RFR: 8088198: Exception thrown from snapshot if dimensions are larger than max texture size

[Kevin Rushforth]

On Tue, 17 Dec 2019 13:47:50 GMT, Frederic Thevenet <github.com+7450507+fthevenet at openjdk.org> wrote:

> This PR aims to address the following issue: JDK-8088198 Exception thrown from snapshot if dimensions are larger than max texture size
> 
> In order to do that, it simply captures snapshots in multiple tiles of maxTextureSize^2 dimensions (or less, as needed), and then recomposes all the tiles into a a single image.
> Other than that, the logic used to do the actual snapshot is unchanged.
> 
> Tests using the existing SnapshotCommon class have been added in a new file named Snapshot3Test under SystemTest/test/javafx/scene.
> These tests pass with the proposed fix, and fail without, throwing " java.lang.IllegalArgumentException: Unrecognized image loader: null"

This will need two reviewers. I want to review it, and I request @arapte to also review.

I won't have time to do a detailed review until the new year. One quick comment: in addition to the new tests you have provided, there are 4 `@Ignore`d tests in [Snapshot2Test.java](https://github.com/openjdk/jfx/blob/master/tests/system/src/test/java/test/javafx/scene/Snapshot2Test.java) that can likely be re-enabled. Look for `TODO: Re-enable this test when RT-22073 is fixed` (RT-22073 was mapped to JDK-8088198).

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PR: https://git.openjdk.java.net/jfx/pull/68