]> git.tdb.fi Git - ttf2png.git/blobdiff - ttf2png.c
Add an option to control distance field border zone
[ttf2png.git] / ttf2png.c
index 96c325454609bd3d9cf4dfd7556f38b17773e1dc..0a66de26cc72f2c09772743db26f6eb7696cd5da 100644 (file)
--- a/ttf2png.c
+++ b/ttf2png.c
@@ -28,7 +28,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 typedef struct sImage
 {
        unsigned w, h;
-       char *data;
+       unsigned char *data;
 } Image;
 
 typedef struct sGlyph
@@ -61,12 +61,31 @@ typedef struct sFont
        Image image;
 } Font;
 
-void usage();
+typedef struct sRange
+{
+       unsigned first;
+       unsigned last;
+} Range;
+
+typedef int bool;
+
+void usage(void);
+int convert_numeric_option(char, int);
+void convert_code_point_range(char, Range *);
+unsigned str_to_code_point(const char *, char **);
+void convert_size(char, unsigned *, unsigned *);
+void sort_and_compact_ranges(Range *, unsigned *);
+int range_cmp(const void *, const void *);
 unsigned round_to_pot(unsigned);
 void *alloc_image_data(size_t, size_t);
-int init_font(Font *, FT_Face, unsigned, unsigned, int);
-int render_grid(Font *, unsigned, unsigned, unsigned, int);
-int render_packed(Font *, unsigned, unsigned);
+int init_font(Font *, FT_Face, const Range *, unsigned, bool, unsigned, unsigned);
+int init_glyphs(Font *, FT_Face, const Range *, bool, unsigned, unsigned);
+int copy_bitmap(const FT_Bitmap *, Image *);
+unsigned sqrti(unsigned);
+unsigned find_distance_to_edge(const Image *, int, int, unsigned);
+int create_distance_field(const FT_Bitmap *, Image *, unsigned, unsigned);
+int render_grid(Font *, unsigned, unsigned, unsigned, bool, bool);
+int render_packed(Font *, unsigned, unsigned, bool);
 int save_defs(const char *, const Font *);
 int save_png(const char *, const Image *, char);
 
@@ -75,19 +94,22 @@ char verbose = 0;
 int main(int argc, char **argv)
 {
        char *fn;
-       int begin = 0;
-       int end = 255;
-       int size = 10;
-       int cpl = 0;
-       int cellw = 0;
-       int cellh = 0;
-       char autohinter = 0;
-       char seq = 0;
-       char alpha = 0;
-       char invert = 0;
-       char pack = 0;
-       int margin = 0;
-       int padding = 1;
+       Range *ranges = NULL;
+       unsigned n_ranges = 0;
+       unsigned size = 10;
+       unsigned cpl = 0;
+       unsigned cellw = 0;
+       unsigned cellh = 0;
+       bool autohinter = 0;
+       bool seq = 0;
+       bool alpha = 0;
+       bool invert = 0;
+       bool pack = 0;
+       unsigned margin = 0;
+       unsigned padding = 1;
+       bool npot = 0;
+       unsigned distfield = 0;
+       unsigned border = 0;
 
        FT_Library freetype;
        FT_Face face;
@@ -106,65 +128,22 @@ int main(int argc, char **argv)
                return 1;
        }
 
