(My font rendering reads the OS settings to determine which rendering mode to use to match the underlying OS, but I think there's no need to do that for canvas.)
Not sure I understand. Are you saying that HTML and SVG text would match the OS's font rendering but HTML5 canvas text would not?
So I suspect that implementations behave the same way. It'll have to be tested, of course.
Last time I spoke to gw there were fair differences in WebRender down to rounding error between different GPUs (and drivers, IIRC), though almost certainly you'll know better the situation nowadays (and wrt Pathfinder).
The only downside is that verifying ReCaptcha takes me around a minute to solve.
This is why we can't have nice things. :/
The site doesn't use HTTPS, perhaps someone is tampering with your connection? Some ISPs have been known to do that, but not for very nefarious purposes AFAIK.
Is that still legal considering the GDPR?
A lot of Canvas is still in software. I'm working to change that, but it's a work in progress…
There's also the 'detect driver bugs' approach since there are test suites out there that detect various driver stack bugs using special shaders, you could run a set of those to identify the GPU (or even driver) being used to rasterize the WebGL content.
Don't we still live in an age where GPU drivers need game-specific driver fixes in order to work correctly? Being bug free is a different question than being free from any noticeable difference in the output, and we seem to not even have reached the bug freedom stage yet.
I mean even Firefox Webrender is only available to Nvidia GPUs at the start, no?
WebRender was locked to NVIDIA as a known target with a known set of driver bugs. They could've chosen AMD or Intel as the target instead and worked to figure out all the relevant driver bugs and worked around them, but for whatever reason they picked NV.
If you switch off hw accel in Chrome and Firefox your canvas performance will tank.