sx > box_x0-min_dist && sx < box_x1+min_dist && sy > box_y0-min_dist && sy < box_y1+min_dist) {
                     int num=0;
                     float ax = x1-x0, ay = y1-y0;
                     float bx = x0 - 2*x1 + x2, by = y0 - 2*y1 + y2;
                     float mx = x0 - sx, my = y0 - sy;
                     float[3] res = [0.0f, 0.0f, 0.0f];
                     float px,py,t,it,dist2;
                     float a_inv = precompute[i];
                     if (a_inv == 0.0) { // if a_inv is 0, it's 2nd degree so use quadratic formula
                        float a = 3*(ax*bx + ay*by);
                        float b = 2*(ax*ax + ay*ay) + (mx*bx+my*by);
                        float c = mx*ax+my*ay;
                        if (fabs(a) < eps2) { // if a is 0, it's linear
                           if (fabs(b) >= eps2) {
                              res[num++] = -c/b;
                           }
                        } else {
                           float discriminant = b*b - 4*a*c;
                           if (discriminant < 0)
                              num = 0;
                           else {
                              float root = cast(float) sqrt(discriminant);
                              res[0] = (-b - root)/(2*a);
                              res[1] = (-b + root)/(2*a);
                              num = 2; // don't bother distinguishing 1-solution case, as code below will still work
                           }
                        }
                     } else {
                        float b = 3*(ax*bx + ay*by) * a_inv; // could precompute this as it doesn't depend on sample point
                        float c = (2*(ax*ax + ay*ay) + (mx*bx+my*by)) * a_inv;
                        float d = (mx*ax+my*ay) * a_inv;
                        num = stbtt__solve_cubic(b, c, d, res.ptr);
                     }
                     dist2 = (x0-sx)*(x0-sx) + (y0-sy)*(y0-sy);
                     if (dist2 < min_dist*min_dist)
                        min_dist = cast(float) sqrt(dist2);

                     if (num >= 1 && res[0] >= 0.0f && res[0] <= 1.0f) {
                        t = res[0], it = 1.0f - t;
                        px = it*it*x0 + 2*t*it*x1 + t*t*x2;
                        py = it*it*y0 + 2*t*it*y1 + t*t*y2;
                        dist2 = (px-sx)*(px-sx) + (py-sy)*(py-sy);
                        if (dist2 < min_dist * min_dist)
                           min_dist = cast(float) sqrt(dist2);
                     }
                     if (num >= 2 && res[1] >= 0.0f && res[1] <= 1.0f) {
                        t = res[1], it = 1.0f - t;
                        px = it*it*x0 + 2*t*it*x1 + t*t*x2;
                        py = it*it*y0 + 2*t*it*y1 + t*t*y2;
                        dist2 = (px-sx)*(px-sx) + (py-sy)*(py-sy);
                        if (dist2 < min_dist * min_dist)
                           min_dist = cast(float) sqrt(dist2);
                     }
                     if (num >= 3 && res[2] >= 0.0f && res[2] <= 1.0f) {
                        t = res[2], it = 1.0f - t;
                        px = it*it*x0 + 2*t*it*x1 + t*t*x2;
                        py = it*it*y0 + 2*t*it*y1 + t*t*y2;
                        dist2 = (px-sx)*(px-sx) + (py-sy)*(py-sy);
                        if (dist2 < min_dist * min_dist)
                           min_dist = cast(float) sqrt(dist2);
                     }
                  }
               }
            }
            if (winding == 0)
               min_dist = -min_dist;  // if outside the shape, value is negative
            val = onedge_value + pixel_dist_scale * min_dist;
            if (val < 0)
               val = 0;
            else if (val > 255)
               val = 255;
            data[(y-iy0)*w+(x-ix0)] = cast(ubyte) val;
         }
      }
      free(precompute);
      free(verts);
   }
   return data;
}

ubyte * 
stbtt_GetCodepointSDF(stbtt_fontinfo *info, float scale, int codepoint, int padding, ubyte onedge_value, float pixel_dist_scale, int *width, int *height, int *xoff, int *yoff)
{
   return stbtt_GetGlyphSDF(info, scale, stbtt_FindGlyphIndex(info, codepoint), padding, onedge_value, pixel_dist_scale, width, height, xoff, yoff);
}

void 
stbtt_FreeSDF(ubyte *bitmap)
{
   free(bitmap);
}

// returns results in whatever encoding you request... but note that 2-byte encodings
// will be BIG-ENDIAN... use stbtt_CompareUTF8toUTF16_bigendian() to compare
const(char)* 
stbtt_GetFontNameString(stbtt_fontinfo* font, int *length, int platformID, int encodingID, int languageID, int nameID)
{
   int i,count,stringOffset;
   ubyte *fc = font.data;
   uint offset = font.fontstart;
   uint nm = stbtt__find_table(fc, offset, "name");
   if (!nm) return null;

   count = ttUSHORT(fc+nm+2);
   stringOffset = nm + ttUSHORT(fc+nm+4);
   for (i=0; i < count; ++i) {
      uint loc = nm + 6 + 12 * i;
      if (platformID == ttUSHORT(fc+loc+0) && encodingID == ttUSHORT(fc+loc+2)
          && languageID == ttUSHORT(fc+loc+4) && nameID == ttUSHORT(fc+loc+6)) {
         *length = ttUSHORT(fc+loc+8);
         return cast(const char *) (fc+stringOffset+ttUSHORT(fc+loc+10));
      }
   }
   return null;
}

int 
stbtt_BakeFontBitmap(const ubyte *data, int offset,
                                float pixel_height, ubyte *pixels, int pw, int ph,
                                int first_char, int num_chars, stbtt_bakedchar *chardata)
{
	return stbtt_BakeFontBitmap_internal(cast(ubyte *) data, offset, pixel_height, pixels, pw, ph, first_char, num_chars, chardata);
}

int 
stbtt_GetFontOffsetForIndex(const ubyte *data, int index)
{
	return stbtt_GetFontOffsetForIndex_internal(cast(ubyte *) data, index);
}

int 
stbtt_GetNumberOfFonts(const ubyte *data)
{
	return stbtt_GetNumberOfFonts_internal(cast(ubyte *) data);
}

int 
stbtt_InitFont(stbtt_fontinfo *info, const ubyte *data, int offset)
{
	return stbtt_InitFont_internal(info, cast(ubyte *) data, offset);
}

int 
stbtt_FindMatchingFont(const ubyte *fontdata, const char *name, int flags)
{
	return stbtt_FindMatchingFont_internal(cast(ubyte *) fontdata, cast(char *) name, flags);
}

int 
stbtt_CompareUTF8toUTF16_bigendian(const char *s1, int len1, const char *s2, int len2)
{
	return stbtt_CompareUTF8toUTF16_bigendian_internal(cast(char *) s1, len1, cast(char *) s2, len2);
}

int 
stbtt_InitFont_internal(stbtt_fontinfo *info, ubyte *data, int fontstart)
{
   uint cmap, t;
   int i,numTables;

   info.data = data;
   info.fontstart = fontstart;
   info.cff = stbtt__new_buf(null, 0);

   cmap = stbtt__find_table(data, fontstart, "cmap");       // required
   info.loca = stbtt__find_table(data, fontstart, "loca"); // required
   info.head = stbtt__find_table(data, fontstart, "head"); // required
   info.glyf = stbtt__find_table(data, fontstart, "glyf"); // required
   info.hhea = stbtt__find_table(data, fontstart, "hhea"); // required
   info.hmtx = stbtt__find_table(data, fontstart, "hmtx"); // required
   info.kern = stbtt__find_table(data, fontstart, "kern"); // not required
   info.gpos = stbtt__find_table(data, fontstart, "GPOS"); // not required

   if (!cmap || !info.head || !info.hhea || !info.hmtx)
      return 0;
   if (info.glyf) {
      // required for truetype
      if (!info.loca) return 0;
   } else {
      // initialization for CFF / Type2 fonts (OTF)
      stbtt__buf b, topdict, topdictidx;
      uint cstype = 2, charstrings = 0, fdarrayoff = 0, fdselectoff = 0;
      uint cff;

      cff = stbtt__find_table(data, fontstart, "CFF ");
      if (!cff) return 0;

      info.fontdicts = stbtt__new_buf(null, 0);
      info.fdselect = stbtt__new_buf(null, 0);

      // @TODO this should use size from table (not 512MB)
      info.cff = stbtt__new_buf(data+cff, 512*1024*1024);
      b = info.cff;

      // read the header
      stbtt__buf_skip(&b, 2);
      stbtt__buf_seek(&b, stbtt__buf_get8(&b)); // hdrsize

      // @TODO the name INDEX could list multiple fonts,
      // but we just use the first one.
      stbtt__cff_get_index(&b);  // name INDEX
      topdictidx = stbtt__cff_get_index(&b);
      topdict = stbtt__cff_index_get(topdictidx, 0);
      stbtt__cff_get_index(&b);  // string INDEX
      info.gsubrs = stbtt__cff_get_index(&b);

      stbtt__dict_get_ints(&topdict, 17, 1, &charstrings);
      stbtt__dict_get_ints(&topdict, 0x100 | 6, 1, &cstype);
      stbtt__dict_get_ints(&topdict, 0x100 | 36, 1, &fdarrayoff);
      stbtt__dict_get_ints(&topdict, 0x100 | 37, 1, &fdselectoff);
      info.subrs = stbtt__get_subrs(b, topdict);

      // we only support Type 2 charstrings
      if (cstype != 2) return 0;
      if (charstrings == 0) return 0;

      if (fdarrayoff) {
         // looks like a CID font
         if (!fdselectoff) return 0;
         stbtt__buf_seek(&b, fdarrayoff);
         info.fontdicts = stbtt__cff_get_index(&b);
         info.fdselect = stbtt__buf_range(&b, fdselectoff, b.size-fdselectoff);
      }

      stbtt__buf_seek(&b, charstrings);
      info.charstrings = stbtt__cff_get_index(&b);
   }

   t = stbtt__find_table(data, fontstart, "maxp");
   if (t)
      info.numGlyphs = ttUSHORT(data+t+4);
   else
      info.numGlyphs = 0xffff;

   info.svg = -1;

   // find a cmap encoding table we understand *now* to avoid searching
   // later. (todo: could make this installable)
   // the same regardless of glyph.
   numTables = ttUSHORT(data + cmap + 2);
   info.index_map = 0;
   for (i=0; i < numTables; ++i) 
	 {
      uint encoding_record = cmap + 4 + 8 * i;
      // find an encoding we understand:
      switch(ttUSHORT(data+encoding_record)) 
			{
         case STBTT_PLATFORM.ID_MICROSOFT:
            switch (ttUSHORT(data+encoding_record+2)) {
               case STBTT_MS_EID.UNICODE_BMP:
               case STBTT_MS_EID.UNICODE_FULL:
                  // MS/Unicode
                  info.index_map = cmap + ttULONG(data+encoding_record+4);
                  break;
							default: break;
            }
            break;
        case STBTT_PLATFORM.ID_UNICODE:
            // Mac/iOS has these
            // all the encodingIDs are unicode, so we don't bother to check it
            info.index_map = cmap + ttULONG(data+encoding_record+4);
            break;
				default: break;
      }
   }

   if (info.index_map == 0)
      return 0;

   info.indexToLocFormat = ttUSHORT(data+info.head + 50);
   return 1;
}

int 
stbtt_FindGlyphIndex(stbtt_fontinfo *info, int unicode_codepoint)
{
   ubyte *data = info.data;
   uint index_map = info.index_map;

   ushort format = ttUSHORT(data + index_map + 0);
   if (format == 0) 
	 { // apple byte encoding
      int bytes = ttUSHORT(data + index_map + 2);
      if (unicode_codepoint < bytes-6)
         return ttBYTE(data + index_map + 6 + unicode_codepoint);
      return 0;
   } 
	 else if (format == 6) 
	 {
      uint first = ttUSHORT(data + index_map + 6);
      uint count = ttUSHORT(data + index_map + 8);
      if (cast(uint) unicode_codepoint >= first && cast(uint) unicode_codepoint < first+count)
         return ttUSHORT(data + index_map + 10 + (unicode_codepoint - first)*2);
      return 0;
   } 
	 else if (format == 2) 
	 {
      assert(0); // @TODO: high-byte mapping for japanese/chinese/korean
      return 0;
   } 
	 else if (format == 4) 
	 { // standard mapping for windows fonts: binary search collection of ranges
      ushort segcount = ttUSHORT(data+index_map+6) >> 1;
      ushort searchRange = ttUSHORT(data+index_map+8) >> 1;
      ushort entrySelector = ttUSHORT(data+index_map+10);
      ushort rangeShift = ttUSHORT(data+index_map+12) >> 1;

      // do a binary search of the segments
      uint endCount = index_map + 14;
      uint search = endCount;

      if (unicode_codepoint > 0xffff)
         return 0;

      // they lie from endCount .. endCount + segCount
      // but searchRange is the nearest power of two, so...
      if (unicode_codepoint >= ttUSHORT(data + search + rangeShift*2))
         search += rangeShift*2;

      // now decrement to bias correctly to find smallest
      search -= 2;
      while (entrySelector) {
         ushort end;
         searchRange >>= 1;
         end = ttUSHORT(data + search + searchRange*2);
         if (unicode_codepoint > end)
            search += searchRange*2;
         --entrySelector;
      }
      search += 2;

      {
         ushort offset, start, last;
         ushort item = cast(ushort) ((search - endCount) >> 1);

         start = ttUSHORT(data + index_map + 14 + segcount*2 + 2 + 2*item);
         last = ttUSHORT(data + endCount + 2*item);
         if (unicode_codepoint < start || unicode_codepoint > last)
            return 0;

         offset = ttUSHORT(data + index_map + 14 + segcount*6 + 2 + 2*item);
         if (offset == 0)
            return cast(ushort)(unicode_codepoint + ttSHORT(data + index_map + 14 + segcount*4 + 2 + 2*item));

         return ttUSHORT(data + offset + (unicode_codepoint-start)*2 + index_map + 14 + segcount*6 + 2 + 2*item);
      }
   } else if (format == 12 || format == 13) {
      uint ngroups = ttULONG(data+index_map+12);
      int low,high;
      low = 0; high = cast(int)ngroups;
      // Binary search the right group.
      while (low < high) {
         int mid = low + ((high-low) >> 1); // rounds down, so low <= mid < high
         uint start_char = ttULONG(data+index_map+16+mid*12);
         uint end_char = ttULONG(data+index_map+16+mid*12+4);
         if (cast(uint) unicode_codepoint < start_char)
            high = mid;
         else if (cast(uint) unicode_codepoint > end_char)
            low = mid+1;
         else {
            uint start_glyph = ttULONG(data+index_map+16+mid*12+8);
            if (format == 12)
               return start_glyph + unicode_codepoint-start_char;
            else // format == 13
               return start_glyph;
         }
      }
      return 0; // not found
   }
   // @TODO
   assert(0);
   return 0;
}

int 
stbtt_GetCodepointShape(stbtt_fontinfo *info, int unicode_codepoint, stbtt_vertex **vertices)
{
   return stbtt_GetGlyphShape(info, stbtt_FindGlyphIndex(info, unicode_codepoint), vertices);
}
int 
stbtt_GetGlyphBox(stbtt_fontinfo *info, int glyph_index, int *x0, int *y0, int *x1, int *y1)
{
   if (info.cff.size) {
      stbtt__GetGlyphInfoT2(info, glyph_index, x0, y0, x1, y1);
   } else {
      int g = stbtt__GetGlyfOffset(info, glyph_index);
      if (g < 0) return 0;

      if (x0) *x0 = ttSHORT(info.data + g + 2);
      if (y0) *y0 = ttSHORT(info.data + g + 4);
      if (x1) *x1 = ttSHORT(info.data + g + 6);
      if (y1) *y1 = ttSHORT(info.data + g + 8);
   }
   return 1;
}

int 
stbtt_GetCodepointBox(stbtt_fontinfo *info, int codepoint, int *x0, int *y0, int *x1, int *y1)
{
   return stbtt_GetGlyphBox(info, stbtt_FindGlyphIndex(info,codepoint), x0,y0,x1,y1);
}

int 
stbtt_IsGlyphEmpty(stbtt_fontinfo *info, int glyph_index)
{
   short numberOfContours;
   int g;
   if (info.cff.size)
      return stbtt__GetGlyphInfoT2(info, glyph_index, null, null, null, null) == 0;
   g = stbtt__GetGlyfOffset(info, glyph_index);
   if (g < 0) return 1;
   numberOfContours = ttSHORT(info.data + g);
   return numberOfContours == 0;
}

int 
stbtt_GetGlyphShape(stbtt_fontinfo *info, int glyph_index, stbtt_vertex **pvertices)
{
   if (!info.cff.size)
      return stbtt_GetGlyphShapeTT(info, glyph_index, pvertices);
   else
      return stbtt_GetGlyphShapeT2(info, glyph_index, pvertices);
}

void 
stbtt_GetGlyphHMetrics(stbtt_fontinfo *info, int glyph_index, int *advanceWidth, int *leftSideBearing)
{
   ushort numOfLongHorMetrics = ttUSHORT(info.data+info.hhea + 34);
   if (glyph_index < numOfLongHorMetrics) {
      if (advanceWidth)     *advanceWidth    = ttSHORT(info.data + info.hmtx + 4*glyph_index);
      if (leftSideBearing)  *leftSideBearing = ttSHORT(info.data + info.hmtx + 4*glyph_index + 2);
   } else {
      if (advanceWidth)     *advanceWidth    = ttSHORT(info.data + info.hmtx + 4*(numOfLongHorMetrics-1));
      if (leftSideBearing)  *leftSideBearing = ttSHORT(info.data + info.hmtx + 4*numOfLongHorMetrics + 2*(glyph_index - numOfLongHorMetrics));
   }
}

