Update: Blocked on https://github.com/flutter/engine/pull/44912 landing,
and merging into google3.
---
Partial work towards https://github.com/flutter/flutter/issues/112498.
_**tl;dr**: In Impeller's backend we intend to _always_ dither
gradients, and never allow any changes long-term (i.e., write your own
shader if you want different behavior) with the assumption that dithered
gradients look better most of the time, and don't typically hurt
elsewhere._
Note that, at the time of this writing, I couldn't find a single case of
this being set explicitly to `true` inside Google, and there are between
[100 and 200 publicly accessible on
GitHub](https://github.com/search?q=%22Paint.enableDithering%22+language%3ADart&type=code&l=Dart),
of which virtually all are setting it explicitly to `true`.
There are some (valid) concerns this would cause a lot of golden-file
image diffs, so I'm going to seek explicit approval from the Google
testing team as well as someone from the framework team before landing
this commit.
In https://skia-review.googlesource.com/c/skia/+/742797 Skia refactored
GrBackend* to not require #ifdefs. This changes
callsites in Flutter to use static functions instead of methods that
were conditionally compiled on those classes.
There should be no functional change.
Fixes https://github.com/flutter/flutter/issues/129073
## Changes to Embedder API
Introduced `FlutterRegion` to represent arbitrary region:
```cpp
typedef struct {
/// The size of this struct. Must be sizeof(FlutterRegion).
size_t struct_size;
/// Number of rectangles in the region.
size_t rects_count;
/// The rectangles that make up the region.
FlutterRect* rects;
} FlutterRegion;
```
Note that this is identical to struct `FlutterDamage` with more generic
naming. Maybe down the line we could deprecate `FlutterDamage` and use
`FlutterRegion` instead.
Introduced `FlutterBackingStorePresentInfo`:
```cpp
typedef struct {
size_t struct_size;
/// The area of the backing store that contains Flutter contents. Pixels
/// outside of this area are transparent and the embedder may choose not
/// to render them. Coordinates are in physical pixels.
FlutterRegion* paint_region;
} FlutterBackingStorePresentInfo;
```
In future this struct may also contain more precise hit test region
(when framework supports it) and/or information relevant to partial
repaint (buffer damage, frame damage).
Added a `backing_store_present_info` field to `FlutterLayer`:
```cpp
typedef struct {
...
/// Extra information for the backing store that the embedder may
/// use during presentation.
FlutterBackingStorePresentInfo* backing_store_present_info;
} FlutterLayer;
```
## Changes to the macOS embedder
This PR adds support for `FLTEnableSurfaceDebugInfo` flag in main bundle
`Info.plist` that enables visual indicators of overlay layers.
## Example of unobstructed platform views
https://github.com/flutter/flutter/assets/96958/09a75eee-316b-4d53-a8b4-d6bb4e1e52f7
## 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] and the [C++,
Objective-C, Java style guides].
- [X] I listed at least one issue that this PR fixes in the description
above.
- [X] I added new tests to check the change I am making or feature I am
adding, or Hixie said the PR is test-exempt. See [testing the engine]
for instructions on writing and running engine tests.
- [X] I updated/added relevant documentation (doc comments with `///`).
- [X] I signed the [CLA].
- [X] All existing and new tests are passing.
If you need help, consider asking for advice on the #hackers-new channel
on [Discord].
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Relands https://github.com/flutter/engine/pull/45131
Fixes https://github.com/flutter/flutter/issues/132416
Differences from last time:
- Some minor merge conflict fixes
- Use the RTree to get the bounds instead of recalculating the bounds
- Make the iOS platform view controller implementation use the impeller-aware slices instead of the display list ones. This has been fixed for Android and the desktop embedding, but I missed iOS. The unit tests weren't actually running before I branched for my PR, @zanderso fixed them up separately and this resulted in catching the failures on post submit last time.
Reverts flutter/engine#45131
This is failing the Impeller variants of the unobstructed platform views tests:
https://ci.chromium.org/ui/p/flutter/builders/prod/Mac%20Production%20Engine%20Drone/132249/overview
```
Failing tests:
-[UnobstructedPlatformViewTests testPlatformViewsMaxOverlays]
-[UnobstructedPlatformViewTests testOneOverlay]
-[UnobstructedPlatformViewTests testOneOverlayPartialIntersection]
-[UnobstructedPlatformViewTests testTwoIntersectingOverlays]
-[UnobstructedPlatformViewTests testOneOverlayAndTwoIntersectingOverlays]
** TEST FAILED **
```
We've retried it a few times so I suspect this isn't a flake.
This is a reland of https://github.com/flutter/engine/pull/44248
Fixes https://github.com/flutter/flutter/issues/132416
Changes from last time:
- The `drawPoints` benchmark was failing to render anything meaningful because of an error in `AiksLayer` that resulted in an infinitely sized bounding rectangle poisoning the bounds with `NaN` (this happens, for example, with a `drawPaint` call, which that benchmark happens to use). Added a test covering this and filed https://github.com/flutter/flutter/issues/132770 to explore ways to avoid this in the future.
- There was a bug in `DlAiksCanvas::SaveLayer` where a `nullptr` `paint` but non-`nullptr` `backdrop` was failing to actually save the layer. This resulted in incorrect rendering.
