ui/views/controls/native/native_view_host.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_CONTROLS_NATIVE_NATIVE_VIEW_HOST_H_
#define UI_VIEWS_CONTROLS_NATIVE_NATIVE_VIEW_HOST_H_
#pragma once

#include <string>

#include "ui/gfx/native_widget_types.h"
#include "ui/views/view.h"

namespace views {

class NativeViewHostWrapper;

// A View type that hosts a gfx::NativeView. The bounds of the native view are
// kept in sync with the bounds of this view as it is moved and sized.
// Under the hood, a platform-specific NativeViewHostWrapper implementation does
// the platform-specific work of manipulating the underlying OS widget type.
class VIEWS_EXPORT NativeViewHost : public View {
 public:
  // The NativeViewHost's class name.
  static const char kViewClassName[];

  // Should views render the focus when on native controls?
  static const bool kRenderNativeControlFocus;

  NativeViewHost();
  virtual ~NativeViewHost();

  // Attach a gfx::NativeView to this View. Its bounds will be kept in sync
  // with the bounds of this View until Detach is called.
  //
  // Because native views are positioned in the coordinates of their parent
  // native view, this function should only be called after this View has been
  // added to a View hierarchy hosted within a valid Widget.
  void Attach(gfx::NativeView native_view);

  // Detach the attached native view. Its bounds and visibility will no
  // longer be manipulated by this View. The native view may be destroyed and
  // detached before calling this function, and this has no effect in that case.
  void Detach();

  // Sets a preferred size for the native view attached to this View.
  void SetPreferredSize(const gfx::Size& size);

  // A NativeViewHost has an associated focus View so that the focus of the
  // native control and of the View are kept in sync. In simple cases where the
  // NativeViewHost directly wraps a native window as is, the associated view
  // is this View. In other cases where the NativeViewHost is part of another
  // view (such as TextField), the actual View is not the NativeViewHost and
  // this method must be called to set that.
  // This method must be called before Attach().
  void set_focus_view(View* view) { focus_view_ = view; }
  View* focus_view() { return focus_view_; }

  // Fast resizing will move the native view and clip its visible region, this
  // will result in white areas and will not resize the content (so scrollbars
  // will be all wrong and content will flow offscreen). Only use this
  // when you're doing extremely quick, high-framerate vertical resizes
  // and don't care about accuracy. Make sure you do a real resize at the
  // end. USE WITH CAUTION.
  void set_fast_resize(bool fast_resize) { fast_resize_ = fast_resize; }
  bool fast_resize() const { return fast_resize_; }

  // Value of fast_resize() the last time Layout() was invoked.
  bool fast_resize_at_last_layout() const {
    return fast_resize_at_last_layout_;
  }

  // Accessor for |native_view_|.
  gfx::NativeView native_view() const { return native_view_; }

  void NativeViewDestroyed();

  // Overridden from View:
  virtual gfx::Size GetPreferredSize() OVERRIDE;
  virtual void Layout() OVERRIDE;
  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
  virtual void VisibilityChanged(View* starting_from, bool is_visible) OVERRIDE;
  virtual void OnFocus() OVERRIDE;
  virtual gfx::NativeViewAccessible GetNativeViewAccessible() OVERRIDE;

 protected:
  virtual bool NeedsNotificationWhenVisibleBoundsChange() const OVERRIDE;
  virtual void OnVisibleBoundsChanged() OVERRIDE;
  virtual void ViewHierarchyChanged(bool is_add,
                                    View* parent,
                                    View* child) OVERRIDE;
  virtual std::string GetClassName() const OVERRIDE;

 private:
  // Detach the native view. |destroyed| is true if the native view is
  // detached because it's being destroyed, or false otherwise.
  void Detach(bool destroyed);

  // The attached native view. There is exactly one native_view_ attached.
  gfx::NativeView native_view_;

  // A platform-specific wrapper that does the OS-level manipulation of the
  // attached gfx::NativeView.
  scoped_ptr<NativeViewHostWrapper> native_wrapper_;

  // The preferred size of this View
  gfx::Size preferred_size_;

  // True if the native view is being resized using the fast method described
  // in the setter/accessor above.
  bool fast_resize_;

  // Value of |fast_resize_| during the last call to Layout.
  bool fast_resize_at_last_layout_;

  // The view that should be given focus when this NativeViewHost is focused.
  View* focus_view_;

  DISALLOW_COPY_AND_ASSIGN(NativeViewHost);
};

}  // namespace views

#endif  // UI_VIEWS_CONTROLS_NATIVE_NATIVE_VIEW_HOST_H_