SubtractRect function (winuser.h)

Article
10/13/2021

The SubtractRect function determines the coordinates of a rectangle formed by subtracting one rectangle from another.

Syntax

BOOL SubtractRect(
  [out] LPRECT     lprcDst,
  [in]  const RECT *lprcSrc1,
  [in]  const RECT *lprcSrc2
);

Parameters

[out] lprcDst

A pointer to a RECT structure that receives the coordinates of the rectangle determined by subtracting the rectangle pointed to by lprcSrc2 from the rectangle pointed to by lprcSrc1.

[in] lprcSrc1

A pointer to a RECT structure from which the function subtracts the rectangle pointed to by lprcSrc2.

[in] lprcSrc2

A pointer to a RECT structure that the function subtracts from the rectangle pointed to by lprcSrc1.

Return value

If the resulting rectangle is empty, the return value is zero.

If the resulting rectangle is not empty, the return value is nonzero.

Remarks

The function only subtracts the rectangle specified by lprcSrc2 from the rectangle specified by lprcSrc1 when the rectangles intersect completely in either the x- or y-direction. For example, if *lprcSrc1 has the coordinates (10,10,100,100) and *lprcSrc2 has the coordinates (50,50,150,150), the function sets the coordinates of the rectangle pointed to by lprcDst to (10,10,100,100). If *lprcSrc1 has the coordinates (10,10,100,100) and *lprcSrc2 has the coordinates (50,10,150,150), however, the function sets the coordinates of the rectangle pointed to by lprcDst to (10,10,50,100). In other words, the resulting rectangle is the bounding box of the geometric difference.

Because applications can use rectangles for different purposes, the rectangle functions do not use an explicit unit of measure. Instead, all rectangle coordinates and dimensions are given in signed, logical values. The mapping mode and the function in which the rectangle is used determine the units of measure.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	winuser.h (include Windows.h)
Library	User32.lib
DLL	User32.dll