Don't throw an exception if the image histogram has no colors

diff --git a/MagickCore/histogram.c b/MagickCore/histogram.c
index ab2cbcf1abfdd160592040401cc2affa0fd7316e..04c56eca0ac3e80bd8e456b6bdbbf9efe6c7239d 100644 (file)
--- a/MagickCore/histogram.c
+++ b/MagickCore/histogram.c
@@ -533,7 +533,7 @@ MagickExport PixelInfo *GetImageHistogram(const Image *image,
   cube_info=ClassifyImageColors(image,exception);
   if (cube_info != (CubeInfo *) NULL)
     {
-      histogram=(PixelInfo *) AcquireQuantumMemory((size_t) cube_info->colors,
+      histogram=(PixelInfo *) AcquireQuantumMemory((size_t) cube_info->colors+1,
         sizeof(*histogram));
       if (histogram == (PixelInfo *) NULL)
         (void) ThrowMagickException(exception,GetMagickModule(),