]> git.tdb.fi Git - ttf2png.git/blobdiff - ttf2png.c
Better documentation
[ttf2png.git] / ttf2png.c
index 67228e533095c119070af16beaa950da87cb8378..b8f48a816c712612049dd21b0ee2b41fc3e83c16 100644 (file)
--- a/ttf2png.c
+++ b/ttf2png.c
@@ -54,7 +54,7 @@ typedef struct sFont
 unsigned round_to_pot(unsigned);
 void usage();
 void init_font(Font *, FT_Face, unsigned, unsigned, int);
-void render_grid(Font *, unsigned, unsigned, int);
+void render_grid(Font *, unsigned, unsigned, unsigned, int);
 void render_packed(Font *);
 int save_defs(const char *, const Font *);
 int save_png(const char *, const Image *, char);
@@ -68,10 +68,12 @@ int main(int argc, char **argv)
        int  end = 255;
        int  size = 10;
        int  cpl = 0;
-       int  cell = 0;
+       int  cellw = 0;
+       int  cellh = 0;
        char autohinter = 0;
        char seq = 0;
        char alpha = 0;
+       char invert = 0;
        char pack = 0;
 
        FT_Library freetype;
@@ -91,7 +93,7 @@ int main(int argc, char **argv)
                return 1;
        }
 
-       while((i = getopt(argc, argv, "r:s:l:c:o:atvh?ed:p")) != -1)
+       while((i = getopt(argc, argv, "r:s:l:c:o:atvh?ed:pi")) != -1)
        {
                char *ptr;
                int  temp;
@@ -132,7 +134,22 @@ int main(int argc, char **argv)
                        cpl = strtol(optarg, NULL, 0);
                        break;
                case 'c':
-                       cell = strtol(optarg, NULL, 0);
+                       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);
+                       }
                        break;
                case 'o':
                        out_fn = optarg;
@@ -159,6 +176,9 @@ int main(int argc, char **argv)
                case 'p':
                        pack = 1;
                        break;
+               case 'i':
+                       invert = 1;
+                       break;
                }
        }
        if(!strcmp(out_fn, "-"))
@@ -207,7 +227,12 @@ int main(int argc, char **argv)
        if(pack)
                render_packed(&font);
        else
-               render_grid(&font, cell, cpl, seq);
+               render_grid(&font, cellw, cellh, cpl, seq);
+       if(invert)
+       {
+               for(i=0; i<font.image.w*font.image.h; ++i)
+                       font.image.data[i] = 255-font.image.data[i];
+       }
        save_png(out_fn, &font.image, alpha);
        if(def_fn)
                save_defs(def_fn, &font);
@@ -242,17 +267,18 @@ void usage()
                "Distributed under the GNU General Public License\n\n"
                "Usage: ttf2png [options] <TTF file>\n\n"
                "Accepted options (default values in [brackets])\n"
-               "  -r  Range of characters to convert in the format low,high [0,255]\n"
+               "  -r  Range of characters 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"
                "  -o  Output file name (or - for stdout) [font.png]\n"
                "  -a  Force autohinter\n"
-               "  -t  Render font to alpha channel\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, rather than by code\n"
+               "  -e  Use cells in sequence, without gaps\n"
                "  -p  Pack the glyphs tightly instead of in a grid\n"
-               "  -d  Write a definition to the given file\n"
+               "  -d  File name for writing glyph definitions\n"
                "  -h  Print this message\n");
 }
 
@@ -313,6 +339,9 @@ void init_font(Font *font, FT_Face face, unsigned first, unsigned last, int auto
                glyph->offset_y = face->glyph->bitmap_top-bmp->rows;
                glyph->advance = (int)(face->glyph->advance.x+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)
                {
                        for(y=0; y<bmp->rows; ++y) for(x=0; x<bmp->width; ++x)
@@ -329,21 +358,14 @@ void init_font(Font *font, FT_Face face, unsigned first, unsigned last, int auto
                printf("Loaded %u glyphs\n", font->n_glyphs);
 }
 
-void render_grid(Font *font, unsigned cell, unsigned cpl, int seq)
+void render_grid(Font *font, unsigned cellw, unsigned cellh, unsigned cpl, int seq)
 {
        unsigned i;
        int      top = 0, bot = 0;
        unsigned first, last;
        unsigned maxw = 0, maxh = 0;
 
