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105 lines
4.7 KiB
C++
105 lines
4.7 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "ContentHelper.h"
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#include "nsQueryFrame.h"
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#include "nsIContent.h"
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#include "nsIScrollableFrame.h"
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#include "nsLayoutUtils.h"
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#include "nsStyleConsts.h"
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#include "nsView.h"
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namespace mozilla {
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namespace widget {
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uint32_t
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ContentHelper::GetTouchActionFromFrame(nsIFrame* aFrame)
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{
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if (!aFrame || !aFrame->GetContent() || !aFrame->GetContent()->GetPrimaryFrame()) {
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// If frame is invalid or null then return default value.
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return NS_STYLE_TOUCH_ACTION_AUTO;
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}
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if (!aFrame->IsFrameOfType(nsIFrame::eSVG) && !aFrame->IsFrameOfType(nsIFrame::eBlockFrame)) {
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// Since touch-action property can be applied to only svg and block-level
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// elements we ignore frames of other types.
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return NS_STYLE_TOUCH_ACTION_AUTO;
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}
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return (aFrame->GetContent()->GetPrimaryFrame()->StyleDisplay()->mTouchAction);
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}
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void
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ContentHelper::UpdateAllowedBehavior(uint32_t aTouchActionValue, bool aConsiderPanning, TouchBehaviorFlags& aOutBehavior)
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{
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if (aTouchActionValue != NS_STYLE_TOUCH_ACTION_AUTO) {
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// Dropping zoom flag since zooming requires touch-action values of all touches
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// to be AUTO.
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aOutBehavior &= ~AllowedTouchBehavior::ZOOM;
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}
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if (aConsiderPanning) {
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if (aTouchActionValue == NS_STYLE_TOUCH_ACTION_NONE) {
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aOutBehavior &= ~AllowedTouchBehavior::VERTICAL_PAN;
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aOutBehavior &= ~AllowedTouchBehavior::HORIZONTAL_PAN;
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}
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// Values pan-x and pan-y set at the same time to the same element do not affect panning constraints.
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// Therefore we need to check whether pan-x is set without pan-y and the same for pan-y.
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if ((aTouchActionValue & NS_STYLE_TOUCH_ACTION_PAN_X) && !(aTouchActionValue & NS_STYLE_TOUCH_ACTION_PAN_Y)) {
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aOutBehavior &= ~AllowedTouchBehavior::VERTICAL_PAN;
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} else if ((aTouchActionValue & NS_STYLE_TOUCH_ACTION_PAN_Y) && !(aTouchActionValue & NS_STYLE_TOUCH_ACTION_PAN_X)) {
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aOutBehavior &= ~AllowedTouchBehavior::HORIZONTAL_PAN;
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}
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}
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}
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ContentHelper::TouchBehaviorFlags
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ContentHelper::GetAllowedTouchBehavior(nsIWidget* aWidget, const nsIntPoint& aPoint)
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{
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nsView *view = nsView::GetViewFor(aWidget);
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nsIFrame *viewFrame = view->GetFrame();
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nsPoint relativePoint = nsLayoutUtils::GetEventCoordinatesRelativeTo(aWidget, aPoint, viewFrame);
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nsIFrame *target = nsLayoutUtils::GetFrameForPoint(viewFrame, relativePoint, nsLayoutUtils::IGNORE_ROOT_SCROLL_FRAME);
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nsIScrollableFrame *nearestScrollableParent = nsLayoutUtils::GetNearestScrollableFrame(target, 0);
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nsIFrame* nearestScrollableFrame = do_QueryFrame(nearestScrollableParent);
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// We're walking up the DOM tree until we meet the element with touch behavior and accumulating
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// touch-action restrictions of all elements in this chain.
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// The exact quote from the spec, that clarifies more:
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// To determine the effect of a touch, find the nearest ancestor (starting from the element itself)
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// that has a default touch behavior. Then examine the touch-action property of each element between
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// the hit tested element and the element with the default touch behavior (including both the hit
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// tested element and the element with the default touch behavior). If the touch-action property of
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// any of those elements disallows the default touch behavior, do nothing. Otherwise allow the element
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// to start considering the touch for the purposes of executing a default touch behavior.
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// Currently we support only two touch behaviors: panning and zooming.
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// For panning we walk up until we meet the first scrollable element (the element that supports panning)
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// or root element.
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// For zooming we walk up until the root element since Firefox currently supports only zooming of the
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// root frame but not the subframes.
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bool considerPanning = true;
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TouchBehaviorFlags behavior = AllowedTouchBehavior::VERTICAL_PAN | AllowedTouchBehavior::HORIZONTAL_PAN |
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AllowedTouchBehavior::ZOOM;
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for (nsIFrame *frame = target; frame && frame->GetContent() && behavior; frame = frame->GetParent()) {
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UpdateAllowedBehavior(GetTouchActionFromFrame(frame), considerPanning, behavior);
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if (frame == nearestScrollableFrame) {
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// We met the scrollable element, after it we shouldn't consider touch-action
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// values for the purpose of panning but only for zooming.
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considerPanning = false;
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}
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}
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return behavior;
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}
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}
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} |