[web] Unify Surface code between Skwasm and CanvasKit #177138
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This pull request undertakes a significant refactoring to unify the Surface abstraction between the CanvasKit and Skwasm rendering backends. It introduces a new set of base classes (Surface, OffscreenSurface, OnscreenSurface) and providers (CanvasProvider, SurfaceProvider) in the compositing directory. Both CanvasKit and Skwasm implementations are updated to conform to these new interfaces, leading to cleaner separation of concerns and more shared code for rasterization logic. The changes align with the Flutter Style Guide and improve the overall architecture.
I have two main points of feedback. First, there's an incomplete initialize method in CkOnscreenSurface that needs to be addressed. Second, a debug print statement was left in the SkwasmRenderer, which should be removed.
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engine/src/flutter/lib/web_ui/lib/src/engine/skwasm/skwasm_impl/image.dart
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Thanks for the review! |
…by introducing `rasterizeToCanvas` and `canvasImageSource` to `Surface` and `CkOffscreenSurface`.
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Drive by...thought? I noticed the code delta shows more lines added than removed. 
Ideas why? |
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I had to add quite a lot of glue code in Skwasm to make the lifecycle of a Surface in Skwasm and CanvasKit. Most of it is just passing simple messages between the engine and Skwasm. There are also some added tests and abstractions. |
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This reverts commit 9eee965.
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Reason for revert: broke skwasm benchmarks |
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…)" (#178085) <!-- start_original_pr_link --> Reverts: #177138 <!-- end_original_pr_link --> <!-- start_initiating_author --> Initiated by: harryterkelsen <!-- end_initiating_author --> <!-- start_revert_reason --> Reason for reverting: broke skwasm benchmarks <!-- end_revert_reason --> <!-- start_original_pr_author --> Original PR Author: harryterkelsen <!-- end_original_pr_author --> <!-- start_reviewers --> Reviewed By: {mdebbar} <!-- end_reviewers --> <!-- start_revert_body --> This change reverts the following previous change: This PR introduces a significant refactoring of the web engine's rendering layer by unifying the `Surface` and `Rasterizer` implementations. These components have been moved from being renderer-specific to a generic `compositing` directory, making the architecture more modular and easier to maintain. The rasterizers are now renderer-agnostic and are provided with renderer-specific surface factories via dependency injection. A new `CanvasProvider` abstraction has also been introduced to manage the lifecycle of the underlying canvas elements. A key outcome of this work is that the Skwasm backend now correctly handles WebGL context loss events. This was achieved by refactoring `SkwasmSurface` to allow the Dart side to manage the `OffscreenCanvas` lifecycle. A communication channel between the main thread and the web worker is now used to gracefully handle context loss and recovery. This effort also included fixing several related bugs around surface sizing, resource cleanup, and callback handling in multi-surface scenarios. To validate these changes, new testing APIs have been added to allow for the creation of renderer-agnostic surface tests. A new test file, `surface_context_lost_test.dart`, has been added to verify the context loss and recovery behavior across all supported renderers, ensuring the new architecture is robust and reliable. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. 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flutter/flutter@e5d5c01...c5e809a 2025-11-06 [email protected] Remove WindowingOwner.hasTopLevelWindows (flutter/flutter#178033) 2025-11-06 [email protected] Fix DropdownMenu escape key does not close the menu (flutter/flutter#178002) 2025-11-06 [email protected] Update documentation tool reference in image.dart (flutter/flutter#177782) 2025-11-06 [email protected] Roll Skia from 4eb2383d38f2 to 5c4e1352128f (5 revisions) (flutter/flutter#178094) 2025-11-06 [email protected] Revert "Refactor OverlayPortal semantics (#173005)" (flutter/flutter#178007) 2025-11-06 98614782+auto-submit[bot]@users.noreply.github.com Reverts "Fix verified input test failure in CI (attempt 4) (#178018)" (flutter/flutter#178089) 2025-11-06 98614782+auto-submit[bot]@users.noreply.github.com Reverts "[web] Unify Surface code between Skwasm and CanvasKit (#177138)" (flutter/flutter#178085) 2025-11-05 [email protected] Fix verified input test failure in CI (attempt 4) (flutter/flutter#178018) 2025-11-05 [email protected] fix: inconsistent horizontal spacing between hours and mins in time picker for non-english language (flutter/flutter#173706) 2025-11-05 [email protected] Roll Fuchsia Linux SDK from mpsxF1gd-jbKNvmpm... to cm88aTLui5yorSGYQ... (flutter/flutter#178074) 2025-11-05 [email protected] Fix(ios): Remove arm64 exclusion to support Xcode 26 simulators (flutter/flutter#177065) 2025-11-05 [email protected] Roll Skia from 2ff897e9b440 to 4eb2383d38f2 (18 revisions) (flutter/flutter#178070) 2025-11-05 [email protected] [web] Unify Surface code between Skwasm and CanvasKit (flutter/flutter#177138) 2025-11-05 [email