//////////////////////////////////////////////////////////////////////////////
//
// antialiasing software rasterizer
//

int 
stbtt_initfont_internal(stbtt_fontinfo *info, ubyte *data, int fontstart)
{
   uint cmap, t;
   int i,numtables;

   info.data = data;
   info.fontstart = fontstart;
   info.cff = stbtt__new_buf(null, 0);

   cmap = stbtt__find_table(data, fontstart, "cmap");       // required
   info.loca = stbtt__find_table(data, fontstart, "loca"); // required
   info.head = stbtt__find_table(data, fontstart, "head"); // required
   info.glyf = stbtt__find_table(data, fontstart, "glyf"); // required
   info.hhea = stbtt__find_table(data, fontstart, "hhea"); // required
   info.hmtx = stbtt__find_table(data, fontstart, "hmtx"); // required
   info.kern = stbtt__find_table(data, fontstart, "kern"); // not required
   info.gpos = stbtt__find_table(data, fontstart, "gpos"); // not required

   if (!cmap || !info.head || !info.hhea || !info.hmtx)
      return 0;
   if (info.glyf) {
      // required for truetype
      if (!info.loca) return 0;
   } else {
      // initialization for cff / type2 fonts (otf)
      stbtt__buf b, topdict, topdictidx;
      uint cstype = 2, charstrings = 0, fdarrayoff = 0, fdselectoff = 0;
      uint cff;

      cff = stbtt__find_table(data, fontstart, "cff ");
      if (!cff) return 0;

      info.fontdicts = stbtt__new_buf(null, 0);
      info.fdselect = stbtt__new_buf(null, 0);

      // @todo this should use size from table (not 512mb)
      info.cff = stbtt__new_buf(data+cff, 512*1024*1024);
      b = info.cff;

      // read the header
      stbtt__buf_skip(&b, 2);
      stbtt__buf_seek(&b, stbtt__buf_get8(&b)); // hdrsize

      // @todo the name index could list multiple fonts,
      // but we just use the first one.
      stbtt__cff_get_index(&b);  // name index
      topdictidx = stbtt__cff_get_index(&b);
      topdict = stbtt__cff_index_get(topdictidx, 0);
      stbtt__cff_get_index(&b);  // string index
      info.gsubrs = stbtt__cff_get_index(&b);

      stbtt__dict_get_ints(&topdict, 17, 1, &charstrings);
      stbtt__dict_get_ints(&topdict, 0x100 | 6, 1, &cstype);
      stbtt__dict_get_ints(&topdict, 0x100 | 36, 1, &fdarrayoff);
      stbtt__dict_get_ints(&topdict, 0x100 | 37, 1, &fdselectoff);
      info.subrs = stbtt__get_subrs(b, topdict);

      // we only support type 2 charstrings
      if (cstype != 2) return 0;
      if (charstrings == 0) return 0;

      if (fdarrayoff) {
         // looks like a cid font
         if (!fdselectoff) return 0;
         stbtt__buf_seek(&b, fdarrayoff);
         info.fontdicts = stbtt__cff_get_index(&b);
         info.fdselect = stbtt__buf_range(&b, fdselectoff, b.size-fdselectoff);
      }

      stbtt__buf_seek(&b, charstrings);
      info.charstrings = stbtt__cff_get_index(&b);
   }

   t = stbtt__find_table(data, fontstart, "maxp");
   if (t)
      info.numGlyphs = ttUSHORT(data+t+4);
   else
      info.numGlyphs = 0xffff;

   info.svg = -1;

   // find a cmap encoding table we understand *now* to avoid searching
   // later. (todo: could make this installable)
   // the same regardless of glyph.
   numtables = ttUSHORT(data + cmap + 2);
   info.index_map = 0;
   for (i=0; i < numtables; ++i) 
	 {
      uint encoding_record = cmap + 4 + 8 * i;
      // find an encoding we understand:
      switch(ttUSHORT(data+encoding_record)) 
			{
         case STBTT_PLATFORM.ID_MICROSOFT:
            switch (ttUSHORT(data+encoding_record+2)) {
               case STBTT_MS_EID.UNICODE_BMP:
               case STBTT_MS_EID.UNICODE_FULL:
                  // ms/unicode
                  info.index_map = cmap + ttULONG(data+encoding_record+4);
                  break;
							default: break;
            }
            break;
        case STBTT_PLATFORM.ID_UNICODE:
            // mac/ios has these
            // all the encodingids are unicode, so we don't bother to check it
            info.index_map = cmap + ttULONG(data+encoding_record+4);
            break;
				default: break;
      }
   }

   if (info.index_map == 0)
      return 0;

   info.indexToLocFormat = ttUSHORT(data+info.head + 50);
   return 1;
}

int 
stbtt_findglyphindex(stbtt_fontinfo *info, int unicode_codepoint)
{
   ubyte *data = info.data;
   uint index_map = info.index_map;

   ushort format = ttUSHORT(data + index_map + 0);
   if (format == 0) 
	 { // apple byte encoding
      int bytes = ttUSHORT(data + index_map + 2);
      if (unicode_codepoint < bytes-6)
         return ttBYTE(data + index_map + 6 + unicode_codepoint);
      return 0;
   } 
	 else if (format == 6) 
	 {
      uint first = ttUSHORT(data + index_map + 6);
      uint count = ttUSHORT(data + index_map + 8);
      if (cast(uint) unicode_codepoint >= first && cast(uint) unicode_codepoint < first+count)
         return ttUSHORT(data + index_map + 10 + (unicode_codepoint - first)*2);
      return 0;
   } 
	 else if (format == 2) 
	 {
      assert(0); // @todo: high-byte mapping for japanese/chinese/korean
      return 0;
   } 
	 else if (format == 4) 
	 { // standard mapping for windows fonts: binary search collection of ranges
      ushort segcount = ttUSHORT(data+index_map+6) >> 1;
      ushort searchrange = ttUSHORT(data+index_map+8) >> 1;
      ushort entryselector = ttUSHORT(data+index_map+10);
      ushort rangeshift = ttUSHORT(data+index_map+12) >> 1;

      // do a binary search of the segments
      uint endcount = index_map + 14;
      uint search = endcount;

      if (unicode_codepoint > 0xffff)
         return 0;

      // they lie from endcount .. endcount + segcount
      // but searchrange is the nearest power of two, so...
      if (unicode_codepoint >= ttUSHORT(data + search + rangeshift*2))
         search += rangeshift*2;

      // now decrement to bias correctly to find smallest
      search -= 2;
      while (entryselector) {
         ushort end;
         searchrange >>= 1;
         end = ttUSHORT(data + search + searchrange*2);
         if (unicode_codepoint > end)
            search += searchrange*2;
         --entryselector;
      }
      search += 2;

      {
         ushort offset, start, last;
         ushort item = cast(ushort) ((search - endcount) >> 1);

         start = ttUSHORT(data + index_map + 14 + segcount*2 + 2 + 2*item);
         last = ttUSHORT(data + endcount + 2*item);
         if (unicode_codepoint < start || unicode_codepoint > last)
            return 0;

         offset = ttUSHORT(data + index_map + 14 + segcount*6 + 2 + 2*item);
         if (offset == 0)
            return cast(ushort)(unicode_codepoint + ttSHORT(data + index_map + 14 + segcount*4 + 2 + 2*item));

         return ttUSHORT(data + offset + (unicode_codepoint-start)*2 + index_map + 14 + segcount*6 + 2 + 2*item);
      }
   } else if (format == 12 || format == 13) {
      uint ngroups = ttULONG(data+index_map+12);
      int low,high;
      low = 0; high = cast(int)ngroups;
      // binary search the right group.
      while (low < high) {
         int mid = low + ((high-low) >> 1); // rounds down, so low <= mid < high
         uint start_char = ttULONG(data+index_map+16+mid*12);
         uint end_char = ttULONG(data+index_map+16+mid*12+4);
         if (cast(uint) unicode_codepoint < start_char)
            high = mid;
         else if (cast(uint) unicode_codepoint > end_char)
            low = mid+1;
         else {
            uint start_glyph = ttULONG(data+index_map+16+mid*12+8);
            if (format == 12)
               return start_glyph + unicode_codepoint-start_char;
            else // format == 13
               return start_glyph;
         }
      }
      return 0; // not found
   }
   // @todo
   assert(0);
   return 0;
}

int 
stbtt_getcodepointshape(stbtt_fontinfo *info, int unicode_codepoint, stbtt_vertex **vertices)
{
   return stbtt_getglyphshape(info, stbtt_findglyphindex(info, unicode_codepoint), vertices);
}
int 
stbtt_getglyphbox(stbtt_fontinfo *info, int glyph_index, int *x0, int *y0, int *x1, int *y1)
{
   if (info.cff.size) {
      stbtt__GetGlyphInfoT2(info, glyph_index, x0, y0, x1, y1);
   } else {
      int g = stbtt__GetGlyfOffset(info, glyph_index);
      if (g < 0) return 0;

      if (x0) *x0 = ttSHORT(info.data + g + 2);
      if (y0) *y0 = ttSHORT(info.data + g + 4);
      if (x1) *x1 = ttSHORT(info.data + g + 6);
      if (y1) *y1 = ttSHORT(info.data + g + 8);
   }
   return 1;
}

int 
stbtt_getcodepointbox(stbtt_fontinfo *info, int codepoint, int *x0, int *y0, int *x1, int *y1)
{
   return stbtt_getglyphbox(info, stbtt_findglyphindex(info,codepoint), x0,y0,x1,y1);
}

int 
stbtt_isglyphempty(stbtt_fontinfo *info, int glyph_index)
{
   short numberofcontours;
   int g;
   if (info.cff.size)
      return stbtt__GetGlyphInfoT2(info, glyph_index, null, null, null, null) == 0;
   g = stbtt__GetGlyfOffset(info, glyph_index);
   if (g < 0) return 1;
   numberofcontours = ttSHORT(info.data + g);
   return numberofcontours == 0;
}

int 
stbtt_getglyphshape(stbtt_fontinfo *info, int glyph_index, stbtt_vertex **pvertices)
{
   if (!info.cff.size)
      return stbtt_GetGlyphShapeTT(info, glyph_index, pvertices);
   else
      return stbtt_GetGlyphShapeT2(info, glyph_index, pvertices);
}

void 
stbtt_getglyphhmetrics(stbtt_fontinfo *info, int glyph_index, int *advancewidth, int *leftsidebearing)
{
   ushort numoflonghormetrics = ttUSHORT(info.data+info.hhea + 34);
   if (glyph_index < numoflonghormetrics) {
      if (advancewidth)     *advancewidth    = ttSHORT(info.data + info.hmtx + 4*glyph_index);
      if (leftsidebearing)  *leftsidebearing = ttSHORT(info.data + info.hmtx + 4*glyph_index + 2);
   } else {
      if (advancewidth)     *advancewidth    = ttSHORT(info.data + info.hmtx + 4*(numoflonghormetrics-1));
      if (leftsidebearing)  *leftsidebearing = ttSHORT(info.data + info.hmtx + 4*numoflonghormetrics + 2*(glyph_index - numoflonghormetrics));
   }
}

int  
stbtt_GetKerningTableLength(stbtt_fontinfo *info)
{
   ubyte *data = info.data + info.kern;

   // we only look at the first table. it must be 'horizontal' and format 0.
   if (!info.kern)
      return 0;
   if (ttUSHORT(data+2) < 1) // number of tables, need at least 1
      return 0;
   if (ttUSHORT(data+8) != 1) // horizontal flag must be set in format
      return 0;

   return ttUSHORT(data+10);
}

int 
stbtt_GetKerningTable(stbtt_fontinfo *info, stbtt_kerningentry* table, int table_length)
{
   ubyte *data = info.data + info.kern;
   int k, length;

   // we only look at the first table. it must be 'horizontal' and format 0.
   if (!info.kern)
      return 0;
   if (ttUSHORT(data+2) < 1) // number of tables, need at least 1
      return 0;
   if (ttUSHORT(data+8) != 1) // horizontal flag must be set in format
      return 0;

   length = ttUSHORT(data+10);
   if (table_length < length)
      length = table_length;

   for (k = 0; k < length; k++)
   {
      table[k].glyph1 = ttUSHORT(data+18+(k*6));
      table[k].glyph2 = ttUSHORT(data+20+(k*6));
      table[k].advance = ttSHORT(data+22+(k*6));
   }

   return length;
}

int 
stbtt_GetGlyphKernAdvance(stbtt_fontinfo *info, int g1, int g2)
{
   int xAdvance = 0;

   if (info.gpos)
      xAdvance += stbtt__GetGlyphGPOSInfoAdvance(info, g1, g2);
   else if (info.kern)
      xAdvance += stbtt__GetGlyphKernInfoAdvance(info, g1, g2);

   return xAdvance;
}

int 
stbtt_GetCodepointKernAdvance(stbtt_fontinfo *info, int ch1, int ch2)
{
   if (!info.kern && !info.gpos) // if no kerning table, don't waste time looking up both codepoint.glyphs
      return 0;
   return stbtt_GetGlyphKernAdvance(info, stbtt_FindGlyphIndex(info,ch1), stbtt_FindGlyphIndex(info,ch2));
}

void 
stbtt_GetCodepointHMetrics(stbtt_fontinfo *info, int codepoint, int *advanceWidth, int *leftSideBearing)
{
   stbtt_GetGlyphHMetrics(info, stbtt_FindGlyphIndex(info,codepoint), advanceWidth, leftSideBearing);
}

void 
stbtt_GetFontVMetrics(stbtt_fontinfo *info, int *ascent, int *descent, int *lineGap)
{
   if (ascent ) *ascent  = ttSHORT(info.data+info.hhea + 4);
   if (descent) *descent = ttSHORT(info.data+info.hhea + 6);
   if (lineGap) *lineGap = ttSHORT(info.data+info.hhea + 8);
}

int 
stbtt_GetFontVMetricsOS2(stbtt_fontinfo *info, int *typoAscent, int *typoDescent, int *typoLineGap)
{
   int tab = stbtt__find_table(info.data, info.fontstart, "OS/2");
   if (!tab)
      return 0;
   if (typoAscent ) *typoAscent  = ttSHORT(info.data+tab + 68);
   if (typoDescent) *typoDescent = ttSHORT(info.data+tab + 70);
   if (typoLineGap) *typoLineGap = ttSHORT(info.data+tab + 72);
   return 1;
}

void 
stbtt_GetFontBoundingBox(stbtt_fontinfo *info, int *x0, int *y0, int *x1, int *y1)
{
   *x0 = ttSHORT(info.data + info.head + 36);
   *y0 = ttSHORT(info.data + info.head + 38);
   *x1 = ttSHORT(info.data + info.head + 40);
   *y1 = ttSHORT(info.data + info.head + 42);
}

float 
stbtt_ScaleForPixelHeight(stbtt_fontinfo *info, float height)
{
   int fheight = ttSHORT(info.data + info.hhea + 4) - ttSHORT(info.data + info.hhea + 6);
   return cast(float) height / fheight;
}

float 
stbtt_ScaleForMappingEmToPixels(stbtt_fontinfo *info, float pixels)
{
   int unitsPerEm = ttUSHORT(info.data + info.head + 18);
   return pixels / unitsPerEm;
}

void 
stbtt_FreeShape(stbtt_fontinfo *info, stbtt_vertex *v)
{
   free(v);
}

ubyte *
stbtt_FindSVGDoc(stbtt_fontinfo *info, int gl)
{
   int i;
   ubyte *data = info.data;
   ubyte *svg_doc_list = data + stbtt__get_svg(cast(stbtt_fontinfo *) info);

   int numEntries = ttUSHORT(svg_doc_list);
   ubyte *svg_docs = svg_doc_list + 2;

