svn commit: r1823594 - /pdfbox/branches/2.0/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/graphics/blend/BlendMode.java

[tilman]

Author: tilman
Date: Thu Feb  8 18:58:33 2018
New Revision: 1823594

URL: http://svn.apache.org/viewvc?rev=1823594&view=rev
Log:
PDFBOX-3000: use the revised PDF 2.0 equations for the blend modes ColorDodge 
and ColorBurn as suggested by Jani Pehkonen

Modified:
    
pdfbox/branches/2.0/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/graphics/blend/BlendMode.java

Modified: 
pdfbox/branches/2.0/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/graphics/blend/BlendMode.java
URL: 
http://svn.apache.org/viewvc/pdfbox/branches/2.0/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/graphics/blend/BlendMode.java?rev=1823594&r1=1823593&r2=1823594&view=diff
==============================================================================
--- 
pdfbox/branches/2.0/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/graphics/blend/BlendMode.java
 (original)
+++ 
pdfbox/branches/2.0/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/graphics/blend/BlendMode.java
 Thu Feb  8 18:58:33 2018
@@ -125,7 +125,16 @@ public abstract class BlendMode
         @Override
         public float blendChannel(float srcValue, float dstValue)
         {
-            return (srcValue < 1) ? Math.min(1, dstValue / (1 - srcValue)) : 1;
+            // See PDF 2.0 specification
+            if (dstValue == 0)
+            {
+                return 0;
+            }
+            if (dstValue >= 1 - srcValue)
+            {
+                return 1;
+            }
+            return dstValue / (1 - srcValue);
         }
     };
 
@@ -134,7 +143,16 @@ public abstract class BlendMode
         @Override
         public float blendChannel(float srcValue, float dstValue)
         {
-            return (srcValue > 0) ? 1 - Math.min(1, (1 - dstValue) / srcValue) 
: 0;
+            // See PDF 2.0 specification
+            if (dstValue == 1)
+            {
+                return 1;
+            }
+            if (1 - dstValue >= srcValue)
+            {
+                return 0;
+            }
+            return 1 - (1 - dstValue) / srcValue;
         }
     };