7cd7603dfa
Due to https://github.com/flutter/flutter/issues/127500 , we can get in a state where enable-impeller is true but we're using Skia. We need to either fall back completely to Skia, make this configuration fatal, or remote the check ---------------- Conversion of SkTextBlobs to impeller::TextFrame objects is one of the most expensive operations in display list dispatching. While the rest of the engine and framework makes a reasonable attempt to cache the SkTextBlobs generated during paragraph construction, the design of the dl dispatcher means that these the Impeller backend will always reconstruct all text frames on each frame - even if the display list/picture that contained those text frames was unchanged. Removing this overhead is one of the goals of https://github.com/flutter/engine/pull/45386 , however this patch is also fairly risky and will be difficult to land. As a more incremental solution, we can instead construct the impeller::TextFrame objects when performing paragraph painting and record them in the display list. This both moves the text frame construction to the UI thread and allows the framework/engine to cache unchanged text frames. This also does not conflict with the dl_aiks_canvas patch directly, and is fine to land before or after it does. (though I'd argue we should land this first). To compare the current performance levels, I ran the complex_layout_scroll perf test, since this is fairly text filled. On a Pixel 6 pro. Across several runs this is a fairly consistent ~1ms raster time improvement. Fixes https://github.com/flutter/flutter/issues/133204
Engine Testing
This directory contains the infrastructure for running tests on the engine, which are most often run by Flutter's continuous integration (CI) systems.
The tests themselves are located in other directories, closer to the source for
each platform, language, and variant. For instance, macOS engine unit tests
written in objective C are located in the same directory as the source files,
but with a Test suffix added (e.g. "FlutterEngineTest.mm" holds the tests for
"FlutterEngine.mm", and they are located in the same directory).
Testing the Engine locally
If you are working on the engine, you will want to be able to run tests locally.
In order to learn the details of how do that, please consult the Flutter Wiki page on the subject.