-       for(i=1;; i<<=1)
-       {
-               first = font->glyphs[0].code&~(i-1);
-               last = first+i-1;
-               if(last>=font->glyphs[font->n_glyphs-1].code)
-                       break;
-       }
-
+       /* Find extremes of the glyph images. */
        for(i=0; i<font->n_glyphs; ++i)
        {
                int y;
@@ -359,38 +381,49 @@ void render_grid(Font *font, unsigned cell, unsigned cpl, int seq)
                        maxh = font->glyphs[i].image.h;
        }
 
-       if(cell==0)
+       if(cellw==0)
        {
-               cell = top-bot;
-               if(maxw>cell)
-                       cell = maxw;
+               /* Establish a large enough cell to hold all glyphs in the range. */
+               int square = (cellh==cellw);
+               cellw = maxw;
+               cellh = top-bot;
+               if(square)
+               {
+                       if(cellh>cellw)
+                               cellw = cellh;
+                       else
+                               cellh = cellw;
+               }
        }
 
        if(verbose>=1)
        {
                printf("Max size:  %u x %u\n", maxw, maxh);
                printf("Y range:   [%d %d]\n", bot, top);
-               if(maxw>cell || top-bot>cell)
-                       fprintf(stderr, "Warning: character size exceeds cell size (%d)\n", cell);
+               printf("Cell size: %u x %u\n", cellw, cellh);
+               if(maxw>cellw || top-bot>cellh)
+                       fprintf(stderr, "Warning: character size exceeds cell size\n");
        }
 
        if(cpl==0)
        {
-               unsigned count = (seq ? font->n_glyphs : last-first+1);
+               /* Determine number of characters per line, trying to fit all the glyphs
+               in a square image. */
                for(i=1;; i<<=1)
                {
-                       cpl = i/cell;
-                       if(cpl>0 && (count+cpl-1)/cpl<=cpl)
+                       cpl = i/cellw;
+                       if(cpl>0 && font->n_glyphs/cpl*cellh<=cpl*cellw)
                                break;
                }
        }
 
-       font->image.w = round_to_pot(cpl*cell);
-       if(seq && font->n_glyphs<last-first+1)
-               font->image.h = (font->n_glyphs+cpl-1)/cpl*cell;
-       else
-               font->image.h = (last-first+cpl)/cpl*cell;
-       font->image.h = round_to_pot(font->image.h);
+       first = font->glyphs[0].code;
+       if(!seq)
+               first -= first%cpl;
+       last = font->glyphs[font->n_glyphs-1].code;
+
+       font->image.w = round_to_pot(cpl*cellw);
+       font->image.h = round_to_pot((last-first+cpl)/cpl*cellh);
 
        font->image.data = (char *)malloc(font->image.w*font->image.h);
        memset(font->image.data, 255, font->image.w*font->image.h);
@@ -398,24 +431,21 @@ void render_grid(Font *font, unsigned cell, unsigned cpl, int seq)
        for(i=0; i<font->n_glyphs; ++i)
        {
                Glyph    *glyph;
-               int      cx, cy;
+               int      ci, cx, cy;
                unsigned x, y;
 
                glyph = &font->glyphs[i];
 
                if(seq)
-               {
-                       cx = (i%cpl)*cell;
-                       cy = (i/cpl)*cell;
-               }
+                       ci = i;
                else
-               {
-                       cx = ((glyph->code-first)%cpl)*cell;
-                       cy = ((glyph->code-first)/cpl)*cell;
-               }
+                       ci = glyph->code-first;
+
+               cx = (ci%cpl)*cellw;
+               cy = (ci/cpl)*cellh;
 
-               if(cell>glyph->image.w)
-                       cx += (cell-glyph->image.w)/2;
+               if(cellw>glyph->image.w)
+                       cx += (cellw-glyph->image.w)/2;
                cy += top-glyph->offset_y-glyph->image.h;
 
                glyph->x = cx;
@@ -434,14 +464,17 @@ void render_packed(Font *font)
 {
        unsigned i;
        unsigned area = 0;
-       unsigned last_h = 0xFFFF;
        char     *used_glyphs;
-       char     *used_pixels;
+       unsigned *used_pixels;
        unsigned cx = 0, cy;
+       unsigned used_h = 0;
 
+       /* Compute the total area occupied by glyphs and padding. */
        for(i=0; i<font->n_glyphs; ++i)
-               area+=(font->glyphs[i].image.w+1)*(font->glyphs[i].image.h+1);
+               area += (font->glyphs[i].image.w+1)*(font->glyphs[i].image.h+1);
 
