matplotlib / matplotlib/matplotlib

[ENH] Support for SBIX-encoded colour glyphs

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topic: text/fonts
Dominant language
Python
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Description

Colour glyphs using the SBIX tables are PNG/JPEG/TIFF images embedded instead of vector glyphs, using tables designed by Apple. FreeType only supports PNG here, with the `png` option linking to `libpng` that we don't currently enable. FreeType has [some example code](https://freetype.org/freetype2/docs/reference/ft2-font_testing_macros.html#ft_has_sbix) for working with bitmap fonts.

Hopefully, as with CBDT/CBLC, we can extract the glyph data and pass it to Pillow (and thus support the other formats as well!)

The major font using this is likely the Apple Color Emoji font, at least based on the copy I found...

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by tracing the existing CBDT/CBLC glyph extraction path and how FreeType capabilities are checked. Compare that path with SBIX tables, then verify that embedded PNG, JPEG, and TIFF glyph data can reach Pillow and that Apple Color Emoji renders correctly.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
computer-graphics
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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