gdft.c   [plain text]

/********************************************/
/* gd interface to freetype library         */
/*                                          */
/* John Ellson   ellson@graphviz.org        */
/********************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "gd.h"
#include "gdhelpers.h"

/* 2.0.10: WIN32, not MSWIN32 */
#ifndef WIN32
#include <unistd.h>
#else
#include <io.h>
#define R_OK 04			/* Needed in Windows */
#endif

/* number of antialised colors for indexed bitmaps */
#define NUMCOLORS 8

char *
gdImageStringTTF (gdImage * im, int *brect, int fg, char *fontlist,
		  double ptsize, double angle, int x, int y, char *string)
{
  /* 2.0.6: valid return */
  return gdImageStringFT (im, brect, fg, fontlist, ptsize,
			  angle, x, y, string);
}

#ifndef HAVE_LIBFREETYPE
char *
gdImageStringFTEx (gdImage * im, int *brect, int fg, char *fontlist,
		   double ptsize, double angle, int x, int y, char *string,
		   gdFTStringExtraPtr strex)
{
  return "libgd was not built with FreeType font support\n";
}

char *
gdImageStringFT (gdImage * im, int *brect, int fg, char *fontlist,
		 double ptsize, double angle, int x, int y, char *string)
{
  return "libgd was not built with FreeType font support\n";
}
#else

#include "gdcache.h"

#ifdef HAVE_FT2BUILD_H
#include "ft2build.h"
#include FT_FREETYPE_H
#include FT_GLYPH_H
#else
#include "freetype/freetype.h"
#include "freetype/ftglyph.h"
#endif

/* number of fonts cached before least recently used is replaced */
#define FONTCACHESIZE 6

/* number of antialias color lookups cached */
#define TWEENCOLORCACHESIZE 32

/*
 * Line separation as a factor of font height.  
 *      No space between if LINESPACE = 1.00 
 *      Line separation will be rounded up to next pixel row.
 */
#define LINESPACE 1.05

/*
 * The character (space) used to separate alternate fonts in the
 * fontlist parameter to gdImageStringFT.
 */
#define LISTSEPARATOR ";"

/*
 * DEFAULT_FONTPATH and PATHSEPARATOR are host type dependent and
 * are normally set by configure in config.h.  These are just
 * some last resort values that might match some Un*x system
 * if building this version of gd separate from graphviz.
 */
#ifndef DEFAULT_FONTPATH
#if defined(__APPLE__) || (defined(__MWERKS__) && defined(macintosh))
#define DEFAULT_FONTPATH "/usr/share/fonts/truetype:/System/Library/Fonts:/Library/Fonts"
#else
#define DEFAULT_FONTPATH "/usr/share/fonts/truetype"
#endif
#endif
#ifndef PATHSEPARATOR
#define PATHSEPARATOR ":"
#endif

#ifndef TRUE
#define FALSE 0
#define TRUE !FALSE
#endif

#define MAX(a,b) ((a)>(b)?(a):(b))
#define MIN(a,b) ((a)<(b)?(a):(b))

typedef struct
{
  char *fontlist;		/* key */
  FT_Library *library;
  FT_Face face;
  FT_Bool have_char_map_unicode, have_char_map_big5, have_char_map_sjis,
    have_char_map_apple_roman;
  gdCache_head_t *glyphCache;
}
font_t;

typedef struct
{
  char *fontlist;		/* key */
  FT_Library *library;
}
fontkey_t;

typedef struct
{
  int pixel;			/* key */
  int bgcolor;			/* key */
  int fgcolor;			/* key *//* -ve means no antialias */
  gdImagePtr im;		/* key */
  int tweencolor;
}
tweencolor_t;

typedef struct
{
  int pixel;			/* key */
  int bgcolor;			/* key */
  int fgcolor;			/* key *//* -ve means no antialias */
  gdImagePtr im;		/* key */
}
tweencolorkey_t;

/********************************************************************
 * gdTcl_UtfToUniChar is borrowed from Tcl ...
 */
/*
 * tclUtf.c --
 *
 *      Routines for manipulating UTF-8 strings.
 *
 * Copyright (c) 1997-1998 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * SCCS: @(#) tclUtf.c 1.25 98/01/28 18:02:43
 */

