From 4267567f5366b237c763d1b93cd09501a483a070 Mon Sep 17 00:00:00 2001
From: Allan Sandfeld Jensen <allan.jensen@qt.io>
Date: Tue, 24 Oct 2017 16:30:31 +0200
Subject: [PATCH] Coalesce wheel events when possible
MIME-Version: 1.0
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Combine wheel events if we are getting more than Chromium can handle.
This improves latency and perceived performance when scrolling with
touchpads or fine-grained mouse, on a slow machine or with a debug
build.
Change-Id: Id847c8e7782e155c28067b6051ce92896b68ca7a
Reviewed-by: Michael Brüning <michael.bruning@qt.io>
---
src/core/render_widget_host_view_qt.cpp | 24 ++++++++++++-
src/core/render_widget_host_view_qt.h | 4 +++
src/core/web_event_factory.cpp | 48 +++++++++++++++++--------
src/core/web_event_factory.h | 1 +
4 files changed, 61 insertions(+), 16 deletions(-)
diff --git a/src/core/render_widget_host_view_qt.cpp b/src/core/render_widget_host_view_qt.cpp
index d1fc7d171..a45383946 100644
--- a/src/core/render_widget_host_view_qt.cpp
+++ b/src/core/render_widget_host_view_qt.cpp
@@ -282,6 +282,7 @@ RenderWidgetHostViewQt::RenderWidgetHostViewQt(content::RenderWidgetHost* widget
, m_cursorPositionWithinSelection(-1)
, m_cursorPosition(0)
, m_emptyPreviousSelection(true)
+ , m_wheelAckPending(false)
{
m_host->SetView(this);
#ifndef QT_NO_ACCESSIBILITY
@@ -1350,7 +1351,28 @@ void RenderWidgetHostViewQt::accessibilityActiveChanged(bool active)
void RenderWidgetHostViewQt::handleWheelEvent(QWheelEvent *ev)
{
- m_host->ForwardWheelEvent(WebEventFactory::toWebWheelEvent(ev, dpiScale()));
+ if (!m_wheelAckPending) {
+ Q_ASSERT(m_pendingWheelEvents.isEmpty());
+ m_wheelAckPending = true;
+ m_host->ForwardWheelEvent(WebEventFactory::toWebWheelEvent(ev, dpiScale()));
+ return;
+ }
+ if (!m_pendingWheelEvents.isEmpty()) {
+ // Try to combine with this wheel event with the last pending one.
+ if (WebEventFactory::coalesceWebWheelEvent(m_pendingWheelEvents.last(), ev, dpiScale()))
+ return;
+ }
+ m_pendingWheelEvents.append(WebEventFactory::toWebWheelEvent(ev, dpiScale()));
+}
+
+void RenderWidgetHostViewQt::WheelEventAck(const blink::WebMouseWheelEvent &/*event*/, content::InputEventAckState /*ack_result*/)
+{
+ m_wheelAckPending = false;
+ if (!m_pendingWheelEvents.isEmpty()) {
+ m_wheelAckPending = true;
+ m_host->ForwardWheelEvent(m_pendingWheelEvents.takeFirst());
+ }
+ // TODO: We could forward unhandled wheelevents to our parent.
}
void RenderWidgetHostViewQt::clearPreviousTouchMotionState()
diff --git a/src/core/render_widget_host_view_qt.h b/src/core/render_widget_host_view_qt.h
index 59e21b853..4b7f9094e 100644
--- a/src/core/render_widget_host_view_qt.h
+++ b/src/core/render_widget_host_view_qt.h
@@ -152,6 +152,7 @@ public:
bool HasAcceleratedSurface(const gfx::Size&) override;
void DidCreateNewRendererCompositorFrameSink(cc::mojom::CompositorFrameSinkClient* renderer_compositor_frame_sink) override;
void SubmitCompositorFrame(const viz::LocalSurfaceId&, cc::CompositorFrame) override;
+ void WheelEventAck(const blink::WebMouseWheelEvent &event, content::InputEventAckState ack_result) override;
void GetScreenInfo(content::ScreenInfo* results);
gfx::Rect GetBoundsInRootWindow() override;
@@ -270,6 +271,9 @@ private:
QString m_surroundingText;
bool m_imeHasHiddenTextCapability;
+
+ bool m_wheelAckPending;
+ QList<blink::WebMouseWheelEvent> m_pendingWheelEvents;
};
} // namespace QtWebEngineCore
diff --git a/src/core/web_event_factory.cpp b/src/core/web_event_factory.cpp
index 18f8d393f..c31de19a2 100644
--- a/src/core/web_event_factory.cpp
+++ b/src/core/web_event_factory.cpp
@@ -1247,38 +1247,56 @@ WebGestureEvent WebEventFactory::toWebGestureEvent(QNativeGestureEvent *ev, doub
}
#endif
-blink::WebMouseWheelEvent WebEventFactory::toWebWheelEvent(QWheelEvent *ev, double dpiScale)
+static void setBlinkWheelEventDelta(blink::WebMouseWheelEvent &webEvent)
{
- WebMouseWheelEvent webEvent;
- webEvent.delta_x = 0;
- webEvent.delta_y = 0;
- webEvent.wheel_ticks_x = 0;
- webEvent.wheel_ticks_y = 0;
- webEvent.SetType(webEventTypeForEvent(ev));
- webEvent.SetModifiers(modifiersForEvent(ev));
- webEvent.SetTimeStampSeconds(currentTimeForEvent(ev));
-
- webEvent.wheel_ticks_x = static_cast<float>(ev->angleDelta().x()) / QWheelEvent::DefaultDeltasPerStep;
- webEvent.wheel_ticks_y = static_cast<float>(ev->angleDelta().y()) / QWheelEvent::DefaultDeltasPerStep;
-
// We can't use the device specific QWheelEvent::pixelDelta(), so we calculate
// a pixel delta based on ticks and scroll per line.
