diff --git a/MagickCore/xwindow.c b/MagickCore/xwindow.c
index 98145ab..6fa824d 100644
--- a/MagickCore/xwindow.c
+++ b/MagickCore/xwindow.c
@@ -484,7 +484,7 @@
     annotate_pixmap;
 
   Quantum
-    virtual_pixel[MaxPixelChannels];
+    virtual_pixel[CompositePixelChannel];
 
   unsigned int
     depth,
@@ -2327,7 +2327,7 @@
     matte;
 
   Quantum
-    virtual_pixel[MaxPixelChannels];
+    virtual_pixel[CompositePixelChannel];
 
   Pixmap
     draw_pixmap;