1 // Copyright 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_ACTION_FILTER_H_ 6 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_ACTION_FILTER_H_ 7 8 #include "base/basictypes.h" 9 #include "content/common/content_export.h" 10 #include "content/common/input/touch_action.h" 11 12 namespace blink { 13 class WebGestureEvent; 14 } 15 16 namespace content { 17 18 // The TouchActionFilter is responsible for filtering scroll and pinch gesture 19 // events according to the CSS touch-action values the renderer has sent for 20 // each touch point. 21 // For details see the touch-action design doc at http://goo.gl/KcKbxQ. 22 class CONTENT_EXPORT TouchActionFilter { 23 public: 24 TouchActionFilter(); 25 26 // Returns true if the supplied gesture event should be dropped based on 27 // the current touch-action state. 28 bool FilterGestureEvent(blink::WebGestureEvent* gesture_event); 29 30 // Called when a set-touch-action message is received from the renderer 31 // for a touch start event that is currently in flight. 32 void OnSetTouchAction(content::TouchAction touch_action); 33 34 // Must be called at least once between when the last gesture events for the 35 // previous touch sequence have passed through the touch action filter and the 36 // time the touch start for the next touch sequence has reached the 37 // renderer. It may be called multiple times during this interval. 38 void ResetTouchAction(); 39 40 TouchAction allowed_touch_action() const { return allowed_touch_action_; } 41 42 // Return the intersection of two TouchAction values. 43 static TouchAction Intersect(TouchAction ta1, TouchAction ta2); 44 45 private: 46 bool ShouldSuppressScroll(const blink::WebGestureEvent& gesture_event); 47 bool FilterScrollEndingGesture(); 48 49 // Whether GestureScroll events should be discarded due to touch-action. 50 bool drop_scroll_gesture_events_; 51 52 // Whether GesturePinch events should be discarded due to touch-action. 53 bool drop_pinch_gesture_events_; 54 55 // Whether a tap ending event in this sequence should be discarded because a 56 // previous GestureTapUnconfirmed event was turned into a GestureTap. 57 bool drop_current_tap_ending_event_; 58 59 // True iff the touch action of the last TapUnconfirmed or Tap event was 60 // TOUCH_ACTION_AUTO. The double tap event depends on the touch action of the 61 // previous tap or tap unconfirmed. Only valid between a TapUnconfirmed or Tap 62 // and the next DoubleTap. 63 bool allow_current_double_tap_event_; 64 65 // What touch actions are currently permitted. 66 TouchAction allowed_touch_action_; 67 68 DISALLOW_COPY_AND_ASSIGN(TouchActionFilter); 69 }; 70 71 } 72 #endif // CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_ACTION_FILTER_H_ 73