/*
 *---------------------------------------------------------------------------
 *
 * gdTcl_UtfToUniChar --
 *
 *      Extract the Tcl_UniChar represented by the UTF-8 string.  Bad
 *      UTF-8 sequences are converted to valid Tcl_UniChars and processing
 *      continues.  Equivalent to Plan 9 chartorune().
 *
 *      The caller must ensure that the source buffer is long enough that
 *      this routine does not run off the end and dereference non-existent
 *      memory looking for trail bytes.  If the source buffer is known to
 *      be '\0' terminated, this cannot happen.  Otherwise, the caller
 *      should call Tcl_UtfCharComplete() before calling this routine to
 *      ensure that enough bytes remain in the string.
 *
 * Results:
 *      *chPtr is filled with the Tcl_UniChar, and the return value is the
 *      number of bytes from the UTF-8 string that were consumed.
 *
 * Side effects:
 *      None.
 *
 *---------------------------------------------------------------------------
 */

#ifdef JISX0208
#include "jisx0208.h"
#endif

#define Tcl_UniChar int
#define TCL_UTF_MAX 3
static int
gdTcl_UtfToUniChar (char *str, Tcl_UniChar * chPtr)
/* str is the UTF8 next character pointer */
/* chPtr is the int for the result */
{
  int byte;

  /* HTML4.0 entities in decimal form, e.g. &#197; */
  byte = *((unsigned char *) str);
  if (byte == '&')
    {
      int i, n = 0;

      byte = *((unsigned char *) (str + 1));
      if (byte == '#')
	{
	  for (i = 2; i < 8; i++)
	    {
	      byte = *((unsigned char *) (str + i));
	      if (byte >= '0' && byte <= '9')
		{
		  n = (n * 10) + (byte - '0');
		}
	      else
		break;
	    }
	  if (byte == ';')
	    {
	      *chPtr = (Tcl_UniChar) n;
	      return ++i;
	    }
	}
    }

  /*
   * Unroll 1 to 3 byte UTF-8 sequences, use loop to handle longer ones.
   */

  byte = *((unsigned char *) str);
#ifdef JISX0208
  if (0xA1 <= byte && byte <= 0xFE)
    {
      int ku, ten;

      ku = (byte & 0x7F) - 0x20;
      ten = (str[1] & 0x7F) - 0x20;
      if ((ku < 1 || ku > 92) || (ten < 1 || ten > 94))
	{
	  *chPtr = (Tcl_UniChar) byte;
	  return 1;
	}

      *chPtr = (Tcl_UniChar) UnicodeTbl[ku - 1][ten - 1];
      return 2;
    }
  else
#endif /* JISX0208 */
  if (byte < 0xC0)
    {
      /*
       * Handles properly formed UTF-8 characters between
       * 0x01 and 0x7F.  Also treats \0 and naked trail
       * bytes 0x80 to 0xBF as valid characters representing
       * themselves.
       */

      *chPtr = (Tcl_UniChar) byte;
      return 1;
    }
  else if (byte < 0xE0)
    {
      if ((str[1] & 0xC0) == 0x80)
	{
	  /*
	   * Two-byte-character lead-byte followed
	   * by a trail-byte.
	   */

	  *chPtr = (Tcl_UniChar) (((byte & 0x1F) << 6) | (str[1] & 0x3F));
	  return 2;
	}
      /*
       * A two-byte-character lead-byte not followed by trail-byte
       * represents itself.
       */

      *chPtr = (Tcl_UniChar) byte;
      return 1;
    }
  else if (byte < 0xF0)
    {
      if (((str[1] & 0xC0) == 0x80) && ((str[2] & 0xC0) == 0x80))
	{
	  /*
	   * Three-byte-character lead byte followed by
	   * two trail bytes.
	   */

	  *chPtr = (Tcl_UniChar) (((byte & 0x0F) << 12)
				  | ((str[1] & 0x3F) << 6) | (str[2] & 0x3F));
	  return 3;
	}
      /*
       * A three-byte-character lead-byte not followed by
       * two trail-bytes represents itself.
       */

      *chPtr = (Tcl_UniChar) byte;
      return 1;
    }
#if TCL_UTF_MAX > 3
  else
    {
      int ch, total, trail;

      total = totalBytes[byte];
      trail = total - 1;
      if (trail > 0)
	{
	  ch = byte & (0x3F >> trail);
	  do
	    {
	      str++;
	      if ((*str & 0xC0) != 0x80)
		{
		  *chPtr = byte;
		  return 1;
		}
	      ch <<= 6;
	      ch |= (*str & 0x3F);
	      trail--;
	    }
	  while (trail > 0);
	  *chPtr = ch;
	  return total;
	}
    }
#endif

