More bounds checking with bottomRight to prevent possible panic in zero size imagesHEADv0.6.1master

1 files changed, 3 insertions, 0 deletions

diff --git a/integral.go b/integral.go
index e3d09bb..99a4da7 100644
--- a/integral.go
+++ b/integral.go
@@ -176,6 +176,9 @@ func (i Image) bottomRight(r image.Rectangle) uint64 {
 	b := i.Bounds()
 	x := lowest(r.Max.X-1, b.Max.X-1)
 	y := lowest(r.Max.Y-1, b.Max.Y-1)
+	if x < 0 || y < 0 {
+		return 0
+	}
 	return i[y][x]
 }