-       while((i = getopt(argc, argv, "r:s:l:c:o:atvh?ed:pim:n:")) != -1)
+       while((i = getopt(argc, argv, "r:s:l:c:o:atvh?ed:pim:n:gf:b:")) != -1)
        {
-               char *ptr;
-               int temp;
                switch(i)
                {
                case 'r':
-                       if(!strcmp(optarg, "all"))
-                       {
-                               begin = 0;
-                               end = 0x110000;
-                       }
-                       else
-                       {
-                               if(!isdigit(optarg[0]))
-                                       temp = -1;
-                               else
-                               {
-                                       temp = strtol(optarg, &ptr, 0);
-                                       if(ptr[0]!=',' || !isdigit(ptr[1]))
-                                               temp = -1;
-                               }
-                               if(temp<0)
-                               {
-                                       printf("Not a valid range: %s\n", optarg);
-                                       exit(1);
-                               }
-                               else
-                               {
-                                       begin = temp;
-                                       end = strtol(ptr+1, NULL, 0);
-                               }
-                       }
+                       ranges = (Range *)realloc(ranges, (++n_ranges)*sizeof(Range));
+                       convert_code_point_range('r', &ranges[n_ranges-1]);
                        break;
                case 's':
-                       size = strtol(optarg, NULL, 0);
+                       size = convert_numeric_option('s', 1);
                        break;
                case 'l':
-                       cpl = strtol(optarg, NULL, 0);
+                       cpl = convert_numeric_option('l', 1);
                        break;
                case 'c':
-                       if(!strcmp(optarg, "auto"))
-                       {
-                               cellw = 0;
-                               cellh = 0;
-                       }
-                       else if(!strcmp(optarg, "autorect"))
-                       {
-                               cellw = 0;
-                               cellh = 1;
-                       }
-                       else
-                       {
-                               cellw = strtol(optarg, &ptr, 0);
-                               if(ptr[0]=='x' && isdigit(ptr[1]))
-                                       cellh = strtol(ptr+1, NULL, 0);
-                               else
-                                       cellh = cellw;
-                       }
+                       convert_size('c', &cellw, &cellh);
                        break;
                case 'o':
                        out_fn = optarg;
@@ -195,10 +174,19 @@ int main(int argc, char **argv)
                        invert = 1;
                        break;
                case 'm':
-                       margin = strtol(optarg, NULL, 0);
+                       margin = convert_numeric_option('m', 0);
                        break;
                case 'n':
-                       padding = strtol(optarg, NULL, 0);
+                       padding = convert_numeric_option('n', 0);
+                       break;
+               case 'g':
+                       npot = 1;
+                       break;
+               case 'f':
+                       distfield = convert_numeric_option('f', 1);
+                       break;
+               case 'b':
+                       border = convert_numeric_option('b', 1);
                        break;
                }
        }
@@ -236,6 +224,14 @@ int main(int argc, char **argv)
                printf("Glyphs:    %ld\n", face->num_glyphs);
        }
 
+       font.size = size;
+       if(distfield)
+       {
+               if(!border)
+                       border = sqrti(font.size);
+               size *= distfield;
+       }
+
        err = FT_Set_Pixel_Sizes(face, 0, size);
        if(err)
        {
@@ -243,24 +239,39 @@ int main(int argc, char **argv)
                return 1;
        }
 
-       font.size = size;
-       err = init_font(&font, face, begin, end, autohinter);
+       if(!n_ranges)
+       {
+               ranges = malloc(sizeof(Range));
+               ranges[0].first = 0;
+               ranges[0].last = 255;
+               n_ranges = 1;
+       }
+       else
+               sort_and_compact_ranges(ranges, &n_ranges);
+
+       err = init_font(&font, face, ranges, n_ranges, autohinter, distfield, border);
        if(err)
                return 1;
 
+       if(!font.n_glyphs)
+       {
+               fprintf(stderr, "No glyphs found in the requested range\n");
+               return 1;
+       }
+
        if(pack)
-               err = render_packed(&font, margin, padding);
+               err = render_packed(&font, margin, padding, npot);
        else
-               err = render_grid(&font, cellw, cellh, cpl, seq);
+               err = render_grid(&font, cellw, cellh, cpl, seq, npot);
        if(err)
                return 1;
 
-       if(invert)
+       if(invert || distfield)
        {
                for(i=0; (unsigned)i<font.image.w*font.image.h; ++i)
                        font.image.data[i] = 255-font.image.data[i];
        }
-       err = save_png(out_fn, &font.image, alpha);
+       err = save_png(out_fn, &font.image, (alpha && !distfield));
        if(err)
                return 1;
 
@@ -272,6 +283,7 @@ int main(int argc, char **argv)
        free(font.glyphs);
        free(font.kerning);
        free(font.image.data);
+       free(ranges);
 
        FT_Done_Face(face);
        FT_Done_FreeType(freetype);
@@ -279,32 +291,195 @@ int main(int argc, char **argv)
        return 0;
 }
 
