ScrollDC

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This function scrolls a rectangle of bits horizontally and vertically.

BOOL
ScrollDC(
HDC
hDC
,
int
dx
,
int
dy
,
const
RECT
*
lprcScroll
,
const
RECT
*
lprcClip
,
HRGN
hrgnUpdate
,
LPRECT
lprcUpdate
);

Parameters

hDC

[in] Handle to the device context that contains the bits to be scrolled.

dx

[in] Specifies the amount, in device units, of horizontal scrolling. This parameter must be a negative value to scroll to the left. Only one of the dxand dyparameters can be nonzero.

dy

[in] Specifies the amount, in device units, of vertical scrolling. This parameter must be a negative value to scroll up. Only one of the dxand dyparameters can be nonzero.

lprcScroll

[in] Long pointer to the RECTstructure containing the coordinates of the scrolling rectangle. The only bits affected by the scroll operation are bits in the intersection of this rectangle and the rectangle specified by lprcClip. If lprcScrollis NULL, the entire client area is used.

lprcClip

[in] Pointer to the RECTstructure containing the coordinates of the clipping rectangle. The only bits that will be painted are the bits that remain inside this rectangle after the scroll operation has been completed. If lprcClipis NULL, the entire client area is used.

hrgnUpdate

[in] Handle to the region uncovered by the scrolling process. ScrollDCdefines this region; it is not necessarily a rectangle.

lprcUpdate

[out] Long pointer to the RECTstructure that receives the coordinates of the rectangle bounding the scrolling update region. This is the largest rectangular area that requires repainting. When the function returns, the values in the structure are in client coordinates, regardless of the mapping mode for the specified device context.

Return Values

Nonzero indicates success. Zero indicates failure. To get extended error information, call GetLastError.

Remarks

If the lprcUpdateparameter is NULL, the system does not compute the update rectangle. If both the hrgnUpdateand lprcUpdateparameters are NULL, the system does not compute the update region. If hrgnUpdateis not NULL, the system proceeds as though it contains a valid handle to the region uncovered by the scrolling process (defined by ScrollDC).

When you must scroll the entire client area of a window, use the ScrollWindowExfunction.

Requirements

Runs on	Versions	Defined in	Include	Link to
Windows CE OS	1.0 and later	Winuser.h		Mgwinmgr.lib

Note This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.

See Also

GetLastError, RECT