   for(i=0; i<numEntries; i++) {
      ubyte *svg_doc = svg_docs + (12 * i);
      if ((gl >= ttUSHORT(svg_doc)) && (gl <= ttUSHORT(svg_doc + 2)))
         return svg_doc;
   }
   return null;
}

int 
stbtt_GetGlyphSVG(stbtt_fontinfo *info, int gl, char** svg)
{
   ubyte *data = info.data;
   ubyte *svg_doc;

   if (info.svg == 0)
      return 0;

   svg_doc = stbtt_FindSVGDoc(info, gl);
   if (svg_doc != null) {
      *svg = cast(char*) data + info.svg + ttULONG(svg_doc + 4);
      return ttULONG(svg_doc + 8);
   } else {
      return 0;
   }
}

int 
stbtt_GetCodepointSVG(stbtt_fontinfo *info, int unicode_codepoint, char** svg)
{
   return stbtt_GetGlyphSVG(info, stbtt_FindGlyphIndex(info, unicode_codepoint), svg);
}
void 
stbtt_GetGlyphBitmapBoxSubpixel(stbtt_fontinfo *font, int glyph, float scale_x, float scale_y,float shift_x, float shift_y, int *ix0, int *iy0, int *ix1, int *iy1)
{
   int x0=0,y0=0,x1,y1; // =0 suppresses compiler warning
   if (!stbtt_GetGlyphBox(font, glyph, &x0,&y0,&x1,&y1)) {
      // e.g. space character
      if (ix0) *ix0 = 0;
      if (iy0) *iy0 = 0;
      if (ix1) *ix1 = 0;
      if (iy1) *iy1 = 0;
   } else {
      // move to integral bboxes (treating pixels as little squares, what pixels get touched)?
      if (ix0) *ix0 = ifloor( x0 * scale_x + shift_x);
      if (iy0) *iy0 = ifloor(-y1 * scale_y + shift_y);
      if (ix1) *ix1 = iceil ( x1 * scale_x + shift_x);
      if (iy1) *iy1 = iceil (-y0 * scale_y + shift_y);
   }
}

void 
stbtt_GetGlyphBitmapBox(stbtt_fontinfo *font, int glyph, float scale_x, float scale_y, int *ix0, int *iy0, int *ix1, int *iy1)
{
   stbtt_GetGlyphBitmapBoxSubpixel(font, glyph, scale_x, scale_y,0.0f,0.0f, ix0, iy0, ix1, iy1);
}

void 
stbtt_GetCodepointBitmapBoxSubpixel(stbtt_fontinfo *font, int codepoint, float scale_x, float scale_y, float shift_x, float shift_y, int *ix0, int *iy0, int *ix1, int *iy1)
{
   stbtt_GetGlyphBitmapBoxSubpixel(font, stbtt_FindGlyphIndex(font,codepoint), scale_x, scale_y,shift_x,shift_y, ix0,iy0,ix1,iy1);
}

void 
stbtt_GetCodepointBitmapBox(stbtt_fontinfo *font, int codepoint, float scale_x, float scale_y, int *ix0, int *iy0, int *ix1, int *iy1)
{
   stbtt_GetCodepointBitmapBoxSubpixel(font, codepoint, scale_x, scale_y,0.0f,0.0f, ix0,iy0,ix1,iy1);
}


ubyte stbtt__buf_get8(stbtt__buf *b)
{
	if(b.cursor >= b.size)
		return 0;
	return b.data[b.cursor++];
}

ubyte stbtt__buf_peek8(stbtt__buf *b)
{
	if(b.cursor >= b.size)
		return 0;
	return b.data[b.cursor];
}

void stbtt__buf_seek(stbtt__buf *b, int o)
{
	assert(!(o > b.size || o < 0));
	b.cursor = (o > b.size || o < 0) ? b.size : o;
}

void stbtt__buf_skip(stbtt__buf *b, int o)
{
	stbtt__buf_seek(b, b.cursor + o);
}

uint stbtt__buf_get(stbtt__buf *b, int n)
{
	uint v = 0;
	int i;
	assert(n >= 1 && n <= 4);
	for (i = 0; i < n; i++)
		v = (v << 8) | stbtt__buf_get8(b);
	return v;
}

stbtt__buf stbtt__new_buf(const void *p, size_t size)
{
	stbtt__buf r;
	assert(size < 0x40000000);
	r.data = cast(ubyte*) p;
	r.size = cast(int) size;
	r.cursor = 0;
	return r;
}

uint stbtt__buf_get16(stbtt__buf* b) => stbtt__buf_get(b, 2);
uint stbtt__buf_get32(stbtt__buf* b) => stbtt__buf_get(b, 4);

stbtt__buf stbtt__buf_range(stbtt__buf *b, int o, int s)
{
	stbtt__buf r = stbtt__new_buf(null, 0);
	if (o < 0 || s < 0 || o > b.size || s > b.size - o) return r;
	r.data = b.data + o;
	r.size = s;
	return r;
}

stbtt__buf stbtt__cff_get_index(stbtt__buf *b)
{
	int count, start, offsize;
	start = b.cursor;
	count = stbtt__buf_get16(b);
	if (count) {
		offsize = stbtt__buf_get8(b);
		assert(offsize >= 1 && offsize <= 4);
		stbtt__buf_skip(b, offsize * count);
		stbtt__buf_skip(b, stbtt__buf_get(b, offsize) - 1);
	}
	return stbtt__buf_range(b, start, b.cursor - start);
}

uint stbtt__cff_int(stbtt__buf *b)
{
	int b0 = stbtt__buf_get8(b);
	if (b0 >= 32 && b0 <= 246)       return b0 - 139;
	else if (b0 >= 247 && b0 <= 250) return (b0 - 247)*256 + stbtt__buf_get8(b) + 108;
	else if (b0 >= 251 && b0 <= 254) return -(b0 - 251)*256 - stbtt__buf_get8(b) - 108;
	else if (b0 == 28)               return stbtt__buf_get16(b);
	else if (b0 == 29)               return stbtt__buf_get32(b);
	assert(0);
	return 0;
}

void stbtt__cff_skip_operand(stbtt__buf *b) 
{
	int v, b0 = stbtt__buf_peek8(b);
	assert(b0 >= 28);
	if (b0 == 30) {
		stbtt__buf_skip(b, 1);
		while (b.cursor < b.size) {
			v = stbtt__buf_get8(b);
			if ((v & 0xF) == 0xF || (v >> 4) == 0xF)
				break;
		}
	} else {
		stbtt__cff_int(b);
	}
}

stbtt__buf stbtt__dict_get(stbtt__buf *b, int key)
{
	stbtt__buf_seek(b, 0);
	while (b.cursor < b.size) {
		int start = b.cursor, end, op;
		while (stbtt__buf_peek8(b) >= 28)
			stbtt__cff_skip_operand(b);
		end = b.cursor;
		op = stbtt__buf_get8(b);
		if (op == 12)  op = stbtt__buf_get8(b) | 0x100;
		if (op == key) return stbtt__buf_range(b, start, end-start);
	}
	return stbtt__buf_range(b, 0, 0);
}

void stbtt__dict_get_ints(stbtt__buf *b, int key, int outcount, uint *_out)
{
	int i;
	stbtt__buf operands = stbtt__dict_get(b, key);
	for (i = 0; i < outcount && operands.cursor < operands.size; i++)
		_out[i] = stbtt__cff_int(&operands);
}

int stbtt__cff_index_count(stbtt__buf *b)
{
	stbtt__buf_seek(b, 0);
	return stbtt__buf_get16(b);
}

stbtt__buf stbtt__cff_index_get(stbtt__buf b, int i)
{
	int count, offsize, start, end;
	stbtt__buf_seek(&b, 0);
	count = stbtt__buf_get16(&b);
	offsize = stbtt__buf_get8(&b);
	assert(i >= 0 && i < count);
	assert(offsize >= 1 && offsize <= 4);
	stbtt__buf_skip(&b, i*offsize);
	start = stbtt__buf_get(&b, offsize);
	end = stbtt__buf_get(&b, offsize);
	return stbtt__buf_range(&b, 2+(count+1)*offsize+start, end - start);
}

ubyte ttBYTE(T)(T* p)  => *(cast(ubyte*)p);
byte  ttCHAR(T)(T* p) => *(cast(byte*) p);

ushort ttUSHORT(const ubyte *p) => cast(ushort)(p[0]*256 + p[1]);
short  ttSHORT (const ubyte *p) => cast(short)(p[0]*256 + p[1]);
uint   ttULONG (const ubyte *p) => cast(uint)((p[0]<<24) + (p[1]<<16) + (p[2]<<8) + p[3]);
int    ttLONG  (const ubyte *p) => cast(int)((p[0]<<24) + (p[1]<<16) + (p[2]<<8) + p[3]);

alias ttFixed = ttLONG;

bool stbtt_tag4(ubyte* p, char c0, char c1, char c2, char c3) => ((p)[0] == (c0) && (p)[1] == (c1) && (p)[2] == (c2) && (p)[3] == (c3));
bool stbtt_tag(ubyte* p, string str) => stbtt_tag4(p,str[0],str[1],str[2],str[3]);

int stbtt__isfont(ubyte *font)
{
   // check the version number
   if (stbtt_tag4(font, '1',0,0,0))  return 1; // TrueType 1
   if (stbtt_tag(font, "typ1"))   return 1; // TrueType with type 1 font -- we don't support this!
   if (stbtt_tag(font, "OTTO"))   return 1; // OpenType with CFF
   if (stbtt_tag4(font, 0,1,0,0)) return 1; // OpenType 1.0
   if (stbtt_tag(font, "true"))   return 1; // Apple specification for TrueType fonts
   return 0;
}

// @OPTIMIZE: binary search
uint stbtt__find_table(ubyte *data, uint fontstart, string tag)
{
   int num_tables = ttUSHORT(data+fontstart+4);
   uint tabledir = fontstart + 12;
   int i;
   for (i=0; i < num_tables; ++i) {
      uint loc = tabledir + 16*i;
      if (stbtt_tag(data+loc+0, tag))
         return ttULONG(data+loc+8);
   }
   return 0;
}

int stbtt_GetFontOffsetForIndex_internal(ubyte* font_collection, int index)
{
   // if it's just a font, there's only one valid index
   if (stbtt__isfont(font_collection))
      return index == 0 ? 0 : -1;

   // check if it's a TTC
   if (stbtt_tag(font_collection, "ttcf")) {
      // version 1?
      if (ttULONG(font_collection+4) == 0x00010000 || ttULONG(font_collection+4) == 0x00020000) {
         int n = ttLONG(font_collection+8);
         if (index >= n)
            return -1;
         return ttULONG(font_collection+12+index*4);
      }
   }

   return -1;
}

int stbtt_GetNumberOfFonts_internal(ubyte *font_collection)
{
   // if it's just a font, there's only one valid font
   if (stbtt__isfont(font_collection))
      return 1;

   // check if it's a TTC
   if (stbtt_tag(font_collection, "ttcf")) 
	 {
      // version 1?
      if (ttULONG(font_collection+4) == 0x00010000 || ttULONG(font_collection+4) == 0x00020000) 
			{
         return ttLONG(font_collection+8);
      }
   }
   return 0;
}

stbtt__buf stbtt__get_subrs(stbtt__buf cff, stbtt__buf fontdict)
{
   uint    subrsoff = 0;
	 uint[2] private_loc = [ 0, 0 ];
   stbtt__buf pdict;
   stbtt__dict_get_ints(&fontdict, 18, 2, private_loc.ptr);
   if (!private_loc[1] || !private_loc[0]) return stbtt__new_buf(null, 0);
   pdict = stbtt__buf_range(&cff, private_loc[1], private_loc[0]);
   stbtt__dict_get_ints(&pdict, 19, 1, &subrsoff);
   if (!subrsoff) return stbtt__new_buf(null, 0);
   stbtt__buf_seek(&cff, private_loc[1]+subrsoff);
   return stbtt__cff_get_index(&cff);
}

// since most people won't use this, find this table the first time it's needed
int stbtt__get_svg(stbtt_fontinfo *info)
{
   uint t;
   if (info.svg < 0) 
	 {
      t = stbtt__find_table(info.data, info.fontstart, "SVG ");
      if (t) 
			{
         uint offset = ttULONG(info.data + t + 2);
         info.svg = t + offset;
      } 
			else 
			{
         info.svg = 0;
      }
   }
   return info.svg;
}

static void stbtt_setvertex(stbtt_vertex *v, ubyte type, int x, int y, int cx, int cy)
{
   v.type = type;
   v.x = cast(short) x;
   v.y = cast(short) y;
   v.cx = cast(short) cx;
   v.cy = cast(short) cy;
}

static int stbtt__GetGlyfOffset(stbtt_fontinfo *info, int glyph_index)
{
   int g1,g2;

   assert(!info.cff.size);

   if (glyph_index >= info.numGlyphs) return -1; // glyph index out of range
   if (info.indexToLocFormat >= 2)    return -1; // unknown index.glyph map format

   if (info.indexToLocFormat == 0) {
      g1 = info.glyf + ttUSHORT(info.data + info.loca + glyph_index * 2) * 2;
      g2 = info.glyf + ttUSHORT(info.data + info.loca + glyph_index * 2 + 2) * 2;
   } else {
      g1 = info.glyf + ttULONG (info.data + info.loca + glyph_index * 4);
      g2 = info.glyf + ttULONG (info.data + info.loca + glyph_index * 4 + 4);
   }

   return g1==g2 ? -1 : g1; // if length is 0, return -1
}

static int stbtt__close_shape(stbtt_vertex *vertices, int num_vertices, int was_off, int start_off,
    int sx, int sy, int scx, int scy, int cx, int cy)
{
   if (start_off) {
      if (was_off)
         stbtt_setvertex(&vertices[num_vertices++], stbtt_curvetype.vcurve, (cx+scx)>>1, (cy+scy)>>1, cx,cy);
      stbtt_setvertex(&vertices[num_vertices++], stbtt_curvetype.vcurve, sx,sy,scx,scy);
   } else {
      if (was_off)
         stbtt_setvertex(&vertices[num_vertices++], stbtt_curvetype.vcurve,sx,sy,cx,cy);
      else
         stbtt_setvertex(&vertices[num_vertices++], stbtt_curvetype.vline,sx,sy,0,0);
   }
   return num_vertices;
}

static int stbtt_GetGlyphShapeTT(stbtt_fontinfo *info, int glyph_index, stbtt_vertex **pvertices)
{
   short numberOfContours;
   ubyte *endPtsOfContours;
   ubyte *data = info.data;
   stbtt_vertex* vertices;
   int num_vertices=0;
   int g = stbtt__GetGlyfOffset(info, glyph_index);

   *pvertices = null;

   if (g < 0) return 0;

   numberOfContours = ttSHORT(data + g);

   if (numberOfContours > 0) {
      ubyte flags=0,flagcount;
      int ins, i,j=0,m,n, next_move, was_off=0, off, start_off=0;
      int x,y,cx,cy,sx,sy, scx,scy;
      ubyte *points;
      endPtsOfContours = (data + g + 10);
      ins = ttUSHORT(data + g + 10 + numberOfContours * 2);
      points = data + g + 10 + numberOfContours * 2 + 2 + ins;

      n = 1+ttUSHORT(endPtsOfContours + numberOfContours*2-2);

      m = n + 2*numberOfContours;  // a loose bound on how many vertices we might need
      vertices = cast(stbtt_vertex *)malloc(m * stbtt_vertex.sizeof);
      if (vertices == null)
         return 0;

      next_move = 0;
      flagcount=0;

      // in first pass, we load uninterpreted data into the allocated array
      // above, shifted to the end of the array so we won't overwrite it when
      // we create our final data starting from the front

      off = m - n; // starting offset for uninterpreted data, regardless of how m ends up being calculated

      // first load flags

      for (i=0; i < n; ++i) {
         if (flagcount == 0) {
            flags = *points++;
            if (flags & 8)
               flagcount = *points++;
         } else
            --flagcount;
         vertices[off+i].type = flags;
      }

      // now load x coordinates
      x=0;
      for (i=0; i < n; ++i) {
         flags = vertices[off+i].type;
         if (flags & 2) {
            short dx = *points++;
            x += (flags & 16) ? dx : -dx; // ???
         } else {
            if (!(flags & 16)) {
               x = x + cast(short) (points[0]*256 + points[1]);
               points += 2;
            }
         }
         vertices[off+i].x = cast(short) x;
      }

      // now load y coordinates
      y=0;
      for (i=0; i < n; ++i) {
         flags = vertices[off+i].type;
         if (flags & 4) {
            short dy = *points++;
            y += (flags & 32) ? dy : -dy; // ???
         } else {
            if (!(flags & 32)) {
               y = y + cast(short) (points[0]*256 + points[1]);
               points += 2;
            }
         }
         vertices[off+i].y = cast(short) y;
      }

