[OpenJDK 2D-Dev] RFR: 8012229: [lcms] Improve performance of color conversion for images with alpha channel [v2]

[Sergey Bylokhov]

> The lcms 2.8 version added support for the cmsFLAGS_COPY_ALPHA flag:
> https://sourceforge.net/p/lcms/mailman/lcms-user/thread/001c01d1c0f3%2484a7cb30%248df76190%24%40ProDigitalSoftware.com/#msg35143398
> 
> which supports alpha channel transportation
> 
> For our usage, it means we can use TYPE_4BYTE_ABGR and TYPE_INT_ARGB directly as a source and destination.
> 
> Some numbers:
> converting new BufferedImage(3000, 3000, TYPE_INT_ARGB) from CS_sRGB to CS_CIEXYZ via op.filter(src, dst).
> //before the fix
> //Benchmark                  Mode  Cnt    Score    Error  Units
> //ColorAlphaConv.testFilter  avgt    5  603,392 ± 12,932  ms/op
> 
> //after the fix
> //Benchmark                  Mode  Cnt    Score   Error  Units
> //ColorAlphaConv.testFilter  avgt    5  121,624 ± 0,906  ms/op
> 
> But still slower than kcms
> //kcms jdk8u60
> //Benchmark                  Mode  Cnt   Score   Error  Units
> //ColorAlphaConv.testFilter  avgt    5  13,256 ± 0,169  ms/op

Sergey Bylokhov has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Merge branch 'master' into JDK-8012229
 - Update ColCvtAlphaDifferentSrcDst.java
 - Initial fix

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3239/files
  - new: https://git.openjdk.java.net/jdk/pull/3239/files/c89a4ca1..60a3dfca

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3239&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3239&range=00-01

  Stats: 4586 lines in 234 files changed: 3018 ins; 664 del; 904 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3239.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3239/head:pull/3239

PR: https://git.openjdk.java.net/jdk/pull/3239