RFR: 8303904: [macos]Transparent Windows Paint Wrong (Opaque, Pixelated) w/o Volatile Buffering [v3]

[anass baya]

> The PR includes two fix : 
> 1 - The first fix targets proper rendering of the transparent image.
> 2 - The second fix ensures the image is painted at the correct resolution to avoid pixelation.

anass baya has updated the pull request incrementally with three additional commits since the last revision:

 - Enhancment step 3
 - Enhancement - step 2
 - enhancement - step 1

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/23430/files
  - new: https://git.openjdk.org/jdk/pull/23430/files/e65d7344..48ad43b7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=23430&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=23430&range=01-02

  Stats: 85 lines in 4 files changed: 21 ins; 53 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/23430.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23430/head:pull/23430

PR: https://git.openjdk.org/jdk/pull/23430