      // now convert them to our format
      num_vertices=0;
      sx = sy = cx = cy = scx = scy = 0;
      for (i=0; i < n; ++i) {
         flags = vertices[off+i].type;
         x     = cast(short) vertices[off+i].x;
         y     = cast(short) vertices[off+i].y;

         if (next_move == i) {
            if (i != 0)
               num_vertices = stbtt__close_shape(vertices, num_vertices, was_off, start_off, sx,sy,scx,scy,cx,cy);

            // now start the new one
            start_off = !(flags & 1);
            if (start_off) {
               // if we start off with an off-curve point, then when we need to find a point on the curve
               // where we can start, and we need to save some state for when we wraparound.
               scx = x;
               scy = y;
               if (!(vertices[off+i+1].type & 1)) {
                  // next point is also a curve point, so interpolate an on-point curve
                  sx = (x + cast(int) vertices[off+i+1].x) >> 1;
                  sy = (y + cast(int) vertices[off+i+1].y) >> 1;
               } else {
                  // otherwise just use the next point as our start point
                  sx = cast(int) vertices[off+i+1].x;
                  sy = cast(int) vertices[off+i+1].y;
                  ++i; // we're using point i+1 as the starting point, so skip it
               }
            } else {
               sx = x;
               sy = y;
            }
            stbtt_setvertex(&vertices[num_vertices++], stbtt_curvetype.vmove,sx,sy,0,0);
            was_off = 0;
            next_move = 1 + ttUSHORT(endPtsOfContours+j*2);
            ++j;
         } else {
            if (!(flags & 1)) { // if it's a curve
               if (was_off) // two off-curve control points in a row means interpolate an on-curve midpoint
                  stbtt_setvertex(&vertices[num_vertices++], stbtt_curvetype.vcurve, (cx+x)>>1, (cy+y)>>1, cx, cy);
               cx = x;
               cy = y;
               was_off = 1;
            } else {
               if (was_off)
                  stbtt_setvertex(&vertices[num_vertices++], stbtt_curvetype.vcurve, x,y, cx, cy);
               else
                  stbtt_setvertex(&vertices[num_vertices++], stbtt_curvetype.vline, x,y,0,0);
               was_off = 0;
            }
         }
      }
      num_vertices = stbtt__close_shape(vertices, num_vertices, was_off, start_off, sx,sy,scx,scy,cx,cy);
   } else if (numberOfContours < 0) {
      // Compound shapes.
      int more = 1;
      ubyte *comp = data + g + 10;
      num_vertices = 0;
      vertices = null;
      while (more) {
         ushort flags, gidx;
         int comp_num_verts = 0, i;
         stbtt_vertex* comp_verts, tmp;
         float[6] mtx = [1,0,0,1,0,0];
				 float m = 0.0, n = 0.0;

         flags = ttSHORT(comp); comp+=2;
         gidx = ttSHORT(comp); comp+=2;

         if (flags & 2) { // XY values
            if (flags & 1) { // shorts
               mtx[4] = ttSHORT(comp); comp+=2;
               mtx[5] = ttSHORT(comp); comp+=2;
            } else {
               mtx[4] = ttCHAR(comp); comp+=1;
               mtx[5] = ttCHAR(comp); comp+=1;
            }
         }
         else {
            // @TODO handle matching point
            assert(0);
         }
         if (flags & (1<<3)) { // WE_HAVE_A_SCALE
            mtx[0] = mtx[3] = ttSHORT(comp)/16384.0f; comp+=2;
            mtx[1] = mtx[2] = 0;
         } else if (flags & (1<<6)) { // WE_HAVE_AN_X_AND_YSCALE
            mtx[0] = ttSHORT(comp)/16384.0f; comp+=2;
            mtx[1] = mtx[2] = 0;
            mtx[3] = ttSHORT(comp)/16384.0f; comp+=2;
         } else if (flags & (1<<7)) { // WE_HAVE_A_TWO_BY_TWO
            mtx[0] = ttSHORT(comp)/16384.0f; comp+=2;
            mtx[1] = ttSHORT(comp)/16384.0f; comp+=2;
            mtx[2] = ttSHORT(comp)/16384.0f; comp+=2;
            mtx[3] = ttSHORT(comp)/16384.0f; comp+=2;
         }

         // Find transformation scales.
         m = cast(float) sqrt(mtx[0]*mtx[0] + mtx[1]*mtx[1]);
         n = cast(float) sqrt(mtx[2]*mtx[2] + mtx[3]*mtx[3]);

         // Get indexed glyph.
         comp_num_verts = stbtt_GetGlyphShape(info, gidx, &comp_verts);
         if (comp_num_verts > 0) {
            // Transform vertices.
            for (i = 0; i < comp_num_verts; ++i) {
               stbtt_vertex* v = &comp_verts[i];
               short x,y;
               x=v.x; y=v.y;
               v.x = cast(short)(m * (mtx[0]*x + mtx[2]*y + mtx[4]));
               v.y = cast(short)(n * (mtx[1]*x + mtx[3]*y + mtx[5]));
               x=v.cx; y=v.cy;
               v.cx = cast(short)(m * (mtx[0]*x + mtx[2]*y + mtx[4]));
               v.cy = cast(short)(n * (mtx[1]*x + mtx[3]*y + mtx[5]));
            }
            // Append vertices.
            tmp = cast(stbtt_vertex*)malloc((num_vertices+comp_num_verts)*stbtt_vertex.sizeof);
            if (!tmp) {
               if (vertices) free(vertices);
               if (comp_verts) free(comp_verts);
               return 0;
            }
            if (num_vertices > 0 && vertices) memcpy(tmp, vertices, num_vertices*stbtt_vertex.sizeof);
            memcpy(tmp+num_vertices, comp_verts, comp_num_verts*stbtt_vertex.sizeof);
            if (vertices) free(vertices);
            vertices = tmp;
            free(comp_verts);
            num_vertices += comp_num_verts;
         }
         // More components ?
         more = flags & (1<<5);
      }
   } else {
      // numberOfCounters == 0, do nothing
   }

   *pvertices = vertices;
   return num_vertices;
}

struct stbtt__csctx
{
   int   bounds;
   int   started;
   float first_x = 0.0, first_y = 0.0;
   float x = 0.0, y = 0.0;
   int   min_x, max_x, min_y, max_y;

   stbtt_vertex* pvertices;
   int           num_vertices;
};

void stbtt__track_vertex(stbtt__csctx *c, int x, int y)
{
   if (x > c.max_x || !c.started) c.max_x = x;
   if (y > c.max_y || !c.started) c.max_y = y;
   if (x < c.min_x || !c.started) c.min_x = x;
   if (y < c.min_y || !c.started) c.min_y = y;
   c.started = 1;
}

void stbtt__csctx_v(stbtt__csctx *c, ubyte type, int x, int y, int cx, int cy, int cx1, int cy1)
{
   if (c.bounds) {
      stbtt__track_vertex(c, x, y);
      if (type == stbtt_curvetype.vcubic) {
         stbtt__track_vertex(c, cx, cy);
         stbtt__track_vertex(c, cx1, cy1);
      }
   } else {
      stbtt_setvertex(&c.pvertices[c.num_vertices], type, x, y, cx, cy);
      c.pvertices[c.num_vertices].cx1 = cast(short) cx1;
      c.pvertices[c.num_vertices].cy1 = cast(short) cy1;
   }
   c.num_vertices++;
}

static void stbtt__csctx_close_shape(stbtt__csctx *ctx)
{
   if (ctx.first_x != ctx.x || ctx.first_y != ctx.y)
      stbtt__csctx_v(ctx, stbtt_curvetype.vline, cast(int)ctx.first_x, cast(int)ctx.first_y, 0, 0, 0, 0);
}

static void stbtt__csctx_rmove_to(stbtt__csctx *ctx, float dx, float dy)
{
   stbtt__csctx_close_shape(ctx);
   ctx.first_x = ctx.x = ctx.x + dx;
   ctx.first_y = ctx.y = ctx.y + dy;
   stbtt__csctx_v(ctx, stbtt_curvetype.vmove, cast(int)ctx.x, cast(int)ctx.y, 0, 0, 0, 0);
}

static void stbtt__csctx_rline_to(stbtt__csctx *ctx, float dx, float dy)
{
   ctx.x += dx;
   ctx.y += dy;
   stbtt__csctx_v(ctx, stbtt_curvetype.vline, cast(int)ctx.x, cast(int)ctx.y, 0, 0, 0, 0);
}

static void stbtt__csctx_rccurve_to(stbtt__csctx *ctx, float dx1, float dy1, float dx2, float dy2, float dx3, float dy3)
{
   float cx1 = ctx.x + dx1;
   float cy1 = ctx.y + dy1;
   float cx2 = cx1 + dx2;
   float cy2 = cy1 + dy2;
   ctx.x = cx2 + dx3;
   ctx.y = cy2 + dy3;
   stbtt__csctx_v(ctx, stbtt_curvetype.vcubic, cast(int)ctx.x, cast(int)ctx.y, cast(int)cx1, cast(int)cy1, cast(int)cx2, cast(int)cy2);
}

static stbtt__buf stbtt__get_subr(stbtt__buf idx, int n)
{
   int count = stbtt__cff_index_count(&idx);
   int bias = 107;
   if (count >= 33900)
      bias = 32768;
   else if (count >= 1240)
      bias = 1131;
   n += bias;
   if (n < 0 || n >= count)
      return stbtt__new_buf(null, 0);
   return stbtt__cff_index_get(idx, n);
}

static stbtt__buf stbtt__cid_get_glyph_subrs(stbtt_fontinfo *info, int glyph_index)
{
   stbtt__buf fdselect = info.fdselect;
   int nranges, start, end, v, fmt, fdselector = -1, i;

   stbtt__buf_seek(&fdselect, 0);
   fmt = stbtt__buf_get8(&fdselect);
   if (fmt == 0) {
      // untested
      stbtt__buf_skip(&fdselect, glyph_index);
      fdselector = stbtt__buf_get8(&fdselect);
   } else if (fmt == 3) {
      nranges = stbtt__buf_get16(&fdselect);
      start = stbtt__buf_get16(&fdselect);
      for (i = 0; i < nranges; i++) {
         v = stbtt__buf_get8(&fdselect);
         end = stbtt__buf_get16(&fdselect);
         if (glyph_index >= start && glyph_index < end) {
            fdselector = v;
            break;
         }
         start = end;
      }
   }
   if (fdselector == -1) stbtt__new_buf(null, 0);
   return stbtt__get_subrs(info.cff, stbtt__cff_index_get(info.fontdicts, fdselector));
}

static int stbtt__run_charstring(stbtt_fontinfo *info, int glyph_index, stbtt__csctx *c)
{
   int in_header = 1, maskbits = 0, subr_stack_height = 0, sp = 0, v, i, b0;
   int has_subrs = 0, clear_stack;
   float[48] s = 0.0;
   stbtt__buf[10] subr_stack;
	 stbtt__buf subrs = info.subrs;
	 stbtt__buf b;
   float f = 0.0;

// #define STBTT__CSERR(s) (0)

   // this currently ignores the initial width value, which isn't needed if we have hmtx
   b = stbtt__cff_index_get(info.charstrings, glyph_index);
   while (b.cursor < b.size) {
      i = 0;
      clear_stack = 1;
      b0 = stbtt__buf_get8(&b);
      switch (b0) {
      // @TODO implement hinting
      case 0x13: // hintmask
      case 0x14: // cntrmask
         if (in_header)
            maskbits += (sp / 2); // implicit "vstem"
         in_header = 0;
         stbtt__buf_skip(&b, (maskbits + 7) / 8);
         break;

      case 0x01: // hstem
      case 0x03: // vstem
      case 0x12: // hstemhm
      case 0x17: // vstemhm
         maskbits += (sp / 2);
         break;

      case 0x15: // rmoveto
         in_header = 0;
         if (sp < 2) return 0; // STBTT__CSERR("rmoveto stack");
         stbtt__csctx_rmove_to(c, s[sp-2], s[sp-1]);
         break;
      case 0x04: // vmoveto
         in_header = 0;
         if (sp < 1) return 0; // STBTT__CSERR("vmoveto stack");
         stbtt__csctx_rmove_to(c, 0, s[sp-1]);
         break;
      case 0x16: // hmoveto
         in_header = 0;
         if (sp < 1) return 0; // STBTT__CSERR("hmoveto stack");
         stbtt__csctx_rmove_to(c, s[sp-1], 0);
         break;

      case 0x05: // rlineto
         if (sp < 2) return 0; // STBTT__CSERR("rlineto stack");
         for (; i + 1 < sp; i += 2)
            stbtt__csctx_rline_to(c, s[i], s[i+1]);
         break;

      // hlineto/vlineto and vhcurveto/hvcurveto alternate horizontal and vertical
      // starting from a different place.

      case 0x07: // vlineto
         if (sp < 1) return 0; // STBTT__CSERR("vlineto stack");
         goto vlineto;
      case 0x06: // hlineto
         if (sp < 1) return 0; // STBTT__CSERR("hlineto stack");
         for (;;) {
            if (i >= sp) break;
            stbtt__csctx_rline_to(c, s[i], 0);
            i++;
      vlineto:
            if (i >= sp) break;
            stbtt__csctx_rline_to(c, 0, s[i]);
            i++;
         }
         break;

      case 0x1F: // hvcurveto
         if (sp < 4) return 0; // STBTT__CSERR("hvcurveto stack");
         goto hvcurveto;
      case 0x1E: // vhcurveto
         if (sp < 4) return 0; // STBTT__CSERR("vhcurveto stack");
         for (;;) {
            if (i + 3 >= sp) break;
            stbtt__csctx_rccurve_to(c, 0, s[i], s[i+1], s[i+2], s[i+3], (sp - i == 5) ? s[i + 4] : 0.0f);
            i += 4;
      hvcurveto:
            if (i + 3 >= sp) break;
            stbtt__csctx_rccurve_to(c, s[i], 0, s[i+1], s[i+2], (sp - i == 5) ? s[i+4] : 0.0f, s[i+3]);
            i += 4;
         }
         break;

      case 0x08: // rrcurveto
         if (sp < 6) return 0; // STBTT__CSERR("rcurveline stack");
         for (; i + 5 < sp; i += 6)
            stbtt__csctx_rccurve_to(c, s[i], s[i+1], s[i+2], s[i+3], s[i+4], s[i+5]);
         break;

      case 0x18: // rcurveline
         if (sp < 8) return 0; // STBTT__CSERR("rcurveline stack");
         for (; i + 5 < sp - 2; i += 6)
            stbtt__csctx_rccurve_to(c, s[i], s[i+1], s[i+2], s[i+3], s[i+4], s[i+5]);
         if (i + 1 >= sp) return 0; // STBTT__CSERR("rcurveline stack");
         stbtt__csctx_rline_to(c, s[i], s[i+1]);
         break;

      case 0x19: // rlinecurve
         if (sp < 8) return 0; // STBTT__CSERR("rlinecurve stack");
         for (; i + 1 < sp - 6; i += 2)
            stbtt__csctx_rline_to(c, s[i], s[i+1]);
         if (i + 5 >= sp) return 0; // STBTT__CSERR("rlinecurve stack");
         stbtt__csctx_rccurve_to(c, s[i], s[i+1], s[i+2], s[i+3], s[i+4], s[i+5]);
         break;

      case 0x1A: // vvcurveto
      case 0x1B: // hhcurveto
         if (sp < 4) return 0; // STBTT__CSERR("(vv|hh)curveto stack");
         f = 0.0;
         if (sp & 1) { f = s[i]; i++; }
         for (; i + 3 < sp; i += 4) {
            if (b0 == 0x1B)
               stbtt__csctx_rccurve_to(c, s[i], f, s[i+1], s[i+2], s[i+3], 0.0);
            else
               stbtt__csctx_rccurve_to(c, f, s[i], s[i+1], s[i+2], 0.0, s[i+3]);
            f = 0.0;
         }
         break;

      case 0x0A: // callsubr
         if (!has_subrs) {
            if (info.fdselect.size)
               subrs = stbtt__cid_get_glyph_subrs(info, glyph_index);
            has_subrs = 1;
         }
				 goto case 0X1D;
      case 0x1D: // callgsubr
         if (sp < 1) return 0; // STBTT_CSERR("call(g|)subr stack");
         v = cast(int) s[--sp];
         if (subr_stack_height >= 10) return 0; // STBTT_CSERR("recursion limit");
         subr_stack[subr_stack_height++] = b;
         b = stbtt__get_subr(b0 == 0x0A ? subrs : info.gsubrs, v);
         if (b.size == 0) return 0; // STBTT_CSERR("subr not found");
         b.cursor = 0;
         clear_stack = 0;
         break;

