Eliminate some nested loops from the packing algorithm

diff --git a/ttf2png.c b/ttf2png.c
index 7e78e84d41de01b10cd4aaa0fd410a8e88ee2e4f..3685b5a106d9e3f9641051b13df4dfaa8ac5aeb1 100644 (file)
--- a/ttf2png.c
+++ b/ttf2png.c
@@ -458,7 +458,7 @@ 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;
 
@@ -475,8 +475,8 @@ void render_packed(Font *font)
 
        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);
 
@@ -488,21 +488,18 @@ 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) ;
+               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;
-               }
+               for(w=0; (cx+w<font->image.w && used_pixels[cx+w]<=cy); ++w) ;
 
                for(i=0; i<font->n_glyphs; ++i)
                {
@@ -543,11 +540,12 @@ 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)