CDC::ScrollDC

Syntax

BOOL ScrollDC( int dx, int dy, LPRECT lpRectScroll, LPRECT lpRectClip, CRgn* pRgnUpdate, LPRECT lpRectUpdate );

Parameters

dx

Specifies the number of horizontal scroll units.

dy

Specifies the number of vertical scroll units.

lpRectScroll

Points to the RECT structure or CRect object that contains the coordinates of the scrolling rectangle.

lpRectClip

Points to the RECT structure or CRect object that contains the coordinates of the clipping rectangle. When this rectangle is smaller than the original pointed to by lpRectScroll, scrolling occurs only in the smaller rectangle.

pRgnUpdate

Identifies the region uncovered by the scrolling process. The ScrollDC function defines this region; it is not necessarily a rectangle.

lpRectUpdate

Points to the RECT structure or CRect object that, upon return, contains the coordinates of the rectangle that bounds the scrolling update region. This is the largest rectangular area that requires repainting.

Remarks

Scrolls a rectangle of bits horizontally and vertically. The lpRectScroll parameter describes the rectangle to be scrolled, dx specifies the number of units to be scrolled horizontally, and dy specifies the number of units to be scrolled vertically.

If lpRectUpdate is NULL, Windows does not compute the update rectangle. If both pRgnUpdate and lpRectUpdate are NULL, Windows does not compute the update region. If pRgnUpdate is not NULL, Windows assumes that it contains a valid region pointer to the region uncovered by the scrolling process (defined by the ScrollDC member function). An application should use the ScrollWindow member function of class CWnd when it is necessary to scroll the entire client area of a window. Otherwise, it should use ScrollDC.

Return Value

TRUE if scrolling is executed; otherwise FALSE.

See Also

CWnd::ScrollWindow, ::ScrollDC, CRgn