chrome/browser/ui/views/panels/taskbar_window_thumbnailer_win.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_BROWSER_UI_VIEWS_PANELS_TASKBAR_WINDOW_THUMBNAILER_WIN_H_
   6 #define CHROME_BROWSER_UI_VIEWS_PANELS_TASKBAR_WINDOW_THUMBNAILER_WIN_H_
   7
   8 #include <vector>
   9 #include "base/memory/scoped_ptr.h"
  10 #include "ui/base/win/hwnd_subclass.h"
  11
  12 class SkBitmap;
  13
  14 class TaskbarWindowThumbnailerDelegateWin {
  15  public:
  16   // Returns the list of handles for all windows that are used to construct the
  17   // thumbnail. If empty list is returned, the snapshot of current window
  18   // is used.
  19   virtual std::vector<HWND> GetSnapshotWindowHandles() const = 0;
  20 };
  21
  22 // Provides the custom thumbnail and live preview for the window that appears
  23 // in the taskbar (Windows 7 and later).
  24 class TaskbarWindowThumbnailerWin : public ui::HWNDMessageFilter {
  25  public:
  26   TaskbarWindowThumbnailerWin(HWND hwnd,
  27                               TaskbarWindowThumbnailerDelegateWin* delegate);
  28   virtual ~TaskbarWindowThumbnailerWin();
  29
  30   // Starts using the custom snapshot for live preview. The snapshot is only
  31   // captured once when the system requests it, so the updates of the panels'
  32   // content will not be automatically reflected in the thumbnail.
  33   void Start();
  34
  35   // Stops providing the custom snapshot for live preview.
  36   void Stop();
  37
  38   // Captures the snapshot now instead of when the system requests it.
  39   void CaptureSnapshot();
  40
  41   // Invalidates the snapshot such that a fresh copy can be obtained next time
  42   // when the system requests it.
  43   void InvalidateSnapshot();
  44
  45   // Provide the snapshot to the new window. If the snapshot is captured for the
  46   // old window, it will also be used for the new window.
  47   void ReplaceWindow(HWND new_hwnd);
  48
  49  private:
  50   // Overridden from ui::HWNDMessageFilter:
  51   virtual bool FilterMessage(HWND hwnd,
  52                              UINT message,
  53                              WPARAM w_param,
  54                              LPARAM l_param,
  55                              LRESULT* l_result) OVERRIDE;
  56
  57   // Message handlers.
  58   bool OnDwmSendIconicThumbnail(int width, int height, LRESULT* l_result);
  59   bool OnDwmSendIconicLivePreviewBitmap(LRESULT* l_result);
  60
  61   // Captures and returns the screenshot of the window. The caller is
  62   // responsible to release the returned SkBitmap instance.
  63   SkBitmap* CaptureWindowImage() const;
  64
  65   HWND hwnd_;
  66   TaskbarWindowThumbnailerDelegateWin* delegate_;  // Weak, owns us.
  67   scoped_ptr<SkBitmap> capture_bitmap_;
  68
  69   DISALLOW_COPY_AND_ASSIGN(TaskbarWindowThumbnailerWin);
  70 };
  71
  72 #endif  // CHROME_BROWSER_UI_VIEWS_PANELS_TASKBAR_WINDOW_THUMBNAILER_WIN_H_