  *chPtr = (Tcl_UniChar) byte;
  return 1;
}

/********************************************************************/
/* font cache functions                                             */

static int
fontTest (void *element, void *key)
{
  font_t *a = (font_t *) element;
  fontkey_t *b = (fontkey_t *) key;

  return (strcmp (a->fontlist, b->fontlist) == 0);
}

static void *
fontFetch (char **error, void *key)
{
  font_t *a;
  fontkey_t *b = (fontkey_t *) key;
  int n;
  int font_found = 0;
  unsigned short platform, encoding;
  char *fontsearchpath, *fontlist;
  char *fullname = NULL;
  char *name, *path, *dir;
  char *strtok_ptr;
  FT_Error err;
  FT_CharMap found = 0;
  FT_CharMap charmap;

  a = (font_t *) gdMalloc (sizeof (font_t));
  a->fontlist = strdup (b->fontlist);
  a->library = b->library;

  /*
   * Search the pathlist for any of a list of font names.
   */
  fontsearchpath = getenv ("GDFONTPATH");
  if (!fontsearchpath)
    fontsearchpath = DEFAULT_FONTPATH;
  fontlist = strdup (a->fontlist);

  /*
   * Must use gd_strtok_r else pointer corrupted by strtok in nested loop.
   */
  for (name = gd_strtok_r (fontlist, LISTSEPARATOR, &strtok_ptr); name;
       name = gd_strtok_r (0, LISTSEPARATOR, &strtok_ptr))
    {
      /* make a fresh copy each time - strtok corrupts it. */
      path = strdup (fontsearchpath);
      /*
       * Allocate an oversized buffer that is guaranteed to be
       * big enough for all paths to be tested.
       */
      fullname = gdRealloc (fullname,
                          strlen (fontsearchpath) + strlen (name) + 6);

      /* if name is an absolute or relative pathname then test directly */
      if (strchr (name, '/')
	  || (name[0] != 0 && name[1] == ':'
	      && (name[2] == '/' || name[2] == '\\')))
	{
	  sprintf (fullname, "%s", name);
	  if (access (fullname, R_OK) == 0)
	    {
	      font_found++;
              /* 2.0.16: memory leak fixed, Gustavo Scotti */
              gdFree(path);
	      break;
	    }
	}
      for (dir = strtok (path, PATHSEPARATOR); dir;
	   dir = strtok (0, PATHSEPARATOR))
	{
	  sprintf (fullname, "%s/%s.ttf", dir, name);
	  if (access (fullname, R_OK) == 0)
	    {
	      font_found++;
	      break;
	    }
	  sprintf (fullname, "%s/%s.pfa", dir, name);
	  if (access (fullname, R_OK) == 0)
	    {
	      font_found++;
	      break;
	    }
	  sprintf (fullname, "%s/%s.pfb", dir, name);
	  if (access (fullname, R_OK) == 0)
	    {
	      font_found++;
	      break;
	    }
	  sprintf (fullname, "%s/%s.dfont", dir, name);
	  if (access (fullname, R_OK) == 0)
	    {
	      font_found++;
	      break;
	    }
	}
      gdFree (path);
      if (font_found)
	break;
    }
  gdFree (fontlist);
  if (!font_found)
    {
      *error = "Could not find/open font";
      /* 2.0.12: TBB: free these. Thanks to Frank Faubert. */
      gdFree (a->fontlist);
      gdFree (fullname);
      gdFree (a);

      return NULL;
    }

  err = FT_New_Face (*b->library, fullname, 0, &a->face);
  if (err)
    {
      /* 2.0.12: TBB: free these. Thanks to Frank Faubert. */
      free (a->fontlist);
      free (fullname);
      gdFree (a);
      *error = "Could not read font";
      return NULL;
    }
  gdFree (fullname);

/* FIXME - This mapping stuff is imcomplete - where is the spec? */

  a->have_char_map_unicode = 0;
  a->have_char_map_big5 = 0;
  a->have_char_map_sjis = 0;
  a->have_char_map_apple_roman = 0;
  for (n = 0; n < a->face->num_charmaps; n++)
    {
      charmap = a->face->charmaps[n];
      platform = charmap->platform_id;
      encoding = charmap->encoding_id;
      if ((platform == 3 && encoding == 1)	/* Windows Unicode */
	  || (platform == 3 && encoding == 0)	/* Windows Symbol */
	  || (platform == 2 && encoding == 1)	/* ISO Unicode */
	  || (platform == 0))
	{			/* Apple Unicode */
	  a->have_char_map_unicode = 1;
	  found = charmap;
	}
      else if (platform == 3 && encoding == 4)
	{			/* Windows Big5 */
	  a->have_char_map_big5 = 1;
	  found = charmap;
	}
      else if (platform == 3 && encoding == 2)
	{			/* Windows Sjis */
	  a->have_char_map_sjis = 1;
	  found = charmap;
	}
      else if ((platform == 1 && encoding == 0)	/* Apple Roman */
	       || (platform == 2 && encoding == 0))
	{			/* ISO ASCII */
	  a->have_char_map_apple_roman = 1;
	  found = charmap;
	}
    }
  if (!found)
    {
      *error = "Unable to find a CharMap that I can handle";
      /* 2.0.12: TBB: free these. Thanks to Frank Faubert. */
      free (a->fontlist);
      gdFree (a);
      return NULL;
    }
  /* 2.0.5: we should actually return this */
  a->face->charmap = found;
  return (void *) a;
}

