libdraw: fix unloadimage() for wide images, libmemdraw: work arround width limit by outputting uncompressed image in writememimage() if compressed blocksize exceeds chunk limit

1 files changed, 22 insertions, 17 deletions

diff --git a/sys/src/libdraw/unloadimage.c b/sys/src/libdraw/unloadimage.c
index ead36b0c8..741c73b6b 100644
--- a/sys/src/libdraw/unloadimage.c
+++ b/sys/src/libdraw/unloadimage.c
@@ -5,8 +5,8 @@
 int
 unloadimage(Image *i, Rectangle r, uchar *data, int ndata)
 {
-	int bpl, n, ntot, dy;
-	uchar *a;
+	int bpl, n, chunk, dx, dy;
+	uchar *a, *start;
 	Display *d;
 
 	if(!rectinrect(r, i->r)){
@@ -18,36 +18,41 @@ unloadimage(Image *i, Rectangle r, uchar *data, int ndata)
 		werrstr("unloadimage: buffer too small");
 		return -1;
 	}
-
+	start = data;
 	d = i->display;
+	chunk = d->bufsize;
 	flushimage(d, 0);	/* make sure subsequent flush is for us only */
-	ntot = 0;
 	while(r.min.y < r.max.y){
+		dx = Dx(r);
+		dy = chunk/bpl;
+		if(dy <= 0){
+			dy = 1;
+			dx = ((chunk*dx)/bpl) & ~7;
+			n = bytesperline(Rect(r.min.x, r.min.y, r.min.x+dx, r.min.y+dy), i->depth);
+			if(unloadimage(i, Rect(r.min.x+dx, r.min.y, r.max.x, r.min.y+dy), data+n, bpl-n) < 0)
+				return -1;
+		} else {
+			if(dy > Dy(r))
+				dy = Dy(r);
+			n = bpl*dy;
+		}
 		a = bufimage(d, 1+4+4*4);
 		if(a == 0){
 			werrstr("unloadimage: %r");
 			return -1;
 		}
-		dy = 8000/bpl;
-		if(dy <= 0){
-			werrstr("unloadimage: image too wide");
-			return -1;
-		}
-		if(dy > Dy(r))
-			dy = Dy(r);
 		a[0] = 'r';
 		BPLONG(a+1, i->id);
 		BPLONG(a+5, r.min.x);
 		BPLONG(a+9, r.min.y);
-		BPLONG(a+13, r.max.x);
+		BPLONG(a+13, r.min.x+dx);
 		BPLONG(a+17, r.min.y+dy);
 		if(flushimage(d, 0) < 0)
 			return -1;
-		n = read(d->fd, data+ntot, ndata-ntot);
-		if(n < 0)
-			return n;
-		ntot += n;
+		if(read(d->fd, data, n) < 0)
+			return -1;
+		data += bpl*dy;
 		r.min.y += dy;
 	}
-	return ntot;
+	return data - start;
 }