      case 0x0B: // return
         if (subr_stack_height <= 0) return 0; // STBTT_CSERR("return outside subr");
         b = subr_stack[--subr_stack_height];
         clear_stack = 0;
         break;

      case 0x0E: // endchar
         stbtt__csctx_close_shape(c);
         return 1;

      case 0x0C: { // two-byte escape
         float dx1 = 0, dx2 = 0, dx3 = 0, dx4 = 0, dx5 = 0, dx6 = 0, dy1 = 0, dy2 = 0, dy3 = 0, dy4 = 0, dy5 = 0, dy6 = 0;
         float dx = 0, dy = 0;
         int b1 = stbtt__buf_get8(&b);
         switch (b1) {
         // @TODO These "flex" implementations ignore the flex-depth and resolution,
         // and always draw beziers.
         case 0x22: // hflex
            if (sp < 7) return 0; // STBTT_CSERR("hflex stack");
            dx1 = s[0];
            dx2 = s[1];
            dy2 = s[2];
            dx3 = s[3];
            dx4 = s[4];
            dx5 = s[5];
            dx6 = s[6];
            stbtt__csctx_rccurve_to(c, dx1, 0, dx2, dy2, dx3, 0);
            stbtt__csctx_rccurve_to(c, dx4, 0, dx5, -dy2, dx6, 0);
            break;

         case 0x23: // flex
            if (sp < 13) return 0; // STBTT_CSERR("flex stack");
            dx1 = s[0];
            dy1 = s[1];
            dx2 = s[2];
            dy2 = s[3];
            dx3 = s[4];
            dy3 = s[5];
            dx4 = s[6];
            dy4 = s[7];
            dx5 = s[8];
            dy5 = s[9];
            dx6 = s[10];
            dy6 = s[11];
            //fd is s[12]
            stbtt__csctx_rccurve_to(c, dx1, dy1, dx2, dy2, dx3, dy3);
            stbtt__csctx_rccurve_to(c, dx4, dy4, dx5, dy5, dx6, dy6);
            break;

         case 0x24: // hflex1
            if (sp < 9) return 0; // STBTT_CSERR("hflex1 stack");
            dx1 = s[0];
            dy1 = s[1];
            dx2 = s[2];
            dy2 = s[3];
            dx3 = s[4];
            dx4 = s[5];
            dx5 = s[6];
            dy5 = s[7];
            dx6 = s[8];
            stbtt__csctx_rccurve_to(c, dx1, dy1, dx2, dy2, dx3, 0);
            stbtt__csctx_rccurve_to(c, dx4, 0, dx5, dy5, dx6, -(dy1+dy2+dy5));
            break;

         case 0x25: // flex1
            if (sp < 11) return 0; // STBTT_CSERR("flex1 stack");
            dx1 = s[0];
            dy1 = s[1];
            dx2 = s[2];
            dy2 = s[3];
            dx3 = s[4];
            dy3 = s[5];
            dx4 = s[6];
            dy4 = s[7];
            dx5 = s[8];
            dy5 = s[9];
            dx6 = dy6 = s[10];
            dx = dx1+dx2+dx3+dx4+dx5;
            dy = dy1+dy2+dy3+dy4+dy5;
            if (fabs(dx) > fabs(dy))
               dy6 = -dy;
            else
               dx6 = -dx;
            stbtt__csctx_rccurve_to(c, dx1, dy1, dx2, dy2, dx3, dy3);
            stbtt__csctx_rccurve_to(c, dx4, dy4, dx5, dy5, dx6, dy6);
            break;

         default:
            return 0; // STBTT_CSERR("unimplemented");
         }
      } break;

      default:
         if (b0 != 255 && b0 != 28 && b0 < 32)
            return 0; // STBTT_CSERR("reserved operator");

         // push immediate
         if (b0 == 255) {
            f = cast(float)cast(int)stbtt__buf_get32(&b) / 0x10000;
         } else {
            stbtt__buf_skip(&b, -1);
            f = cast(float)cast(short)stbtt__cff_int(&b);
         }
         if (sp >= 48) return 0; // STBTT_CSERR("push stack overflow");
         s[sp++] = f;
         clear_stack = 0;
         break;
      }
      if (clear_stack) sp = 0;
   }
   return 0; // STBTT_CSERR("no endchar");

// #undef STBTT__CSERR
}

static int stbtt_GetGlyphShapeT2(stbtt_fontinfo *info, int glyph_index, stbtt_vertex **pvertices)
{
   // runs the charstring twice, once to count and once to output (to avoid realloc)
   stbtt__csctx count_ctx  = {bounds: 1, first_x: 0.0, first_y: 0.0, x: 0.0, y: 0.0};
   stbtt__csctx output_ctx = {bounds: 0, first_x: 0.0, first_y: 0.0, x: 0.0, y: 0.0};
   if (stbtt__run_charstring(info, glyph_index, &count_ctx)) {
      *pvertices = cast(stbtt_vertex*)malloc(count_ctx.num_vertices*stbtt_vertex.sizeof);
      output_ctx.pvertices = *pvertices;
      if (stbtt__run_charstring(info, glyph_index, &output_ctx)) {
         assert(output_ctx.num_vertices == count_ctx.num_vertices);
         return output_ctx.num_vertices;
      }
   }
   *pvertices = null;
   return 0;
}

static int stbtt__GetGlyphInfoT2(stbtt_fontinfo *info, int glyph_index, int *x0, int *y0, int *x1, int *y1)
{
   stbtt__csctx c = {bounds: 1, first_x: 0.0, first_y: 0.0, x: 0.0, y: 0.0};
   int r = stbtt__run_charstring(info, glyph_index, &c);
   if (x0)  *x0 = r ? c.min_x : 0;
   if (y0)  *y0 = r ? c.min_y : 0;
   if (x1)  *x1 = r ? c.max_x : 0;
   if (y1)  *y1 = r ? c.max_y : 0;
   return r ? c.num_vertices : 0;
}

static int stbtt__GetGlyphKernInfoAdvance(stbtt_fontinfo *info, int glyph1, int glyph2)
{
   ubyte *data = info.data + info.kern;
   uint needle, straw;
   int l, r, m;

   // we only look at the first table. it must be 'horizontal' and format 0.
   if (!info.kern)
      return 0;
   if (ttUSHORT(data+2) < 1) // number of tables, need at least 1
      return 0;
   if (ttUSHORT(data+8) != 1) // horizontal flag must be set in format
      return 0;

   l = 0;
   r = ttUSHORT(data+10) - 1;
   needle = glyph1 << 16 | glyph2;
   while (l <= r) {
      m = (l + r) >> 1;
      straw = ttULONG(data+18+(m*6)); // note: unaligned read
      if (needle < straw)
         r = m - 1;
      else if (needle > straw)
         l = m + 1;
      else
         return ttSHORT(data+22+(m*6));
   }
   return 0;
}

static int stbtt__GetCoverageIndex(ubyte *coverageTable, int glyph)
{
   ushort coverageFormat = ttUSHORT(coverageTable);
   switch (coverageFormat) {
      case 1: {
         ushort glyphCount = ttUSHORT(coverageTable + 2);

         // Binary search.
         int l=0, r=glyphCount-1, m;
         int straw, needle=glyph;
         while (l <= r) {
            ubyte *glyphArray = coverageTable + 4;
            ushort glyphID;
            m = (l + r) >> 1;
            glyphID = ttUSHORT(glyphArray + 2 * m);
            straw = glyphID;
            if (needle < straw)
               r = m - 1;
            else if (needle > straw)
               l = m + 1;
            else {
               return m;
            }
         }
         break;
      }

      case 2: {
         ushort rangeCount = ttUSHORT(coverageTable + 2);
         ubyte *rangeArray = coverageTable + 4;

         // Binary search.
         int l=0, r=rangeCount-1, m;
         int strawStart, strawEnd, needle=glyph;
         while (l <= r) {
            ubyte *rangeRecord;
            m = (l + r) >> 1;
            rangeRecord = rangeArray + 6 * m;
            strawStart = ttUSHORT(rangeRecord);
            strawEnd = ttUSHORT(rangeRecord + 2);
            if (needle < strawStart)
               r = m - 1;
            else if (needle > strawEnd)
               l = m + 1;
            else {
               ushort startCoverageIndex = ttUSHORT(rangeRecord + 4);
               return startCoverageIndex + glyph - strawStart;
            }
         }
         break;
      }

      default: return -1; // unsupported
   }

   return -1;
}

static int  stbtt__GetGlyphClass(ubyte *classDefTable, int glyph)
{
   ushort classDefFormat = ttUSHORT(classDefTable);
   switch (classDefFormat)
   {
      case 1: {
         ushort startGlyphID = ttUSHORT(classDefTable + 2);
         ushort glyphCount = ttUSHORT(classDefTable + 4);
         ubyte *classDef1ValueArray = classDefTable + 6;

         if (glyph >= startGlyphID && glyph < startGlyphID + glyphCount)
            return cast(int)ttUSHORT(classDef1ValueArray + 2 * (glyph - startGlyphID));
         break;
      }

      case 2: {
         ushort classRangeCount = ttUSHORT(classDefTable + 2);
         ubyte *classRangeRecords = classDefTable + 4;

         // Binary search.
         int l=0, r=classRangeCount-1, m;
         int strawStart, strawEnd, needle=glyph;
         while (l <= r) {
            ubyte *classRangeRecord;
            m = (l + r) >> 1;
            classRangeRecord = classRangeRecords + 6 * m;
            strawStart = ttUSHORT(classRangeRecord);
            strawEnd = ttUSHORT(classRangeRecord + 2);
            if (needle < strawStart)
               r = m - 1;
            else if (needle > strawEnd)
               l = m + 1;
            else
               return cast(int)ttUSHORT(classRangeRecord + 4);
         }
         break;
      }

      default:
         return -1; // Unsupported definition type, return an error.
   }

   // "All glyphs not assigned to a class fall into class 0". (OpenType spec)
   return 0;
}

static int stbtt__GetGlyphGPOSInfoAdvance(stbtt_fontinfo *info, int glyph1, int glyph2)
{
   ushort lookupListOffset;
   ubyte *lookupList;
   ushort lookupCount;
   ubyte *data;
   int i, sti;

   if (!info.gpos) return 0;

   data = info.data + info.gpos;

   if (ttUSHORT(data+0) != 1) return 0; // Major version 1
   if (ttUSHORT(data+2) != 0) return 0; // Minor version 0

   lookupListOffset = ttUSHORT(data+8);
   lookupList = data + lookupListOffset;
   lookupCount = ttUSHORT(lookupList);

   for (i=0; i<lookupCount; ++i) {
      ushort lookupOffset = ttUSHORT(lookupList + 2 + 2 * i);
      ubyte *lookupTable = lookupList + lookupOffset;

      ushort lookupType = ttUSHORT(lookupTable);
      ushort subTableCount = ttUSHORT(lookupTable + 4);
      ubyte *subTableOffsets = lookupTable + 6;
      if (lookupType != 2) // Pair Adjustment Positioning Subtable
         continue;

      for (sti=0; sti<subTableCount; sti++) {
         ushort subtableOffset = ttUSHORT(subTableOffsets + 2 * sti);
         ubyte *table = lookupTable + subtableOffset;
         ushort posFormat = ttUSHORT(table);
         ushort coverageOffset = ttUSHORT(table + 2);
         int coverageIndex = stbtt__GetCoverageIndex(table + coverageOffset, glyph1);
         if (coverageIndex == -1) continue;

         switch (posFormat) {
            case 1: {
               int l, r, m;
               int straw, needle;
               ushort valueFormat1 = ttUSHORT(table + 4);
               ushort valueFormat2 = ttUSHORT(table + 6);
               if (valueFormat1 == 4 && valueFormat2 == 0) { // Support more formats?
                  int valueRecordPairSizeInBytes = 2;
                  ushort pairSetCount = ttUSHORT(table + 8);
                  ushort pairPosOffset = ttUSHORT(table + 10 + 2 * coverageIndex);
                  ubyte *pairValueTable = table + pairPosOffset;
                  ushort pairValueCount = ttUSHORT(pairValueTable);
                  ubyte *pairValueArray = pairValueTable + 2;

                  if (coverageIndex >= pairSetCount) return 0;

                  needle=glyph2;
                  r=pairValueCount-1;
                  l=0;

                  // Binary search.
                  while (l <= r) {
                     ushort secondGlyph;
                     ubyte *pairValue;
                     m = (l + r) >> 1;
                     pairValue = pairValueArray + (2 + valueRecordPairSizeInBytes) * m;
                     secondGlyph = ttUSHORT(pairValue);
                     straw = secondGlyph;
                     if (needle < straw)
                        r = m - 1;
                     else if (needle > straw)
                        l = m + 1;
                     else {
                        short xAdvance = ttSHORT(pairValue + 2);
                        return xAdvance;
                     }
                  }
               } else
                  return 0;
               break;
            }

            case 2: {
               ushort valueFormat1 = ttUSHORT(table + 4);
               ushort valueFormat2 = ttUSHORT(table + 6);
               if (valueFormat1 == 4 && valueFormat2 == 0) { // Support more formats?
                  ushort classDef1Offset = ttUSHORT(table + 8);
                  ushort classDef2Offset = ttUSHORT(table + 10);
                  int glyph1class = stbtt__GetGlyphClass(table + classDef1Offset, glyph1);
                  int glyph2class = stbtt__GetGlyphClass(table + classDef2Offset, glyph2);

                  ushort class1Count = ttUSHORT(table + 12);
                  ushort class2Count = ttUSHORT(table + 14);
                  ubyte* class1Records, class2Records;
                  short xAdvance;

                  if (glyph1class < 0 || glyph1class >= class1Count) return 0; // malformed
                  if (glyph2class < 0 || glyph2class >= class2Count) return 0; // malformed

                  class1Records = table + 16;
                  class2Records = class1Records + 2 * (glyph1class * class2Count);
                  xAdvance = ttSHORT(class2Records + 2 * glyph2class);
                  return xAdvance;
               } else
                  return 0;
               break;
            }

            default:
               return 0; // Unsupported position format
         }
      }
   }

   return 0;
}


//////////////////////////////////////////////////////////////////////////////
//
//  Rasterizer

struct stbtt__hheap_chunk
{
	stbtt__hheap_chunk *next;
};

struct stbtt__hheap
{
	stbtt__hheap_chunk *head;
	void   *first_free;
	int    num_remaining_in_head_chunk;
};

void *stbtt__hheap_alloc(stbtt__hheap *hh, size_t size)
{
	if (hh.first_free) {
		void *p = hh.first_free;
		hh.first_free = * cast(void **) p;
		return p;
	} else {
		if (hh.num_remaining_in_head_chunk == 0) {
			int count = (size < 32 ? 2000 : size < 128 ? 800 : 100);
			stbtt__hheap_chunk *c = cast(stbtt__hheap_chunk *)malloc(stbtt__hheap_chunk.sizeof + size * count);
			if (c == null)
				return null;
			c.next = hh.head;
			hh.head = c;
			hh.num_remaining_in_head_chunk = count;
		}
		--hh.num_remaining_in_head_chunk;
		return cast(char*) (hh.head) + stbtt__hheap_chunk.sizeof + size * hh.num_remaining_in_head_chunk;
	}
}

void stbtt__hheap_free(stbtt__hheap *hh, void *p)
{
   *cast(void **) p = hh.first_free;
   hh.first_free = p;
}

void stbtt__hheap_cleanup(stbtt__hheap *hh)
{
   stbtt__hheap_chunk *c = hh.head;
   while (c) {
      stbtt__hheap_chunk *n = c.next;
      free(c);
      c = n;
   }
}

struct stbtt__edge 
{
   float x0 = 0.0, y0 = 0.0, x1 = 0.0, y1 = 0.0;
   int invert;
}

struct stbtt__active_edge
{
   stbtt__active_edge *next;
   static if(STBTT_RASTERIZER_VERSION == 1)
	 {
		 int x,dx;
		 float ey = 0.0;
		 int direction;
	 }
	 else static if(STBTT_RASTERIZER_VERSION == 2)
	 {
		 float fx = 0.0, fdx = 0.0, fdy = 0.0;
		 float direction = 0.0;
		 float sy = 0.0;
		 float ey = 0.0;
	 }
	 else static assert(false, "Unrecognized value of STBTT_RASTERIZER_VERSION");
}

static if(STBTT_RASTERIZER_VERSION == 1)
{
	enum STBTT_FIXSHIFT = 10;
	enum STBTT_FIX      = (1 << STBTT_FIXSHIFT);
	enum STBTT_FIXMASK  = (STBTT_FIX-1);


	static stbtt__active_edge *stbtt__new_active(stbtt__hheap *hh, stbtt__edge *e, int off_x, float start_point)
	{
		 stbtt__active_edge *z = cast(stbtt__active_edge *) stbtt__hheap_alloc(hh, stbtt__active_edge.sizeof);
		 float dxdy = (e.x1 - e.x0) / (e.y1 - e.y0);
		 assert(z != null);
		 if (!z) return z;

