wrench

wrench is a tool for debugging webrender outside of a browser engine.

headless

wrench has an optional headless mode for use in continuous integration. To run in headless mode, instead of using cargo run -- args, use ./headless.py args.

replay and show

Binary recordings can be generated by webrender and replayed with wrench replay. Enable binary recording in RendererOptions.

RendererOptions {
    ...
    recorder: Some(Box::new(BinaryRecorder::new("wr-frame.bin"))),
    ...
}

If you are working on gecko integration you can enable recording in webrender_bindings/src/bindings.rs by setting

static ENABLE_RECORDING: bool = true;

wrench replay --save yaml will convert the recording into frames described in yaml. Frames can then be replayed with wrench show.

reftest

Wrench also has a reftest system for catching regressions.

• To run all reftests, run script/headless.py reftest
• To run specific reftests, run script/headless.py reftest path/to/test/or/dir
• To examine test failures, use the reftest analyzer
• To add a new reftest, create an example frame and a reference frame in reftests/ and then add an entry to reftests/reftest.list