til_fb: fixup clipping of til_fb_fragment_copy()

Apparently no existing were really taking advantage of this
ability.  The x,y,w,h parameters are also supposed to impart clip
bounds, should they be smaller than the union of the src and dest
fragments.

1 files changed, 4 insertions, 4 deletions

diff --git a/src/til_fb.h b/src/til_fb.h
index d346bd7..9daef63 100644
--- a/src/til_fb.h
+++ b/src/til_fb.h
@@ -137,10 +137,10 @@ static inline int til_fb_fragment_put_pixel_checked(til_fb_fragment_t *fragment,
 /* copy a fragment, x,y,width,height are absolute coordinates within the frames, and will be clipped to the overlapping fragment areas */
 static inline void til_fb_fragment_copy(til_fb_fragment_t *dest, uint32_t flags, int x, int y, int width, int height, til_fb_fragment_t *src)
 {
-	int	X = MAX(dest->x, src->x);
-	int	Y = MAX(dest->y, src->y);
-	int	W = MIN(dest->x + dest->width, src->x + src->width) - X;
-	int	H = MIN(dest->y + dest->height, src->y + src->height) - Y;
+	int	X = MAX(MAX(dest->x, src->x), x);
+	int	Y = MAX(MAX(dest->y, src->y), y);
+	int	W = MIN(MIN(dest->x + dest->width, src->x + src->width), x + width) - X;
+	int	H = MIN(MIN(dest->y + dest->height, src->y + src->height), y + height) - Y;
 
 	assert(W >= 0 && H >= 0);