-void usage()
+void usage(void)
 {
        printf("ttf2png 1.1 - True Type Font to PNG converter\n"
-               "Copyright (c) 2004-2008  Mikko Rasa, Mikkosoft Productions\n"
+               "Copyright (c) 2004-2018  Mikko Rasa, Mikkosoft Productions\n"
                "Distributed under the GNU General Public License\n\n");
 
        printf("Usage: ttf2png [options] <TTF file>\n\n");
 
        printf("Accepted options (default values in [brackets])\n"
-               "  -r  Range of characters to convert [0,255]\n"
+               "  -r  Range of code points to convert [0,255]\n"
                "  -s  Font size to use, in pixels [10]\n"
-               "  -l  Number of characters to put in one line [auto]\n"
-               "  -c  Character cell size, in pixels [auto]\n"
+               "  -l  Number of glyphs to put in one line [auto]\n"
+               "  -c  Glyph cell size, in pixels (grid mode only) [auto]\n"
                "  -o  Output file name (or - for stdout) [font.png]\n");
        printf("  -a  Force autohinter\n"
                "  -t  Render glyphs to alpha channel\n"
                "  -i  Invert colors of the glyphs\n"
                "  -v  Increase the level of verbosity\n"
-               "  -e  Use cells in sequence, without gaps\n"
+               "  -e  Use cells in sequence, without gaps (grid mode only)\n"
                "  -p  Pack the glyphs tightly instead of in a grid\n"
-               "  -m  Margin around image edges in packed mode [0]\n"
-               "  -n  Padding between packed glyphs [1]\n"
+               "  -m  Margin around image edges (packed mode only) [0]\n"
+               "  -n  Padding between glyphs (packed mode only) [1]\n"
+               "  -g  Allow non-power-of-two result\n"
+               "  -f  Create a distance field texture\n"
                "  -d  File name for writing glyph definitions\n"
                "  -h  Print this message\n");
 }
 
+int convert_numeric_option(char opt, int min_value)
+{
+       int value;
+       char *ptr;
+
+       value = strtol(optarg, &ptr, 0);
+       if(value<min_value || *ptr)
+       {
+               printf("Invalid option argument in -%c %s\n", opt, optarg);
+               exit(1);
+       }
+
+       return value;
+}
+
+void convert_code_point_range(char opt, Range *range)
+{
+       int value;
+       char *ptr;
+
+       if(!strcmp(optarg, "all"))
+       {
+               range->first = 0;
+               range->last = 0x10FFFF;
+               return;
+       }
+
+       value = str_to_code_point(optarg, &ptr);
+       if(value>0 && *ptr==',')
+       {
+               range->first = value;
+               value = str_to_code_point(ptr+1, &ptr);
+               if(value>0 && !*ptr)
+               {
+                       range->last = value;
+                       return;
+               }
+       }
+
+       printf("Invalid option argument in -%c %s\n", opt, optarg);
+       exit(1);
+}
+
+unsigned str_to_code_point(const char *nptr, char **endptr)
+{
+       if(nptr[0]=='U' && nptr[1]=='+')
+               return strtoul(nptr+2, endptr, 16);
+       else if(nptr[0]&0x80)
+       {
+               unsigned bytes;
+               unsigned code;
+               unsigned i;
+
+               if(endptr)
+                       *endptr = (char *)nptr;
+
+               for(bytes=1; (bytes<4 && (nptr[0]&(0x80>>bytes))); ++bytes)
+                       if((nptr[bytes]&0xC0)!=0x80)
+                               return 0;
+               if(bytes<2)
+                       return 0;
+
+               code = nptr[0]&(0x3F>>bytes);
+               for(i=1; i<bytes; ++i)
+                       code = (code<<6)|(nptr[i]&0x3F);
+
+               if(endptr)
+                       *endptr = (char *)nptr+bytes;
+
+               return code;
+       }
+       else if(isdigit(nptr[0]))
+               return strtoul(nptr, endptr, 0);
+       else
+       {
+               if(endptr)
+                       *endptr = (char *)nptr+1;
+               return *nptr;
+       }
+}
+
+void convert_size(char opt, unsigned *width, unsigned *height)
+{
+       int value;
+       char *ptr;
+
+       if(!strcmp(optarg, "auto"))
+       {
+               *width = 0;
+               *height = 0;
+               return;
+       }
+       else if(!strcmp(optarg, "autorect"))
+       {
+               *width = 0;
+               *height = 1;
+               return;
+       }
+
+       value = strtol(optarg, &ptr, 0);
+       if(value>0)
+       {
+               *width = value;
+               if(*ptr=='x')
+               {
+                       value = strtol(ptr+1, &ptr, 0);
+                       if(value>0 && !*ptr)
+                       {
+                               *height = value;
+                               return;
+                       }
+               }
+               else if(!*ptr)
+               {
+                       *height = *width;
+                       return;
+               }
+       }
+
+       printf("Invalid option argument in -%c %s\n", opt, optarg);
+       exit(1);
+}
+
+void sort_and_compact_ranges(Range *ranges, unsigned *n_ranges)
+{
+       unsigned i, j;
+
+       if(!*n_ranges)
+               return;
+
+       qsort(ranges, *n_ranges, sizeof(Range), &range_cmp);
+       for(i=0, j=1; j<*n_ranges; ++j)
+       {
+               if(ranges[i].last+1>=ranges[j].first)
+               {
+                       if(ranges[j].last>ranges[i].last)
+                               ranges[i].last = ranges[j].last;
+               }
+               else
+               {
+                       ++i;
+                       if(i!=j)
+                               ranges[i] = ranges[j];
+               }
+       }
+
+       *n_ranges = i+1;
+}
+
+int range_cmp(const void *p1, const void *p2)
+{
+       const Range *r1 = (const Range *)p1;
+       const Range *r2 = (const Range *)p2;
+       if(r1->first!=r2->first)
+               return (r1->first<r2->first ? -1 : 1);
+       else if(r1->last!=r2->last)
+               return (r1->last<r2->last ? -1 : 1);
+       else
+               return 0;
+}
+
 unsigned round_to_pot(unsigned n)
 {
        n -= 1;
@@ -341,13 +516,14 @@ void *alloc_image_data(size_t a, size_t b)
        return ptr;
 }
 