		 // round dx down to avoid overshooting
		 if (dxdy < 0)
				z.dx = -ifloor(STBTT_FIX * -dxdy);
		 else
				z.dx = ifloor(STBTT_FIX * dxdy);

		 z.x = ifloor(STBTT_FIX * e.x0 + z.dx * (start_point - e.y0)); // use z.dx so when we offset later it's by the same amount
		 z.x -= off_x * STBTT_FIX;

		 z.ey = e.y1;
		 z.next = 0;
		 z.direction = e.invert ? 1 : -1;
		 return z;
	}
}
else static if(STBTT_RASTERIZER_VERSION == 2)
{
	static stbtt__active_edge *stbtt__new_active(stbtt__hheap *hh, stbtt__edge *e, int off_x, float start_point)
	{
		stbtt__active_edge *z = cast(stbtt__active_edge *) stbtt__hheap_alloc(hh, stbtt__active_edge.sizeof);
		float dxdy = (e.x1 - e.x0) / (e.y1 - e.y0);
		assert(z != null);
		//assert(e.y0 <= start_point);
		if (!z) return z;
		z.fdx = dxdy;
		z.fdy = dxdy != 0.0f ? (1.0f/dxdy) : 0.0f;
		z.fx = e.x0 + dxdy * (start_point - e.y0);
		z.fx -= off_x;
		z.direction = e.invert ? 1.0f : -1.0f;
		z.sy = e.y0;
		z.ey = e.y1;
		z.next = null;
		return z;
	}
}
else static assert(false, "Unrecognized value of STBTT_RASTERIZER_VERSION");


static if(STBTT_RASTERIZER_VERSION == 1)
{
	static void stbtt__fill_active_edges(ubyte *scanline, int len, stbtt__active_edge *e, int max_weight)
	{
		// non-zero winding fill
		int x0=0, w=0;

		while (e) {
			if (w == 0) {
				// if we're currently at zero, we need to record the edge start point
				x0 = e.x; w += e.direction;
			} else {
				int x1 = e.x; w += e.direction;
				// if we went to zero, we need to draw
				if (w == 0) {
					int i = x0 >> STBTT_FIXSHIFT;
					int j = x1 >> STBTT_FIXSHIFT;

					if (i < len && j >= 0) {
						if (i == j) {
							// x0,x1 are the same pixel, so compute combined coverage
							scanline[i] = scanline[i] + cast(ubyte) ((x1 - x0) * max_weight >> STBTT_FIXSHIFT);
						} else {
							if (i >= 0) // add antialiasing for x0
								scanline[i] = scanline[i] + cast(ubyte) (((STBTT_FIX - (x0 & STBTT_FIXMASK)) * max_weight) >> STBTT_FIXSHIFT);
							else
								i = -1; // clip

							if (j < len) // add antialiasing for x1
								scanline[j] = scanline[j] + cast(ubyte) (((x1 & STBTT_FIXMASK) * max_weight) >> STBTT_FIXSHIFT);
							else
								j = len; // clip

							for (++i; i < j; ++i) // fill pixels between x0 and x1
								scanline[i] = scanline[i] + cast(ubyte) max_weight;
						}
					}
				}
			}

			e = e.next;
		}
	}

	static void stbtt__rasterize_sorted_edges(stbtt__bitmap *result, stbtt__edge *e, int n, int vsubsample, int off_x, int off_y)
	{
		stbtt__hheap hh = { 0, 0, 0 };
		stbtt__active_edge *active = null;
		int y,j=0;
		int max_weight = (255 / vsubsample);  // weight per vertical scanline
		int s; // vertical subsample index
		ubyte[512] scanline_data;
	 	ubyte*     scanline;

		if (result.w > 512)
			scanline = cast(ubyte *)malloc(result.w);
		else
			scanline = scanline_data;

		y = off_y * vsubsample;
		e[n].y0 = (off_y + result.h) * cast(float) vsubsample + 1;

		while (j < result.h) {
			memset(scanline, 0, result.w);
			for (s=0; s < vsubsample; ++s) {
				// find center of pixel for this scanline
				float scan_y = y + 0.5f;
				stbtt__active_edge **step = &active;

				// update all active edges;
				// remove all active edges that terminate before the center of this scanline
				while (*step) {
					stbtt__active_edge * z = *step;
					if (z.ey <= scan_y) {
						*step = z.next; // delete from list
						assert(z.direction);
						z.direction = 0;
						stbtt__hheap_free(&hh, z);
					} else {
						z.x += z.dx; // advance to position for current scanline
						step = &((*step).next); // advance through list
					}
				}

				// resort the list if needed
				for(;;) {
					int changed=0;
					step = &active;
					while (*step && (*step).next) {
						if ((*step).x > (*step).next.x) {
							stbtt__active_edge *t = *step;
							stbtt__active_edge *q = t.next;

							t.next = q.next;
							q.next = t;
							*step = q;
							changed = 1;
						}
						step = &(*step).next;
					}
					if (!changed) break;
				}

				// insert all edges that start before the center of this scanline -- omit ones that also end on this scanline
				while (e.y0 <= scan_y) {
					if (e.y1 > scan_y) {
						stbtt__active_edge *z = stbtt__new_active(&hh, e, off_x, scan_y);
						if (z != null) {
							// find insertion point
							if (active == null)
								active = z;
							else if (z.x < active.x) {
								// insert at front
								z.next = active;
								active = z;
							} else {
								// find thing to insert AFTER
								stbtt__active_edge *p = active;
								while (p.next && p.next.x < z.x)
									p = p.next;
								// at this point, p.next.x is NOT < z.x
								z.next = p.next;
								p.next = z;
							}
						}
					}
					++e;
				}

				// now process all active edges in XOR fashion
				if (active)
					stbtt__fill_active_edges(scanline, result.w, active, max_weight);

				++y;
			}
			memcpy(result.pixels + j * result.stride, scanline, result.w);
			++j;
		}

		stbtt__hheap_cleanup(&hh);

		if (scanline != scanline_data)
			free(scanline);
	}
}
else static if(STBTT_RASTERIZER_VERSION == 2)
{
	static void stbtt__handle_clipped_edge(float *scanline, int x, stbtt__active_edge *e, float x0, float y0, float x1, float y1)
	{
		if (y0 == y1) return;
		assert(y0 < y1);
		assert(e.sy <= e.ey);
		if (y0 > e.ey) return;
		if (y1 < e.sy) return;
		if (y0 < e.sy) {
			x0 += (x1-x0) * (e.sy - y0) / (y1-y0);
			y0 = e.sy;
		}
		if (y1 > e.ey) {
			x1 += (x1-x0) * (e.ey - y1) / (y1-y0);
			y1 = e.ey;
		}

		if (x0 == x)
			assert(x1 <= x+1);
		else if (x0 == x+1)
			assert(x1 >= x);
		else if (x0 <= x)
			assert(x1 <= x);
		else if (x0 >= x+1)
			assert(x1 >= x+1);
		else
			assert(x1 >= x && x1 <= x+1);

		if (x0 <= x && x1 <= x)
			scanline[x] += e.direction * (y1-y0);
		else if (x0 >= x+1 && x1 >= x+1) 
		{

		}
		else {
			assert(x0 >= x && x0 <= x+1 && x1 >= x && x1 <= x+1);
			scanline[x] += e.direction * (y1-y0) * (1-((x0-x)+(x1-x))/2); // coverage = 1 - average x position
		}
	}

	static float stbtt__sized_trapezoid_area(float height, float top_width, float bottom_width)
	{
		assert(top_width >= 0);
		assert(bottom_width >= 0);
		return (top_width + bottom_width) / 2.0f * height;
	}

	static float stbtt__position_trapezoid_area(float height, float tx0, float tx1, float bx0, float bx1)
	{
		return stbtt__sized_trapezoid_area(height, tx1 - tx0, bx1 - bx0);
	}

	static float stbtt__sized_triangle_area(float height, float width)
	{
		return height * width / 2;
	}

	static void stbtt__fill_active_edges_new(float *scanline, float *scanline_fill, int len, stbtt__active_edge *e, float y_top)
	{
		float y_bottom = y_top+1;

		while (e) {
			// brute force every pixel

			// compute intersection points with top & bottom
			assert(e.ey >= y_top);

			if (e.fdx == 0) {
				float x0 = e.fx;
				if (x0 < len) {
					if (x0 >= 0) {
						stbtt__handle_clipped_edge(scanline,cast(int) x0,e, x0,y_top, x0,y_bottom);
						stbtt__handle_clipped_edge(scanline_fill-1,cast(int) x0+1,e, x0,y_top, x0,y_bottom);
					} else {
						stbtt__handle_clipped_edge(scanline_fill-1,0,e, x0,y_top, x0,y_bottom);
					}
				}
			} else {
				float x0 = e.fx;
				float dx = e.fdx;
				float xb = x0 + dx;
				float x_top, x_bottom;
				float sy0,sy1;
				float dy = e.fdy;
				assert(e.sy <= y_bottom && e.ey >= y_top);

				// compute endpoints of line segment clipped to this scanline (if the
				// line segment starts on this scanline. x0 is the intersection of the
				// line with y_top, but that may be off the line segment.
				if (e.sy > y_top) {
					x_top = x0 + dx * (e.sy - y_top);
					sy0 = e.sy;
				} else {
					x_top = x0;
					sy0 = y_top;
				}
				if (e.ey < y_bottom) {
					x_bottom = x0 + dx * (e.ey - y_top);
					sy1 = e.ey;
				} else {
					x_bottom = xb;
					sy1 = y_bottom;
				}

				if (x_top >= 0 && x_bottom >= 0 && x_top < len && x_bottom < len) {
					// from here on, we don't have to range check x values

					if (cast(int) x_top == cast(int) x_bottom) {
						float height = 0.0;
						// simple case, only spans one pixel
						int x = cast(int) x_top;
						height = (sy1 - sy0) * e.direction;
						assert(x >= 0 && x < len);
						scanline[x]      += stbtt__position_trapezoid_area(height, x_top, x+1.0f, x_bottom, x+1.0f);
						scanline_fill[x] += height; // everything right of this pixel is filled
					} else {
						int x,x1,x2;
						float y_crossing = 0.0, y_final = 0.0, step = 0.0, sign = 0.0, area = 0.0;
						// covers 2+ pixels
						if (x_top > x_bottom) {
							// flip scanline vertically; signed area is the same
							float t = 0.0;
							sy0 = y_bottom - (sy0 - y_top);
							sy1 = y_bottom - (sy1 - y_top);
							t = sy0, sy0 = sy1, sy1 = t;
							t = x_bottom, x_bottom = x_top, x_top = t;
							dx = -dx;
							dy = -dy;
							t = x0, x0 = xb, xb = t;
						}
						assert(dy >= 0);
						assert(dx >= 0);

						x1 = cast(int) x_top;
						x2 = cast(int) x_bottom;
						// compute intersection with y axis at x1+1
						y_crossing = y_top + dy * (x1+1 - x0);

						// compute intersection with y axis at x2
						y_final = y_top + dy * (x2 - x0);

						//           x1    x_top                            x2    x_bottom
						//     y_top  +------|-----+------------+------------+--------|---+------------+
						//            |            |            |            |            |            |
						//            |            |            |            |            |            |
						//       sy0  |      Txxxxx|............|............|............|............|
						// y_crossing |            *xxxxx.......|............|............|............|
						//            |            |     xxxxx..|............|............|............|
						//            |            |     /-   xx*xxxx........|............|............|
						//            |            | dy <       |    xxxxxx..|............|............|
						//   y_final  |            |     \-     |          xx*xxx.........|............|
						//       sy1  |            |            |            |   xxxxxB...|............|
						//            |            |            |            |            |            |
						//            |            |            |            |            |            |
						//  y_bottom  +------------+------------+------------+------------+------------+
						//
						// goal is to measure the area covered by '.' in each pixel

						// if x2 is right at the right edge of x1, y_crossing can blow up, github #1057
						// @TODO: maybe test against sy1 rather than y_bottom?
						if (y_crossing > y_bottom)
							y_crossing = y_bottom;

						sign = e.direction;

						// area of the rectangle covered from sy0..y_crossing
						area = sign * (y_crossing-sy0);

						// area of the triangle (x_top,sy0), (x1+1,sy0), (x1+1,y_crossing)
						scanline[x1] += stbtt__sized_triangle_area(area, x1+1 - x_top);

						// check if final y_crossing is blown up; no test case for this
						if (y_final > y_bottom) {
							y_final = y_bottom;
							dy = (y_final - y_crossing ) / (x2 - (x1+1)); // if denom=0, y_final = y_crossing, so y_final <= y_bottom
						}

						// in second pixel, area covered by line segment found in first pixel
						// is always a rectangle 1 wide * the height of that line segment; this
						// is exactly what the variable 'area' stores. it also gets a contribution
						// from the line segment within it. the THIRD pixel will get the first
						// pixel's rectangle contribution, the second pixel's rectangle contribution,
						// and its own contribution. the 'own contribution' is the same in every pixel except
						// the leftmost and rightmost, a trapezoid that slides down in each pixel.
						// the second pixel's contribution to the third pixel will be the
						// rectangle 1 wide times the height change in the second pixel, which is dy.

						step = sign * dy * 1; // dy is dy/dx, change in y for every 1 change in x,
																	// which multiplied by 1-pixel-width is how much pixel area changes for each step in x
																	// so the area advances by 'step' every time

						for (x = x1+1; x < x2; ++x) {
							scanline[x] += area + step/2; // area of trapezoid is 1*step/2
							area += step;
						}
						assert(fabs(area) <= 1.01f); // accumulated error from area += step unless we round step down
						assert(sy1 > y_final-0.01f);

						// area covered in the last pixel is the rectangle from all the pixels to the left,
						// plus the trapezoid filled by the line segment in this pixel all the way to the right edge
						scanline[x2] += area + sign * stbtt__position_trapezoid_area(sy1-y_final, cast(float) x2, x2+1.0f, x_bottom, x2+1.0f);

						// the rest of the line is filled based on the total height of the line segment in this pixel
						scanline_fill[x2] += sign * (sy1-sy0);
					}
				} else {
					// if edge goes outside of box we're drawing, we require
					// clipping logic. since this does not match the intended use
					// of this library, we use a different, very slow brute
					// force implementation
					// note though that this does happen some of the time because
					// x_top and x_bottom can be extrapolated at the top & bottom of
					// the shape and actually lie outside the bounding box
					int x;
					for (x=0; x < len; ++x) {
						// cases:
						//
						// there can be up to two intersections with the pixel. any intersection
						// with left or right edges can be handled by splitting into two (or three)
						// regions. intersections with top & bottom do not necessitate case-wise logic.
						//
						// the old way of doing this found the intersections with the left & right edges,
						// then used some simple logic to produce up to three segments in sorted order
						// from top-to-bottom. however, this had a problem: if an x edge was epsilon
						// across the x border, then the corresponding y position might not be distinct
						// from the other y segment, and it might ignored as an empty segment. to avoid
						// that, we need to explicitly produce segments based on x positions.