protected] Update more missing ninja deps (flutter/flutter#178079) 2025-11-05 [email protected] Add ninja / cmake deps to failing tests (flutter/flutter#178054) 2025-11-05 [email protected] [web] Don't add webparagraph suite to CI (flutter/flutter#177681) 2025-11-05 [email protected] Fixing broken link in engine readme (flutter/flutter#177987) 2025-11-05 [email protected] Print reason for adb command failure in verified input test (attempt 3) (flutter/flutter#178005) 2025-11-05 [email protected] Fix `ReorderableList` items jumping when drag direction reverses mid-animation (flutter/flutter#173241) 2025-11-05 [email protected] Replace deprecated `withOpacity` in `overflow_bar.0.dart` example (flutter/flutter#177813) 2025-11-05 [email protected] Replace deprecated `withOpacity` in `data_table.1.dart` example (flutter/flutter#177812) 2025-11-05 [email protected] Replace deprecated `withOpacity` in `switch.1.dart` example (flutter/flutter#177811) 2025-11-04 [email protected] Roll Skia from c89b6118266b to 2ff897e9b440 (6 revisions) (flutter/flutter#177999) 2025-11-04 [email protected] Fix verified input test in CI (attempt 2) (flutter/flutter#177961) 2025-11-04 [email protected] Replace rendering for solid color circles (both filled and stroked) to use SDFs (flutter/flutter#177482) 2025-11-04 [email protected] Roll Fuchsia Linux SDK from vxK5obzfr1X9P2kSh... to mpsxF1gd-jbKNvmpm... (flutter/flutter#177996) 2025-11-04 [email protected] Validate that platforms specified in .ci.yaml target names match the platforms defined in the platform_properties section (flutter/flutter#177523) 2025-11-04 [email protected] Roll Packages from 1a7075b to 3d926aa (6 revisions) (flutter/flutter#177998) 2025-11-04 [email protected] Remove dead code from snippet_generator (flutter/flutter#174440) If this roll has caused a breakage, revert this CL and stop the roller using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC [email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md
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This PR introduces a significant refactoring of the web engine's rendering layer by unifying the `Surface` and `Rasterizer` implementations. These components have been moved from being renderer-specific to a generic `compositing` directory, making the architecture more modular and easier to maintain. The rasterizers are now renderer-agnostic and are provided with renderer-specific surface factories via dependency injection. A new `CanvasProvider` abstraction has also been introduced to manage the lifecycle of the underlying canvas elements. A key outcome of this work is that the Skwasm backend now correctly handles WebGL context loss events. This was achieved by refactoring `SkwasmSurface` to allow the Dart side to manage the `OffscreenCanvas` lifecycle. A communication channel between the main thread and the web worker is now used to gracefully handle context loss and recovery. This effort also included fixing several related bugs around surface sizing, resource cleanup, and callback handling in multi-surface scenarios. To validate these changes, new testing APIs have been added to allow for the creation of renderer-agnostic surface tests. A new test file, `surface_context_lost_test.dart`, has been added to verify the context loss and recovery behavior across all supported renderers, ensuring the new architecture is robust and reliable. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed. <!-- Links --> [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md
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…er#177138)" (flutter#178085) <!-- start_original_pr_link --> Reverts: flutter#177138 <!-- end_original_pr_link --> <!-- start_initiating_author --> Initiated by: harryterkelsen <!-- end_initiating_author --> <!-- start_revert_reason --> Reason for reverting: broke skwasm benchmarks <!-- end_revert_reason --> <!-- start_original_pr_author --> Original PR Author: harryterkelsen <!-- end_original_pr_author --> <!-- start_reviewers --> Reviewed By: {mdebbar} <!-- end_reviewers --> <!-- start_revert_body --> This change reverts the following previous change: This PR introduces a significant refactoring of the web engine's rendering layer by unifying the `Surface` and `Rasterizer` implementations. These components have been moved from being renderer-specific to a generic `compositing` directory, making the architecture more modular and easier to maintain. The rasterizers are now renderer-agnostic and are provided with renderer-specific surface factories via dependency injection. A new `CanvasProvider` abstraction has also been introduced to manage the lifecycle of the underlying canvas elements. A key outcome of this work is that the Skwasm backend now correctly handles WebGL context loss events. This was achieved by refactoring `SkwasmSurface` to allow the Dart side to manage the `OffscreenCanvas` lifecycle. A communication channel between the main thread and the web worker is now used to gracefully handle context loss and recovery. This effort also included fixing several related bugs around surface sizing, resource cleanup, and callback handling in multi-surface scenarios. To validate these changes, new testing APIs have been added to allow for the creation of renderer-agnostic surface tests. A new test file, `surface_context_lost_test.dart`, has been added to verify the context loss and recovery behavior across all supported renderers, ensuring the new architecture is robust and reliable. