skia2/modules/canvaskit/README.md
Kevin Lubick d1285b131b Upgrade CanvasKit emscripten to version 1.39.16.
Changes are largely mechanical.  Non-mechanical changes to support newer
versions of emscripten are enumerated below, in format ${EMSCRIPTEN_VERSION}:
${RELEVANT_CHANGE}.

- 1.39.9: TOTAL_MEMORY has been renamed INITIAL_MEMORY.
- 1.39.12: passing of linker flags to wasm-ld has changed in a way that requires
  supplying `--no-entry` to avoid error message "wasm-ld: error: entry symbol
  not defined (pass --no-entry to suppress): main".
- 1.39.16: The factory function created by using `MODULARIZE` build option now
  returns a Promise instead of the module instance.  As such, the ready.js
  workaround is removed.  Note this is a breaking API change for CanvasKit,
  which now uses just `then()` and not `ready().then()`.
- 1.38.33: `emsdk install` hasn't required the `-64bit` suffix on version names
  since `1.38.33`, so we remove them.  E.g. `emsdk install sdk-1.39.6-64bit`
  simply becomes `emsdk install sdk-1.39.16`.

cf. https://github.com/emscripten-core/emscripten/blob/master/ChangeLog.md

Bug: NONE
Change-Id: Iabec4bd5ad7db2e0715ad42c2e4cf7d67b192b4c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/291182
Reviewed-by: Kevin Lubick <kjlubick@google.com>
2020-05-21 14:18:48 +00:00

3.1 KiB

Prerequisites

To compile CanvasKit, you will first need to install emscripten. This will set the environment EMSDK (among others) which is required for compilation.

Compile and Test Locally

make release  # make debug is much faster and has better error messages
make local-example

This will print a local endpoint for viewing the example. You can experiment with the CanvasKit API by modifying ./canvaskit/example.html and refreshing the page. For some more experimental APIs, there's also ./canvaskit/extra.html.

For other available build targets, see Makefile and compile.sh. For example, building a stripped-down version of CanvasKit with no text support or any of the "extras", one might run:

./compile.sh no_skottie no_particles no_font

Such a stripped-down version is about half the size of the default release build.

Infrastructure Playbook

When dealing with CanvasKit (or PathKit) on our bots, we use Docker. Check out $SKIA_ROOT/infra/wasm-common/docker/README.md for more on building/editing the images used for building and testing.

Updating the version of Emscripten we build/test with

This presumes you have updated emscripten locally to a newer version of the sdk and verified/fixed any build issues that have arisen.

  1. Edit $SKIA_ROOT/infra/wasm-common/docker/emsdk-base/Dockerfile to install and activate the desired version of Emscripten.
  2. Edit $SKIA_ROOT/infra/wasm-common/docker/Makefile to have EMSDK_VERSION be set to that desired version. If there is a suffix that is not _v1, reset it to be _v1. If testing the image later does not work and edits are made to the emsdk-base Dockerfile to correct that, increment to _v2,_v3, etc to force the bots to pick up the new image.
  3. In $SKIA_ROOT/infra/wasm-common/docker/, run make publish_emsdk_base
  4. Edit $SKIA_ROOT/infra/canvaskit/docker/canvaskit-emsdk/Dockerfile to be based off the new version from step 2. CanvasKit has its own docker image because it needs a few extra dependencies to build with font support.
  5. Edit $SKIA_ROOT/infra/canvaskit/docker/Makefile to have the same version from step 2. It's easiest to keep the emsdk-base and canvaskit-emsdk versions be in lock-step.
  6. In $SKIA_ROOT/infra/canvaskit/docker/, run make publish_canvaskit_emsdk.
  7. In $SKIA_ROOT/infra/bots/recipe_modules/build/, update canvaskit.py and pathkit.py to have DOCKER_IMAGE point to the desired tagged Docker containers from steps 2 and 5 (which should be the same).
  8. In $SKIA_ROOT/infra/bots/, run make train to re-train the recipes.
  9. Optional: Run something like git grep 1\\.38\\. in $SKIA_ROOT to see if there are any other references that need updating.
  10. Upload a CL with all the changes. Run all Test.+CanvasKit, Perf.+CanvasKit, Test.+PathKit, Perf.+PathKit jobs to make sure the new builds pass all tests and don't crash the perf harnesses.
  11. Send out CL for review. Feel free to point the reviewer at these steps.