-int init_font(Font *font, FT_Face face, unsigned first, unsigned last, int autohinter)
+int init_font(Font *font, FT_Face face, const Range *ranges, unsigned n_ranges, bool autohinter, unsigned distfield, unsigned border)
 {
        unsigned i, j;
        unsigned size = 0;
+       int scale = (distfield>0 ? distfield : 1);
 
-       font->ascent = (face->size->metrics.ascender+63)>>6;
-       font->descent = (face->size->metrics.descender+63)>>6;
+       font->ascent = (face->size->metrics.ascender/scale+63)/64;
+       font->descent = (face->size->metrics.descender/scale-63)/64;
 
        if(verbose>=1)
        {
@@ -357,11 +533,56 @@ int init_font(Font *font, FT_Face face, unsigned first, unsigned last, int autoh
 
        font->n_glyphs = 0;
        font->glyphs = NULL;
-       for(i=first; i<=last; ++i)
+       for(i=0; i<n_ranges; ++i)
+               if(init_glyphs(font, face, &ranges[i], autohinter, distfield, border))
+                       return -1;
+
+       if(verbose>=1)
+               printf("Loaded %u glyphs\n", font->n_glyphs);
+
+       font->n_kerning = 0;
+       font->kerning = NULL;
+       for(i=0; i<font->n_glyphs; ++i) for(j=0; j<font->n_glyphs; ++j)
+               if(j!=i)
+               {
+                       FT_Vector kerning;
+                       FT_Get_Kerning(face, font->glyphs[i].index, font->glyphs[j].index, FT_KERNING_DEFAULT, &kerning);
+
+                       /* FreeType documentation says that vertical kerning is practically
+                       never used, so we ignore it. */
+                       if(kerning.x)
+                       {
+                               Kerning *kern;
+
+                               if(font->n_kerning>=size)
+                               {
+                                       size += 16;
+                                       font->kerning = (Kerning *)realloc(font->kerning, size*sizeof(Kerning));
+                               }
+
+                               kern = &font->kerning[font->n_kerning++];
+                               kern->left_code = font->glyphs[i].code;
+                               kern->right_code = font->glyphs[j].code;
+                               kern->distance = (kerning.x/scale+32)/64;
+                       }
+               }
+
+       if(verbose>=1)
+               printf("Loaded %d kerning pairs\n", font->n_kerning);
+
+       return 0;
+}
+
+int init_glyphs(Font *font, FT_Face face, const Range *range, bool autohinter, unsigned distfield, unsigned border)
+{
+       unsigned i, j;
+       unsigned size = font->n_glyphs;
+       int scale = (distfield>0 ? distfield : 1);
+
+       for(i=range->first; i<=range->last; ++i)
        {
                unsigned n;
                FT_Bitmap *bmp = &face->glyph->bitmap;
-               unsigned x, y;
                int flags = 0;
                Glyph *glyph;
 
