From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 4 May 2018 21:07:23 +0000 (+0300)
Subject: Add an option to control distance field border zone
X-Git-Url: http://git.tdb.fi/?p=ttf2png.git;a=commitdiff_plain;h=a815ebe3941e2157639365806e9186e49ee944b5

Add an option to control distance field border zone
---

diff --git a/Readme b/Readme
index 7695e61..c4fc9d0 100644
--- a/Readme
+++ b/Readme
@@ -80,6 +80,10 @@ Command-line options
     stored without alpha and with large/positive values indicating the inside
     of glyphs; the -t and -i options are ignored.
 
+  -b <pixels>
+    Set the border zone width for distance field.  The default is the square
+    root of the font size.
+
   -d
     File name to write glyph definitions.  See the section below for details.
 
diff --git a/ttf2png.c b/ttf2png.c
index 1c17c6b..0a66de2 100644
--- a/ttf2png.c
+++ b/ttf2png.c
@@ -78,8 +78,8 @@ 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, const Range *, unsigned, bool, unsigned);
-int init_glyphs(Font *, FT_Face, const Range *, bool, 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);
@@ -109,6 +109,7 @@ int main(int argc, char **argv)
 	unsigned padding = 1;
 	bool npot = 0;
 	unsigned distfield = 0;
+	unsigned border = 0;
 
 	FT_Library freetype;
 	FT_Face face;
@@ -127,7 +128,7 @@ int main(int argc, char **argv)
 		return 1;
 	}
 
-	while((i = getopt(argc, argv, "r:s:l:c:o:atvh?ed:pim:n:gf:")) != -1)
+	while((i = getopt(argc, argv, "r:s:l:c:o:atvh?ed:pim:n:gf:b:")) != -1)
 	{
 		switch(i)
 		{
@@ -184,6 +185,9 @@ int main(int argc, char **argv)
 		case 'f':
 			distfield = convert_numeric_option('f', 1);
 			break;
+		case 'b':
+			border = convert_numeric_option('b', 1);
+			break;
 		}
 	}
 	if(!strcmp(out_fn, "-"))
@@ -222,7 +226,11 @@ int main(int argc, char **argv)
 
 	font.size = size;
 	if(distfield)
+	{
+		if(!border)
+			border = sqrti(font.size);
 		size *= distfield;
+	}
 
 	err = FT_Set_Pixel_Sizes(face, 0, size);
 	if(err)
@@ -241,7 +249,7 @@ int main(int argc, char **argv)
 	else
 		sort_and_compact_ranges(ranges, &n_ranges);
 
-	err = init_font(&font, face, ranges, n_ranges, autohinter, distfield);
+	err = init_font(&font, face, ranges, n_ranges, autohinter, distfield, border);
 	if(err)
 		return 1;
 
@@ -508,7 +516,7 @@ void *alloc_image_data(size_t a, size_t b)
 	return ptr;
 }
 
-int init_font(Font *font, FT_Face face, const Range *ranges, unsigned n_ranges, bool autohinter, unsigned distfield)
+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;
@@ -526,7 +534,7 @@ int init_font(Font *font, FT_Face face, const Range *ranges, unsigned n_ranges,
 	font->n_glyphs = 0;
 	font->glyphs = NULL;
 	for(i=0; i<n_ranges; ++i)
-		if(init_glyphs(font, face, &ranges[i], autohinter, distfield))
+		if(init_glyphs(font, face, &ranges[i], autohinter, distfield, border))
 			return -1;
 
 	if(verbose>=1)
@@ -565,7 +573,7 @@ int init_font(Font *font, FT_Face face, const Range *ranges, unsigned n_ranges,
 	return 0;
 }
 
-int init_glyphs(Font *font, FT_Face face, const Range *range, bool autohinter, unsigned distfield)
+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;
@@ -632,11 +640,9 @@ int init_glyphs(Font *font, FT_Face face, const Range *range, bool autohinter, u
 		start from the bottom. */
 		if(distfield)
 		{
-			unsigned margin = 3;
-
-			glyph->offset_x -= margin;
-			glyph->offset_y -= margin;
-			create_distance_field(bmp, &glyph->image, distfield, margin);
+			glyph->offset_x -= border;
+			glyph->offset_y -= border;
+			create_distance_field(bmp, &glyph->image, distfield, border);
 		}
 		else
 		{