Bug 795567 - Part 2: Introduce ContentHelper class that will be responsible for retrieving touch-action info from content and setting it to widget. r=kats

This commit is contained in:
Nick Lebedev 2014-01-15 10:03:15 -05:00
parent f28ec5074b
commit 3bc8322d83
3 changed files with 147 additions and 0 deletions

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

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef __mozilla_widget_ContentHelper_h__
#define __mozilla_widget_ContentHelper_h__
#include "nsIFrame.h"
#include "nsIWidget.h"
#include "mozilla/layers/APZCTreeManager.h"
namespace mozilla {
namespace widget {
/*
* Allow different platform widgets to access Content/DOM stuff.
*/
class ContentHelper
{
typedef mozilla::layers::AllowedTouchBehavior AllowedTouchBehavior;
typedef uint32_t TouchBehaviorFlags;
private:
static uint32_t GetTouchActionFromFrame(nsIFrame* aFrame);
static void UpdateAllowedBehavior(uint32_t aTouchActionValue, bool aConsiderPanning, TouchBehaviorFlags& aOutBehavior);
public:
/*
* Performs hit testing on content, finds frame that corresponds to the aPoint and retrieves
* touch-action css property value from it according the rules specified in the spec:
* http://www.w3.org/TR/pointerevents/#the-touch-action-css-property.
*/
static TouchBehaviorFlags GetAllowedTouchBehavior(nsIWidget* aWidget, const nsIntPoint& aPoint);
};
}
}
#endif /*__mozilla_widget_ContentHelper_h__ */

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EXPORTS += [
'APZCCallbackHelper.h',
'ContentHelper.h',
'GfxDriverInfo.h',
'GfxInfoBase.h',
'GfxInfoCollector.h',
@ -13,6 +14,7 @@ EXPORTS += [
UNIFIED_SOURCES += [
'APZCCallbackHelper.cpp',
'ContentHelper.cpp',
'GfxDriverInfo.cpp',
'GfxInfoBase.cpp',
'GfxInfoCollector.cpp',