[OpenJDK 2D-Dev] Java's definition of the SRC operator

[Jim Graham]

SRC behaves like SRC, but AA is another part of the equation.  It works 
like this (for any rule):

blendresult = PORTER_DUFF(rule, rendercolor, dstcolor, extraalpha)
// For SRC, blendresult = rendercolor modulated by extra alpha
storedresult = INTERP(dstcolor, blendresult, aacoverage)
// For full aa coverage, storedresult = blendresult

The only part of this that could possibly be interpreted as "behaving 
like SRC_OVER" would be the second INTERP and it depends on the aa 
coverage, not on the alpha of the colors involved.  Is that what they 
were talking about?

But, the interior of shapes should all have full aa coverage and so 
should just store the blendresult (which, in the case of SRC is 
rendercolor)...

			...jim

On 10/29/10 12:06 PM, Clemens Eisserer wrote:
> Hi,
>
> Some users reported problems with the IntelliJ Idea's editor when
> running with xrender enabled.
> It turned out that there are some differences between how Java and
> xrender interpret the SRC operator.
>
> Is the general rule, that SRC behaves like SRC_OVER when antialiasing
> is enabled?
> Are there some special cases that need to be taken care of?
>
> Thanks, Clemens