subpixels: clientrect, getBoxQuads, getBBox etc allow high precision measurements which can expose subpixels
links
- old issue: #29564 (closed) (nothing to see, it's all in this description)
- upstream: 1507879
- example of methods: https://canvasblocker.kkapsner.de/test/domRectTest.php
We can control a lot of measurement entropy via other means per platform: such as unified look and feel, default fonts + sizes per language, controlling available fonts, etc. This ticket is not about those. This is about possible subpixels
All these methods, and we could add textMetrics to the list, can be subtlely randomized now Firefox has a seed per eTLD+1 per session .. THIS. IS. THE. WAY. (after standardizing everything else).