JDK-6563801 : alpha values mistakenly applied twice in DrawImage.renderImageXform()
  • Type: Bug
  • Component: client-libs
  • Sub-Component: 2d
  • Affected Version: 6
  • Priority: P4
  • Status: Closed
  • Resolution: Duplicate
  • OS: generic
  • CPU: generic
  • Submitted: 2007-05-31
  • Updated: 2018-06-26
  • Resolved: 2018-06-26
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JDK 8
8-poolResolved
Related Reports
Duplicate :  
JDK-8062164 - Incorrect color conversion, when bicubic interpolation is used
Description
In some cases, it is possible to get incorrect blending results (alpha values
appear to be applied twice) when transforming an image with JDK 6 or higher.
This only occurs for certain destination types where a native MaskBlit loop is
not implemented (e.g. OpenGLSurface, a TYPE_FLOAT BufferedImage, and so on).
Comments
This was fixed in JDK 9 as https://bugs.openjdk.java.net/browse/JDK-8062164 http://hg.openjdk.java.net/jdk9/jdk9/jdk/rev/748091d834cf
26-06-2018
EVALUATION The problem is in DrawImage.renderImageXform(): BufferedImage tmpimg = new BufferedImage(dx2-dx1, dy2-dy1, BufferedImage.TYPE_INT_ARGB); We should create the intermediate image as TYPE_INT_ARGB_PRE, not TYPE_INT_ARGB. It should be relatively easy to come up with a regression test for this by rendering into a TYPE_CUSTOM image or an OGL-accelerated VolatileImage.
31-05-2007