ScrollResult RootFrameViewport::handleWheel(const PlatformWheelEvent& event)
{
updateScrollAnimator();
ScrollableArea& primary = !m_invertScrollOrder ? layoutViewport() : visualViewport();
ScrollableArea& secondary = !m_invertScrollOrder ? visualViewport() : layoutViewport();
ScrollResult viewScrollResult = primary.handleWheel(event);
// The visual viewport will only accept pixel scrolls.
if (!event.canScroll() || event.granularity() == ScrollByPageWheelEvent)
return viewScrollResult;
// TODO(sataya.m) : The delta in PlatformWheelEvent is negative when scrolling the
// wheel towards the user, so negate it to get the scroll delta that should be applied
// to the page. unusedScrollDelta computed in the ScrollResult is also negative. Say
// there is WheelEvent({0, -10} and page scroll by 2px and unusedScrollDelta computed
// is {0, -8}. Due to which we have to negate the unusedScrollDelta to obtain the expected
// animation.Please address http://crbug.com/504389.
DoublePoint oldOffset = secondary.scrollPositionDouble();
DoublePoint locationDelta;
if (viewScrollResult.didScroll()) {
locationDelta = -DoublePoint(viewScrollResult.unusedScrollDeltaX, viewScrollResult.unusedScrollDeltaY);
} else {
if (event.railsMode() != PlatformEvent::RailsModeVertical)
locationDelta.setX(-event.deltaX());
if (event.railsMode() != PlatformEvent::RailsModeHorizontal)
locationDelta.setY(-event.deltaY());
}
DoublePoint targetPosition = secondary.clampScrollPosition(
secondary.scrollPositionDouble() + toDoubleSize(locationDelta));
secondary.setScrollPosition(targetPosition, UserScroll);
DoublePoint usedLocationDelta(secondary.scrollPositionDouble() - oldOffset);
bool didScrollX = viewScrollResult.didScrollX || usedLocationDelta.x();
bool didScrollY = viewScrollResult.didScrollY || usedLocationDelta.y();
return ScrollResult(didScrollX, didScrollY, -viewScrollResult.unusedScrollDeltaX - usedLocationDelta.x(), -viewScrollResult.unusedScrollDeltaY - usedLocationDelta.y());
}
void AutoscrollController::animate(double) {
if (!m_autoscrollLayoutObject || !m_autoscrollLayoutObject->frame()) {
stopAutoscroll();
return;
}
EventHandler& eventHandler =
m_autoscrollLayoutObject->frame()->eventHandler();
IntSize offset = m_autoscrollLayoutObject->calculateAutoscrollDirection(
eventHandler.lastKnownMousePosition());
IntPoint selectionPoint = eventHandler.lastKnownMousePosition() + offset;
switch (m_autoscrollType) {
case AutoscrollForDragAndDrop:
if (WTF::monotonicallyIncreasingTime() -
m_dragAndDropAutoscrollStartTime >
autoscrollDelay)
m_autoscrollLayoutObject->autoscroll(
m_dragAndDropAutoscrollReferencePosition);
break;
case AutoscrollForSelection:
if (!eventHandler.mousePressed()) {
stopAutoscroll();
return;
}
eventHandler.updateSelectionForMouseDrag();
m_autoscrollLayoutObject->autoscroll(selectionPoint);
break;
case NoAutoscroll:
break;
case AutoscrollForMiddleClickCanStop:
case AutoscrollForMiddleClick:
DCHECK(RuntimeEnabledFeatures::middleClickAutoscrollEnabled());
if (!middleClickAutoscrollInProgress()) {
stopAutoscroll();
return;
}
if (FrameView* view = m_autoscrollLayoutObject->frame()->view())
updateMiddleClickAutoscrollState(view,
eventHandler.lastKnownMousePosition());
FloatSize delta = calculateAutoscrollDelta();
if (delta.isZero())
break;
ScrollResult result =
m_autoscrollLayoutObject->scroll(ScrollByPixel, delta);
LayoutObject* layoutObject = m_autoscrollLayoutObject;
while (!m_didLatchForMiddleClickAutoscroll && !result.didScroll()) {
if (layoutObject->node() && layoutObject->node()->isDocumentNode()) {
Element* owner = toDocument(layoutObject->node())->localOwner();
layoutObject = owner ? owner->layoutObject() : nullptr;
} else {
layoutObject = layoutObject->parent();
}
if (!layoutObject) {
break;
}
if (layoutObject && layoutObject->isBox() &&
toLayoutBox(layoutObject)->canBeScrolledAndHasScrollableArea())
result = toLayoutBox(layoutObject)->scroll(ScrollByPixel, delta);
}
if (result.didScroll()) {
m_didLatchForMiddleClickAutoscroll = true;
m_autoscrollLayoutObject = toLayoutBox(layoutObject);
}
break;
}
if (m_autoscrollType != NoAutoscroll && m_autoscrollLayoutObject)
m_page->chromeClient().scheduleAnimation(
m_autoscrollLayoutObject->frame()->view());
}