Initial revision

src/libdraw/unloadimage.c

@@ -0,0 +1,53 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+
+int
+unloadimage(Image *i, Rectangle r, uchar *data, int ndata)
+{
+	int bpl, n, ntot, dy;
+	uchar *a;
+	Display *d;
+
+	if(!rectinrect(r, i->r)){
+		werrstr("unloadimage: bad rectangle");
+		return -1;
+	}
+	bpl = bytesperline(r, i->depth);
+	if(ndata < bpl*Dy(r)){
+		werrstr("unloadimage: buffer too small");
+		return -1;
+	}
+
+	d = i->display;
+	flushimage(d, 0);	/* make sure subsequent flush is for us only */
+	ntot = 0;
+	while(r.min.y < r.max.y){
+		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+17, r.min.y+dy);
+		if(flushimage(d, 0) < 0)
+			return -1;
+		n = _drawmsgread(d, data+ntot, ndata-ntot);
+		if(n < 0)
+			return n;
+		ntot += n;
+		r.min.y += dy;
+	}
+	return ntot;
+}