chrome_render_widget_host_view_mac_history_swiper.h revision a3f6a49ab37290eeeb8db0f41ec0f1cb74a68be7 
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 CHROME_BROWSER_RENDERER_HOST_CHROME_RENDER_WIDGET_HOST_VIEW_MAC_HISTORY_SWIPER_
6#define CHROME_BROWSER_RENDERER_HOST_CHROME_RENDER_WIDGET_HOST_VIEW_MAC_HISTORY_SWIPER_
7
8#import <Cocoa/Cocoa.h>
9
10@class HistorySwiper;
11@protocol HistorySwiperDelegate
12// Return NO from this method is the view/render_widget_host should not
13// allow history swiping.
14- (BOOL)shouldAllowHistorySwiping;
15// The history overlay is added to the view returning from this method.
16- (NSView*)viewThatWantsHistoryOverlay;
17@end
18
19namespace history_swiper {
20enum NavigationDirection {
21  kBackwards = 0,
22  kForwards,
23};
24} // history_swiper
25
26// Responsible for maintaining state for 2-finger swipe history navigation.
27// Relevant blink/NSWindow touch events must be passed to this class.
28// We want to be able to cancel history swipes if the user's swipe has a lot of
29// vertical motion. The API [NSEvent trackSwipeEventWithOptions] doesn't give
30// vertical swipe distance, and it swallows the touch events so that we can't
31// independently gather them either. Instead of using that api, we manually
32// track all touch events using the low level APIs touches*WithEvent:
33@class HistoryOverlayController;
34@interface HistorySwiper : NSObject {
35 @private
36  // If the viewport is scrolled all the way to the left or right.
37  // Used for history swiping.
38  BOOL isPinnedLeft_;
39  BOOL isPinnedRight_;
40
41  // If the main frame has a horizontal scrollbar.
42  // Used for history swiping.
43  BOOL hasHorizontalScrollbar_;
44
45  // If a scroll event came back unhandled from the renderer. Set to |NO| at
46  // the start of a scroll gesture, and then to |YES| if a scroll event comes
47  // back unhandled from the renderer.
48  // Used for history swiping.
49  BOOL gotUnhandledWheelEvent_;
50
51  // This controller will exist if and only if the UI is in history swipe mode.
52  HistoryOverlayController* historyOverlay_;
53  // Each gesture received by the window is given a unique id.
54  // The id is monotonically increasing.
55  int currentGestureId_;
56  // The location of the fingers when the gesture started.
57  NSPoint gestureStartPoint_;
58  // The current location of the fingers in the gesture.
59  NSPoint gestureCurrentPoint_;
60  // A flag that indicates that there is an ongoing gesture.
61  // The method [NSEvent touchesMatchingPhase:inView:] is only valid for events
62  // that are part of a gesture.
63  BOOL inGesture_;
64  // Each time a new gesture begins, we must get a new start point.
65  // This ivar determines whether the start point is valid.
66  int gestureStartPointValid_;
67  // The id of the last gesture that we processed as a history swipe.
68  int lastProcessedGestureId_;
69  // A flag that indicates that we cancelled the history swipe for the current
70  // gesture.
71  BOOL historySwipeCancelled_;
72  // A flag that indicates the user's intended direction with the history swipe.
73  history_swiper::NavigationDirection historySwipeDirection_;
74  // A flag that indicates whether the gesture has its direction inverted.
75  BOOL historySwipeDirectionInverted_;
76
77  id<HistorySwiperDelegate> delegate_;
78}
79
80// Many event types are passed in, but the only one we care about is
81// NSScrollWheel. We look at the phase to determine whether to trigger history
82// swiping
83- (BOOL)handleEvent:(NSEvent*)event;
84- (void)gotUnhandledWheelEvent;
85- (void)scrollOffsetPinnedToLeft:(BOOL)left toRight:(BOOL)right;
86- (void)setHasHorizontalScrollbar:(BOOL)hasHorizontalScrollbar;
87
88// The event passed in is a gesture event, and has touch data associated with
89// the trackpad.
90- (void)touchesBeganWithEvent:(NSEvent*)event;
91- (void)touchesMovedWithEvent:(NSEvent*)event;
92- (void)touchesCancelledWithEvent:(NSEvent*)event;
93- (void)touchesEndedWithEvent:(NSEvent*)event;
94- (void)beginGestureWithEvent:(NSEvent*)event;
95- (void)endGestureWithEvent:(NSEvent*)event;
96
97// Designated initializer.
98- (id)initWithDelegate:(id<HistorySwiperDelegate>)delegate;
99
100@property (nonatomic, assign) id<HistorySwiperDelegate> delegate;
101
102@end
103
104#endif // CHROME_BROWSER_RENDERER_HOST_CHROME_RENDER_WIDGET_HOST_VIEW_MAC_HISTORY_SWIPER_
105