static void
fontRelease (void *element)
{
  font_t *a = (font_t *) element;

  FT_Done_Face (a->face);
  gdFree (a->fontlist);
  gdFree ((char *) element);
}

/********************************************************************/
/* tweencolor cache functions                                            */

static int
tweenColorTest (void *element, void *key)
{
  tweencolor_t *a = (tweencolor_t *) element;
  tweencolorkey_t *b = (tweencolorkey_t *) key;

  return (a->pixel == b->pixel
	  && a->bgcolor == b->bgcolor
	  && a->fgcolor == b->fgcolor && a->im == b->im);
}

/*
 * Computes a color in im's color table that is part way between
 * the background and foreground colors proportional to the gray
 * pixel value in the range 0-NUMCOLORS. The fg and bg colors must already
 * be in the color table for palette images. For truecolor images the
 * returned value simply has an alpha component and gdImageAlphaBlend
 * does the work so that text can be alpha blended across a complex
 * background (TBB; and for real in 2.0.2).
 */
static void *
tweenColorFetch (char **error, void *key)
{
  tweencolor_t *a;
  tweencolorkey_t *b = (tweencolorkey_t *) key;
  int pixel, npixel, bg, fg;
  gdImagePtr im;

  a = (tweencolor_t *) gdMalloc (sizeof (tweencolor_t));
  pixel = a->pixel = b->pixel;
  bg = a->bgcolor = b->bgcolor;
  fg = a->fgcolor = b->fgcolor;
  im = b->im;

  /* if fg is specified by a negative color idx, then don't antialias */
  if (fg < 0)
    {
      if ((pixel + pixel) >= NUMCOLORS)
	a->tweencolor = -fg;
      else
	a->tweencolor = bg;
    }
  else
    {
      npixel = NUMCOLORS - pixel;
      if (im->trueColor)
	{
	  /* 2.0.1: use gdImageSetPixel to do the alpha blending work,
	     or to just store the alpha level. All we have to do here
	     is incorporate our knowledge of the percentage of this
	     pixel that is really "lit" by pushing the alpha value
	     up toward transparency in edge regions. */
	  a->tweencolor = gdTrueColorAlpha (gdTrueColorGetRed (fg),
					    gdTrueColorGetGreen (fg),
					    gdTrueColorGetBlue (fg),
					    gdAlphaMax -
					    (gdTrueColorGetAlpha (fg) *
					     pixel / NUMCOLORS));
	}
      else
	{
	  a->tweencolor = gdImageColorResolve (im,
					       (pixel * im->red[fg] +
						npixel * im->red[bg]) /
					       NUMCOLORS,
					       (pixel * im->green[fg] +
						npixel * im->green[bg]) /
					       NUMCOLORS,
					       (pixel * im->blue[fg] +
						npixel * im->blue[bg]) /
					       NUMCOLORS);
	}
    }
  return (void *) a;
}

static void
tweenColorRelease (void *element)
{
  gdFree ((char *) element);
}

/* draw_bitmap - transfers glyph bitmap to GD image */
static char *
gdft_draw_bitmap (gdCache_head_t * tc_cache, gdImage * im, int fg,
		  FT_Bitmap bitmap, int pen_x, int pen_y)
{
  unsigned char *pixel = NULL;
  int *tpixel = NULL;
  int x, y, row, col, pc, pcr;

  tweencolor_t *tc_elem;
  tweencolorkey_t tc_key;