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. 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This PR introduces a significant refactoring of the web engine's rendering layer by unifying the `Surface` and `Rasterizer` implementations. These components have been moved from being renderer-specific to a generic `compositing` directory, making the architecture more modular and easier to maintain. The rasterizers are now renderer-agnostic and are provided with renderer-specific surface factories via dependency injection. A new `CanvasProvider` abstraction has also been introduced to manage the lifecycle of the underlying canvas elements. A key outcome of this work is that the Skwasm backend now correctly handles WebGL context loss events. This was achieved by refactoring `SkwasmSurface` to allow the Dart side to manage the `OffscreenCanvas` lifecycle. A communication channel between the main thread and the web worker is now used to gracefully handle context loss and recovery. This effort also included fixing several related bugs around surface sizing, resource cleanup, and callback handling in multi-surface scenarios. To validate these changes, new testing APIs have been added to allow for the creation of renderer-agnostic surface tests. A new test file, `surface_context_lost_test.dart`, has been added to verify the context loss and recovery behavior across all supported renderers, ensuring the new architecture is robust and reliable. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed. <!-- Links --> [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md
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…er#177138)" (flutter#178085) <!-- start_original_pr_link --> Reverts: flutter#177138 <!-- end_original_pr_link --> <!-- start_initiating_author --> Initiated by: harryterkelsen <!-- end_initiating_author --> <!-- start_revert_reason --> Reason for reverting: broke skwasm benchmarks <!-- end_revert_reason --> <!-- start_original_pr_author --> Original PR Author: harryterkelsen <!-- end_original_pr_author --> <!-- start_reviewers --> Reviewed By: {mdebbar} <!-- end_reviewers --> <!-- start_revert_body --> This change reverts the following previous change: This PR introduces a significant refactoring of the web engine's rendering layer by unifying the `Surface` and `Rasterizer` implementations. These components have been moved from being renderer-specific to a generic `compositing` directory, making the architecture more modular and easier to maintain. The rasterizers are now renderer-agnostic and are provided with renderer-specific surface factories via dependency injection. A new `CanvasProvider` abstraction has also been introduced to manage the lifecycle of the underlying canvas elements. A key outcome of this work is that the Skwasm backend now correctly handles WebGL context loss events. This was achieved by refactoring `SkwasmSurface` to allow the Dart side to manage the `OffscreenCanvas` lifecycle. A communication channel between the main thread and the web worker is now used to gracefully handle context loss and recovery. This effort also included fixing several related bugs around surface sizing, resource cleanup, and callback handling in multi-surface scenarios. To validate these changes, new testing APIs have been added to allow for the creation of renderer-agnostic surface tests. A new test file, `surface_context_lost_test.dart`, has been added to verify the context loss and recovery behavior across all supported renderers, ensuring the new architecture is robust and reliable. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. **Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed. <!-- Links --> [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md <!-- end_revert_body --> Co-authored-by: auto-submit[bot] <[email protected]>
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This PR introduces a significant refactoring of the web engine's rendering layer by unifying the
SurfaceandRasterizerimplementations. These components have been moved from being renderer-specific to a genericcompositingdirectory, making the architecture more modular and easier to maintain. The rasterizers are now renderer-agnostic and are provided with renderer-specific surface factories via dependency injection. A newCanvasProviderabstraction has also been introduced to manage the lifecycle of the underlying canvas elements.A key outcome of this work is that the Skwasm backend now correctly handles WebGL context loss events. This was achieved by refactoring
SkwasmSurfaceto allow the Dart side to manage theOffscreenCanvaslifecycle. A communication channel between the main thread and the web worker is now used to gracefully handle context loss and recovery. This effort also included fixing several related bugs around surface sizing, resource cleanup, and callback handling in multi-surface scenarios.To validate these changes, new testing APIs have been added to allow for the creation of renderer-agnostic surface tests. A new test file,
surface_context_lost_test.dart, has been added to verify the context loss and recovery behavior across all supported renderers, ensuring the new architecture is robust and reliable.Pre-launch Checklist
///).If you need help, consider asking for advice on the #hackers-new channel on Discord.
Note: The Flutter team is currently trialing the use of Gemini Code Assist for GitHub. Comments from the
gemini-code-assistbot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.