						// rename variables to clearly-defined pairs
						float y0 = y_top;
						float x1 = cast(float) (x);
						float x2 = cast(float) (x+1);
						float x3 = xb;
						float y3 = y_bottom;

						// x = e.x + e.dx * (y-y_top)
						// (y-y_top) = (x - e.x) / e.dx
						// y = (x - e.x) / e.dx + y_top
						float y1 = (x - x0) / dx + y_top;
						float y2 = (x+1 - x0) / dx + y_top;

						if (x0 < x1 && x3 > x2) {         // three segments descending down-right
							stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x1,y1);
							stbtt__handle_clipped_edge(scanline,x,e, x1,y1, x2,y2);
							stbtt__handle_clipped_edge(scanline,x,e, x2,y2, x3,y3);
						} else if (x3 < x1 && x0 > x2) {  // three segments descending down-left
							stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x2,y2);
							stbtt__handle_clipped_edge(scanline,x,e, x2,y2, x1,y1);
							stbtt__handle_clipped_edge(scanline,x,e, x1,y1, x3,y3);
						} else if (x0 < x1 && x3 > x1) {  // two segments across x, down-right
							stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x1,y1);
							stbtt__handle_clipped_edge(scanline,x,e, x1,y1, x3,y3);
						} else if (x3 < x1 && x0 > x1) {  // two segments across x, down-left
							stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x1,y1);
							stbtt__handle_clipped_edge(scanline,x,e, x1,y1, x3,y3);
						} else if (x0 < x2 && x3 > x2) {  // two segments across x+1, down-right
							stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x2,y2);
							stbtt__handle_clipped_edge(scanline,x,e, x2,y2, x3,y3);
						} else if (x3 < x2 && x0 > x2) {  // two segments across x+1, down-left
							stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x2,y2);
							stbtt__handle_clipped_edge(scanline,x,e, x2,y2, x3,y3);
						} else {  // one segment
							stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x3,y3);
						}
					}
				}
			}
			e = e.next;
		}
	}

	// directly AA rasterize edges w/o supersampling
	static void stbtt__rasterize_sorted_edges(stbtt__bitmap *result, stbtt__edge *e, int n, int vsubsample, int off_x, int off_y)
	{
		stbtt__hheap hh;
		stbtt__active_edge *active = null;
		int y,j=0, i;
		float[129] scanline_data = 0.0;
	 	float* scanline, scanline2;

		// STBTT__NOTUSED(vsubsample);

		if (result.w > 64)
			scanline = cast(float *)malloc((result.w*2+1) * float.sizeof);
		else
			scanline = scanline_data.ptr;

		scanline2 = scanline + result.w;

		y = off_y;
		e[n].y0 = cast(float) (off_y + result.h) + 1;

		while (j < result.h) {
			// find center of pixel for this scanline
			float scan_y_top    = y + 0.0f;
			float scan_y_bottom = y + 1.0f;
			stbtt__active_edge **step = &active;

			memset(scanline , 0, result.w*float.sizeof);
			memset(scanline2, 0, (result.w+1)*float.sizeof);

			// update all active edges;
			// remove all active edges that terminate before the top of this scanline
			while (*step) {
				stbtt__active_edge * z = *step;
				if (z.ey <= scan_y_top) {
					*step = z.next; // delete from list
					assert(z.direction);
					z.direction = 0;
					stbtt__hheap_free(&hh, z);
				} else {
					step = &((*step).next); // advance through list
				}
			}

			// insert all edges that start before the bottom of this scanline
			while (e.y0 <= scan_y_bottom) {
				if (e.y0 != e.y1) {
					stbtt__active_edge *z = stbtt__new_active(&hh, e, off_x, scan_y_top);
					if (z != null) {
						if (j == 0 && off_y != 0) {
							if (z.ey < scan_y_top) {
								// this can happen due to subpixel positioning and some kind of fp rounding error i think
								z.ey = scan_y_top;
							}
						}
						assert(z.ey >= scan_y_top); // if we get really unlucky a tiny bit of an edge can be out of bounds
																				// insert at front
						z.next = active;
						active = z;
					}
				}
				++e;
			}

			// now process all active edges
			if (active)
				stbtt__fill_active_edges_new(scanline, scanline2+1, result.w, active, scan_y_top);

			{
				float sum = 0;
				for (i=0; i < result.w; ++i) {
					float k;
					int m;
					sum += scanline2[i];
					k = scanline[i] + sum;
					k = cast(float) fabs(k)*255 + 0.5f;
					m = cast(int) k;
					if (m > 255) m = 255;
					result.pixels[j*result.stride + i] = cast(ubyte) m;
				}
			}
			// advance all the edges
			step = &active;
			while (*step) {
				stbtt__active_edge *z = *step;
				z.fx += z.fdx; // advance to position for current scanline
				step = &((*step).next); // advance through list
			}

			++y;
			++j;
		}

		stbtt__hheap_cleanup(&hh);

		if (scanline != scanline_data.ptr)
			free(scanline);
	}
}
else static assert(false, "Unrecognized value of STBTT_RASTERIZER_VERSION");

bool STBTT__COMPARE(stbtt__edge* a, stbtt__edge* b) => a.y0 < b.y0;

static void stbtt__sort_edges_ins_sort(stbtt__edge *p, int n)
{
   int i,j;
   for (i=1; i < n; ++i) 
	 {
      stbtt__edge  t = p[i];
			stbtt__edge* a = &t;
      j = i;
      while (j > 0) 
			{
         stbtt__edge *b = &p[j-1];
         int c = STBTT__COMPARE(a,b);
         if (!c) break;
         p[j] = p[j-1];
         --j;
      }
      if (i != j)
         p[j] = t;
   }
}

static void stbtt__sort_edges_quicksort(stbtt__edge *p, int n)
{
   /* threshold for transitioning to insertion sort */
   while (n > 12) {
      stbtt__edge t = {x0: 0.0, y0: 0.0, x1: 0.0, y1: 0.0};
      int c01,c12,c,m,i,j;

      /* compute median of three */
      m = n >> 1;
      c01 = STBTT__COMPARE(&p[0], &p[m]);
      c12 = STBTT__COMPARE(&p[m], &p[n-1]);
      /* if 0 >= mid >= end, or 0 < mid < end, then use mid */
      if (c01 != c12) {
         /* otherwise, we'll need to swap something else to middle */
         int z;
         c = STBTT__COMPARE(&p[0],&p[n-1]);
         /* 0>mid && mid<n:  0>n => n; 0<n => 0 */
         /* 0<mid && mid>n:  0>n => 0; 0<n => n */
         z = (c == c12) ? 0 : n-1;
         t = p[z];
         p[z] = p[m];
         p[m] = t;
      }
      /* now p[m] is the median-of-three */
      /* swap it to the beginning so it won't move around */
      t = p[0];
      p[0] = p[m];
      p[m] = t;

      /* partition loop */
      i=1;
      j=n-1;
      for(;;) {
         /* handling of equality is crucial here */
         /* for sentinels & efficiency with duplicates */
         for (;;++i) {
            if (!STBTT__COMPARE(&p[i], &p[0])) break;
         }
         for (;;--j) {
            if (!STBTT__COMPARE(&p[0], &p[j])) break;
         }
         /* make sure we haven't crossed */
         if (i >= j) break;
         t = p[i];
         p[i] = p[j];
         p[j] = t;

         ++i;
         --j;
      }
      /* recurse on smaller side, iterate on larger */
      if (j < (n-i)) {
         stbtt__sort_edges_quicksort(p,j);
         p = p+i;
         n = n-i;
      } else {
         stbtt__sort_edges_quicksort(p+i, n-i);
         n = j;
      }
   }
}

static void stbtt__sort_edges(stbtt__edge *p, int n)
{
   stbtt__sort_edges_quicksort(p, n);
   stbtt__sort_edges_ins_sort(p, n);
}

struct stbtt__point
{
   float x = 0.0, y = 0.0;
};

static void stbtt__rasterize(stbtt__bitmap *result, stbtt__point *pts, int *wcount, int windings, float scale_x, float scale_y, float shift_x, float shift_y, int off_x, int off_y, int invert)
{
   float y_scale_inv = invert ? -scale_y : scale_y;
   stbtt__edge *e;
   int n,i,j,k,m;
	 static if(STBTT_RASTERIZER_VERSION == 1)
	 {
		 int vsubsample = result.h < 8 ? 15 : 5;
	 }
	 else static if(STBTT_RASTERIZER_VERSION == 2)
	 {
		 int vsubsample = 1;
	 }
	 else static assert(false, "Unrecognized value of STBTT_RASTERIZER_VERSION");

   // vsubsample should divide 255 evenly; otherwise we won't reach full opacity

   // now we have to blow out the windings into explicit edge lists
   n = 0;
   for (i=0; i < windings; ++i)
      n += wcount[i];

   e = cast(stbtt__edge *)malloc(stbtt__edge.sizeof * (n+1)); // add an extra one as a sentinel
   if (e == null) return;
   n = 0;

   m=0;
   for (i=0; i < windings; ++i) {
      stbtt__point *p = pts + m;
      m += wcount[i];
      j = wcount[i]-1;
      for (k=0; k < wcount[i]; j=k++) {
         int a=k,b=j;
         // skip the edge if horizontal
         if (p[j].y == p[k].y)
            continue;
         // add edge from j to k to the list
         e[n].invert = 0;
         if (invert ? p[j].y > p[k].y : p[j].y < p[k].y) {
            e[n].invert = 1;
            a=j,b=k;
         }
         e[n].x0 = p[a].x * scale_x + shift_x;
         e[n].y0 = (p[a].y * y_scale_inv + shift_y) * vsubsample;
         e[n].x1 = p[b].x * scale_x + shift_x;
         e[n].y1 = (p[b].y * y_scale_inv + shift_y) * vsubsample;
         ++n;
      }
   }

   // now sort the edges by their highest point (should snap to integer, and then by x)
   //STBTT_sort(e, n, sizeof(e[0]), stbtt__edge_compare);
   stbtt__sort_edges(e, n);

   // now, traverse the scanlines and find the intersections on each scanline, use xor winding rule
   stbtt__rasterize_sorted_edges(result, e, n, vsubsample, off_x, off_y);

   free(e);
}

static void stbtt__add_point(stbtt__point *points, int n, float x, float y)
{
   if (!points) return; // during first pass, it's unallocated
   points[n].x = x;
   points[n].y = y;
}

// tessellate until threshold p is happy... @TODO warped to compensate for non-linear stretching
static int stbtt__tesselate_curve(stbtt__point *points, int *num_points, float x0, float y0, float x1, float y1, float x2, float y2, float objspace_flatness_squared, int n)
{
   // midpoint
   float mx = (x0 + 2*x1 + x2)/4;
   float my = (y0 + 2*y1 + y2)/4;
   // versus directly drawn line
   float dx = (x0+x2)/2 - mx;
   float dy = (y0+y2)/2 - my;
   if (n > 16) // 65536 segments on one curve better be enough!
      return 1;
   if (dx*dx+dy*dy > objspace_flatness_squared) { // half-pixel error allowed... need to be smaller if AA
      stbtt__tesselate_curve(points, num_points, x0,y0, (x0+x1)/2.0f,(y0+y1)/2.0f, mx,my, objspace_flatness_squared,n+1);
      stbtt__tesselate_curve(points, num_points, mx,my, (x1+x2)/2.0f,(y1+y2)/2.0f, x2,y2, objspace_flatness_squared,n+1);
   } else {
      stbtt__add_point(points, *num_points,x2,y2);
      *num_points = *num_points+1;
   }
   return 1;
}

static void stbtt__tesselate_cubic(stbtt__point *points, int *num_points, float x0, float y0, float x1, float y1, float x2, float y2, float x3, float y3, float objspace_flatness_squared, int n)
{
   // @TODO this "flatness" calculation is just made-up nonsense that seems to work well enough
   float dx0 = x1-x0;
   float dy0 = y1-y0;
   float dx1 = x2-x1;
   float dy1 = y2-y1;
   float dx2 = x3-x2;
   float dy2 = y3-y2;
   float dx = x3-x0;
   float dy = y3-y0;
   float longlen = cast(float) (sqrt(dx0*dx0+dy0*dy0)+sqrt(dx1*dx1+dy1*dy1)+sqrt(dx2*dx2+dy2*dy2));
   float shortlen = cast(float) sqrt(dx*dx+dy*dy);
   float flatness_squared = longlen*longlen-shortlen*shortlen;

   if (n > 16) // 65536 segments on one curve better be enough!
      return;

   if (flatness_squared > objspace_flatness_squared) {
      float x01 = (x0+x1)/2;
      float y01 = (y0+y1)/2;
      float x12 = (x1+x2)/2;
      float y12 = (y1+y2)/2;
      float x23 = (x2+x3)/2;
      float y23 = (y2+y3)/2;

      float xa = (x01+x12)/2;
      float ya = (y01+y12)/2;
      float xb = (x12+x23)/2;
      float yb = (y12+y23)/2;

      float mx = (xa+xb)/2;
      float my = (ya+yb)/2;

      stbtt__tesselate_cubic(points, num_points, x0,y0, x01,y01, xa,ya, mx,my, objspace_flatness_squared,n+1);
      stbtt__tesselate_cubic(points, num_points, mx,my, xb,yb, x23,y23, x3,y3, objspace_flatness_squared,n+1);
   } else {
      stbtt__add_point(points, *num_points,x3,y3);
      *num_points = *num_points+1;
   }
}

//////////////////////////////////////////////////////////////////////////////
//
// bitmap baking
//
// This is SUPER-CRAPPY packing to keep source code small

static int stbtt_BakeFontBitmap_internal(ubyte *data, int offset,  // font location (use offset=0 for plain .ttf)
                                float pixel_height,                     // height of font in pixels
                                ubyte *pixels, int pw, int ph,  // bitmap to be filled in
                                int first_char, int num_chars,          // characters to bake
                                stbtt_bakedchar *chardata)
{
   float scale;
   int x,y,bottom_y, i;
   stbtt_fontinfo f;
   if (!stbtt_InitFont(&f, data, offset))
      return -1;
   memset(pixels, 0, pw*ph); // background of 0 around pixels
   x=y=1;
   bottom_y = 1;

   scale = stbtt_ScaleForPixelHeight(&f, pixel_height);

   for (i=0; i < num_chars; ++i) {
      int advance, lsb, x0,y0,x1,y1,gw,gh;
      int g = stbtt_FindGlyphIndex(&f, first_char + i);
      stbtt_GetGlyphHMetrics(&f, g, &advance, &lsb);
      stbtt_GetGlyphBitmapBox(&f, g, scale,scale, &x0,&y0,&x1,&y1);
      gw = x1-x0;
      gh = y1-y0;
      if (x + gw + 1 >= pw)
         y = bottom_y, x = 1; // advance to next row
      if (y + gh + 1 >= ph) // check if it fits vertically AFTER potentially moving to next row
         return -i;
      assert(x+gw < pw);
      assert(y+gh < ph);
      stbtt_MakeGlyphBitmap(&f, pixels+x+y*pw, gw,gh,pw, scale,scale, g);
      chardata[i].x0 = cast(short) x;
      chardata[i].y0 = cast(short) y;
      chardata[i].x1 = cast(short) (x + gw);
      chardata[i].y1 = cast(short) (y + gh);
      chardata[i].xadvance = scale * advance;
      chardata[i].xoff     = cast(float) x0;
      chardata[i].yoff     = cast(float) y0;
      x = x + gw + 1;
      if (y+gh+1 > bottom_y)
         bottom_y = y+gh+1;
   }
   return bottom_y;
}

//////////////////////////////////////////////////////////////////////////////
//
// rectangle packing replacement routines if you don't have stb_rect_pack.h
//


alias stbrp_coord = int;

////////////////////////////////////////////////////////////////////////////////////
//                                                                                //
//                                                                                //
// COMPILER WARNING ?!?!?                                                         //
//                                                                                //
//                                                                                //
// if you get a compile warning due to these symbols being defined more than      //
// once, move #include "stb_rect_pack.h" before #include "stb_truetype.h"         //
//                                                                                //
////////////////////////////////////////////////////////////////////////////////////

struct stbrp_context
{
   int width,height;
   int x,y,bottom_y;
};

struct stbrp_node
{
   ubyte x;
};

struct stbrp_rect
{
   stbrp_coord x,y;
   int id,w,h,was_packed;
};

static void stbrp_init_target(stbrp_context *con, int pw, int ph, stbrp_node *nodes, int num_nodes)
{
   con.width  = pw;
   con.height = ph;
   con.x = 0;
   con.y = 0;
   con.bottom_y = 0;
   // STBTT__NOTUSED(nodes);
   // STBTT__NOTUSED(num_nodes);
}

static void stbrp_pack_rects(stbrp_context *con, stbrp_rect *rects, int num_rects)
{
   int i;
   for (i=0; i < num_rects; ++i) {
      if (con.x + rects[i].w > con.width) {
         con.x = 0;
         con.y = con.bottom_y;
      }
      if (con.y + rects[i].h > con.height)
         break;
      rects[i].x = con.x;
      rects[i].y = con.y;
      rects[i].was_packed = 1;
      con.x += rects[i].w;
      if (con.y + rects[i].h > con.bottom_y)
         con.bottom_y = con.y + rects[i].h;
   }
   for (   ; i < num_rects; ++i)
      rects[i].was_packed = 0;
}

//////////////////////////////////////////////////////////////////////////////
//
// bitmap baking
//
// This is SUPER-AWESOME (tm Ryan Gordon) packing using stb_rect_pack.h. If
// stb_rect_pack.h isn't available, it uses the BakeFontBitmap strategy.
enum STBTT__OVER_MASK = (STBTT_MAX_OVERSAMPLE-1);

static void stbtt__h_prefilter(ubyte *pixels, int w, int h, int stride_in_bytes, uint kernel_width)
{
   ubyte[STBTT_MAX_OVERSAMPLE] buffer;
   int safe_w = w - kernel_width;
   int j;
   memset(buffer.ptr, 0, STBTT_MAX_OVERSAMPLE); // suppress bogus warning from VS2013 -analyze
   for (j=0; j < h; ++j) {
      int i;
      uint total;
      memset(buffer.ptr, 0, kernel_width);

      total = 0;

