delay taking screenshot to allow GPU thread to render the frame #12896
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| // ------------------------------------------------------------------- | ||
| // UI : <-- build --> | ||
| // GPU : <-- rasterize --> | ||
| // Gap : | 1 second or more | |
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You might as well say 2 seconds here.
| // Gap : | 1 second or more | | ||
| // Driver: <-- screenshot --> | ||
| // | ||
| // The artificial gap should be long enough for the GPU thread to |
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This sounds a little hypothetical. It might be better to say something like: a two second delay is long enough for any reasonable GPU request to be rasterized.
| description: Flutter non-plugin UI integration tests. | ||
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| dependencies: | ||
| image: 1.1.29 |
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please make sure to run flutter update-packages --force-upgrade when adding dependencies
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Interesting. We already depend on image: 1.1.29 in another package. This change has no intention to upgrade our packages to new versions. Perhaps we need another mode in the flutter update-packages command that completes the list of transitive dependencies without upgrading?
| // The two-second gap should be long enough for the GPU thread to | ||
| // finish rasterizing the frame, but not longer than necessary to keep | ||
| // driver tests as fast a possible. | ||
| await new Future<Null>.delayed(const Duration(seconds: 2)); |
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It seems like we should just be able to wait until the GPU thread is done, instead.
@chinmaygarde is there a way for the engine to signal the driver (e.g. via the observatory port) that the GPU thread is now idle and taking a screenshot is safe? Or even better, is there a way to have _flutter.screenshot itself just wait for the GPU to be idle before taking the screenshot?
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My impression was that the engine-side change would need to be substantial enough that it's not worth making it just for taking a screenshot. That said, this PR also adds a test that reproduces the problem very reliably, so if we decide to pursue an engine-side fix, there's now an easy way to confirm that it works.
…ter#12896) * delay taking screenshot to allow GPU thread to render the frame * address comments
Fixes #11021
Fixes #12243