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CDC::DrawDragRect

Call this member function repeatedly to redraw a drag rectangle.

void DrawDragRect( 
   LPCRECT lpRect, 
   SIZE size, 
   LPCRECT lpRectLast, 
   SIZE sizeLast, 
   CBrush* pBrush = NULL, 
   CBrush* pBrushLast = NULL  
);
lpRect

Points to a RECT structure or a CRect object that specifies the logical coordinates of a rectangle — in this case, the end position of the rectangle being redrawn.

size

Specifies the displacement from the top-left corner of the outer border to the top-left corner of the inner border (that is, the thickness of the border) of a rectangle.

lpRectLast

Points to a RECT structure or a CRect object that specifies the logical coordinates of the position of a rectangle — in this case, the original position of the rectangle being redrawn.

sizeLast

Specifies the displacement from the top-left corner of the outer border to the top-left corner of the inner border (that is, the thickness of the border) of the original rectangle being redrawn.

pBrush

Pointer to a brush object. Set to NULL to use the default halftone brush.

pBrushLast

Pointer to the last brush object used. Set to NULL to use the default halftone brush.

Call it in a loop as you sample mouse position, in order to give visual feedback. When you call DrawDragRect, the previous rectangle is erased and a new one is drawn. For example, as the user drags a rectangle across the screen, DrawDragRect will erase the original rectangle and redraw a new one in its new position. By default, DrawDragRect draws the rectangle by using a halftone brush to eliminate flicker and to create the appearance of a smoothly moving rectangle.

The first time you call DrawDragRect, the lpRectLast parameter should be NULL.

Header: afxwin.h

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