Support vertical fonts (vmtx / vhea table parsing) #728
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Thanks! How did you produce the example images? Don't we need to adapt the drawing functions and the demo pages as well in order to implement a toggle for vertical writing? |
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First screenshot is using HTML + CSS in Firefox. I would like to keep the footprint of this PR small. I'm not trying to cater to all vertical writing use cases, just parse these tables and make the data available. |
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Fixes #618, #726
Description
This adds parsing for vmtx / vhea tables so the library consumer has the necessary information to draw glyphs vertically.
Motivation and Context
It's part of the spec.
How Has This Been Tested?
Tested through canvas drawing with sample fonts. This PR only adds new variables that the user can read. It does not modify existing logic, and thus has a very low chance of regression.
Screenshots (if appropriate):
Sample vertical text rendering via CSS
writing-mode: tb-rlin Firefox (expected behavior):Sample vertical text rendering using opentype.js + canvas (actual behavior).
Types of changes
Checklist:
npm run testand all tests passed green (including code styling checks).