$OpenBSD: patch-src_assemble_h,v 1.1.1.1 2009/04/19 11:14:37 sthen Exp $
--- src/assemble.h.orig	Sat Mar  8 23:16:23 2008
+++ src/assemble.h	Fri Apr 17 20:18:16 2009
@@ -81,14 +81,18 @@ void checkpoint(pair<ImageType*, AlphaType*> &p, Image
             Threshold<AlphaPixelType, ImagePixelComponentType>, AlphaAccessor>
             ThresholdingAccessor;
  
+    AlphaType* alphaType = p.second;
+    ImagePixelComponentType alphaMaxValue = AlphaTraits<ImagePixelComponentType>::max();
+    ImagePixelComponentType alphaZeroValue = AlphaTraits<ImagePixelComponentType>::zero();
+    AlphaPixelType numericZeroValue = NumericTraits<AlphaPixelType>::zero();
+    Threshold<AlphaPixelType, ImagePixelComponentType> curThreshold =
+        Threshold<AlphaPixelType, ImagePixelComponentType>(numericZeroValue,
+                                                           numericZeroValue,
+                                                           alphaMaxValue,
+                                                           alphaZeroValue);
     ThresholdingAccessor ata(
-            Threshold<AlphaPixelType, ImagePixelComponentType>(
-                    NumericTraits<AlphaPixelType>::zero(),
-                    NumericTraits<AlphaPixelType>::zero(),
-                    AlphaTraits<ImagePixelComponentType>::max(),
-                    AlphaTraits<ImagePixelComponentType>::zero()
-            ),
-            (p.second)->accessor());
+            curThreshold,
+            alphaType->accessor());
 
     try {
         exportImageAlpha(srcImageRange(*(p.first)),
@@ -118,12 +122,15 @@ void import(const ImageImportInfo &info,
 
     // Threshold the alpha mask so that all pixels are either contributing
     // or not contributing.
+    ImagePixelComponentType imagePixelMaxValue = AlphaTraits<ImagePixelComponentType>::max();
+    AlphaPixelType alphaPixelMaxValue = AlphaTraits<AlphaPixelType>::max();
+    AlphaPixelType alphaPixelZeroValue = AlphaTraits<AlphaPixelType>::zero();
     ThresholdingAccessor ata(
             Threshold<ImagePixelComponentType, AlphaPixelType>(
-                    AlphaTraits<ImagePixelComponentType>::max() / 2,
-                    AlphaTraits<ImagePixelComponentType>::max(),
-                    AlphaTraits<AlphaPixelType>::zero(),
-                    AlphaTraits<AlphaPixelType>::max()
+                    imagePixelMaxValue / 2,
+                    imagePixelMaxValue,
+                    alphaPixelZeroValue,
+                    alphaPixelMaxValue
             ),
             alpha.second);