1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6
7 #include "TouchActionHelper.h"
8
9 #include "mozilla/layers/IAPZCTreeManager.h"
10 #include "nsContainerFrame.h"
11 #include "nsIScrollableFrame.h"
12 #include "nsLayoutUtils.h"
13
14 namespace mozilla {
15 namespace layers {
16
UpdateAllowedBehavior(uint32_t aTouchActionValue,bool aConsiderPanning,TouchBehaviorFlags & aOutBehavior)17 void TouchActionHelper::UpdateAllowedBehavior(
18 uint32_t aTouchActionValue, bool aConsiderPanning,
19 TouchBehaviorFlags& aOutBehavior) {
20 if (aTouchActionValue != NS_STYLE_TOUCH_ACTION_AUTO) {
21 // Double-tap-zooming need property value AUTO
22 aOutBehavior &= ~AllowedTouchBehavior::DOUBLE_TAP_ZOOM;
23 if (aTouchActionValue != NS_STYLE_TOUCH_ACTION_MANIPULATION) {
24 // Pinch-zooming need value AUTO or MANIPULATION
25 aOutBehavior &= ~AllowedTouchBehavior::PINCH_ZOOM;
26 }
27 }
28
29 if (aConsiderPanning) {
30 if (aTouchActionValue == NS_STYLE_TOUCH_ACTION_NONE) {
31 aOutBehavior &= ~AllowedTouchBehavior::VERTICAL_PAN;
32 aOutBehavior &= ~AllowedTouchBehavior::HORIZONTAL_PAN;
33 }
34
35 // Values pan-x and pan-y set at the same time to the same element do not
36 // affect panning constraints. Therefore we need to check whether pan-x is
37 // set without pan-y and the same for pan-y.
38 if ((aTouchActionValue & NS_STYLE_TOUCH_ACTION_PAN_X) &&
39 !(aTouchActionValue & NS_STYLE_TOUCH_ACTION_PAN_Y)) {
40 aOutBehavior &= ~AllowedTouchBehavior::VERTICAL_PAN;
41 } else if ((aTouchActionValue & NS_STYLE_TOUCH_ACTION_PAN_Y) &&
42 !(aTouchActionValue & NS_STYLE_TOUCH_ACTION_PAN_X)) {
43 aOutBehavior &= ~AllowedTouchBehavior::HORIZONTAL_PAN;
44 }
45 }
46 }
47
GetAllowedTouchBehavior(nsIWidget * aWidget,nsIFrame * aRootFrame,const LayoutDeviceIntPoint & aPoint)48 TouchBehaviorFlags TouchActionHelper::GetAllowedTouchBehavior(
49 nsIWidget* aWidget, nsIFrame* aRootFrame,
50 const LayoutDeviceIntPoint& aPoint) {
51 TouchBehaviorFlags behavior = AllowedTouchBehavior::VERTICAL_PAN |
52 AllowedTouchBehavior::HORIZONTAL_PAN |
53 AllowedTouchBehavior::PINCH_ZOOM |
54 AllowedTouchBehavior::DOUBLE_TAP_ZOOM;
55
56 nsPoint relativePoint =
57 nsLayoutUtils::GetEventCoordinatesRelativeTo(aWidget, aPoint, aRootFrame);
58
59 nsIFrame* target = nsLayoutUtils::GetFrameForPoint(
60 aRootFrame, relativePoint, nsLayoutUtils::IGNORE_ROOT_SCROLL_FRAME);
61 if (!target) {
62 return behavior;
63 }
64 nsIScrollableFrame* nearestScrollableParent =
65 nsLayoutUtils::GetNearestScrollableFrame(target, 0);
66 nsIFrame* nearestScrollableFrame = do_QueryFrame(nearestScrollableParent);
67
68 // We're walking up the DOM tree until we meet the element with touch behavior
69 // and accumulating touch-action restrictions of all elements in this chain.
70 // The exact quote from the spec, that clarifies more:
71 // To determine the effect of a touch, find the nearest ancestor (starting
72 // from the element itself) that has a default touch behavior. Then examine
73 // the touch-action property of each element between the hit tested element
74 // and the element with the default touch behavior (including both the hit
75 // tested element and the element with the default touch behavior). If the
76 // touch-action property of any of those elements disallows the default touch
77 // behavior, do nothing. Otherwise allow the element to start considering the
78 // touch for the purposes of executing a default touch behavior.
79
80 // Currently we support only two touch behaviors: panning and zooming.
81 // For panning we walk up until we meet the first scrollable element (the
82 // element that supports panning) or root element. For zooming we walk up
83 // until the root element since Firefox currently supports only zooming of the
84 // root frame but not the subframes.
85
86 bool considerPanning = true;
87
88 for (nsIFrame* frame = target; frame && frame->GetContent() && behavior;
89 frame = frame->GetParent()) {
90 UpdateAllowedBehavior(nsLayoutUtils::GetTouchActionFromFrame(frame),
91 considerPanning, behavior);
92
93 if (frame == nearestScrollableFrame) {
94 // We met the scrollable element, after it we shouldn't consider
95 // touch-action values for the purpose of panning but only for zooming.
96 considerPanning = false;
97 }
98 }
99
100 return behavior;
101 }
102
103 } // namespace layers
104 } // namespace mozilla
105