The Tor Browser: widget/xpwidgets/ContentHelper.cpp@b8a032363ba2

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

     1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

     2 /* This Source Code Form is subject to the terms of the Mozilla Public

     3  * License, v. 2.0. If a copy of the MPL was not distributed with this

     4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     6 #include "ContentHelper.h"

     7 #include "nsQueryFrame.h"

     8 #include "nsIContent.h"

     9 #include "nsIScrollableFrame.h"

    10 #include "nsLayoutUtils.h"

    11 #include "nsStyleConsts.h"

    12 #include "nsView.h"

    14 namespace mozilla {

    15 namespace widget {

    17 uint32_t

    18 ContentHelper::GetTouchActionFromFrame(nsIFrame* aFrame)

    19 {

    20   if (!aFrame || !aFrame->GetContent() || !aFrame->GetContent()->GetPrimaryFrame()) {

    21     // If frame is invalid or null then return default value.

    22     return NS_STYLE_TOUCH_ACTION_AUTO;

    23   }

    25   if (!aFrame->IsFrameOfType(nsIFrame::eSVG) && !aFrame->IsFrameOfType(nsIFrame::eBlockFrame)) {

    26     // Since touch-action property can be applied to only svg and block-level

    27     // elements we ignore frames of other types.

    28     return NS_STYLE_TOUCH_ACTION_AUTO;

    29   }

    31   return (aFrame->GetContent()->GetPrimaryFrame()->StyleDisplay()->mTouchAction);

    32 }

    34 void

    35 ContentHelper::UpdateAllowedBehavior(uint32_t aTouchActionValue, bool aConsiderPanning, TouchBehaviorFlags& aOutBehavior)

    36 {

    37   if (aTouchActionValue != NS_STYLE_TOUCH_ACTION_AUTO) {

    38     // Double-tap-zooming need property value AUTO

    39     aOutBehavior &= ~AllowedTouchBehavior::DOUBLE_TAP_ZOOM;

    40     if (aTouchActionValue != NS_STYLE_TOUCH_ACTION_MANIPULATION) {

    41       // Pinch-zooming need value AUTO or MANIPULATION

    42       aOutBehavior &= ~AllowedTouchBehavior::PINCH_ZOOM;

    43     }

    44   }

    46   if (aConsiderPanning) {

    47     if (aTouchActionValue == NS_STYLE_TOUCH_ACTION_NONE) {

    48       aOutBehavior &= ~AllowedTouchBehavior::VERTICAL_PAN;

    49       aOutBehavior &= ~AllowedTouchBehavior::HORIZONTAL_PAN;

    50     }

    52     // Values pan-x and pan-y set at the same time to the same element do not affect panning constraints.

    53     // Therefore we need to check whether pan-x is set without pan-y and the same for pan-y.

    54     if ((aTouchActionValue & NS_STYLE_TOUCH_ACTION_PAN_X) && !(aTouchActionValue & NS_STYLE_TOUCH_ACTION_PAN_Y)) {

    55       aOutBehavior &= ~AllowedTouchBehavior::VERTICAL_PAN;

    56     } else if ((aTouchActionValue & NS_STYLE_TOUCH_ACTION_PAN_Y) && !(aTouchActionValue & NS_STYLE_TOUCH_ACTION_PAN_X)) {

    57       aOutBehavior &= ~AllowedTouchBehavior::HORIZONTAL_PAN;

    58     }

    59   }

    60 }

    62 ContentHelper::TouchBehaviorFlags

    63 ContentHelper::GetAllowedTouchBehavior(nsIWidget* aWidget, const nsIntPoint& aPoint)

    64 {

    65   nsView *view = nsView::GetViewFor(aWidget);

    66   nsIFrame *viewFrame = view->GetFrame();

    68   nsPoint relativePoint = nsLayoutUtils::GetEventCoordinatesRelativeTo(aWidget, aPoint, viewFrame);

    70   nsIFrame *target = nsLayoutUtils::GetFrameForPoint(viewFrame, relativePoint, nsLayoutUtils::IGNORE_ROOT_SCROLL_FRAME);

    71   nsIScrollableFrame *nearestScrollableParent = nsLayoutUtils::GetNearestScrollableFrame(target, 0);

    72   nsIFrame* nearestScrollableFrame = do_QueryFrame(nearestScrollableParent);

    74   // We're walking up the DOM tree until we meet the element with touch behavior and accumulating

    75   // touch-action restrictions of all elements in this chain.

    76   // The exact quote from the spec, that clarifies more:

    77   // To determine the effect of a touch, find the nearest ancestor (starting from the element itself)

    78   // that has a default touch behavior. Then examine the touch-action property of each element between

    79   // the hit tested element and the element with the default touch behavior (including both the hit

    80   // tested element and the element with the default touch behavior). If the touch-action property of

    81   // any of those elements disallows the default touch behavior, do nothing. Otherwise allow the element

    82   // to start considering the touch for the purposes of executing a default touch behavior.

    84   // Currently we support only two touch behaviors: panning and zooming.

    85   // For panning we walk up until we meet the first scrollable element (the element that supports panning)

    86   // or root element.

    87   // For zooming we walk up until the root element since Firefox currently supports only zooming of the

    88   // root frame but not the subframes.

    90   bool considerPanning = true;

    91   TouchBehaviorFlags behavior = AllowedTouchBehavior::VERTICAL_PAN | AllowedTouchBehavior::HORIZONTAL_PAN |

    92                                 AllowedTouchBehavior::PINCH_ZOOM | AllowedTouchBehavior::DOUBLE_TAP_ZOOM;

    94   for (nsIFrame *frame = target; frame && frame->GetContent() && behavior; frame = frame->GetParent()) {

    95     UpdateAllowedBehavior(GetTouchActionFromFrame(frame), considerPanning, behavior);

    97     if (frame == nearestScrollableFrame) {

    98       // We met the scrollable element, after it we shouldn't consider touch-action

    99       // values for the purpose of panning but only for zooming.

   100       considerPanning = false;

   101     }

   102   }

   104   return behavior;

   105 }

   107 }

   108 }

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