  /* copy to image, mapping colors */
  tc_key.fgcolor = fg;
  tc_key.im = im;
  /* Truecolor version; does not require the cache */
  if (im->trueColor)
    {
      for (row = 0; row < bitmap.rows; row++)
	{
	  pc = row * bitmap.pitch;
	  pcr = pc;
	  y = pen_y + row;
	  /* clip if out of bounds */
          /* 2.0.16: clipping rectangle, not image bounds */
          if ((y > im->cy2) || (y < im->cy1))
	    continue;
	  for (col = 0; col < bitmap.width; col++, pc++)
	    {
	      int level;
	      if (bitmap.pixel_mode == ft_pixel_mode_grays)
		{
		  /*
		   * Scale to 128 levels of alpha for gd use.
		   * alpha 0 is opacity, so be sure to invert at the end
		   */
		  level = (bitmap.buffer[pc] * gdAlphaMax /
			   (bitmap.num_grays - 1));
		}
	      else if (bitmap.pixel_mode == ft_pixel_mode_mono)
		{
		  /* 2.0.5: mode_mono fix from Giuliano Pochini */
		  level =
		    ((bitmap.
		      buffer[(col >> 3) +
			     pcr]) & (1 << (~col & 0x07))) ?
		    gdAlphaTransparent : gdAlphaOpaque;
		}
	      else
		{
		  return "Unsupported ft_pixel_mode";
		}
	      if ((fg >= 0) && (im->trueColor))
		{
		  /* Consider alpha in the foreground color itself to be an
		     upper bound on how opaque things get, when truecolor is
		     available. Without truecolor this results in far too many
		     color indexes. */
		  level =
		    level * (gdAlphaMax -
			     gdTrueColorGetAlpha (fg)) / gdAlphaMax;
		}
	      level = gdAlphaMax - level;
	      x = pen_x + col;
	      /* clip if out of bounds */
              /* 2.0.16: clip to clipping rectangle, Matt McNabb */
              if ((x > im->cx2) || (x < im->cx1))
		continue;
	      /* get pixel location in gd buffer */
	      tpixel = &im->tpixels[y][x];
	      if (fg < 0)
		{
		  if (level < (gdAlphaMax / 2))
		    {
		      *tpixel = -fg;
		    }
		}
	      else
		{
		  if (im->alphaBlendingFlag)
		    {
		      *tpixel =
			gdAlphaBlend (*tpixel,
				      (level << 24) + (fg & 0xFFFFFF));
		    }
		  else
		    {
		      *tpixel = (level << 24) + (fg & 0xFFFFFF);
		    }
		}
	    }
	}
      return (char *) NULL;
    }
  /* Non-truecolor case, restored to its more or less original form */
  for (row = 0; row < bitmap.rows; row++)
    {
      int pcr;
      pc = row * bitmap.pitch;
      pcr = pc;
      if (bitmap.pixel_mode == ft_pixel_mode_mono)
	pc *= 8;		/* pc is measured in bits for monochrome images */

      y = pen_y + row;

      /* clip if out of bounds */
      if (y >= im->sy || y < 0)
	continue;

      for (col = 0; col < bitmap.width; col++, pc++)
	{
	  if (bitmap.pixel_mode == ft_pixel_mode_grays)
	    {
	      /*
	       * Round to NUMCOLORS levels of antialiasing for
	       * index color images since only 256 colors are
	       * available.
	       */
	      tc_key.pixel = ((bitmap.buffer[pc] * NUMCOLORS)
			      + bitmap.num_grays / 2)
		/ (bitmap.num_grays - 1);
	    }
	  else if (bitmap.pixel_mode == ft_pixel_mode_mono)
	    {
	      tc_key.pixel = ((bitmap.buffer[pc / 8]
			       << (pc % 8)) & 128) ? NUMCOLORS : 0;
	      /* 2.0.5: mode_mono fix from Giuliano Pochini */
	      tc_key.pixel =
		((bitmap.
		  buffer[(col >> 3) +
			 pcr]) & (1 << (~col & 0x07))) ? NUMCOLORS : 0;
	    }
	  else
	    {
	      return "Unsupported ft_pixel_mode";
	    }
	  if (tc_key.pixel > 0)	/* if not background */
	    {
	      x = pen_x + col;

	      /* clip if out of bounds */
	      if (x >= im->sx || x < 0)
		continue;
	      /* get pixel location in gd buffer */
	      pixel = &im->pixels[y][x];
	      if (tc_key.pixel == NUMCOLORS)
		{
		  /* use fg color directly. gd 2.0.2: watch out for
		     negative indexes (thanks to David Marwood). */
		  *pixel = (fg < 0) ? -fg : fg;
		}
	      else
		{
		  /* find antialised color */

		  tc_key.bgcolor = *pixel;
		  tc_elem = (tweencolor_t *) gdCacheGet (tc_cache, &tc_key);
		  *pixel = tc_elem->tweencolor;
		}
	    }
	}
    }
  return (char *) NULL;
}

static int
gdroundupdown (FT_F26Dot6 v1, int updown)
{
  return (!updown)
    ? (v1 < 0 ? ((v1 - 63) >> 6) : v1 >> 6)
    : (v1 > 0 ? ((v1 + 63) >> 6) : v1 >> 6);
}

extern int any2eucjp (char *, char *, unsigned int);

