MFC中的CRect

CRect

环境VS2013
头文件：#include <afxwin.h>

A CRect object can be passed as a function parameter wherever a RECT structure, LPCRECT, or LPRECT can be passed.

当需要 RECT*、LPCRECT、LPRECT 类型参数传参时，可以直接使用CRect。
因为重载操作符了
operator LPCRECT         Converts a CRect to an LPCRECT.
operator LPRECT         Converts a CRect to an LPRECT.


常用函数：

Construction

CRect( );
CRect( int l, int t, int r, int b );
CRect( const RECT& srcRect );
CRect( LPCRECT lpSrcRect );
CRect( POINT point, SIZE size );
CRect( POINT topLeft, POINT bottomRight );
例子：
    CRect rc1;//VS2013默认构造 0,0,0,0；注：VC6.0 可能不是全0，只是不初始化
    CRect rc2(10, 10, 200, 100);
    

Operations（操作函数）

• 获取宽度、高度

Width()
Height()
Size()
例子：
    //宽高
    int w = rc2.Width();
    int h = rc2.Height();
    CSize sz = rc2.Size();//cx:width cy:height

• 获取点坐标

TopLeft()        Returns the top-left point of CRect.
BottomRight()    Returns the bottom-right point of CRect.
CenterPoint()    Returns the centerpoint of CRect. (return CPoint((left+right)/2, (top+bottom)/2);)

• 判断是否为空矩形（一种是全0，一种是面积为0）

IsRectEmpty()    Determines whether CRect is empty. CRect is empty if the width and/or height are 0.
IsRectNull()    Determines whether the top, bottom, left, and right member variables are all equal to 0.

• 判断 pt 点是否在矩形内（在边界上返回TRUE）

PtInRect(POINT pt)        Determines whether the specified point lies within CRect.

• 设置矩形坐标点

void SetRect( int l, int t, int r, int b );

• 放大矩形/缩小矩形

InflateRect(..)    Increases the width and height of CRect.
void InflateRect( int x, int y );
void InflateRect( SIZE size );
void InflateRect( LPCRECT lpRect );
void InflateRect( int l, int t, int r, int b );

DeflateRect(..)    Decreases the width and height of CRect.
void DeflateRect( int x, int y );
void DeflateRect( SIZE size );
void DeflateRect( LPCRECT lpRect );
void DeflateRect( int l, int t, int r, int b );

例子：

    CRect rc(10, 10, 200, 100);
    rc.InflateRect(5, 6); // (10-5, 10-6, 200+5, 100+6) --> (5, 4, 205, 106)
    rc.SetRect(10, 10, 200, 100);
    rc.InflateRect(1, 2, 3, 4); // (10-1, 10-2, 200+3, 100+4) --> (9, 8, 203, 104)
    rc.SetRect(10, 10, 200, 100);
    rc.InflateRect(-5, 6); // (10+5, 10-6, 200-5, 100+6) --> (15, 4, 195, 106)
    rc.SetRect(10, 10, 200, 100);
    rc.InflateRect(-5, -6); //相当于缩小矩形 rc.DeflateRect(5, 6); --> (15, 16, 195, 94)

    rc.SetRect(10, 10, 200, 100);
    rc.DeflateRect(5, 6); // --> (15, 16, 195, 94)
    rc.SetRect(10, 10, 200, 100);
    rc.DeflateRect(1, 2, 3, 4); // (10+1, 10+2, 200-3, 100-4) --> (11, 12, 197, 96)

• 正常化矩形

NormalizeRect()        Standardizes the height and width of CRect.
例子：
CRect rect1(110, 100, 250, 310);
CRect rect2(250, 310, 110, 100);

rect1.NormalizeRect();
rect2.NormalizeRect();

// rect1 should be unchanged
// rect2 becomes (110, 100, 250, 310)

ASSERT(rect1 == rect2);

• 平移矩形

void OffsetRect( int x, int y );
void OffsetRect( POINT point );
void OffsetRect( SIZE size );

例子：

    CRect rc(10, 10, 200, 100);
    rc.OffsetRect(5, 6);//left +5, right +5 ; top +6, bottom +6  --> (15, 16, 205, 106)
    rc.SetRect(10, 10, 200, 100);
    rc.InflateRect(5, 6);// left -5, right +5 ; top -6, bottom +6  --> (5, 4, 205, 106)
    //对比
    // OffsetRect(x,y) :表示平移，左右的坐标都加x，上下的坐标都加y
    // InflateRect(x,y):表示放大，左减右加 x，上减下加 y

    // 另外 void InflateRect( int l, int t, int r, int b ); 可以等价 void OffsetRect( int x, int y );
    rc.SetRect(10, 10, 200, 100);
    rc.InflateRect(-5, -6, 5, 6);//等价 rc.OffsetRect(5, 6); --> (15, 16, 205, 106)

• 矩形lprcSrc1中减去lprcSrc2得到的矩形区域结果。

注：lprcSrc1与lprcSrc2这两个矩形必须在水平或垂直方向完全相交。换句话说，倘若在lprcSrc1中拿掉与lprcSrc2相交的部分，结果必须是个矩形。
 BOOL SubtractRect( LPCRECT lpRectSrc1, LPCRECT lpRectSrc2 ); 
例子：

    CRect rc1(10, 10, 200, 200);
    CRect rc2(10, 10, 200, 100);
    CRect rcRes;
    rcRes.SubtractRect(rc1, rc2);//rcRes = (10,100,200,200)

