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
Fixes https://github.com/flutter/flutter/issues/126878
This disables device private upload on iOS when backgrounded, and disables mipmap generation when backgrounded.
We don't have a good way to test the core problem in this repo because it only reproduces on physical iOS hardware - simulators don't really care if you do this stuff in the background.
I'll write a devicelab test in the framework to capture this. In the mean time it can be reviewed.
We could consider making the IOManager a shared_ptr instead of having an fml::WeakPtr and that'd clean up some of the extra arguments to engine construction - or we could consider vending the sync switch from impeller::Context unconditionally, but it's pretty iOS specific...
This PR refactors `Rasterizer` so that the resubmit information is
returned as a temporary struct instead of stored permanently as class
member. This limits the lifetime of these values and reduces class
members.
Additionally, this benefits the multi-view project: if the rasterizer is
going to store multiple surfaces, what variables should be stored in a
map from view IDs? Should all surfaces have a to-be-submitted record?
The answer is "no", because these information is only temporary.
This PR should not need unit tests since it's only a refactor.
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above.
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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
Fixes https://github.com/flutter/flutter/issues/123307 - for Android, iOS, and Web, for the main display only (https://github.com/flutter/flutter/issues/125938 tracks supporting multiple displays, https://github.com/flutter/flutter/issues/125939 for desktop).
Desktop will need to be implemented for this, but given priority for a couple of our customers targetting foldable devices on Android I'm inclined to get this in before desktop can be finished.
The main concern for this right now is that on some Android foldable devices, setting a preferred orientation will cause letterboxing and the `MediaQuery` will _never_ get the full screen size when unfolded. This causes apps to think the screen is smaller than it is, as they've mainly been using `MediaQueryData.size` to figure this out. Android's recommendation is to not set a preferred orientation, and if you must to use the new method introduced in `ViewUtil.java` to calculate the maximal window size.
Removes the physical model layer and associated engine code. This was already deprecated and removed in the framework. By removing it in the engine, we can also remove the need for layer tree diff/paint/preroll to have the device pixel ratio. This will simplify some of the multi-view work
Fixes https://github.com/flutter/flutter/issues/125720
These keep turning up, so I did a little bash-fu to find them all.
```bash
grep -lL "#pragma once" $(grep -lL "#ifndef .*_H_" $(find . | grep "\.h$")) | cut -c 3-
```
No change in functionality. I've just renamed the TU's to replace `display_list_` to `dl_`. I am sure there are chances to make the naming better. For instance, the op receiver still being named a dispatcher.
With this PR we no longer need to hold DisplayLists in GPUObject wrappers and they can be disposed instantly instead of queueing on the Unref thread.
This will definitely be a win for Impeller as none of the objects used in a frame now require queueing, but the performance impact on apps running on top of skia is less clear if they depend on a lot of images inside their DisplayLists that still need to be queued to be freed. After getting further in the work, it looks like only decoded images need to use the protected DlImage wrappers and most of those should survive many frames before they are disposed. That should hopefully leave very few unrefs happening per frame.
~There are 3 unit tests in `shell_unittests.cc` and `embedder_metal_unittests.mm` that are now GSKIP'd as they now invoke code that needs a fully initialized UIDartState in order to protect their images. I will look into fixing the tests and/or making the code they invoke provide protection without relying on UIDartState.~ (This looks to be fixed in the latest commit by simply not creating DlImageGPUs all over the source base and simply catching only those that end up in UI data structures. There is actually existing code in one of the modules that feeds ui.Image with an answer to wrap the image in a DlImageGPU if it has a skia image anyway, so most of these additional uses of DlImageGPU that were having trouble getting the Skia unref queue just didn't need it anyway.)
In Skia, there is such a timeline event in `SnapshotControllerSkia::DoMakeRasterSnapshot`. Therefore, since Impeller wants to mimic Skia and this event does take a long time sometimes, it seems reasonable to add this.
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Fixes https://github.com/flutter/flutter/issues/124269
Manually verified this is safe on an iPhone 11.
We're not creating/encoding command buffers in this path so it's ok.
AFAICT the test I added would fail if we started doing that because it
doesn't provide any real command buffer interfaces. Most of the code
here is related to tests.