@@ -372,14 +593,32 @@ int init_font(Font *font, FT_Face face, unsigned first, unsigned last, int autoh
                if(autohinter)
                        flags |= FT_LOAD_FORCE_AUTOHINT;
                FT_Load_Glyph(face, n, flags);
-               FT_Render_Glyph(face->glyph, FT_RENDER_MODE_NORMAL);
+               FT_Render_Glyph(face->glyph, (distfield ? FT_RENDER_MODE_MONO : FT_RENDER_MODE_NORMAL));
 
                if(verbose>=2)
-                       printf("  Char %u: glyph %u, size %dx%d\n", i, n, bmp->width, bmp->rows);
+               {
+                       printf("  Code point U+%04X", i);
+                       if(i>=0x20 && i<0x7F)
+                               printf(" (%c)", i);
+                       else if(i>=0xA0 && i<=0x10FFFF)
+                       {
+                               char utf8[5];
+                               unsigned bytes;
+
+                               for(bytes=2; i>>(1+bytes*5); ++bytes) ;
+                               for(j=0; j<bytes; ++j)
+                                       utf8[j] = 0x80 | ((i>>((bytes-j-1)*6))&0x3F);
+                               utf8[0] |= 0xF0<<(4-bytes);
+                               utf8[j] = 0;
+
+                               printf(" (%s)", utf8);
+                       }
+                       printf(": glyph %u, size %dx%d\n", n, bmp->width/scale, bmp->rows/scale);
+               }
 
-               if(bmp->pixel_mode!=FT_PIXEL_MODE_GRAY)
+               if(bmp->pixel_mode!=FT_PIXEL_MODE_GRAY && bmp->pixel_mode!=FT_PIXEL_MODE_MONO)
                {
-                       fprintf(stderr, "Warning: Glyph %u skipped, not grayscale\n", n);
+                       fprintf(stderr, "Warning: Glyph %u skipped, incompatible pixel mode\n", n);
                        continue;
                }
 
@@ -392,71 +631,165 @@ int init_font(Font *font, FT_Face face, unsigned first, unsigned last, int autoh
                glyph = &font->glyphs[font->n_glyphs++];
                glyph->index = n;
                glyph->code = i;
-               glyph->image.w = bmp->width;
-               glyph->image.h = bmp->rows;
-               glyph->image.data = (char *)malloc(bmp->width*bmp->rows);
-               if(!glyph->image.data)
-               {
-                       fprintf(stderr, "Cannot allocate %d bytes of memory for glyph\n", bmp->width*bmp->rows);
-                       return -1;
-               }
-               glyph->offset_x = face->glyph->bitmap_left;
-               glyph->offset_y = face->glyph->bitmap_top-bmp->rows;
-               glyph->advance = (int)(face->glyph->advance.x+32)/64;
+               glyph->offset_x = (int)(face->glyph->bitmap_left+scale/2)/scale;
+               glyph->offset_y = (int)(face->glyph->bitmap_top-bmp->rows+scale/2)/scale;
+               glyph->advance = (int)(face->glyph->advance.x/scale+32)/64;
 
                /* Copy the glyph image since FreeType uses a global buffer, which would
                be overwritten by the next glyph.  Negative pitch means the scanlines
                start from the bottom. */
-               if(bmp->pitch<0)
+               if(distfield)
                {
-                       for(y=0; y<bmp->rows; ++y) for(x=0; x<bmp->width; ++x)
-                               glyph->image.data[x+(glyph->image.h-1-y)*glyph->image.w] = bmp->buffer[x-y*bmp->pitch];
+                       glyph->offset_x -= border;
+                       glyph->offset_y -= border;
+                       create_distance_field(bmp, &glyph->image, distfield, border);
                }
                else
                {
-                       for(y=0; y<bmp->rows; ++y) for(x=0; x<bmp->width; ++x)
-                               glyph->image.data[x+y*glyph->image.w] = bmp->buffer[x+y*bmp->pitch];
+                       if(copy_bitmap(bmp, &glyph->image))
+                               return -1;
                }
        }
 
-       if(verbose>=1)
-               printf("Loaded %u glyphs\n", font->n_glyphs);
+       return 0;
+}
 
