RFR: 8255724: [XRender] the BlitRotateClippedArea test fails on Linux in the XR pipeline

[Sergey Bylokhov]

On Tue, 19 Oct 2021 09:56:07 GMT, Jayathirth D V <jdv at openjdk.org> wrote:

> This test was added under https://bugs.openjdk.java.net/browse/JDK-8255722 to verify rotated blit operation. But it started failing XRender pipeline because of pixel color mismatch. Looks like we have minor difference in pixel color because of arithmetic precision differences in transformations.
> 
> This test fails every-time in XRender without tolerance and passes with +/-1 in Color values in CI systems. Updated test to use +/-1 tolerance as mentioned in JBS. Added this little tolerance in Color will not change functionality that we are verifying in this test.

actually it does change the meaning of the test, take a look how it generate the pattern in the drawing image, to check many combination of colors. And in fact it found a bug in the XRender, so it will be good to preserve that strict requirements in the test for other/new pipelines.

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PR: https://git.openjdk.java.net/jdk/pull/6002