From cceae8ad0a87064fa06b8a1855dcd6c65195453f Mon Sep 17 00:00:00 2001
From: Dobrica Pavlinusic <dpavlin@rot13.org>
Date: Fri, 5 Oct 2012 14:33:24 +0200
Subject: [PATCH] add negative x,y checking in dimRect

---
 blitbuffer.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/blitbuffer.c b/blitbuffer.c
index 6345025d7..90e2e55d5 100644
--- a/blitbuffer.c
+++ b/blitbuffer.c
@@ -489,6 +489,27 @@ static int dimRect(lua_State *L) {
 	uint8_t *dstptr;
 
 	int cy, cx;
+
+	if (x < 0) {
+		if ( x + w > 0 ) {
+			w = w + x;
+			x = 0;
+		} else {
+			//printf("## invertRect x out of bound\n");
+			return 0;
+		}
+	}
+
+	if (y < 0) {
+		if ( y + h > 0 ) {
+			h = h + y;
+			y = 0;
+		} else {
+			//printf("## invertRect y out of bound\n");
+			return 0;
+		}
+	}
+
 	if(w <= 0 || h <= 0 || x >= dst->w || y >= dst->h) {
 		return 0;
 	}