Convert chromium wheel delta to physical pixels on macOS (flutter/engine#49028)
This has been previously done for Safari in Firefox in
https://github.com/flutter/engine/pull/35428. I'm not entirely sure
since which release, but for past couple of months Chromium seems to be
reporting logical pixels during scroll events as well, which now makes
scrolling on Chrome / macOs 2x slower.
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diff --git a/engine/src/flutter/lib/web_ui/lib/src/engine/pointer_binding.dart b/engine/src/flutter/lib/web_ui/lib/src/engine/pointer_binding.dart
index d4cb966..3794a7b 100644
--- a/engine/src/flutter/lib/web_ui/lib/src/engine/pointer_binding.dart
+++ b/engine/src/flutter/lib/web_ui/lib/src/engine/pointer_binding.dart
@@ -656,7 +656,7 @@
deltaX *= _view.physicalSize.width;
deltaY *= _view.physicalSize.height;
case domDeltaPixel:
- if (operatingSystem == OperatingSystem.macOs && (isSafari || isFirefox)) {
+ if (operatingSystem == OperatingSystem.macOs) {
// Safari and Firefox seem to report delta in logical pixels while
// Chrome uses physical pixels.
deltaX *= _view.devicePixelRatio;
diff --git a/engine/src/flutter/lib/web_ui/test/engine/pointer_binding_test.dart b/engine/src/flutter/lib/web_ui/test/engine/pointer_binding_test.dart
index 0e27270..d877f9b 100644
--- a/engine/src/flutter/lib/web_ui/test/engine/pointer_binding_test.dart
+++ b/engine/src/flutter/lib/web_ui/test/engine/pointer_binding_test.dart
@@ -815,13 +815,12 @@
);
test(
- 'converts scroll delta to physical pixels (Firefox)',
+ 'converts scroll delta to physical pixels (macOs)',
() {
final _ButtonedEventMixin context = _PointerEventContext();
const double dpi = 2.5;
debugOperatingSystemOverride = OperatingSystem.macOs;
- debugBrowserEngineOverride = BrowserEngine.firefox;
EngineFlutterDisplay.instance.debugOverrideDevicePixelRatio(dpi);
final List<ui.PointerDataPacket> packets = <ui.PointerDataPacket>[];
@@ -854,52 +853,6 @@
expect(packets[0].data[0].scrollDeltaY, equals(10.0 * dpi));
EngineFlutterDisplay.instance.debugOverrideDevicePixelRatio(1.0);
- debugOperatingSystemOverride = null;
- debugBrowserEngineOverride = null;
- },
- );
-
- test(
- 'scroll delta are already in physical pixels (Chrome)',
- () {
- final _ButtonedEventMixin context = _PointerEventContext();
-
- const double dpi = 2.5;
- debugOperatingSystemOverride = OperatingSystem.macOs;
- debugBrowserEngineOverride = BrowserEngine.blink;
- EngineFlutterDisplay.instance.debugOverrideDevicePixelRatio(dpi);
-
- final List<ui.PointerDataPacket> packets = <ui.PointerDataPacket>[];
- ui.PlatformDispatcher.instance.onPointerDataPacket = (ui.PointerDataPacket packet) {
- packets.add(packet);
- };
-
- rootElement.dispatchEvent(context.wheel(
- buttons: 0,
- clientX: 10,
- clientY: 10,
- deltaX: 10,
- deltaY: 10,
- ));
-
- expect(packets, hasLength(1));
-
-
- // An add will be synthesized.
- expect(packets[0].data, hasLength(2));
- expect(packets[0].data[0].change, equals(ui.PointerChange.add));
- // Scroll deltas should NOT be multiplied by `dpi`.
- expect(packets[0].data[0].scrollDeltaX, equals(10.0));
- expect(packets[0].data[0].scrollDeltaY, equals(10.0));
-
- expect(packets[0].data[1].change, equals(ui.PointerChange.hover));
- expect(packets[0].data[1].signalKind, equals(ui.PointerSignalKind.scroll));
- // Scroll deltas should NOT be multiplied by `dpi`.
- expect(packets[0].data[0].scrollDeltaX, equals(10.0));
- expect(packets[0].data[0].scrollDeltaY, equals(10.0));
-
- EngineFlutterDisplay.instance.debugOverrideDevicePixelRatio(1.0);
- debugOperatingSystemOverride = null;
debugBrowserEngineOverride = null;
},
);