-       size = 0;
-       font->n_kerning = 0;
-       font->kerning = NULL;
-       for(i=0; i<font->n_glyphs; ++i) for(j=0; j<font->n_glyphs; ++j)
-               if(j!=i)
+int copy_bitmap(const FT_Bitmap *bmp, Image *image)
+{
+       unsigned x, y;
+       unsigned char *src;
+       unsigned char *dst;
+
+       image->w = bmp->width;
+       image->h = bmp->rows;
+       if(!image->w || !image->h)
+       {
+               image->data = NULL;
+               return 0;
+       }
+
+       image->data = (unsigned char *)malloc(image->w*image->h);
+       if(!image->data)
+       {
+               fprintf(stderr, "Cannot allocate %d bytes of memory for glyph\n", image->w*image->h);
+               return -1;
+       }
+
+       if(bmp->pitch<0)
+               src = bmp->buffer+(bmp->rows-1)*-bmp->pitch;
+       else
+               src = bmp->buffer;
+       dst = image->data;
+
+       for(y=0; y<bmp->rows; ++y)
+       {
+               if(bmp->pixel_mode==FT_PIXEL_MODE_MONO)
                {
-                       FT_Vector kerning;
-                       FT_Get_Kerning(face, font->glyphs[i].index, font->glyphs[j].index, FT_KERNING_DEFAULT, &kerning);
+                       for(x=0; x<bmp->width; ++x)
+                               dst[x] = ((src[x/8]&(0x80>>(x%8))) ? 0xFF : 0x00);
+               }
+               else
+               {
+                       for(x=0; x<bmp->width; ++x)
+                               dst[x] = src[x];
+               }
 
-                       /* FreeType documentation says that vertical kerning is practically
-                       never used, so we ignore it. */
-                       if(kerning.x)
-                       {
-                               Kerning *kern;
+               src += bmp->pitch;
+               dst += image->w;
+       }
 
-                               if(font->n_kerning>=size)
-                               {
-                                       size += 16;
-                                       font->kerning = (Kerning *)realloc(font->kerning, size*sizeof(Kerning));
-                               }
+       return 0;
+}
 
-                               kern = &font->kerning[font->n_kerning++];
-                               kern->left_code = font->glyphs[i].code;
-                               kern->right_code = font->glyphs[j].code;
-                               kern->distance = kerning.x/64;
+unsigned sqrti(unsigned num)
+{
+       unsigned result = (num>0xFFFF ? 0xFFFF : 0x100);
+       while(result && result*result>=result+num)
+               result -= (result*result+result-num)/(result*2);
+
+       return result;
+}
+
+unsigned find_distance_to_edge(const Image *image, int origin_x, int origin_y, unsigned range)
+{
+       unsigned i, j;
+       int x, y;
+       unsigned char origin_pixel = 0;
+       unsigned closest = range*range;
+
+       if(origin_x>=0 && (unsigned)origin_x<image->w && origin_y>=0 && (unsigned)origin_y<image->h)
+               origin_pixel = image->data[origin_x+origin_y*image->w];
+
+       x = origin_x-1;
+       y = origin_y-1;
+       for(i=1; (i<range && i*i<=closest); ++i, --x, --y) for(j=0; j<4; ++j)
+       {
+               unsigned k;
+               int dx = (j==0 ? 1 : j==2 ? -1 : 0);
+               int dy = (j==1 ? 1 : j==3 ? -1 : 0);
+
+               for(k=0; k<i*2; ++k, x+=dx, y+=dy)
+               {
+                       unsigned char pixel = 0;
+                       if(x>=0 && (unsigned)x<image->w && y>=0 && (unsigned)y<image->h)
+                               pixel = image->data[x+y*image->w];
+                               
+                       if((pixel^origin_pixel)&0x80)
+                       {
+                               unsigned d = 2*i*i + k*k - 2*k*i;
+                               if(d<closest)
+                                       closest = d;
                        }
                }
+       }
 
