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.
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_
8 #import <Cocoa/Cocoa.h>
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;
19 namespace history_swiper {
20 enum NavigationDirection {
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 {
36 // If the viewport is scrolled all the way to the left or right.
37 // Used for history swiping.
41 // If the main frame has a horizontal scrollbar.
42 // Used for history swiping.
43 BOOL hasHorizontalScrollbar_;
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_;
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.
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
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_;
77 id<HistorySwiperDelegate> delegate_;
79 // Magic mouse and touchpad swipe events are identical except magic mouse
80 // events do not generate NSTouch callbacks. Since we rely on NSTouch
81 // callbacks to determine vertical scrolling, magic mouse swipe events use an
82 // entirely different set of logic.
84 // The two event types do not play well together. Just calling the API
85 // `[NSEvent trackSwipeEventWithOptions:]` will block touches{Began, Moved, *}
86 // callbacks for a non-deterministic period of time (even after the swipe has
89 // Cumulative scroll delta since scroll gesture start. Only valid during
90 // scroll gesture handling. Used for history swiping.
91 NSSize mouseScrollDelta_;
94 // Many event types are passed in, but the only one we care about is
95 // NSScrollWheel. We look at the phase to determine whether to trigger history
97 - (BOOL)handleEvent:(NSEvent*)event;
98 - (void)gotUnhandledWheelEvent;
99 - (void)scrollOffsetPinnedToLeft:(BOOL)left toRight:(BOOL)right;
100 - (void)setHasHorizontalScrollbar:(BOOL)hasHorizontalScrollbar;
102 // The event passed in is a gesture event, and has touch data associated with
104 - (void)touchesBeganWithEvent:(NSEvent*)event;
105 - (void)touchesMovedWithEvent:(NSEvent*)event;
106 - (void)touchesCancelledWithEvent:(NSEvent*)event;
107 - (void)touchesEndedWithEvent:(NSEvent*)event;
108 - (void)beginGestureWithEvent:(NSEvent*)event;
109 - (void)endGestureWithEvent:(NSEvent*)event;
111 // These methods control whether a given view is allowed to rubberband in the
112 // given direction. This is inversely related to whether the view is allowed to
113 // 2-finger history swipe in the given direction.
114 - (BOOL)canRubberbandLeft:(NSView*)view;
115 - (BOOL)canRubberbandRight:(NSView*)view;
117 // Designated initializer.
118 - (id)initWithDelegate:(id<HistorySwiperDelegate>)delegate;
120 @property (nonatomic, assign) id<HistorySwiperDelegate> delegate;
124 // Exposed only for unit testing, do not call directly.
125 @interface HistorySwiper (PrivateExposedForTesting)
126 + (void)resetMagicMouseState;
129 #endif // CHROME_BROWSER_RENDERER_HOST_CHROME_RENDER_WIDGET_HOST_VIEW_MAC_HISTORY_SWIPER_