+       /* Find an image size that's no higher than wide, allowing for some
+       imperfections in the packing. */
        for(font->image.w=1;; font->image.w<<=1)
        {
                font->image.h = (area*5/4)/font->image.w;
@@ -450,10 +483,14 @@ void render_packed(Font *font)
        }
        font->image.h = round_to_pot(font->image.h);
 
+       /* 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 *)malloc(font->image.w*font->image.h);
        memset(font->image.data, 255, font->image.w*font->image.h);
-       used_pixels = (char *)malloc(font->image.w*font->image.h);
-       memset(used_pixels, 0, font->image.w*font->image.h);
+       used_pixels = (unsigned *)malloc(font->image.w*sizeof(unsigned));
+       memset(used_pixels, 0, font->image.w*sizeof(unsigned));
        used_glyphs = (char *)malloc(font->n_glyphs);
        memset(used_glyphs, 0, font->n_glyphs);
 
@@ -463,17 +500,25 @@ void render_packed(Font *font)
                unsigned x, y;
                Glyph    *glyph = NULL;
                unsigned best_score = 0;
+               unsigned target_h = 0;
+
+               /* Find the leftmost free pixel on this row.    Also record the lowest extent of glyphs
+               to the left of the free position. */
+               for(; (cx<font->image.w && used_pixels[cx]>cy); ++cx)
+                       if(used_pixels[cx]-cy-1>target_h)
+                               target_h = used_pixels[cx]-cy-1;
 
-               for(; (cx<font->image.w && used_pixels[cx+cy*font->image.w]); ++cx) ;
                if(cx>=font->image.w)
                {
                        cx = 0;
                        ++cy;
-                       last_h = 0xFFFF;
                        continue;
                }
-               for(w=0; (cx+w<font->image.w && !used_pixels[cx+w+cy*font->image.w]); ++w) ;
 
+               /* Count the free pixel at this position. */
+               for(w=0; (cx+w<font->image.w && used_pixels[cx+w]<=cy); ++w) ;
+
+               /* Find a suitable glyph to put here. */
                for(i=0; i<font->n_glyphs; ++i)
                {
                        Glyph *g;
@@ -483,8 +528,11 @@ void render_packed(Font *font)
                        {
                                unsigned score;
 
+                               /* Prefer glyphs that would reach exactly as low as the ones left
+                               of here.  This aims to create a straight edge at the bottom for
+                               lining up further glyphs. */
                                score = g->image.h+1;
-                               if(g->image.h==last_h)
+                               if(g->image.h==target_h)
                                        score *= g->image.w;
                                else
                                        score += g->image.w;
@@ -513,15 +561,21 @@ void render_packed(Font *font)
                                continue;
                        font->image.data[cx+x+(cy+y)*font->image.w] = 255-glyph->image.data[x+y*glyph->image.w];
                }
-               for(y=0; y<glyph->image.h+2; ++y) for(x=0; x<glyph->image.w+2; ++x)
+               for(x=0; x<glyph->image.w+2; ++x)
                {
-                       if(cx+x<1 || cx+x>font->image.w || cy+y<1 || cy+y>font->image.h)
+                       if(cx+x<1 || cx+x>font->image.w)
                                continue;
-                       used_pixels[cx+x-1+(cy+y-1)*font->image.w] = 1;
+                       if(used_pixels[cx+x-1]<cy+glyph->image.h+1)
+                               used_pixels[cx+x-1] = cy+glyph->image.h+1;
                }
 
-               last_h = glyph->image.h;
+               if(cy+glyph->image.h>used_h)
+                       used_h = cy+glyph->image.h;
        }
+
+       /* Trim the image to the actually used size, in case the original estimate
+       was too pessimistic. */
+       font->image.h = round_to_pot(used_h);
 }
 
 int save_defs(const char *fn, const Font *font)
@@ -536,7 +590,11 @@ int save_defs(const char *fn, const Font *font)
                return -1;
        }
 
+       fprintf(out, "# Image/font info:\n");
+       fprintf(out, "# width height size ascent descent\n");
        fprintf(out, "%d %d %d %d %d\n", font->image.w, font->image.h, font->size, font->ascent, font->descent);
+       fprintf(out, "\n# Glyph info:\n");
+       fprintf(out, "# code x y width height offset_x offset_y advance\n");
        for(i=0; i<font->n_glyphs; ++i)
        {
                const Glyph *g = &font->glyphs[i];