/* Persistent font cache until explicitly cleared */
/*     Fonts can be used across multiple images */
static gdCache_head_t *fontCache;
static FT_Library library;

void
gdFreeFontCache ()
{
  if (fontCache)
    {
      gdCacheDelete (fontCache);
      FT_Done_FreeType (library);
    }
}

/********************************************************************/
/* gdImageStringFT -  render a utf8 string onto a gd image          */

char *
gdImageStringFT (gdImage * im, int *brect, int fg, char *fontlist,
		 double ptsize, double angle, int x, int y, char *string)
{
  return gdImageStringFTEx (im, brect, fg, fontlist,
			    ptsize, angle, x, y, string, 0);
}

char *
gdImageStringFTEx (gdImage * im, int *brect, int fg, char *fontlist,
		   double ptsize, double angle, int x, int y, char *string,
		   gdFTStringExtraPtr strex)
{
  FT_BBox bbox, glyph_bbox;
  FT_Matrix matrix;
  FT_Vector pen, delta, penf;
  FT_Face face;
  FT_Glyph image;
  FT_GlyphSlot slot;
  FT_Error err;
  FT_Bool use_kerning;
  FT_UInt glyph_index, previous;
  double sin_a = sin (angle);
  double cos_a = cos (angle);
  int len, i = 0, ch;
  int x1 = 0, y1 = 0;
  font_t *font;
  fontkey_t fontkey;
  char *next;
  char *tmpstr = 0;
  int render = (im && (im->trueColor || (fg <= 255 && fg >= -255)));
  FT_BitmapGlyph bm;
  /* 2.0.13: Bob Ostermann: don't force autohint, that's just for testing 
    freetype and doesn't look as good */
  int render_mode = FT_LOAD_DEFAULT;
  int m, mfound;
  /* Now tuneable thanks to Wez Furlong */
  double linespace = LINESPACE;
  /* 2.0.6: put this declaration with the other declarations! */
  /*
   *   make a new tweenColorCache on every call
   *   because caching colormappings between calls
   *   is not safe. If the im-pointer points to a
   *   brand new image, the cache gives out bogus
   *   colorindexes.          -- 27.06.2001 <krisku@arrak.fi>
   */
  gdCache_head_t *tc_cache;

  if (strex)
    {
      if ((strex->flags & gdFTEX_LINESPACE) == gdFTEX_LINESPACE)
	{
	  linespace = strex->linespacing;
	}
    }
  tc_cache = gdCacheCreate (TWEENCOLORCACHESIZE,
			    tweenColorTest, tweenColorFetch,
			    tweenColorRelease);

/***** initialize font library and font cache on first call ******/

  if (!fontCache)
    {
      if (FT_Init_FreeType (&library))
	{
	  gdCacheDelete (tc_cache);
	  return "Failure to initialize font library";
	}
      fontCache = gdCacheCreate (FONTCACHESIZE,
				 fontTest, fontFetch, fontRelease);
    }
/*****/

  /* get the font (via font cache) */
  fontkey.fontlist = fontlist;
  fontkey.library = &library;
  font = (font_t *) gdCacheGet (fontCache, &fontkey);
  if (!font)
    {
      gdCacheDelete (tc_cache);
      return fontCache->error;
    }
  face = font->face;		/* shortcut */
  slot = face->glyph;		/* shortcut */

  if (FT_Set_Char_Size (face, 0, (FT_F26Dot6) (ptsize * 64),
			GD_RESOLUTION, GD_RESOLUTION))
    {
      gdCacheDelete (tc_cache);
      return "Could not set character size";
    }

  matrix.xx = (FT_Fixed) (cos_a * (1 << 16));
  matrix.yx = (FT_Fixed) (sin_a * (1 << 16));
  matrix.xy = -matrix.yx;
  matrix.yy = matrix.xx;

  penf.x = penf.y = 0;		/* running position of non-rotated string */
  pen.x = pen.y = 0;		/* running position of rotated string */
  bbox.xMin = bbox.xMax = bbox.yMin = bbox.yMax = 0;

