Animated Rotation

chrome/browser/ui/touch/animation/screen_rotation.h

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_UI_TOUCH_ANIMATION_SCREEN_ROTATION_H_
+#define CHROME_BROWSER_UI_TOUCH_ANIMATION_SCREEN_ROTATION_H_
+#pragma once
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/bind.h"
+#include "ui/base/animation/animation_delegate.h"
+#include "ui/gfx/point.h"
+#include "ui/gfx/size.h"
+#include "views/paint_listener.h"
+
+namespace ui {
+class InterpolatedTransform;
+class Layer;
+class SlideAnimation;
+class Transform;
+}
+
+namespace gfx {
+class Rect;
+}
+
+namespace views {
+class View;
+class PaintLock;
+}
+
+// Classes that wish to be notified when a screen rotation completes must
+// implement the screen rotation listener interface.
+class ScreenRotationListener {
+ public:
+  virtual void OnScreenRotationCompleted(const ui::Transform& target_transform,
+                                         const gfx::Rect& target_bounds) = 0;
+ protected:
+  virtual ~ScreenRotationListener();
+};
+
+// A screen rotation represents a single transition from one screen orientation
+// to another. The  intended usage is that a new instance of the class is
+// created for every transition. It is possible to update the target orientation
+// in the middle of a transition.
+class ScreenRotation : public ui::AnimationDelegate,
+                       public views::PaintListener {
+ public:
+  // The screen rotation does not own the view or the listener, and these
+  // objects are required to outlive the Screen rotation object.
+  ScreenRotation(views::View* view,
+                 ScreenRotationListener* listener,
+                 float old_degrees,
+                 float new_degrees);
+  virtual ~ScreenRotation();
+
+  // Initializes the screen rotation and starts |animation_|.
+  void Start();
+
+  // Called after the animation is finished and the view has completed painting
+  // in its final state.
+  void Finalize();
+
+  // Use this function to change the target orientation mid animation. The
+  // currently running transition will complete at the same time as it was going
+  // to originally, but in a different orientation.
+  void SetTarget(float degrees);
+
+  // Implementation of views::PaintListener
+  void OnPainted(views::View* view) OVERRIDE;
+  void OnComposited(views::View* view) OVERRIDE;
+
+ private:
+  // Implementation of ui::AnimationDelegate
+  virtual void AnimationEnded(const ui::Animation* anim) OVERRIDE;
+  virtual void AnimationProgressed(const ui::Animation* anim) OVERRIDE;
+
+  // Initializes |interpolated_transform_|, |new_origin_|, |new_size_|, and
+  // (if it has not already been initialized) |old_transform_|
+  void Init();
+
+  // Converts degrees to an angle in the range [-180, 180).
+  int NormalizeAngle(int degrees);
+
+  // We occasionally need to wait for a paint to finish before progressing.
+  // This function (which is triggered by OnPainted and OnComposited) does
+  // any pending work.
+  void DoPendingWork();
+
+  // This is the view that will be animated. The animation will operate mainly
+  // on |view_|'s layer, but it is used upon completion of the rotation to
+  // update the bounds.
+  views::View* view_;
+
+  // A ScreenRotation may be associated with a listener that is notified when
+  // the screen rotation completes.
+  ScreenRotationListener* listener_;
+
+  // The animation object that instigates stepping of the animation.
+  scoped_ptr<ui::SlideAnimation> animation_;
+
+  // Generates the intermediate transformation matrices used during the
+  // animation.
+  scoped_ptr<ui::InterpolatedTransform> interpolated_transform_;
+
+  // Ensures that the view is not repainted during the screen rotation.
+  scoped_ptr<views::PaintLock> paint_lock_;
+
+  // The original orientation (not updated by |SetTarget|.
+  float old_degrees_;
+
+  // The target orientation.
+  float new_degrees_;
+
+  // We keep track of the last step of the animation in case we change our
+  // target in the middle and have to create a new transition from last_t_ to 1
+  float last_t_;
+
+  // The target size for |view_|
+  gfx::Size new_size_;
+
+  // The target origin for |view_|
+  gfx::Point new_origin_;
+
+  // This is the duration of the transition in milliseconds
+  int duration_;
+
+  // These are used by DoPendingWork to decide what needs to be done.
+  bool animation_started_;
+  bool animation_stopped_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScreenRotation);
+};
+
+#endif  // CHROME_BROWSER_UI_TOUCH_ANIMATION_SCREEN_ROTATION_H_