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.
In the Impeller backend, we **only** support dithering of _gradients_. In addition, it will be the default (and only option).
In the [process of enabling dithering by default](https://github.com/flutter/engine/pull/44705), i.e.
```diff
class Paint {
- static bool enableDithering = false;
+ static bool enableDithering = true;
}
```
... we realized with internal Google testing this will now apply dithering on more than just gradients, i.e. images in the Skia backend. Since we won't support dithering of images in the Impeller backend, this PR gives a "hint" on whether the `colorSource` (if one is set) can be dithered by the contrived rules we've created.
When a saveLayer is rendered with an ImageFilter that modifies the bounds of the rendered pixels, and some of the content of that saveLayer did not intersect the clip, but the filtered output of that content did intersect the clip, we might not accumulate the bounds of those rendering operations into the DisplayList bounds.
This bug was not encountered during practical testing, but showed up on some testing with the new NOP culling code.
For now, this bug only affects the accuracy of the reported bounds of the DisplayList, but that can affect raster caching and potentially the layer culling done in the LayerTree. It might also affect the accuracy of the RTree associated with the DisplayList, which would only show up in rare circumstances when the indicated operation was used in the presence of an embedded view.
Fixes https://github.com/flutter/flutter/issues/129862
This reverts commit cd52c0ce82b37bc9d16bea26fbd1753174c49e42.
These changes were exposing an underlying bug in the DisplayListMatrixClipTracker that has now been fixed independently (https://github.com/flutter/engine/pull/43664). There are no changes to the commit being relanded here, it has been tested on the Wondrous app which demonstrated the regression before the NOP culling feature was reverted and it now works fine due to the fix of the underlying cause.
Most of the #include directives for SkPicture are removed except where they are still functional. Many comments rewritten to no longer be SkPicture-centric.
- DL unit tests still use it for consistency testing
- rasterizer/engine still use it for screen shot support
- Fuchsia still uses it extensively
Addresses most of https://github.com/flutter/flutter/issues/128060
Most of the uses of SkPicture and Recorder are removed from the engine sources. The few that remain are:
- DisplayList <-> Skia consistency testing code
- Legacy code only used from Fuchsia
- Dart CanvasKit uses which aren't actually using the local Skia sources or libraries
These are all comment and include file changes and so the testing is in the building.
Reverts flutter/engine#42584. (Thanks to @jonahwilliams for bisecting)
With this change, layers are getting clipped incorrectly when rendering
platform views in Wondrous.
Update flutter engine includes to be more specific about use of Skia includes.
These changes are required to unblock the Skia roller that has new streamlined include files.
The original PR caused some golden test failures down the line, likely due to bad analysis of when the combined BlendMode and color would result in a NOP situation.
This PR adds tests that go through every BlandMode and pair it with a variety of colors and Color/ImageFilters to verify that the operations are only omitted when they actually produce no change in the output. It also checks the validity of the "modifies_transparent_black" property of DisplayLists which can be used in place of the current CanvasSpy/DlOpSpy classes.
The description from the [previous PR](https://github.com/flutter/engine/pull/41463) updated with the new name of the DL property:
---------------------------------
This optimization avoids recording unnecessary render operations that will not affect the output and also eliminates the need for "draw detection" mechanisms like `DlOpSpy` and `CanvasSpy` by remembering if any non-transparent operations were included. The `DlOpSpy` unit tests were updated to check if the results from that object match the new `DisplayList::modifies_transparent_black()` method.
Fixes https://github.com/flutter/flutter/issues/125338
In addition, this change will unblock some other Issues:
- https://github.com/flutter/flutter/issues/125318
- https://github.com/flutter/flutter/issues/125403
Part of an ongoing set of efforts to address https://github.com/flutter/flutter/issues/106448
Move the checkerboard layer unit tests onto the DisplayList version of the paint contexts and fix some bugs in the reusability of the DisplayListBuilder that this migration uncovered.
This optimization avoids recording unnecessary render operations that will not affect the output and also eliminates the need for "draw detection" mechanisms like `DlOpSpy` and `CanvasSpy` by remembering if any non-transparent operations were included. The `DlOpSpy` unit tests were updated to check if the results from that object match the new `DisplayList::affects_transparent_surface()` method.
Fixes https://github.com/flutter/flutter/issues/125338
In addition, this change will unblock some other Issues:
- https://github.com/flutter/flutter/issues/125318
- https://github.com/flutter/flutter/issues/125403
* add support to run dl_canvas_unittests on GPU surfaces (off by default)
* empty commit to trigger build
* conditionally include platform-specific surface provider headers
* ignore DL test files during license checks
* typo
* add dependencies to rendertests to hopefully build on Windows
* remove benchmarking deps from dl_rendertests
* more changes to get Windows rendertests to link
* add --enable-gl synonym and prevent non-SW surface provider dest on Windows
* fix gn formatting
* review feedback