  use_kerning = FT_HAS_KERNING (face);
  previous = 0;
  if (fg < 0)
    {
      render_mode |= FT_LOAD_MONOCHROME;
    }
  /* 2.0.12: allow explicit specification of the preferred map;
     but we still fall back if it is not available. */
  m = gdFTEX_Unicode;
  if (strex && (strex->flags & gdFTEX_CHARMAP))
    {
      m = strex->charmap;
    }
  /* Try all three types of maps, but start with the specified one */
  mfound = 0;
  for (i = 0; (i < 3); i++)
    {
      switch (m)
	{
	case gdFTEX_Unicode:
	  if (font->have_char_map_unicode)
	    {
	      mfound = 1;
	    }
	  break;
	case gdFTEX_Shift_JIS:
	  if (font->have_char_map_sjis)
	    {
	      mfound = 1;
	    }
	  break;
	case gdFTEX_Big5:
	  {
	    /* This was the 'else' case, we can't really 'detect' it */
	    mfound = 1;
	  }
	  break;
	}
      if (mfound)
	{
	  break;
	}
      m++;
      m %= 3;
    }
  if (!mfound)
    {
      /* No character set found! */
      return "No character set found";
    }

#ifndef JISX0208
  if (font->have_char_map_sjis)
    {
#endif
      if ((tmpstr = (char *) gdMalloc (BUFSIZ)))
	{
	  any2eucjp (tmpstr, string, BUFSIZ);
	  next = tmpstr;
	}
      else
	{
	  next = string;
	}
#ifndef JISX0208
    }
  else
    {
      next = string;
    }
#endif
  while (*next)
    {
      ch = *next;

      /* carriage returns */
      if (ch == '\r')
	{
	  penf.x = 0;
	  x1 = (penf.x * cos_a - penf.y * sin_a + 32) / 64;
	  y1 = (penf.x * sin_a + penf.y * cos_a + 32) / 64;
	  pen.x = pen.y = 0;
	  previous = 0;		/* clear kerning flag */
	  next++;
	  continue;
	}
      /* newlines */
      if (ch == '\n')
	{
          /* 2.0.13: reset penf.x. Christopher J. Grayce */
	  penf.x = 0;
	  penf.y -= face->size->metrics.height * linespace;
	  penf.y = (penf.y - 32) & -64;	/* round to next pixel row */
	  x1 = (penf.x * cos_a - penf.y * sin_a + 32) / 64;
	  y1 = (penf.x * sin_a + penf.y * cos_a + 32) / 64;
	  pen.x = pen.y = 0;
	  previous = 0;		/* clear kerning flag */
	  next++;
	  continue;
	}
      switch (m)
	{
	case gdFTEX_Unicode:
	  if (font->have_char_map_unicode)
	    {
	      /* use UTF-8 mapping from ASCII */
	      len = gdTcl_UtfToUniChar (next, &ch);
	      next += len;
	    }
	  break;
	case gdFTEX_Shift_JIS:
	  if (font->have_char_map_sjis)
	    {
	      unsigned char c;
	      int jiscode;
	      c = *next;
	      if (0xA1 <= c && c <= 0xFE)
		{
		  next++;
		  jiscode = 0x100 * (c & 0x7F) + ((*next) & 0x7F);

		  ch = (jiscode >> 8) & 0xFF;
		  jiscode &= 0xFF;

		  if (ch & 1)
		    jiscode += 0x40 - 0x21;
		  else
		    jiscode += 0x9E - 0x21;

		  if (jiscode >= 0x7F)
		    jiscode++;
		  ch = (ch - 0x21) / 2 + 0x81;
		  if (ch >= 0xA0)
		    ch += 0x40;

		  ch = (ch << 8) + jiscode;
		}
	      else
		{
		  ch = c & 0xFF;	/* don't extend sign */
		}
	      next++;
	    }
	  break;
	case gdFTEX_Big5:
	  {
	    /*
	     * Big 5 mapping:
	     * use "JIS-8 half-width katakana" coding from 8-bit characters. Ref:
	     * ftp://ftp.ora.com/pub/examples/nutshell/ujip/doc/japan.inf-032092.sjs
	     */
	    ch = (*next) & 0xFF;	/* don't extend sign */
	    next++;
	    if (ch >= 161	/* first code of JIS-8 pair */
		&& *next)
	      {			/* don't advance past '\0' */
		/* TBB: Fix from Kwok Wah On: & 255 needed */
		ch = (ch * 256) + ((*next) & 255);
		next++;
	      }
	  }
	  break;
	}
      /* set rotation transform */
      FT_Set_Transform (face, &matrix, NULL);
      /* Convert character code to glyph index */
      glyph_index = FT_Get_Char_Index (face, ch);

      /* retrieve kerning distance and move pen position */
      if (use_kerning && previous && glyph_index)
	{
	  FT_Get_Kerning (face, previous, glyph_index,
			  ft_kerning_default, &delta);
	  pen.x += delta.x;
	  /* 2.0.12: indispensable for an accurate bounding box. */
	  penf.x += delta.x;
	}

