Gecko has an obscure quality-of-implementation feature, which tries to render ligatures across style changes and elements (no one else does this). Basically it just chops up the glyphs by drawing them multiple times, with extra clip rects. For now I'm making this fallback to gecko/blobs. Longterm we either need to impl this or decide this isn't worth carrying forward.

For now falling back is probably fine. If we wanted to implement this we could probably do it without additional support from WebRender. Whether we want to is, I agree, an open question.

Oops patch to wrong bug.

Comment on attachment 8912350 [details] Bug 1403261 - enable native webrender handling of partial ligatures. https://reviewboard.mozilla.org/r/183676/#review189336

lol jeff thanks but that was the accidental patch that was already merged on the proper bug.

Patch up to turn this on. Once the patch in https://bugzilla.mozilla.org/show_bug.cgi?id=1401653 lands, this basically just works so might as well just flip the switch, stress out our clipping code a bit more.

Should fix the shadow clipping issue before landing this.

(In reply to Alexis Beingessner [:Gankro] from comment #0) > Longterm we either need to impl this or decide this isn't worth carrying > forward. Note that Blink does plan to fix this in their layout engine rewrite: https://bugs.chromium.org/p/chromium/issues/detail?id=796943

try push: https://treeherder.mozilla.org/#/jobs?repo=try&revision=22ea0394bf013ba1cf33a426af8441fac4f84985

bluh, legit failure on linux CI; not seeing it locally on macos. I'll check it out tomorrow morning on the linux box.

Problem was a typo, new try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=dbbe60de4f5904a4759fcdd1617459fcdf36c144

Found why implementing GetSize never seemed to work (it was insufficient!) try push: https://treeherder.mozilla.org/#/jobs?repo=try&revision=a051ac78f2cf5c8db23f27af2adffa34efc5b9c6

results: looks good; two new passes on windows because we're no longer comparing some native content to fallback content (subpixel vs greyscale).

Comment on attachment 8912350 [details] Bug 1403261 - enable native webrender handling of partial ligatures. https://reviewboard.mozilla.org/r/183676/#review244716

Comment on attachment 8968896 [details] Bug 1403261 - remove fuzziness (no longer comparing fallback to native). https://reviewboard.mozilla.org/r/237622/#review244714

Pushed by kgupta@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/0b822d43971f enable native webrender handling of partial ligatures. r=jrmuizel,mstange https://hg.mozilla.org/integration/autoland/rev/cea91957ffe4 remove fuzziness (no longer comparing fallback to native). r=mstange

https://hg.mozilla.org/mozilla-central/rev/0b822d43971f https://hg.mozilla.org/mozilla-central/rev/cea91957ffe4