clip out of range values when we go to labs

jcupitt · jcupitt · commit 088330c112ae · 2024-07-13T09:27:26.000+01:00
diff --git a/libvips/colour/Lab2LabS.c b/libvips/colour/Lab2LabS.c
@@ -7,6 +7,8 @@
  *	- cleanups
  * 20/9/12
  * 	- redo as a class
+ * 13/7/24
+ *	- clip out of range values
  */
 
 /*
@@ -61,9 +63,9 @@ vips_Lab2LabS_line(VipsColour *colour, VipsPel *out, VipsPel **in, int width)
 	int i;
 
 	for (i = 0; i < width; i++) {
-		q[0] = p[0] * (32767.0 / 100.0);
-		q[1] = p[1] * (32768.0 / 128.0);
-		q[2] = p[2] * (32768.0 / 128.0);
+		q[0] = VIPS_CLIP(0, p[0] * (32767.0 / 100.0), SHRT_MAX);
+		q[1] = VIPS_CLIP(SHRT_MIN, p[1] * (32768.0 / 128.0), SHRT_MAX);
+		q[2] = VIPS_CLIP(SHRT_MIN, p[2] * (32768.0 / 128.0), SHRT_MAX);
 
 		q += 3;
 		p += 3;
