ScrollWindow
The ScrollWindow
function scrolls the content of the specified window s client area. This
function exists for backward compatibility. For new applications, use the ScrollWindowEx
function.
BOOL ScrollWindow(
|
HWND hWnd, |
// handle of window
to scroll |
|
int XAmount, |
// amount of
horizontal scrolling |
|
int YAmount, |
// amount of
vertical scrolling |
|
CONST RECT *lpRect, |
// address of
structure with scroll rectangle |
|
CONST RECT *lpClipRect
|
// address of
structure with clip rectangle |
|
); |
|
Parameters
hWnd
Identifies
the window where the client area is to be scrolled.
XAmount
Specifies the
amount, in device units, of horizontal scrolling. If the window being scrolled
has the CS_OWNDC or CS_CLASSDC style, then this parameter uses logical units
rather than device units. This parameter must be a negative value to scroll the
content of the window to the left.
YAmount
Specifies the
amount, in device units, of vertical scrolling. If the window being scrolled
has the CS_OWNDC or CS_CLASSDC style, then this parameter uses logical units
rather than device units. This parameter must be a negative value to scroll the
content of the window up.
lpRect
Points to the
RECT
structure specifying the portion of the client area to be scrolled. If this
parameter is NULL, the entire client area is scrolled.
lpClipRect
Points to the
RECT structure containing the coordinates of the clipping rectangle.
Only device bits within the clipping rectangle are affected. Bits scrolled from
the outside of the rectangle to the inside are painted; bits scrolled from the
inside of the rectangle to the outside are not painted.
Return Values
If the
function succeeds, the return value is nonzero.
If the
function fails, the return value is zero. To get extended error information,
call GetLastError.
Remarks
If the caret
is in the window being scrolled, ScrollWindow automatically hides the
caret to prevent it from being erased and then restores the caret after the
scrolling is finished. The caret position is adjusted accordingly.
The area
uncovered by ScrollWindow is not repainted, but it is combined into the
window s update region. The application eventually receives a WM_PAINT message
notifying it that the region must be repainted. To repaint the uncovered area
at the same time the scrolling is in action, call the UpdateWindow
function immediately after calling ScrollWindow.
If the lpRect
parameter is NULL, the positions of any child windows in the window are offset
by the amount specified by the XAmount and YAmount parameters;
invalid (unpainted) areas in the window are also offset. ScrollWindow is
faster when lpRect is NULL.
If lpRect
is not NULL, the positions of child windows are not changed and invalid areas
in the window are not offset. To prevent updating problems when lpRect
is not NULL, call UpdateWindow to repaint the window before calling ScrollWindow.
See Also