- There was a bug in `impeller::Canvas::DrawPicture` that resulted in incorrect stencil depth counting. That was fixed separately by @bdero, but was the cause of incorrect rendering in some Wonderous screens.
- I've added a simple implementation for `AiksLayer::IsReplacing`. It does not currently compare as deeply as the `DisplayListLayer` version potentially does, but it is good enough to avoid the regression noted in https://github.com/flutter/flutter/issues/132071. That regression was on a benchmark that greatly benefits from partial repaint. With the new implementation, it still gains partial repaint where it previously did not. There is more work that can be done here, filed https://github.com/flutter/flutter/issues/133361 to track that work.
I merged but did not fully integrate the `DisplayListBuilder`/`CanvasToReceiver` work that @flar has done. I have a local experiment with that, but would prefer to see this land and run through the device lab so we get some better comparison numbers for which one performs better.
DisplayListBuilder grew over time from a class that implemented a developer-unfriendly stateful API into one that implemented both the developer-friendly DlCanvas API as well as its original stateful API. Over time, the stateful API was buried under a "testing only" facade.
In the meantime, the optimization features that it applies to the DlCanvas calls before it records the operations in a DlOp store are useful without the recording process and so I've been wanting to break those into 2 parts for a while with the goal of removing all stateful APIs from DisplayListBuilder (see https://github.com/flutter/flutter/issues/108303).
This PR takes a major step along that direction by splitting DisplayListBuilder into essentially a convenience class that marries 2 new classes together to achieve its old functionality:
- `DlCanvasToReceiver` - a class that implements DlCanvas, optimizes common situations, and then sends commands to any object that implements `DlOpReceiver`
- `DlOpRecorder` - an implementation of DlOpReceiver that records the operations in a buffer from which to create a `DisplayList` object
- `DisplayListBuilder` now inherits from DlCanvasToReceiver to get the optimizations and provides it with an instance of `DlOpRecorder` as the receiver that it will send its results to
- Similarly, a `DlCanvasToReceiver` instance could be directed to an `impeller:DlDispatcher` to achieve a more straight-through path from the DlCanvas interface to impeller Pictures.
Fixes https://github.com/flutter/flutter/issues/130141
The primary goal of this patch is to move dispatching of `dart:ui` `Canvas` commands to the UI thread.
Before this patch, the architecture is something like:
## UI Thread
- `dart:ui` talks to `DisplayListBuilder`, a `DlCanvas` implementation.
- `DisplayListBuilder` does some clip/bounds tracking and creates a `DisplayList` object that is held by `dart:ui`'s `Picture` objects.
- `DisplayList`s are added to `DisplayListLayer`s in `flow`.
## Raster Thread
- `flow` flattens the various operations into a single `DisplayList` via another `DisplayListBuilder`.
- A `DlOpReceiver`implementation converts that `DisplayList` into an `Aiks` `Canvas`/`Picture`.
After this patch, the architecture instead looks like:
## UI Thread
- No change for Skia.
- If Impeller, use a new `DlCanvasImplementation` that talks to `Aiks`'s `Canvas`.
- If Impeller, `dart:ui` Picture's now hold an `Aiks` `Picture`, which get shared into `AiksLayer`s in `flow`.
## Raster thread
- No change for Skia, but some light refactoring for places that assumed a `DisplayListBuilder` where they really just needed a `DlCanvas`.
- The `Aiks` `Picture`s are combined using new API on `DlCanvas` and still backed by `Aiks`.
These changes show significant improvement on raster times on Android and only very small regressions on UI times in local testing, see https://gist.github.com/dnfield/26528090194c9f5abdbac13cdcbf4f79 for old gallery transition perf numbers.
Many of the other changes in this patch are related to the following:
- Making `DlRTree` usable for Impeller.
- It would be nice to have a version of DlRTree that speaks `impeller::Rect`.
- Creating the requisite classes to support `EmbeddedViews` so that Desktop works.
This patch does not remove the `impeller::DlDispatcher`, which now would only be used in tests.
This PR is to add support for the expanded/collapsed-state semantics flag to the engine. After adding another PR to Flutter, we will be able to support the expanded/collapsed state in semantics for submenu buttons.
Related to [#127617](https://github.com/flutter/flutter/issues/127617) in flutter
Fixes https://github.com/flutter/flutter/issues/130514
The context wasn't current so we couldn't get the GL version.
The extension lookup was throwing an invalid enum error, the desktop opengl docs say to use a different method.
Actually works now, though there is some issue with the default fbo stencil so I've filled https://github.com/flutter/flutter/issues/130048
Other issues:
* ~~Rendering looks wrong~~
* ~~Resizing window hangs~~
* ~~Reactor isn't set up correctly and all blit passes are currently failing.~~
* ~~Needs to handle falling back to sample count of 1 like we do on Android~~.
We'd like to (or already are) using the concurrent message loop for high priority rendering tasks like PSO construction and render pass encoding. The default priority level for the engine managed concurrent message loop is 2, which is a significantly lower priority than the raster thread at -5. This is almost certainly causing priority inversion.
We must move back to dedicated runners so we can adjust thread priorities.
This test sometimes caused assertion failures when running on Windows with ANGLE. The process may be unable to safely clean up global objects if GL commands are pending when the test exits.