      // make kernel_width a constant in common cases so compiler can optimize out the divide
      switch (kernel_width) {
         case 2:
            for (i=0; i <= safe_w; ++i) {
               total += pixels[i] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
               pixels[i] = cast(ubyte) (total / 2);
            }
            break;
         case 3:
            for (i=0; i <= safe_w; ++i) {
               total += pixels[i] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
               pixels[i] = cast(ubyte) (total / 3);
            }
            break;
         case 4:
            for (i=0; i <= safe_w; ++i) {
               total += pixels[i] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
               pixels[i] = cast(ubyte) (total / 4);
            }
            break;
         case 5:
            for (i=0; i <= safe_w; ++i) {
               total += pixels[i] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
               pixels[i] = cast(ubyte) (total / 5);
            }
            break;
         default:
            for (i=0; i <= safe_w; ++i) {
               total += pixels[i] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
               pixels[i] = cast(ubyte) (total / kernel_width);
            }
            break;
      }

      for (; i < w; ++i) {
         assert(pixels[i] == 0);
         total -= buffer[i & STBTT__OVER_MASK];
         pixels[i] = cast(ubyte) (total / kernel_width);
      }

      pixels += stride_in_bytes;
   }
}

static void stbtt__v_prefilter(ubyte *pixels, int w, int h, int stride_in_bytes, uint kernel_width)
{
   ubyte[STBTT_MAX_OVERSAMPLE] buffer;
   int safe_h = h - kernel_width;
   int j;
   memset(buffer.ptr, 0, STBTT_MAX_OVERSAMPLE); // suppress bogus warning from VS2013 -analyze
   for (j=0; j < w; ++j) {
      int i;
      uint total;
      memset(buffer.ptr, 0, kernel_width);

      total = 0;

      // make kernel_width a constant in common cases so compiler can optimize out the divide
      switch (kernel_width) {
         case 2:
            for (i=0; i <= safe_h; ++i) {
               total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
               pixels[i*stride_in_bytes] = cast(ubyte) (total / 2);
            }
            break;
         case 3:
            for (i=0; i <= safe_h; ++i) {
               total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
               pixels[i*stride_in_bytes] = cast(ubyte) (total / 3);
            }
            break;
         case 4:
            for (i=0; i <= safe_h; ++i) {
               total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
               pixels[i*stride_in_bytes] = cast(ubyte) (total / 4);
            }
            break;
         case 5:
            for (i=0; i <= safe_h; ++i) {
               total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
               pixels[i*stride_in_bytes] = cast(ubyte) (total / 5);
            }
            break;
         default:
            for (i=0; i <= safe_h; ++i) {
               total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
               buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
               pixels[i*stride_in_bytes] = cast(ubyte) (total / kernel_width);
            }
            break;
      }

      for (; i < h; ++i) {
         assert(pixels[i*stride_in_bytes] == 0);
         total -= buffer[i & STBTT__OVER_MASK];
         pixels[i*stride_in_bytes] = cast(ubyte) (total / kernel_width);
      }

      pixels += 1;
   }
}

float stbtt__oversample_shift(int oversample)
{
   if (!oversample)
      return 0.0f;

   // The prefilter is a box filter of width "oversample",
   // which shifts phase by (oversample - 1)/2 pixels in
   // oversampled space. We want to shift in the opposite
   // direction to counter this.
   return cast(float)-(oversample - 1) / (2.0f * cast(float)oversample);
}

//////////////////////////////////////////////////////////////////////////////
//
// sdf computation
//

T STBTT_min(T)(T a, T b) => a < b ? a : b;
T STBTT_max(T)(T a, T b) => a < b ? b : a;

int stbtt__ray_intersect_bezier(float[2] orig, float[2] ray, float[2] q0, float[2] q1, float[2] q2, float[2][2] hits)
{
   float q0perp = q0[1]*ray[0] - q0[0]*ray[1];
   float q1perp = q1[1]*ray[0] - q1[0]*ray[1];
   float q2perp = q2[1]*ray[0] - q2[0]*ray[1];
   float roperp = orig[1]*ray[0] - orig[0]*ray[1];

   float a = q0perp - 2*q1perp + q2perp;
   float b = q1perp - q0perp;
   float c = q0perp - roperp;

   float s0 = 0., s1 = 0.;
   int num_s = 0;

   if (a != 0.0) {
      float discr = b*b - a*c;
      if (discr > 0.0) {
         float rcpna = -1 / a;
         float d = cast(float) sqrt(discr);
         s0 = (b+d) * rcpna;
         s1 = (b-d) * rcpna;
         if (s0 >= 0.0 && s0 <= 1.0)
            num_s = 1;
         if (d > 0.0 && s1 >= 0.0 && s1 <= 1.0) {
            if (num_s == 0) s0 = s1;
            ++num_s;
         }
      }
   } else {
      // 2*b*s + c = 0
      // s = -c / (2*b)
      s0 = c / (-2 * b);
      if (s0 >= 0.0 && s0 <= 1.0)
         num_s = 1;
   }

   if (num_s == 0)
      return 0;
   else {
      float rcp_len2 = 1 / (ray[0]*ray[0] + ray[1]*ray[1]);
      float rayn_x = ray[0] * rcp_len2, rayn_y = ray[1] * rcp_len2;

      float q0d =   q0[0]*rayn_x +   q0[1]*rayn_y;
      float q1d =   q1[0]*rayn_x +   q1[1]*rayn_y;
      float q2d =   q2[0]*rayn_x +   q2[1]*rayn_y;
      float rod = orig[0]*rayn_x + orig[1]*rayn_y;

      float q10d = q1d - q0d;
      float q20d = q2d - q0d;
      float q0rd = q0d - rod;

      hits[0][0] = q0rd + s0*(2.0f - 2.0f*s0)*q10d + s0*s0*q20d;
      hits[0][1] = a*s0+b;

      if (num_s > 1) {
         hits[1][0] = q0rd + s1*(2.0f - 2.0f*s1)*q10d + s1*s1*q20d;
         hits[1][1] = a*s1+b;
         return 2;
      } else {
         return 1;
      }
   }
}

static int equal(float[2] a, float[2] b)
{
   return (a[0] == b[0] && a[1] == b[1]);
}

static int stbtt__compute_crossings_x(float x, float y, int nverts, stbtt_vertex *verts)
{
   int   i;
   float[2] orig = 0.0;
	 float[2] ray  = [ 1, 0 ];
   float y_frac  = 0.0;
   int   winding = 0;

   // make sure y never passes through a vertex of the shape
   y_frac = y % 1.0f;
   if (y_frac < 0.01f)
      y += 0.01f;
   else if (y_frac > 0.99f)
      y -= 0.01f;

   orig[0] = x;
   orig[1] = y;

   // test a ray from (-infinity,y) to (x,y)
   for (i=0; i < nverts; ++i) {
      if (verts[i].type == stbtt_curvetype.vline) {
         int x0 = cast(int) verts[i-1].x, y0 = cast(int) verts[i-1].y;
         int x1 = cast(int) verts[i  ].x, y1 = cast(int) verts[i  ].y;
         if (y > STBTT_min(y0,y1) && y < STBTT_max(y0,y1) && x > STBTT_min(x0,x1)) {
            float x_inter = (y - y0) / (y1 - y0) * (x1-x0) + x0;
            if (x_inter < x)
               winding += (y0 < y1) ? 1 : -1;
         }
      }
      if (verts[i].type == stbtt_curvetype.vcurve) {
         int x0 = cast(int) verts[i-1].x , y0 = cast(int) verts[i-1].y ;
         int x1 = cast(int) verts[i  ].cx, y1 = cast(int) verts[i  ].cy;
         int x2 = cast(int) verts[i  ].x , y2 = cast(int) verts[i  ].y ;
         int ax = STBTT_min(x0,STBTT_min(x1,x2)), ay = STBTT_min(y0,STBTT_min(y1,y2));
         int by = STBTT_max(y0,STBTT_max(y1,y2));
         if (y > ay && y < by && x > ax) {
            float[2]    q0 = 0.0, q1 = 0.0, q2 = 0.0;
            float[2][2] hits = 0;
            q0[0] = cast(float)x0;
            q0[1] = cast(float)y0;
            q1[0] = cast(float)x1;
            q1[1] = cast(float)y1;
            q2[0] = cast(float)x2;
            q2[1] = cast(float)y2;
            if (equal(q0,q1) || equal(q1,q2)) {
               x0 = cast(int)verts[i-1].x;
               y0 = cast(int)verts[i-1].y;
               x1 = cast(int)verts[i  ].x;
               y1 = cast(int)verts[i  ].y;
               if (y > STBTT_min(y0,y1) && y < STBTT_max(y0,y1) && x > STBTT_min(x0,x1)) {
                  float x_inter = (y - y0) / (y1 - y0) * (x1-x0) + x0;
                  if (x_inter < x)
                     winding += (y0 < y1) ? 1 : -1;
               }
            } else {
               int num_hits = stbtt__ray_intersect_bezier(orig, ray, q0, q1, q2, hits);
               if (num_hits >= 1)
                  if (hits[0][0] < 0)
                     winding += (hits[0][1] < 0 ? -1 : 1);
               if (num_hits >= 2)
                  if (hits[1][0] < 0)
                     winding += (hits[1][1] < 0 ? -1 : 1);
            }
         }
      }
   }
   return winding;
}

static float stbtt__cuberoot( float x )
{
   if (x<0)
      return -cast(float) pow(-x,1.0f/3.0f);
   else
      return  cast(float) pow( x,1.0f/3.0f);
}

// x^3 + a*x^2 + b*x + c = 0
static int stbtt__solve_cubic(float a, float b, float c, float* r)
{
   float s = -a / 3;
   float p = b - a*a / 3;
   float q = a * (2*a*a - 9*b) / 27 + c;
   float p3 = p*p*p;
   float d = q*q + 4*p3 / 27;
   if (d >= 0) {
      float z = cast(float) sqrt(d);
      float u = (-q + z) / 2;
      float v = (-q - z) / 2;
      u = stbtt__cuberoot(u);
      v = stbtt__cuberoot(v);
      r[0] = s + u + v;
      return 1;
   } else {
      float u = cast(float) sqrt(-p/3);
      float v = cast(float) acos(-sqrt(-27/p3) * q / 2) / 3; // p3 must be negative, since d is negative
      float m = cast(float) cos(v);
      float n = cast(float) cos(v-3.141592/2)*1.732050808f;
      r[0] = s + u * 2 * m;
      r[1] = s - u * (m + n);
      r[2] = s - u * (m - n);

      //assert( fabs(((r[0]+a)*r[0]+b)*r[0]+c) < 0.05f);  // these asserts may not be safe at all scales, though they're in bezier t parameter units so maybe?
      //assert( fabs(((r[1]+a)*r[1]+b)*r[1]+c) < 0.05f);
      //assert( fabs(((r[2]+a)*r[2]+b)*r[2]+c) < 0.05f);
      return 3;
   }
}

//////////////////////////////////////////////////////////////////////////////
//
// font name matching -- recommended not to use this
//

// check if a utf8 string contains a prefix which is the utf16 string; if so return length of matching utf8 string
static int stbtt__CompareUTF8toUTF16_bigendian_prefix(ubyte *s1, int len1, ubyte *s2, int len2)
{
   int i=0;

   // convert utf16 to utf8 and compare the results while converting
   while (len2) {
      ushort ch = s2[0]*256 + s2[1];
      if (ch < 0x80) {
         if (i >= len1) return -1;
         if (s1[i++] != ch) return -1;
      } else if (ch < 0x800) {
         if (i+1 >= len1) return -1;
         if (s1[i++] != 0xc0 + (ch >> 6)) return -1;
         if (s1[i++] != 0x80 + (ch & 0x3f)) return -1;
      } else if (ch >= 0xd800 && ch < 0xdc00) {
         uint c;
         ushort ch2 = s2[2]*256 + s2[3];
         if (i+3 >= len1) return -1;
         c = ((ch - 0xd800) << 10) + (ch2 - 0xdc00) + 0x10000;
         if (s1[i++] != 0xf0 + (c >> 18)) return -1;
         if (s1[i++] != 0x80 + ((c >> 12) & 0x3f)) return -1;
         if (s1[i++] != 0x80 + ((c >>  6) & 0x3f)) return -1;
         if (s1[i++] != 0x80 + ((c      ) & 0x3f)) return -1;
         s2 += 2; // plus another 2 below
         len2 -= 2;
      } else if (ch >= 0xdc00 && ch < 0xe000) {
         return -1;
      } else {
         if (i+2 >= len1) return -1;
         if (s1[i++] != 0xe0 + (ch >> 12)) return -1;
         if (s1[i++] != 0x80 + ((ch >> 6) & 0x3f)) return -1;
         if (s1[i++] != 0x80 + ((ch     ) & 0x3f)) return -1;
      }
      s2 += 2;
      len2 -= 2;
   }
   return i;
}

static int stbtt_CompareUTF8toUTF16_bigendian_internal(char *s1, int len1, char *s2, int len2)
{
   return len1 == stbtt__CompareUTF8toUTF16_bigendian_prefix(cast(ubyte*) s1, len1, cast(ubyte*) s2, len2);
}

static int stbtt__matchpair(ubyte *fc, uint nm, ubyte *name, int nlen, int target_id, int next_id)
{
   int i;
   int count = ttUSHORT(fc+nm+2);
   int stringOffset = nm + ttUSHORT(fc+nm+4);

   for (i=0; i < count; ++i) {
      uint loc = nm + 6 + 12 * i;
      int id = ttUSHORT(fc+loc+6);
      if (id == target_id) {
         // find the encoding
         int platform = ttUSHORT(fc+loc+0), encoding = ttUSHORT(fc+loc+2), language = ttUSHORT(fc+loc+4);

         // is this a Unicode encoding?
         if (platform == 0 || (platform == 3 && encoding == 1) || (platform == 3 && encoding == 10)) {
            int slen = ttUSHORT(fc+loc+8);
            int off = ttUSHORT(fc+loc+10);

            // check if there's a prefix match
            int matchlen = stbtt__CompareUTF8toUTF16_bigendian_prefix(name, nlen, fc+stringOffset+off,slen);
            if (matchlen >= 0) {
               // check for target_id+1 immediately following, with same encoding & language
               if (i+1 < count && ttUSHORT(fc+loc+12+6) == next_id && ttUSHORT(fc+loc+12) == platform && ttUSHORT(fc+loc+12+2) == encoding && ttUSHORT(fc+loc+12+4) == language) {
                  slen = ttUSHORT(fc+loc+12+8);
                  off = ttUSHORT(fc+loc+12+10);
                  if (slen == 0) {
                     if (matchlen == nlen)
                        return 1;
                  } else if (matchlen < nlen && name[matchlen] == ' ') {
                     ++matchlen;
                     if (stbtt_CompareUTF8toUTF16_bigendian_internal(cast(char*) (name+matchlen), nlen-matchlen, cast(char*)(fc+stringOffset+off),slen))
                        return 1;
                  }
               } else {
                  // if nothing immediately following
                  if (matchlen == nlen)
                     return 1;
               }
            }
         }

         // @TODO handle other encodings
      }
   }
   return 0;
}

static int stbtt__matches(ubyte *fc, uint offset, ubyte *name, int flags)
{
   int nlen = cast(int)strlen(cast(char *)name);
   uint nm,hd;
   if (!stbtt__isfont(fc+offset)) return 0;

   // check italics/bold/underline flags in macStyle...
   if (flags) {
      hd = stbtt__find_table(fc, offset, "head");
      if ((ttUSHORT(fc+hd+44) & 7) != (flags & 7)) return 0;
   }

   nm = stbtt__find_table(fc, offset, "name");
   if (!nm) return 0;

   if (flags) {
      // if we checked the macStyle flags, then just check the family and ignore the subfamily
      if (stbtt__matchpair(fc, nm, name, nlen, 16, -1))  return 1;
      if (stbtt__matchpair(fc, nm, name, nlen,  1, -1))  return 1;
      if (stbtt__matchpair(fc, nm, name, nlen,  3, -1))  return 1;
   } else {
      if (stbtt__matchpair(fc, nm, name, nlen, 16, 17))  return 1;
      if (stbtt__matchpair(fc, nm, name, nlen,  1,  2))  return 1;
      if (stbtt__matchpair(fc, nm, name, nlen,  3, -1))  return 1;
   }

   return 0;
}

static int stbtt_FindMatchingFont_internal(ubyte *font_collection, char *name_utf8, int flags)
{
   int i;
   for (i=0;;++i) {
      int off = stbtt_GetFontOffsetForIndex(font_collection, i);
      if (off < 0) return off;
      if (stbtt__matches(cast(ubyte *) font_collection, off, cast(ubyte*) name_utf8, flags))
         return off;
   }
}

