Interpolated transforms

ui/gfx/interpolated_transform.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 UI_GFX_INTERPOLATED_TRANSFORM_H_
+#define UI_GFX_INTERPOLATED_TRANSFORM_H_
+#pragma once
+
+#include "ui/gfx/transform.h"
+#include "base/memory/scoped_ptr.h"
+#include "ui/gfx/point.h"
+
+namespace ui {
+
+class InterpolatedTransform {

[sky, 2011/06/28 15:39:14]

Add a description of this class. Same comment for all classes.

+ public:
+  InterpolatedTransform();
+  InterpolatedTransform(float start_time, float end_time);

[sky, 2011/06/28 15:39:14]

Document what start_time and end_time are.

+  virtual ~InterpolatedTransform() {}

[sky, 2011/06/28 15:39:14]

Don't inline this.

+
+  // Returns the interpolated transform at time t. Note: not virtual.
+  ui::Transform Interpolate(float t) const;
+
+  // Takes ownership of the other Interpolated Transform.
+  void Compose(InterpolatedTransform* other) { child_.reset(other); }

[sky, 2011/06/28 15:39:14]

Don't inline this since it may run destructors. Also, the method doesn't really
indicate it takes ownership. SetChild is much clearer.

+
+ protected:
+  virtual ui::Transform InterpolateButDoNotCompose(float t) const = 0;

[sky, 2011/06/28 15:39:14]

Description.

+
+  float ValueBetween(float time, float start_value, float end_value) const;

[sky, 2011/06/28 15:39:14]

description.

+
+ private:
+  float start_time_;
+  float end_time_;
+
+  scoped_ptr<InterpolatedTransform> child_;

[sky, 2011/06/28 15:39:14]

Description.

+
+  DISALLOW_COPY_AND_ASSIGN(InterpolatedTransform);
+};
+
+class InterpolatedRotation : public InterpolatedTransform {
+ public:
+  InterpolatedRotation(float start_degrees, float end_degrees);
+  InterpolatedRotation(float start_degrees,
+                       float end_degrees,
+                       float start_time,
+                       float end_time);
+  virtual ~InterpolatedRotation() {}
+
+ protected:
+  virtual ui::Transform InterpolateButDoNotCompose(float t) const;
+
+ private:
+  float start_degrees_;
+  float end_degrees_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterpolatedRotation);
+};
+
+class InterpolatedScale : public InterpolatedTransform {
+ public:
+  InterpolatedScale(float start_scale, float end_scale);
+  InterpolatedScale(float start_scale,
+                    float end_scale,
+                    float start_time,
+                    float end_time);
+  virtual ~InterpolatedScale() {}
+
+ protected:
+  virtual ui::Transform InterpolateButDoNotCompose(float t) const;
+
+ private:
+  float start_scale_;
+  float end_scale_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterpolatedScale);
+};
+
+class InterpolatedTranslation : public InterpolatedTransform {
+ public:
+  InterpolatedTranslation(const gfx::Point& start_pos,
+                          const gfx::Point& end_pos);
+  InterpolatedTranslation(const gfx::Point& start_pos,
+                          const gfx::Point& end_pos,
+                          float start_time,
+                          float end_time);
+  virtual ~InterpolatedTranslation() {}
+
+ protected:
+  virtual ui::Transform InterpolateButDoNotCompose(float t) const;
+
+ private:
+  gfx::Point start_pos_;
+  gfx::Point end_pos_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterpolatedTranslation);
+};
+
+// This class is only useful when composed with other transforms,
+// see InterpolatedTransformAboutPivot
+class InterpolatedConstantTransform : public InterpolatedTransform {
+ public:
+  InterpolatedConstantTransform(const ui::Transform& transform);
+  virtual ~InterpolatedConstantTransform() {}
+
+ protected:
+  virtual ui::Transform InterpolateButDoNotCompose(float t) const;
+
+ private:
+  ui::Transform transform_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterpolatedConstantTransform);
+};
+
+class InterpolatedTransformAboutPivot : public InterpolatedTransform {
+ public:
+  InterpolatedTransformAboutPivot(const gfx::Point& pivot,
+                                  InterpolatedTransform* transform);

[sky, 2011/06/28 15:39:14]

Document ownership of transform (and for next method).

+  InterpolatedTransformAboutPivot(const gfx::Point& pivot,
+                                  InterpolatedTransform* transform,
+                                  float start_time,
+                                  float end_time);
+  virtual ~InterpolatedTransformAboutPivot() {}
+
+ protected:
+  virtual ui::Transform InterpolateButDoNotCompose(float t) const;
+
+ private:
+  void Init(const gfx::Point& pivot, InterpolatedTransform* transform);
+
+  scoped_ptr<InterpolatedTransform> transform_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterpolatedTransformAboutPivot);
+};
+
+} // namespace ui
+
+#endif // UI_GFX_INTERPOLATED_TRANSFORM_H_