V2

ui/views/layout/layout_manager.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_VIEWS_LAYOUT_LAYOUT_MANAGER_H_
+#define UI_VIEWS_LAYOUT_LAYOUT_MANAGER_H_
+#pragma once
+
+namespace gfx {
+class Size;
+}
+
+namespace ui {
+
+class View;
+
+////////////////////////////////////////////////////////////////////////////////
+// LayoutManager interface
+//
+//  An interface implemented by an object that manages sizing of a View's
+//  children.
+//
+class LayoutManager {
+ public:
+  virtual ~LayoutManager() {}
+
+  // Notification that this LayoutManager has been installed on a particular
+  // host.
+  virtual void Installed(View* host) {}
+
+  // Notification that this LayoutManager has been uninstalled on a particular
+  // host.
+  virtual void Uninstalled(View* host) {}
+
+  // Lay out the children of |host| according to implementation-specific
+  // heuristics. The graphics used during painting is provided to allow for
+  // string sizing.
+  virtual void Layout(View* host) = 0;
+
+  // Return the preferred size which is the size required to give each
+  // children their respective preferred size.
+  virtual gfx::Size GetPreferredSize(View* host) = 0;
+
+  // Returns the preferred height for the specified width. The default
+  // implementation returns the value from GetPreferredSize.
+  virtual int GetPreferredHeightForWidth(View* host, int width);
+
+  // Notification that a view has been added.
+  virtual void ViewAdded(View* host, View* view) {}
+
+  // Notification that a view has been removed.
+  virtual void ViewRemoved(View* host, View* view) {}
+};
+
+}  // namespace ui
+
+#endif // UI_VIEWS_LAYOUT_LAYOUT_MANAGER_H_