diff --git a/areaplan.md b/areaplan.md
index b085aa9..b7e705b 100644
--- a/areaplan.md
+++ b/areaplan.md
@@ -127,6 +127,7 @@ func our_drawRect(self C.id, rect C.struct_xrect) {
 		hasAlpha:YES
 		isPlanar:NO
 		colorSpaceName:NSCalibratedRGBColorSpace		// TODO NSDeviceRGBColorSpace?
+		bitmapFormat:NSAlphaNonpremultipliedBitmapFormat
 		bytesPerRow:i.Stride
 		bitsPerPixel:32]
 	[bitmap drawAtPoint:NSMakePoint(cliprect.x, cliprect.y)]