App list: Added contents view custom animation framework.

ui/app_list/views/contents_animator.h

Index: ui/app_list/views/contents_animator.h
diff --git a/ui/app_list/views/contents_animator.h b/ui/app_list/views/contents_animator.h
new file mode 100644
index 0000000000000000000000000000000000000000..6bbb0b729af473e9c7ee6f3c77792fd1c6aaff16
--- /dev/null
+++ b/ui/app_list/views/contents_animator.h
@@ -0,0 +1,77 @@
+// Copyright 2014 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_APP_LIST_VIEWS_CONTENTS_ANIMATOR_H_
+#define UI_APP_LIST_VIEWS_CONTENTS_ANIMATOR_H_
+
+#include <string>
+
+#include "base/macros.h"
+
+namespace gfx {
+class Rect;
+}
+
+namespace app_list {
+
+class ContentsView;
+
+// Manages an animation between two specific pages of the ContentsView.
+// Different subclasses implement different animations, so we can have a custom
+// animation for each pair of pages. Animations are reversible (if A -> B is
+// implemented, B -> A will implicitly be the inverse animation).
+class ContentsAnimator {
+ public:
+  ContentsAnimator(ContentsView* contents_view);
+
+  virtual ~ContentsAnimator();
+
+  // Gets the name of the animator, for testing.
+  virtual std::string NameForTests() const = 0;
+
+  // Updates the state of the ContentsView. |progress| is the amount of progress
+  // made on the animation, where 0.0 is the beginning and 1.0 is the end.
+  virtual void Update(double progress, int from_page, int to_page) = 0;

[calamity, 2014/11/05 06:29:07]

Mention that the animations need to handle this linearly so that reversibility
is maintained.

[Matt Giuca, 2014/11/06 00:32:59]

Done.

+

[calamity, 2014/11/05 06:29:07]

How are you planning to handle object creation/destruction (e.g the temporary
app icon views that will be used in the StartToApps animation)?

[Matt Giuca, 2014/11/06 00:32:58]

I hadn't thought about it. It's probably safe to store those things in the
ContentsAnimator subclass itself (given that there will only be one animation
active at a particular time).

[calamity, 2014/11/06 05:34:47]

I was more concerned about _when_ you would perform those tasks. I guess you can
just always clean up on progress == 1/0. Let me know if you think of a better
way.

[Matt Giuca, 2014/11/10 04:08:26]

Yeah I started implementing it since this discussion. It was a bit messy. I
would initialize it on the first update I receive, and clean up the from_page
when progress == 1, clean up the to_page when progress == 0.

I could provide an init and cleanup method but it would get confusing with the
reversing. How about we add those as we need them.

[calamity, 2014/11/10 05:18:55]

Ack.

+ protected:
+  ContentsView* contents_view() { return contents_view_; }
+
+  // Gets the origin (the off-screen resting place) for a given launcher page
+  // with index |page_index|.
+  gfx::Rect GetOffscreenPageBounds(int page_index) const;
+
+ private:
+  ContentsView* contents_view_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContentsAnimator);
+};
+
+// Simple animator that slides pages in and out vertically. Appropriate for any
+// page pair.
+class DefaultAnimator : public ContentsAnimator {
+ public:
+  DefaultAnimator(ContentsView* contents_view);
+

[calamity, 2014/11/05 06:29:07]

Destructor?

[Matt Giuca, 2014/11/06 00:32:59]

Done.

+  // ContentsAnimator overrides:
+  std::string NameForTests() const override;
+  void Update(double progress, int from_page, int to_page) override;
+
+  DISALLOW_COPY_AND_ASSIGN(DefaultAnimator);
+};
+
+// Animator between the start page and apps grid page.
+class StartToAppsAnimator : public ContentsAnimator {
+ public:
+  StartToAppsAnimator(ContentsView* contents_view);
+

[calamity, 2014/11/05 06:29:07]

Destructor?

[Matt Giuca, 2014/11/06 00:32:59]

Done.

+  // ContentsAnimator overrides:
+  std::string NameForTests() const override;
+  void Update(double progress, int start_page, int apps_page) override;
+
+  DISALLOW_COPY_AND_ASSIGN(StartToAppsAnimator);
+};
+
+}  // app_list
+
+#endif  // UI_APP_LIST_VIEWS_CONTENTS_ANIMATOR_H_