X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=ttf2png.c;h=e702c9fe9446859a99a45c209511f192da00c495;hb=dde53369347a9b0a37823746166aac1f2a3eee7d;hp=7e78e84d41de01b10cd4aaa0fd410a8e88ee2e4f;hpb=dc56acaec174575c5c27f6135a40abca511bc88e;p=ttf2png.git

diff --git a/ttf2png.c b/ttf2png.c
index 7e78e84..e702c9f 100644
--- a/ttf2png.c
+++ b/ttf2png.c
@@ -33,6 +33,7 @@ typedef struct sImage
 
 typedef struct sGlyph
 {
+	unsigned index;
 	unsigned code;
 	Image    image;
 	unsigned x, y;
@@ -41,6 +42,13 @@ typedef struct sGlyph
 	int      advance;
 } Glyph;
 
+typedef struct sKerning
+{
+	unsigned left_code;
+	unsigned right_code;
+	int distance;
+} Kerning;
+
 typedef struct sFont
 {
 	unsigned size;
@@ -48,6 +56,8 @@ typedef struct sFont
 	int      descent;
 	unsigned n_glyphs;
 	Glyph    *glyphs;
+	unsigned n_kerning;
+	Kerning  *kerning;
 	Image    image;
 } Font;
 
@@ -267,24 +277,24 @@ 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");
 }
 
 void init_font(Font *font, FT_Face face, unsigned first, unsigned last, int autohinter)
 {
-	unsigned i;
+	unsigned i, j;
 	unsigned size = 0;
 
 	font->ascent = (face->size->metrics.ascender+63)>>6;
@@ -331,6 +341,7 @@ void init_font(Font *font, FT_Face face, unsigned first, unsigned last, int auto
 		}
 
 		glyph = &font->glyphs[font->n_glyphs++];
+		glyph->index = n;
 		glyph->code = i;
 		glyph->image.w = bmp->width;
 		glyph->image.h = bmp->rows;
@@ -339,6 +350,9 @@ 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)
@@ -353,6 +367,37 @@ void init_font(Font *font, FT_Face face, unsigned first, unsigned last, int auto
 
 	if(verbose>=1)
 		printf("Loaded %u glyphs\n", font->n_glyphs);
+
+	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)
+		{
+			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/64;
+			}
+		}
+
+	if(verbose>=1)
+		printf("Loaded %d kerning pairs\n", font->n_kerning);
 }
 
 void render_grid(Font *font, unsigned cellw, unsigned cellh, unsigned cpl, int seq)
@@ -362,6 +407,7 @@ void render_grid(Font *font, unsigned cellw, unsigned cellh, unsigned cpl, int s
 	unsigned first, last;
 	unsigned maxw = 0, maxh = 0;
 
+	/* Find extremes of the glyph images. */
 	for(i=0; i<font->n_glyphs; ++i)
 	{
 		int y;
@@ -379,6 +425,7 @@ void render_grid(Font *font, unsigned cellw, unsigned cellh, unsigned cpl, int s
 
 	if(cellw==0)
 	{
+		/* Establish a large enough cell to hold all glyphs in the range. */
 		int square = (cellh==cellw);
 		cellw = maxw;
 		cellh = top-bot;
@@ -402,6 +449,8 @@ void render_grid(Font *font, unsigned cellw, unsigned cellh, unsigned cpl, int s
 
 	if(cpl==0)
 	{
+		/* Determine number of characters per line, trying to fit all the glyphs
+		in a square image. */
 		for(i=1;; i<<=1)
 		{
 			cpl = i/cellw;
@@ -458,13 +507,16 @@ void render_packed(Font *font)
 	unsigned i;
 	unsigned area = 0;
 	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);
 
+	/* 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;
@@ -473,10 +525,14 @@ 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);
 
@@ -488,22 +544,23 @@ void render_packed(Font *font)
 		unsigned best_score = 0;
 		unsigned target_h = 0;
 
-		for(; (cx<font->image.w && used_pixels[cx+cy*font->image.w]); ++cx) ;
+		/* 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;
+
 		if(cx>=font->image.w)
 		{
 			cx = 0;
 			++cy;
 			continue;
 		}
-		for(w=0; (cx+w<font->image.w && !used_pixels[cx+w+cy*font->image.w]); ++w) ;
 
-		for(x=0; x<cx; ++x)
-		{
-			for(y=0; (cy+y+1<font->image.h && used_pixels[cx-x+(cy+y+1)*font->image.w]); ++y) ;
-			if(y>target_h)
-				target_h = y;
-		}
+		/* 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;
@@ -513,6 +570,9 @@ 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==target_h)
 					score *= g->image.w;
@@ -543,17 +603,20 @@ 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;
 		}
 
 		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);
 }
 
@@ -569,11 +632,22 @@ int save_defs(const char *fn, const Font *font)
 		return -1;
 	}
 
-	fprintf(out, "%d %d %d %d %d\n", font->image.w, font->image.h, font->size, font->ascent, font->descent);
+	fprintf(out, "# Image/font info:\n");
+	fprintf(out, "# width height size ascent descent\n");
+	fprintf(out, "font %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];
-		fprintf(out, "%u %u %u %u %u %d %d %d\n", g->code, g->x, g->y, g->image.w, g->image.h, g->offset_x, g->offset_y, g->advance);
+		fprintf(out, "glyph %u %u %u %u %u %d %d %d\n", g->code, g->x, g->y, g->image.w, g->image.h, g->offset_x, g->offset_y, g->advance);
+	}
+	fprintf(out, "\n# Kerning info:\n");
+	fprintf(out, "# left right distance\n");
+	for(i=0; i<font->n_kerning; ++i)
+	{
+		const Kerning *k = &font->kerning[i];
+		fprintf(out, "kern %u %u %d\n", k->left_code, k->right_code, k->distance);
 	}
 
 	fclose(out);