The PR improves the code size and runtime performance of fallback font selection.
### Performance improvements
Initialization of the data structures to support fallback font selection has been moved from creating the FallbackFontManager (first frame) to the first use, i.e. the first frame actually needing a fallback font.
The numbers reported below are for a lightly edited version of the counter demo that appends to the counter about ~300 missing code points that need ~25 fallback fonts to cover the missing code points. Timings taken from a few profiles on my performance workstation.
| | Before | After |
| --- | ---: | ---: |
| FallbackFontManager() |~100ms | <2ms |
| First need | 0ms | 12ms |
| Subsequent need | 20-30ms | <1ms |
### Size improvements
| | Before | After | Î |
| --- | ---: | ---: | ---: |
| main.dart.js | 1586405 | 1477319 | -109086 (-6.87%) |
| brotli -9 | 427304 | 401611 | -25693 (-6.01%) |
### Algorithm notes
#### Startup
The old algorithm built an interval tree from the code point ranges of the ~140 fallback fonts and uses the interval tree to build a list of fonts that support each missing code point. The new algorithm uses a binary search map that directly produces the list of fonts. There are fewer binary search ranges (~22k) than the aggregate ranges for all the fonts (~26k).
Most of the startup time gain comes from using a data unpacks directly into a useful form rather than needing processing to build an interval tree (~12ms vs ~100ms).
#### Running
The runtime for font selection is greatly improved for several reasons
- The code point space is partitioned into components so that code point counting can be batched.
- When a font is selected, the counts are updated incrementally rather than being recomputed.
- The counts are held in fields of the NotoFont and component objects rather than in Maps or Sets.
Batching, incremental update and avoiding hash tables are roughly multiplicative in effect.
## Issues
- https://github.com/flutter/flutter/issues/131440
*If you had to change anything in the [flutter/tests] repo, include a link to the migration guide as per the [breaking change policy].*
[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
This implements platform views in Skwasm. There are a number of substantial changes rolled up in this change, including:
* Reworked the rendering system to use multiple canvases with a single WebGL context, via ImageBitmap rendering.
* Reworked our object management and bindings to use the `__externref_t` construct in C code.
* Upgraded emscripten to a much newer version
* Generified skwasm's scene builder to be able to work with any renderer that can produce `ImageBitmap` objects from Pictures, and whose `Canvas`, `Picture` and `ImageFilter` objects conform to `SceneCanvas`/`ScenePicture`/`SceneImageFilter`
For platform views themselves, most stuff is implemented except for clipping. I plan on doing that in a subsequent change.
In the spirit of keeping the happy path's output as clean as possible, let's hide the many lines printed by `pub get` even when it's successful.
If `pub get` fails, its output will be printed on the terminal.
A ~~simpler~~ very similar version of https://github.com/flutter/engine/pull/43854
* Makes it harder for users to accidentally remove default configuration values, while still allowing them to do so if needed (configuration is now overridden with a subset of values, rather than passing a full configuration object).
* Moves `merge` from the configuration object and into the override method.
* Removes a test-only configuration option:
* `window._flutter_canvaskit_variant_for_test_only`
[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
At some point, we started setting `useColorEmoji` to true in our tests, but we were doing it in a way that resets all other configurations to their defaults. This caused the `canvasKitVariant` config to be lost and always set to the default `auto`.
This PR fixes the issue and adds tests to:
1. Make sure that the CanvasKit suite always runs with a specific variant (not `auto`).
2. Make sure the given CanvasKit variant makes it all the way through to the tests.
The test harness uses a backdoor (a global JS property on `window`) to communicate which canvaskit variant it's using. The test then compares that with `configuration.canvasKitVariant` to make sure they match. If they don't match, then the configuration was lost somewhere on the way.
Fixes https://github.com/flutter/flutter/issues/130993
Using ansi colors in LUCI results in output that looks like:
```
00:00 [32m+0[0m: [1m[90mloading flutter_tester_emulation_golden_test.dart[0m[0m
00:01 [32m+0[0m: [1m[90mloading flutter_tester_emulation_golden_test.dart[0m[0m
00:02 [32m+0[0m: [1m[90mloading flutter_tester_emulation_golden_test.dart[0m[0m
```
This PR disables colors on LUCI so that we get clean output that's easily scannable and searchable.
This implements full text rendering with the Skwasm renderer.
The font fallback logic has been refactored to decouple the font fallback manager from any CanvasKit-specific types and functions.
A chunk of CanvasKit text rendering tests have been ported over to the renderer-agnostic `ui` tests.
Fixes https://github.com/flutter/flutter/issues/126339
This fixes https://github.com/flutter/flutter/issues/85793
The script that generates the font fallback data also rolls a package to CIPD with these files and updates the DEPS to download those files from CIPD. This makes sure that these tests are hermetic.
* [web] New gn for building CanvasKit
* Use toolchain_args to override CanvasKit gn args
* Use correct path for the generated canvaskit files
* Put toolchain close to target
* remove extra toolchains
* remove extra import
* add canvaskit_lite to archive
* fix local canvaskit path in tests
* add some guards using visibility and asserts
* renames
* formatting
* rename mistake
* Add github issue to the TODO
* Update buildroot sha
* clang-tidy error
* skip canvaskit targets when not needed
