The AnimateWindow function enables you to produce special effects when showing or hiding windows. There are four types of animation: roll, slide, collapse or expand, and alpha-blended fade.
Syntax
BOOL AnimateWindow(
HWND hwnd,
DWORD dwTime,
DWORD dwFlags
);
Parameters
- hwnd
-
[in] Handle to the window to animate. The calling thread must own this window.
- dwTime
-
[in] Specifies how long it takes to play the animation, in milliseconds. Typically, an animation takes 200 milliseconds to play.
- dwFlags
-
[in] Specifies the type of animation. This parameter can be one or more of the following values. Note that, by default, these flags take effect when showing a window. To take effect when hiding a window, use AW_HIDE and a logical OR operator with the appropriate flags.
AW_SLIDE- Uses slide animation. By default, roll animation is used. This flag is ignored when used with AW_CENTER.
AW_ACTIVATE- Activates the window. Do not use this value with AW_HIDE.
AW_BLEND- Uses a fade effect. This flag can be used only if hwnd is a top-level window.
AW_HIDE- Hides the window. By default, the window is shown.
AW_CENTER- Makes the window appear to collapse inward if AW_HIDE is used or expand outward if the AW_HIDE is not used. The various direction flags have no effect.
AW_HOR_POSITIVE- Animates the window from left to right. This flag can be used with roll or slide animation. It is ignored when used with AW_CENTER or AW_BLEND.
AW_HOR_NEGATIVE- Animates the window from right to left. This flag can be used with roll or slide animation. It is ignored when used with AW_CENTER or AW_BLEND.
AW_VER_POSITIVE- Animates the window from top to bottom. This flag can be used with roll or slide animation. It is ignored when used with AW_CENTER or AW_BLEND.
AW_VER_NEGATIVE- Animates the window from bottom to top. This flag can be used with roll or slide animation. It is ignored when used with AW_CENTER or AW_BLEND.
Return Value
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero. The function will fail in the following situations:
- If the window uses the window region. Windows XP: This does not cause the function to fail.
- If the window is already visible and you are trying to show the window.
- If the window is already hidden and you are trying to hide the window.
- If there is no direction specified for the slide or roll animation.
- When trying to animate a child window with AW_BLEND.
- If the thread does not own the window. Note that, in this case, AnimateWindow fails but GetLastError returns ERROR_SUCCESS.
To get extended error information, call the GetLastError function.
Remarks
To show or hide a window without special effects, use ShowWindow.
When using slide or roll animation, you must specify the direction. It can be either AW_HOR_POSITIVE, AW_HOR_NEGATIVE, AW_VER_POSITIVE, or AW_VER_NEGATIVE.
You can combine AW_HOR_POSITIVE or AW_HOR_NEGATIVE with AW_VER_POSITIVE or AW_VER_NEGATIVE to animate a window diagonally.
The window procedures for the window and its child windows should handle any WM_PRINT or WM_PRINTCLIENT messages. Dialog boxes, controls, and common controls already handle WM_PRINTCLIENT. The default window procedure already handles WM_PRINT.
If a child window is displayed partially clipped, when it is animated it will have holes where it is clipped.
AnimateWindow supports RTL windows.
Avoid animating a window that has a drop shadow because it produces visually distracting, jerky animations.
Function Information
| Minimum DLL Version | user32.dll |
|---|
| Header | Declared in Winuser.h, include Windows.h |
|---|
| Import library | User32.lib |
|---|
| Minimum operating systems |
Windows 98, Windows 2000 |
|---|
See Also