content/browser/web_contents/web_contents_view_overscroll_animator_mac.h

   1 // Copyright 2014 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_WEB_CONTENTS_WEB_CONTENTS_VIEW_OVERSCROLL_ANIMATOR_MAC_H_
   6 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_OVERSCROLL_ANIMATOR_MAC_H_
   7
   8 #import <Cocoa/Cocoa.h>
   9
  10 namespace content {
  11 class WebContentsImpl;
  12
  13 // The direction of the overscroll animations. Backwards means that the user
  14 // wants to navigate backwards in the navigation history. The opposite applies
  15 // to forwards.
  16 enum OverscrollAnimatorDirection {
  17   OVERSCROLL_ANIMATOR_DIRECTION_BACKWARDS,
  18   OVERSCROLL_ANIMATOR_DIRECTION_FORWARDS,
  19 };
  20 }  // namespace content
  21
  22 // NSViews that intend to manage the animation associated with an overscroll
  23 // must implement this protocol.
  24 @protocol WebContentsOverscrollAnimator
  25 // Some implementations require the WebContentsView to supply a snapshot of a
  26 // previous navigation state. This method determines whether the snapshot passed
  27 // to the overscroll animator is expected to be non-nil.
  28 - (BOOL)needsNavigationSnapshot;
  29
  30 // Begin an overscroll animation. The method -needsNavigationSnapshot determines
  31 // whether |snapshot| can be nil.
  32 - (void)beginOverscrollInDirection:
  33             (content::OverscrollAnimatorDirection)direction
  34                 navigationSnapshot:(NSImage*)snapshot;
  35
  36 // Due to the nature of some of the overscroll animations, implementators of
  37 // this protocol must have control over the layout of the RenderWidgetHost's
  38 // NativeView. When there is no overscroll animation in progress, the
  39 // implementor must guarantee that the frame of the RenderWidgetHost's
  40 // NativeView in screen coordinates is the same as its own frame in screen
  41 // coordinates.
  42 // Due to the odd ownership cycles of the RenderWidgetHost's NativeView, it is
  43 // important that its presence in the NSView hierarchy is the only strong
  44 // reference, and that when it gets removed from the NSView hierarchy, it will
  45 // be dealloc'ed shortly thereafter.
  46 - (void)addRenderWidgetHostNativeView:(NSView*)view;
  47
  48 // During an overscroll animation, |progress| ranges from 0 to 2, and indicates
  49 // how close the overscroll is to completing. If the overscroll ends with
  50 // |progress| >= 1, then the overscroll is considered completed.
  51 - (void)updateOverscrollProgress:(CGFloat)progress;
  52
  53 // Animate the finish of the overscroll and perform a navigation. The navigation
  54 // may not happen synchronously, but is guaranteed to eventually occur.
  55 - (void)completeOverscroll:(content::WebContentsImpl*)webContents;
  56
  57 // Animate the cancellation of the overscroll.
  58 - (void)cancelOverscroll;
  59 @end
  60
  61 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_VIEW_OVERSCROLL_ANIMATOR_MAC_H_