Stick windows to sides of workspaces

ash/wm/dock/docked_window_resizer.h

+// Copyright (c) 2013 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 ASH_WM_DOCK_DOCK_WINDOW_RESIZER_H_
+#define ASH_WM_DOCK_DOCK_WINDOW_RESIZER_H_
+
+#include "ash/wm/window_resizer.h"
+#include "base/compiler_specific.h"
+
+namespace gfx {
+class Point;
+class Rect;
+}
+
+namespace aura {
+class RootWindow;
+}
+
+namespace ash {
+
+namespace internal {
+class DockedWindowLayoutManager;
+}
+
+// DockWindowResizer is used by ToplevelWindowEventFilter to handle dragging,
+// moving or resizing of a window while it is docked to the side of a screen.
+class ASH_EXPORT DockedWindowResizer : public WindowResizer {
+ public:
+  virtual ~DockedWindowResizer();
+
+  // Creates a new DockWindowResizer. The caller takes ownership of the
+  // returned object. The ownership of |next_window_resizer| is taken by the
+  // returned object. Returns NULL if not resizable.
+  static DockedWindowResizer* Create(WindowResizer* next_window_resizer,
+                                     aura::Window* window,
+                                     const gfx::Point& location,
+                                     int window_component);
+
+  // WindowResizer:
+  virtual void Drag(const gfx::Point& location, int event_flags) OVERRIDE;
+  virtual void CompleteDrag(int event_flags) OVERRIDE;
+  virtual void RevertDrag() OVERRIDE;
+  virtual aura::Window* GetTarget() OVERRIDE;
+  virtual const gfx::Point& GetInitialLocation() const OVERRIDE;
+
+ private:
+  // Creates DockWindowResizer that adds the ability to attach / detach
+  // windows to / from the dock. This object takes ownership of
+  // |next_window_resizer|.
+  DockedWindowResizer(WindowResizer* next_window_resizer,
+                      const Details& details);
+
+  // Checks if the provided window bounds should snap to the side of a screen.
+  // If so the offset returned gives the necessary adjustment to snap.
+  void MaybeSnapToSide(const gfx::Rect& bounds, gfx::Point* offset);
+
+  // Tracks the window's initial position and attachment at the start of a drag
+  // and informs the DockLayoutManager that a drag has started if necessary.
+  void StartedDragging();
+
+  // Informs the DockLayoutManager that the drag is complete if it was informed
+  // of the drag start.
+  void FinishDragging();
+
+  const Details details_;
+
+  gfx::Point last_location_;
+
+  // Wraps a window resizer and adds detaching / reattaching during drags.
+  scoped_ptr<WindowResizer> next_window_resizer_;
+
+  // Dock container window.
+  internal::DockedWindowLayoutManager* dock_layout_;
+
+  // Set to true once Drag() is invoked and the bounds of the window change.
+  bool did_move_or_resize_;
+
+  DISALLOW_COPY_AND_ASSIGN(DockedWindowResizer);
+};
+
+}  // namespace ash
+
+#endif  // ASH_WM_DOCK_DOCK_WINDOW_RESIZER_H_