RFR: 8290866: Apple Color Emoji turns gray after JavaFX version 18

[Andy Goryachev]

On Thu, 23 Feb 2023 20:43:29 GMT, Phil Race <prr at openjdk.org> wrote:

> This fix properly supports colour rendering of Emoji on macOS
> 
> 
> On other platforms the Emoji will be rendered as ordinary greyscale glyphs - if there is font
> support for the requested code point.
> 
> A simple manual test is provided which uses a Text node, Label control
> and editable TextField control.
> 
> Some highlights of the code
> - To determine if it is a color emoji glyph probe the 'sbix' font table which is what is used by Apple
> - Text runs now break at an Emoji glyph
> - The Emoji is retrieved as an BGRA image - ie 4 channel including alpha
> - It was necessary to retrieve the Emoji glyph bounds via a different CoreText API since
>    the bounds that were being retrieved were wrong for the Emoji image - causing clipping
> - It was necessary to retrieve the Emoji code point advance via a CoreText API since
>    the HMTX metrics were very wrong - causing overlapping glyphs
> - drawString checks if it is an Emoji run and redirects to a new drawColorGlyph method
>    which draws the image as a texture
> - All 3 rendering pipelines have this support and have been verified on all 3 desktop platforms

Another question: on non-retina monitor, emojis appear blurry when text size is set to 12.  I vaguely recall that when resizing down, the resizing operation might be followed by a sharpening filter (or perhaps some other op can be used?).
I don't think this is a deal breaker though.  
What do you think?

modules/javafx.graphics/src/main/java/com/sun/javafx/font/coretext/CTGlyph.java line 281:

> 279:             return (w * 4); // has alpha
> 280:         } else {
> 281:           return isLCDGlyph() ? w * 3 : w;

indentation?

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PR: https://git.openjdk.org/jfx/pull/1047