libdraw: add 2*font syntax for scaled fonts

An experiment.

Change-Id: I40660a211b8372701597d80f7e86917e94cccbaa
Reviewed-on: https://plan9port-review.googlesource.com/1161
Reviewed-by: Russ Cox <rsc@swtch.com>

1 files changed, 59 insertions, 1 deletions

diff --git a/src/libdraw/getsubfont.c b/src/libdraw/getsubfont.c
index 0d8be9ff..3f3b6954 100644
--- a/src/libdraw/getsubfont.c
+++ b/src/libdraw/getsubfont.c
@@ -8,8 +8,10 @@
 
 int _fontpipe(char*);
 
+static void scalesubfont(Subfont*, int);
+
 Subfont*
-_getsubfont(Display *d, char *name)
+_getsubfont(Display *d, Font *ff, char *name)
 {
 	int fd;
 	Subfont *f;
@@ -36,5 +38,61 @@ _getsubfont(Display *d, char *name)
 	if(f == 0)
 		fprint(2, "getsubfont: can't read %s: %r\n", name);
 	close(fd);
+	if(ff->scale != 1 && ff->scale != 0)
+		scalesubfont(f, ff->scale);
 	return f;
 }
+
+static void
+scalesubfont(Subfont *f, int scale)
+{
+	Image *i;
+	Rectangle r, r2;
+	int y, x, x2, j;
+	uchar *src, *dst;
+	int srcn, dstn, n, mask, v, pack;
+	
+	r = f->bits->r;
+	r2 = r;
+	r2.min.x *= scale;
+	r2.min.y *= scale;
+	r2.max.x *= scale;
+	r2.max.y *= scale;
+	
+	srcn = bytesperline(r, f->bits->depth);
+	src = malloc(srcn);
+	dstn = bytesperline(r2, f->bits->depth);
+	dst = malloc(dstn+1);
+	i = allocimage(f->bits->display, r2, f->bits->chan, 0, DBlack);
+	for(y=r.min.y; y < r.max.y; y++) {
+		n = unloadimage(f->bits, Rect(r.min.x, y, r.max.x, y+1), src, srcn);
+		if(n != srcn)
+			sysfatal("scalesubfont: bad unload: %d < %d: %r", n, srcn);
+		memset(dst, 0, dstn+1);
+		pack = 8 / f->bits->depth;
+		mask = (1<<f->bits->depth) - 1;
+		for(x=0; x<Dx(r); x++) {
+			v = ((src[x/pack] << ((x%pack)*f->bits->depth)) >> (8 - f->bits->depth)) & mask;
+			for(j=0; j<scale; j++) {
+				x2 = x*scale+j;
+				dst[x2/pack] |= v << (8 - f->bits->depth) >> ((x2%pack)*f->bits->depth);
+			}
+		}
+		if(dst[dstn] != 0)
+			sysfatal("overflow dst");
+		for(j=0; j<scale; j++)
+			loadimage(i, Rect(r2.min.x, y*scale+j, r2.max.x, y*scale+j+1), dst, dstn);
+	}
+	freeimage(f->bits);
+	f->bits = i;
+	f->height *= scale;
+	f->ascent *= scale;
+	
+	for(j=0; j<f->n; j++) {
+		f->info[j].x *= scale;
+		f->info[j].top *= scale;
+		f->info[j].bottom *= scale;
+		f->info[j].left *= scale;
+		f->info[j].width *= scale;
+	}
+}