Colour Font pixel size limit

Glyphs
1

I’ve currently got a colour font exporting correctly, but having some difficulties in Chrome (Version 73.0.3683.86 (Official Build) (64-bit)) — When the pixel size is equal to or greater than 129 pixels, the font turns B&W:

37
37342×868 4.77 KB

Current config of the file is:

(
        {
        "Export COLR Table" = 1;
    },
        {
        "Export SVG Table" = 1;
    },
        {
        "Color Palette for SVG" = 0;
    },
        {
        "Color Palette for CPAL" = 0;
    },
        {
        "Color Layers to SVG" = 1;
    },
        {
        "Export sbix Table" = 0;
    }
)

Any thoughts on why the colour aspect should be breaking?

Thanks!

2

What does Chrome support say?

3

Unable to find much info about it to be honest.
Found a bug report for Chrome here https://bugs.chromium.org/p/chromium/issues/detail?id=617379

Do you have any colour fonts (in a similar config) that you’re able to test to see if the bug is a chrome or font-specific issue?

4

Obviously not in the font, because under certain circumstances, Chrome can display the color info properly. It’s the circumstances that need to be investigated. Seems like Chrome is switching to a different rendering scheme at certain pixel sizes.

5

Also looks like it’s happening in Safari on Mojave too, so looks like a web-kit issue

6

Chrome is not rendering the glyphs itself but calles to CoreText, the macOS rasteriser. This would explain the similar result in Safari and Chrome.

7

The above behaviour is happening on OSX 10.12 (Sierra)
When viewed on OSX 10.13 (High Sierra), going above 128px does work, but now yields a pixelated variant in Chrome.

18
18338×1110 2.07 KB

In High Sierra, installing the font locally, regardless of size gives a perfect render within TextEdit etc.