static const float cDefaultQtScrollStep = 20.f;
#if (QT_VERSION >= QT_VERSION_CHECK(5, 9, 0))
- const int wheelScrollLines = QGuiApplication::styleHints()->wheelScrollLines();
+ static const int wheelScrollLines = QGuiApplication::styleHints()->wheelScrollLines();
#else
- const int wheelScrollLines = 3;
+ static const int wheelScrollLines = 3;
#endif
webEvent.delta_x = webEvent.wheel_ticks_x * wheelScrollLines * cDefaultQtScrollStep;
webEvent.delta_y = webEvent.wheel_ticks_y * wheelScrollLines * cDefaultQtScrollStep;
+}
+
+blink::WebMouseWheelEvent WebEventFactory::toWebWheelEvent(QWheelEvent *ev, double dpiScale)
+{
+ WebMouseWheelEvent webEvent;
+ webEvent.SetType(webEventTypeForEvent(ev));
+ webEvent.SetModifiers(modifiersForEvent(ev));
+ webEvent.SetTimeStampSeconds(currentTimeForEvent(ev));
webEvent.SetPositionInWidget(ev->x() / dpiScale, ev->y() / dpiScale);
webEvent.SetPositionInScreen(ev->globalX(), ev->globalY());
+ webEvent.wheel_ticks_x = static_cast<float>(ev->angleDelta().x()) / QWheelEvent::DefaultDeltasPerStep;
+ webEvent.wheel_ticks_y = static_cast<float>(ev->angleDelta().y()) / QWheelEvent::DefaultDeltasPerStep;
+ setBlinkWheelEventDelta(webEvent);
+
return webEvent;
}
+bool WebEventFactory::coalesceWebWheelEvent(blink::WebMouseWheelEvent &webEvent, QWheelEvent *ev, double dpiScale)
+{
+ if (webEventTypeForEvent(ev) != webEvent.GetType())
+ return false;
+ if (modifiersForEvent(ev) != webEvent.GetModifiers())
+ return false;
+
+ webEvent.SetTimeStampSeconds(currentTimeForEvent(ev));
+ webEvent.SetPositionInWidget(ev->x() / dpiScale, ev->y() / dpiScale);
+ webEvent.SetPositionInScreen(ev->globalX(), ev->globalY());
+
+ webEvent.wheel_ticks_x += static_cast<float>(ev->angleDelta().x()) / QWheelEvent::DefaultDeltasPerStep;
+ webEvent.wheel_ticks_y += static_cast<float>(ev->angleDelta().y()) / QWheelEvent::DefaultDeltasPerStep;
+ setBlinkWheelEventDelta(webEvent);
+
+ return true;
+}
+
content::NativeWebKeyboardEvent WebEventFactory::toWebKeyboardEvent(QKeyEvent *ev)
{
content::NativeWebKeyboardEvent webKitEvent(reinterpret_cast<gfx::NativeEvent>(ev));
diff --git a/src/core/web_event_factory.h b/src/core/web_event_factory.h
index 259795c1f..5758af848 100644
--- a/src/core/web_event_factory.h
+++ b/src/core/web_event_factory.h
@@ -68,6 +68,7 @@ public:
static blink::WebGestureEvent toWebGestureEvent(QNativeGestureEvent *, double dpiScale);
#endif
static blink::WebMouseWheelEvent toWebWheelEvent(QWheelEvent*, double dpiScale);
+ static bool coalesceWebWheelEvent(blink::WebMouseWheelEvent &, QWheelEvent*, double dpiScale);
static content::NativeWebKeyboardEvent toWebKeyboardEvent(QKeyEvent*);
};
--
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