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Cache computed window.physicalSize in a FrameReference (flutter/engine#15955)

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Yegor 2020-01-24 13:21:16 -08:00 committed by GitHub
parent 62a99c60c5
commit 3f4a2380cd
1 changed files with 20 additions and 15 deletions
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35
engine/src/flutter/lib/web_ui/lib/src/engine/window.dart
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@ -47,11 +47,24 @@ class EngineWindow extends ui.Window {
@override
ui.Size get physicalSize {
if (_physicalSize?.value == null) {
_computePhysicalSize();
}
assert(_physicalSize != null);
assert(_physicalSize.value != null);
return _physicalSize.value;
}
/// Computes the physical size of the screen from [html.window].
///
/// This function is expensive. It triggers browser layout if there are
/// pending DOM writes.
void _computePhysicalSize() {
bool override = false;
assert(() {
if (webOnlyDebugPhysicalSizeOverride != null) {
_physicalSize = webOnlyDebugPhysicalSizeOverride;
_physicalSize = FrameReference<ui.Size>(webOnlyDebugPhysicalSizeOverride);
override = true;
}
return true;
@ -68,23 +81,15 @@ class EngineWindow extends ui.Window {
windowInnerWidth = html.window.innerWidth * devicePixelRatio;
windowInnerHeight = html.window.innerHeight * devicePixelRatio;
}
if (windowInnerWidth != _lastKnownWindowInnerWidth ||
windowInnerHeight != _lastKnownWindowInnerHeight) {
_lastKnownWindowInnerWidth = windowInnerWidth;
_lastKnownWindowInnerHeight = windowInnerHeight;
_physicalSize = ui.Size(
windowInnerWidth,
windowInnerHeight,
);
}
_physicalSize = FrameReference<ui.Size>(ui.Size(
windowInnerWidth,
windowInnerHeight,
));
}
return _physicalSize;
}
ui.Size _physicalSize = ui.Size.zero;
double _lastKnownWindowInnerWidth = -1;
double _lastKnownWindowInnerHeight = -1;
/// Lazily populated and cleared at the end of the frame.
FrameReference<ui.Size> _physicalSize;
/// Overrides the value of [physicalSize] in tests.
ui.Size webOnlyDebugPhysicalSizeOverride;