-       if(verbose>=1)
-               printf("Loaded %d kerning pairs\n", font->n_kerning);
+       return sqrti(closest*0x3F01)/range;
+}
+
+int create_distance_field(const FT_Bitmap *bmp, Image *image, unsigned scale, unsigned margin)
+{
+       unsigned x, y;
+       Image base_image;
+
+       if(!bmp->width || !bmp->rows)
+       {
+               image->w = 0;
+               image->h = 0;
+               image->data = NULL;
+               return 0;
+       }
+
+       if(copy_bitmap(bmp, &base_image))
+               return -1;
+
+       image->w = (base_image.w-1)/scale+2*margin+1;
+       image->h = (base_image.h-1)/scale+2*margin+1;
+       image->data = (unsigned char *)malloc(image->w*image->h);
+       if(!image->data)
+       {
+               fprintf(stderr, "Cannot allocate %d bytes of memory for glyph\n", image->w*image->h);
+               free(base_image.data);
+               return -1;
+       }
+
+       for(y=0; y<image->h; ++y) for(x=0; x<image->w; ++x)
+       {
+               int bx = (x-margin)*scale+scale/2;
+               int by = (y-margin)*scale+scale/2;
+               unsigned char pixel = find_distance_to_edge(&base_image, bx, by, margin*scale);
+               if(bx>=0 && (unsigned)bx<base_image.w && by>=0 && (unsigned)by<base_image.h)
+                       pixel |= base_image.data[bx+by*base_image.w]&0x80;
+               if(!(pixel&0x80))
+                       pixel = 0x80-pixel;
+               image->data[x+y*image->w] = pixel;
+       }
+
+       free(base_image.data);
 
        return 0;
 }
 
-int render_grid(Font *font, unsigned cellw, unsigned cellh, unsigned cpl, int seq)
+int render_grid(Font *font, unsigned cellw, unsigned cellh, unsigned cpl, bool seq, bool npot)
 {
        unsigned i;
        int top = 0, bot = 0;
@@ -520,13 +853,17 @@ int render_grid(Font *font, unsigned cellw, unsigned cellh, unsigned cpl, int se
                first -= first%cpl;
        last = font->glyphs[font->n_glyphs-1].code;
 
-       font->image.w = round_to_pot(cpl*cellw);
+       font->image.w = cpl*cellw;
+       if(!npot)
+               font->image.w = round_to_pot(font->image.w);
        if(seq)
-               font->image.h = round_to_pot((font->n_glyphs+cpl-1)/cpl*cellh);
+               font->image.h = (font->n_glyphs+cpl-1)/cpl*cellh;
        else
-               font->image.h = round_to_pot((last-first+cpl)/cpl*cellh);
+               font->image.h = (last-first+cpl)/cpl*cellh;
+       if(!npot)
+               font->image.h = round_to_pot(font->image.h);
 
-       font->image.data = (char *)alloc_image_data(font->image.w, font->image.h);
+       font->image.data = (unsigned char *)alloc_image_data(font->image.w, font->image.h);
        if(!font->image.data)
                return -1;
        memset(font->image.data, 255, font->image.w*font->image.h);
@@ -565,7 +902,7 @@ int render_grid(Font *font, unsigned cellw, unsigned cellh, unsigned cpl, int se
        return 0;
 }
 
-int render_packed(Font *font, unsigned margin, unsigned padding)
+int render_packed(Font *font, unsigned margin, unsigned padding, bool npot)
 {
        unsigned i;
        size_t area = 0;
@@ -586,23 +923,24 @@ int render_packed(Font *font, unsigned margin, unsigned padding)
                area = a;
        }
 
-       /* Find an image size that's no higher than wide, allowing for some
-       imperfections in the packing. */
+       /* Find an image size that's approximately square. */
        for(font->image.w=1;; font->image.w<<=1)
        {
                if(font->image.w<=margin*2)
                        continue;
-               font->image.h = (area*5/4)/(font->image.w-margin*2)+margin*2;
+               font->image.h = area/(font->image.w-margin*2)+margin*2;
                if(font->image.h<=font->image.w)
                        break;
        }
-       font->image.h = round_to_pot(font->image.h);
+
+       /* Add some extra space to accommodate packing imperfections. */
+       font->image.h = font->image.h*3/2;
 
        /* Allocate arrays for storing the image and keeping track of used pixels and
        glyphs.  Since glyphs are rectangular and the image is filled starting from
        the top, it's enough to track the number of used pixels at the top of each
        column. */
-       font->image.data = (char *)alloc_image_data(font->image.w, font->image.h);
+       font->image.data = (unsigned char *)alloc_image_data(font->image.w, font->image.h);
        if(!font->image.data)
                return -1;
        memset(font->image.data, 255, font->image.w*font->image.h);
@@ -692,7 +1030,9 @@ int render_packed(Font *font, unsigned margin, unsigned padding)
 
        /* Trim the image to the actually used size, in case the original estimate
        was too pessimistic. */
-       font->image.h = round_to_pot(used_h);
+       font->image.h = used_h;
+       if(!npot)
+               font->image.h = round_to_pot(font->image.h);
 
        free(used_glyphs);
        free(used_pixels);