Glenn Watson
4c9e9b99b1
A tile cache whose world offset is fractional (e.g. a transformed, flex-centered scroller laid out at an x.5 position) built its composite clip from the pic->world transform, while the tiles themselves are placed on the compositor device grid, whose offset get_relative_scale_offset rounds to an integer. The resulting up-to-a-pixel mismatch between the two grids clipped the max-side content, dropping the right and bottom edges (e.g. two sides of a 1px border went missing). Compute device_clip_rect from the compositor transform instead, matching the grid the tiles are drawn on. When the tile cache is already device aligned this is identical to the previous result. Adds a wrench reftest (tiles/tile-cache-fractional-offset) that renders a border in a fractional-offset tile cache against a reference whose slice clip is widened by a background rect so it cannot crop. Differential Revision: https://phabricator.services.mozilla.com/D311989
WebRender
WebRender is a GPU-based 2D rendering engine written in Rust. Firefox, the research web browser Servo, and other GUI frameworks draw with it. It currently uses the OpenGL API internally.
Note that the canonical home for this code is in gfx/wr folder of the mozilla-central repository at https://hg.mozilla.org/mozilla-central. The Github repository at https://github.com/servo/webrender should be considered a downstream mirror, although it contains additional metadata (such as Github wiki pages) that do not exist in mozilla-central. Pull requests against the Github repository are still being accepted, although once reviewed, they will be landed on mozilla-central first and then mirrored back. If you are familiar with the mozilla-central contribution workflow, filing bugs in Bugzilla and submitting patches there would be preferred.
Update as a Dependency
After updating shaders in WebRender, go to servo and:
- Go to the servo directory and do ./mach update-cargo -p webrender
- Create a pull request to servo
Use WebRender with Servo
To use a local copy of WebRender with servo, go to your servo build directory and:
- Edit Cargo.toml
- Add at the end of the file:
[patch."https://github.com/servo/webrender"]
"webrender" = { path = "<path>/webrender" }
"webrender_api" = { path = "<path>/webrender_api" }
where <path> is the path to your local copy of WebRender.
- Build as normal
Documentation
The Wiki has a few pages describing the internals and conventions of WebRender.
Testing
Tests run using OSMesa to get consistent rendering across platforms.
Still there may be differences depending on font libraries on your system, for example.
See this gist for how to make the text tests useful in Fedora, for example.