CBaseWindow class
[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
The CBaseWindow class is a base class for managing windows. Video renderers can use this class to create video windows. To use this class, create a derived class that inherits from CBaseWindow. In the derived class:
- Implement the pure virtual method CBaseWindow::GetClassWindowStyles, which defines the window styles.
- Override the CBaseWindow::OnReceiveMessage method, which handles window messages.
- Implement a destructor that calls the CBaseWindow::DoneWithWindow method.
Before using an instance of the derived class, call the CBaseWindow::PrepareWindow method.
| Protected Member Variables | Description |
|---|---|
| m_hInstance | Handle to the module instance. |
| m_hwnd | Handle to the object's window. |
| m_hdc | Handle to the window's device context. |
| m_Width | Width of the client area, in pixels. |
| m_Height | Height of the client area, in pixels. |
| m_bActivated | Flag that specifies whether the window has been activated. |
| m_pClassName | Static string that contains the name of the window class. |
| m_ClassStyles | Class styles for the window. |
| m_WindowStyles | Window styles for the window. |
| m_WindowStylesEx | Extended window styles for the window. |
| m_ShowStageMessage | Private message that brings the window to the foreground. |
| m_ShowStageTop | Private message that sets the window style to WS_EX_TOPMOST. |
| m_RealizePalette | Private message that realizes the palette. |
| m_MemoryDC | Handle to the memory device context. |
| m_hPalette | Handle to the window's palette. |
| m_bNoRealize | Flag that specifies whether the window should realize its palette. |
| m_bBackground | Flag that specifies whether the palette should be a background palette. |
| m_bRealizing | Flag that specifies whether a new palette is being realized. |
| m_WindowLock | Critical section, to serialize access to the object. |
| m_bDoGetDC | Flag that specifies whether to retrieve the device context. |
| m_bDoPostToDestroy | Flag that specifies whether the window posts or sends its destruction message. |
| Protected Methods | Description |
| OnPaletteChange | Handles palette-change messages. Virtual. |
| Public Methods | Description |
| CBaseWindow | Constructor method. |
| DoneWithWindow | Destroys the window. Virtual. |
| PrepareWindow | Creates the window. Virtual. |
| InactivateWindow | Inactivates the window. Virtual. |
| ActivateWindow | Sizes the window according to the requirements of the derived class. Virtual. |
| OnSize | Handles WM_SIZE messages. Virtual. |
| OnClose | Handles WM_CLOSE messages. Virtual. |
| GetDefaultRect | Retrieves the default size of the client area. Virtual. |
| UninitialiseWindow | Releases the window's resources. Virtual. |
| InitialiseWindow | Initializes the window. Virtual. |
| CompleteConnect | Notifies the window that the renderer's input pin has been connected. |
| DoCreateWindow | Creates the window. |
| PerformanceAlignWindow | Aligns the window to a DWORD boundary, for maximum performance. |
| DoShowWindow | Sets the window's show state. |
| PaintWindow | Causes the window to be repainted. |
| DoSetWindowForeground | Brings the window to the foreground. |
| SetPalette | Installs a palette for the window. Virtual. |
| SetRealize | Specifies whether the window realizes palettes. |
| DoRealisePalette | Realizes the window's current palette. Virtual. |
| PossiblyEatMessage | Enables a derived class to forward messages to another window. Virtual. |
| GetWindowWidth | Retrieves the current width of the window. |
| GetWindowHeight | Retrieves the current height of the window. |
| GetWindowHWND | Retrieves a handle to the window. |
| GetMemoryHDC | Retrieves a handle to the memory device context. |
| GetWindowHDC | Retrieves a handle to the window's device context. |
| OnReceiveMessage | Handles window messages. Virtual. |
| UnsetPalette | Deletes the window's current palette and restores the default system palette. |
| Pure Virtual Methods | Description |
| GetClassWindowStyles | Retrieves the window's class styles and window styles. |
Requirements
| Requirement | Value |
|---|---|
| Header |
|
| Library |
|