On Fri, 20 Jan 2023 06:02:53 GMT, Sergey Bylokhov <s...@openjdk.org> wrote:
> The "default destination" for the ColorConverOp is used when the user passes > "null" as the DST parameter. In this case, the "ColorConverOp.filter" creates > the default image and uses ComponentColorModel: 8 bits per color component > and optionally 8 bits for the alpha channel. For example for the ARGB source > default destination will be RGBA format. Note that the RGBA format is not > supported by BufferedImage directly, so the CUSTOM image type will be used. > > Generic filtering of the CUSTOM image type is slow because we cannot pass > that format directly to the CMM. But it would be good to support CUSTOM > images that were created by the ColorConverOp. > > Support of the default destination w/o alpha was implemented as part of the > https://bugs.openjdk.org/browse/JDK-8005530. Since then we added support of > the alpha to CMM code https://bugs.openjdk.org/browse/JDK-8012229. > Now we can improve the performance of the default destination if it has the > alpha channel. > > The numbers for filtering opaque and transparent images to the null > destination: > <img width="705" alt="8300725" > src="https://user-images.githubusercontent.com/14138494/213744370-241726f9-6653-403e-bb90-ce98fc089945.png"> all tests passed ------------- Marked as reviewed by prr (Reviewer). PR: https://git.openjdk.org/jdk/pull/12110