[OpenJDK 2D-Dev] RFR: 8263583: Emoji rendering on macOS

[Sergey Bylokhov]

On Wed, 17 Mar 2021 10:45:00 GMT, Dmitry Batrak <dbatrak at openjdk.org> wrote:

>>> What kind of test are you having in mind? I can extend the added MacEmoji.java test, that will check that 'something' is painted to different types of BufferedImage-s and/or with transforms applied. Or you want me to add a manual test case?
>> 
>> The automated tests will be enough, not sure about 'something is painted' however, it is better to check that it works.
>
> @mrserb I don't know how to check automatically that glyph painting works correctly. Could you please suggest a way to do it? In JetBrains Runtime we have a test that checks that rendered emoji glyph matches one of stored 'golden images', but I don't think that's suitable for OpenJDK, unless someone will volunteer to update that list when the need arises (e.g. when newer version of macOS changes the font, or rendering details). At the moment, we have already 7 golden images for a single glyph in our repository.

You the current image from the MacEmoji test as a golden image for other formats/transforms/extraalpha/etc. For example, if DST type is changed then it is unlikely the shape of the emoji will be changed as well, or if it is too big/ too small.

BTW It will be good if the test will fail on the current metal implementation.

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PR: https://git.openjdk.java.net/jdk/pull/3007