      /* load glyph image into the slot (erase previous one) */
      err = FT_Load_Glyph (face, glyph_index, render_mode);
      if (err)
	{
	  gdCacheDelete (tc_cache);
	  return "Problem loading glyph";
	}

      /* transform glyph image */
      FT_Get_Glyph (slot, &image);
      if (brect)
	{			/* only if need brect */
	  FT_Glyph_Get_CBox (image, ft_glyph_bbox_gridfit, &glyph_bbox);
	  glyph_bbox.xMin += penf.x;
	  glyph_bbox.yMin += penf.y;
	  glyph_bbox.xMax += penf.x;
	  glyph_bbox.yMax += penf.y;
	  if (ch == ' ')	/* special case for trailing space */
	    glyph_bbox.xMax += slot->metrics.horiAdvance;
	  if (!i)
	    {			/* if first character, init BB corner values */
	      bbox.xMin = glyph_bbox.xMin;
	      bbox.yMin = glyph_bbox.yMin;
	      bbox.xMax = glyph_bbox.xMax;
	      bbox.yMax = glyph_bbox.yMax;
	    }
	  else
	    {
	      if (bbox.xMin > glyph_bbox.xMin)
		bbox.xMin = glyph_bbox.xMin;
	      if (bbox.yMin > glyph_bbox.yMin)
		bbox.yMin = glyph_bbox.yMin;
	      if (bbox.xMax < glyph_bbox.xMax)
		bbox.xMax = glyph_bbox.xMax;
	      if (bbox.yMax < glyph_bbox.yMax)
		bbox.yMax = glyph_bbox.yMax;
	    }
	  i++;
	}

      if (render)
	{
	  if (image->format != ft_glyph_format_bitmap)
	    {
	      err = FT_Glyph_To_Bitmap (&image, ft_render_mode_normal, 0, 1);
	      if (err)
		{
		  gdCacheDelete (tc_cache);
		  return "Problem rendering glyph";
		}
	    }

	  /* now, draw to our target surface */
	  bm = (FT_BitmapGlyph) image;
	  gdft_draw_bitmap (tc_cache, im, fg, bm->bitmap,
			    x + x1 + ((pen.x + 31) >> 6) + bm->left,
			    y - y1 + ((pen.y + 31) >> 6) - bm->top);
	}

      /* record current glyph index for kerning */
      previous = glyph_index;

      /* increment pen position */
      pen.x += image->advance.x >> 10;
      pen.y -= image->advance.y >> 10;

      penf.x += slot->metrics.horiAdvance;

      FT_Done_Glyph (image);
    }

  if (brect)
    {				/* only if need brect */
      /* For perfect rounding, must get sin(a + pi/4) and sin(a - pi/4). */
      double d1 = sin (angle + 0.78539816339744830962);
      double d2 = sin (angle - 0.78539816339744830962);

      /* rotate bounding rectangle */
      brect[0] = (int) (bbox.xMin * cos_a - bbox.yMin * sin_a);
      brect[1] = (int) (bbox.xMin * sin_a + bbox.yMin * cos_a);
      brect[2] = (int) (bbox.xMax * cos_a - bbox.yMin * sin_a);
      brect[3] = (int) (bbox.xMax * sin_a + bbox.yMin * cos_a);
      brect[4] = (int) (bbox.xMax * cos_a - bbox.yMax * sin_a);
      brect[5] = (int) (bbox.xMax * sin_a + bbox.yMax * cos_a);
      brect[6] = (int) (bbox.xMin * cos_a - bbox.yMax * sin_a);
      brect[7] = (int) (bbox.xMin * sin_a + bbox.yMax * cos_a);

      /* scale, round and offset brect */
      brect[0] = x + gdroundupdown (brect[0], d2 > 0);
      brect[1] = y - gdroundupdown (brect[1], d1 < 0);
      brect[2] = x + gdroundupdown (brect[2], d1 > 0);
      brect[3] = y - gdroundupdown (brect[3], d2 > 0);
      brect[4] = x + gdroundupdown (brect[4], d2 < 0);
      brect[5] = y - gdroundupdown (brect[5], d1 > 0);
      brect[6] = x + gdroundupdown (brect[6], d1 < 0);
      brect[7] = y - gdroundupdown (brect[7], d2 < 0);
    }

  if (tmpstr)
    gdFree (tmpstr);
  gdCacheDelete (tc_cache);
  return (char *) NULL;
}

#endif /* HAVE_LIBFREETYPE */