From fc5841aa95872eddc403b9618747d07ca9a92c91 Mon Sep 17 00:00:00 2001
From: glenda <glenda@r51>
Date: Sun, 23 Nov 2025 00:31:40 +0000
Subject: [PATCH] glyph metrics

---
 ufx2font.c | 107 ++++++++++++++++++++++++-----------------------------
 1 file changed, 48 insertions(+), 59 deletions(-)

diff --git a/ufx2font.c b/ufx2font.c
index 7f1ee919996e922a7bb2a6fa37c394a0379525c2..0ff846b9906c663c8b8c3792090a05717578e181 100644
--- a/ufx2font.c
+++ b/ufx2font.c
@@ -5,6 +5,8 @@
 
 /* entry has 1 byte in widtab + 8 bytes per tile */
 #define ufxlen(n) ((n)*(n)*8)
+#define max(a, b) ((a) > (b) ? (a) : (b))
+#define min(a, b) ((a) < (b) ? (a) : (b))
 
 
 enum{
@@ -41,7 +43,7 @@ struct GlyphInfo{
 };
 
 
-uint fwidth, nglyphs, glyphlen, glyphedge;
+uint fwidth, nglyphs, glyphlen, glyphedge, baseline;
 
 uchar setconv, donaive, doholes;
 struct MapFile *mapfiles, *lastmf;
@@ -341,49 +343,28 @@ loadufx(char *infile)
 
 	Bterm(b);
 }
-void
-testcol(uchar len, uint offset, uchar *top, uchar *bot)
-{
-	uchar mask;
-
-	if(len > 8)
-		len = 8;
-	mask = 0xff<<(8-len);
-
-	for(*top = 0; *top < glyphedge; (*top)++){
-		print("gbitmaps[off+top]=%2ux; mask=%2ux\n", gbitmaps[offset + *top], mask);
-		if(gbitmaps[offset + *top] & mask != 0)
-			break;
-	}
-	
-	for(*bot = (glyphedge - 1); *bot >= *top; (*bot)--)
-		if(gbitmaps[offset + *bot] & mask != 0)
-			break;
-}
-/*
 uchar
-highbit(uchar b)
+testscanline(uchar *bitmap, int rowlen)
 {
-	uchar i = 0;
-	while(b != 0){
-		i++;
-		b >>= 1;
+	uchar mask, x;
+	for(x = 0; x <= (rowlen-1)/8; x++){
+		/* ignore the right edge of the last byte */
+		mask = 0xff << (8-min(8, rowlen-x*8));
+		if((bitmap[x*glyphedge] & mask) != 0)
+			return 1;
 	}
 
-	return 8 - i;	// returns 8 if b == 0
+	return 0;	
 }
-uchar
-findleft(uint offset)
-{
-	uchar left = 0;
-}
-*/
 void
 parseglyphs(char *file)
 {
-	uint i, offset;
+	uint i, y, top, bot, *botfreqs = nil, bestfreq;
 	int rowlen;
-	uchar top, bot;
+	uchar *bitmap;
+
+	if(baseline < 1)
+		botfreqs = calloc(glyphedge, sizeof(uint));
 
 	for(i = 0; i < nglyphs; i++){
 		rowlen = ginfo[i].width;
@@ -393,31 +374,30 @@ parseglyphs(char *file)
 			fprint(2, "%s: %s: 0x%2x: bad width %dpx, truncating\n", argv0, file, i, rowlen);
 			rowlen = glyphedge;
 		}
+		bitmap = gbitmaps+i*glyphlen;
+
+		for(y = 0; y < glyphedge; y++)
+			if(testscanline(bitmap+y, rowlen))
+				break;
+		top = y;
+		for(y = glyphedge-1; y >= top; y--)
+			if(testscanline(bitmap+y, rowlen))
+				break;
+		bot = y;
+
+		ginfo[i].top = top; ginfo[i].bottom = bot;
+		if(baseline < 1 && top <= bot)	/* don't count empty glyphs */
+			botfreqs[bot]++;
+	}
 
-		offset = glyphlen * i;
-		ginfo[i].top = glyphedge;
-		ginfo[i].bottom = 0;
-
-		while(rowlen > 0){
-			testcol(rowlen, offset, &top, &bot);
-			if(top < ginfo[i].top)
-				ginfo[i].top = top;
-			if(bot > ginfo[i].bottom)
-				ginfo[i].bottom = bot;
-
-			// TODO: calculate .left, maybe?
-
-			offset += glyphedge;
-			rowlen -= 8;
-		}
-
-		if(ginfo[i].top == glyphedge){
-			// blank glyph
-			ginfo[i].top = 0;
-			ginfo[i].bottom = glyphedge - 1;
+	if(baseline < 1){
+		bestfreq = 0;
+		for(i = 0; i < glyphedge; i++){
+			if(botfreqs[i] > bestfreq){
+				baseline = i;
+				bestfreq = botfreqs[i];
+			}
 		}
-
-		print("glyphs[%2x]: rowlen=%02d top=%02d bottom=%02d\n", i, ginfo[i].width, ginfo[i].top, ginfo[i].bottom);
 	}
 }
 
@@ -425,7 +405,7 @@ parseglyphs(char *file)
 void
 usage(void)
 {
-	fprint(2, "usage: %s [-nh] [-m mapfile] [-l length] [-x width] in.ufx out/\n", argv0);
+	fprint(2, "usage: %s [-nh] [-b baseline] [-m mapfile] [-l length] [-x width] in.ufx out/\n", argv0);
 	exits("usage");
 }
 
@@ -462,6 +442,11 @@ main(int argc, char **argv)
 		lastmf->next = nil;
 		lastmf->mappings = nil;
 		break;
+	case 'b':
+		baseline = atoi(EARGF(usage()));
+		if(baseline < 1)
+			sysfatal("-b: baseline must be in range 1-width*8");
+		break;
 	default:
 		usage();
 	}ARGEND;
@@ -476,6 +461,8 @@ main(int argc, char **argv)
 
 
 	sniffdims(infile);
+	if(baseline >= glyphedge)
+		sysfatal("-b: baseline must be in range 1-width*8");
 
 	for(mf = mapfiles; mf != nil; mf = mf->next)
 		parsemapfile(mf);
@@ -486,4 +473,6 @@ main(int argc, char **argv)
 
 	loadufx(infile);
 	parseglyphs(infile);
+
+	print("baseline=%ud\n", baseline);
 }