From b8ace0a40f3cad1d0b56568c4ac61d63dbd190d9 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 23 Nov 2012 19:04:52 +0200
Subject: [PATCH] Eliminate some nested loops from the packing algorithm

---
 ttf2png.c | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/ttf2png.c b/ttf2png.c
index 7e78e84..3685b5a 100644
--- 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)
-- 
2.43.0