    //若去掉后不是矩形则返回rc1
    rcRes.SubtractRect(rc1, CRect(10,10,50,50));// rcRes =  (10, 10, 200, 200)
    rcRes.SubtractRect(rc1, CRect(2, 2, 50, 50));// rcRes =  (10, 10, 200, 200)
    rcRes.SubtractRect(rc1, CRect(100, 100, 200, 200));// rcRes =  (10, 10, 200, 200)

    // 只要去掉俩个矩形的交集后还是一个矩形就行
    rcRes.SubtractRect(rc1, CRect(25, 0, 300, 300));// rcRes =  (10, 10, 25, 200)
    rcRes.SubtractRect(rc1, CRect(2, 50, 500, 300));// rcRes =  (10, 10, 200, 50)

• 获得能包含这两个矩形的最小矩形

 BOOL UnionRect( LPCRECT lpRect1, LPCRECT lpRect2 ); 
例子：

    CRect   rect1(100, 0, 200, 300);
    CRect   rect2(0, 100, 300, 200);
    CRect   rect3;
    // 获得能放下两个矩形的最小矩形
    rect3.UnionRect(&rect1, &rect2);// (0, 0, 300, 300)
    rect3.UnionRect(CRect(10, 10, 50, 50), CRect(100, 100, 150, 150));// (10, 10, 150, 150)
    rect3.UnionRect(CRect(10, 10, 50, 50), CRect(10, 10, 15, 15));// (10, 10, 50, 50)
    rect3.UnionRect(CRect(10, 10, 50, 50), CRect(8, 9, 15, 15));// (8, 9, 50, 50)

• 获取两个矩形的交集矩形

 BOOL IntersectRect( LPCRECT lpRect1, LPCRECT lpRect2 ); 
例子：

    CRect   rect1(100, 0, 200, 300);
    CRect   rect2(0, 100, 300, 200);
    CRect   rect3;
    // 获得能两个矩形的交集矩形
    rect3.IntersectRect(rect1, rect2);// (100, 100, 200, 200)
    rect3.IntersectRect(CRect(10, 10, 50, 50), CRect(100, 100, 150, 150));// (0, 0, 0, 0)
    rect3.IntersectRect(CRect(10, 10, 50, 50), CRect(10, 10, 15, 15));// (10, 10, 15, 15)
    rect3.IntersectRect(CRect(10, 10, 50, 50), CRect(8, 9, 15, 15));// (10, 10, 15, 15)
    rect3.IntersectRect(CRect(10, 10, 50, 50), CRect(0, 0, 100, 100));// (10, 10, 50, 50)

    另外：
Operators （操作符重载）

operator LPCRECT         Converts a CRect to an LPCRECT.
operator LPRECT         Converts a CRect to an LPRECT.
operator =                 Copies the dimensions of a rectangle to CRect.
operator ==             Determines whether CRect is equal to a rectangle.
operator !=             Determines whether CRect is not equal to a rectangle.
operator +=             Adds the specified offsets to CRect or inflates CRect.
operator –=             Subtracts the specified offsets from CRect or deflates CRect.
operator &=             Sets CRect equal to the intersection of CRect and a rectangle.
operator |=             Sets CRect equal to the union of CRect and a rectangle.
operator +                 Adds the given offsets to CRect or inflates CRect and returns the resulting CRect.
operator –                 Subtracts the given offsets from CRect or deflates CRect and returns the resulting CRect.
operator &                 Creates the intersection of CRect and a rectangle and returns the resulting CRect.
operator |                 Creates the union of CRect and a rectangle and returns the resulting CRect. 

CRect::operator +

CRect operator +( POINT point ) const;

CRect operator +( LPCRECT lpRect ) const;

CRect operator +( SIZE size ) const;

Return Value

The CRect resulting from moving or inflating CRect by the number of units specified in the parameter.

Example

    CRect   rect1(100, 235, 200, 335);
    CPoint   pt(35, 65);
    CRect   rect2;

    rect2 = rect1 + pt;

    CRect   rectResult(135, 300, 235, 400);

    ASSERT(rectResult == rect2);

CRect::operator -

CRect operator -( POINT point ) const;

CRect operator -( SIZE size ) const;

CRect operator -( LPCRECT lpRect ) const;

Return Value

The CRect resulting from moving or deflating CRect by the number of units specified in the parameter.

Example

    CRect   rect1(100, 235, 200, 335);
    CPoint   pt(35, 65);
    CRect   rect2;

    rect2 = rect1 - pt;

    CRect   rectResult(65, 170, 165, 270);

    ASSERT(rect2 == rectResult);

CRect::operator &

CRect operator &( const RECT& rect2 ) const;

Return Value

A CRect that is the intersection of CRect and rect2.

Example

    CRect   rect1(100, 0, 200, 300);
    CRect   rect2(0, 100, 300, 200);
    CRect   rect3;

    rect3 = rect1 & rect2;

    CRect   rectResult(100, 100, 200, 200);
    ASSERT(rectResult == rect3);

CRect::operator |

CRect operator |( const RECT& rect2 ) const;

Return Value

A CRect that is the union of CRect and rect2.

Remarks

Returns a CRect that is the union of CRect and rect2. The union is the smallest rectangle that contains both rectangles.

Example

    CRect   rect1(100, 0, 200, 300);
    CRect   rect2(0, 100, 300, 200);
    CRect   rect3;

    rect3 = rect1 | rect2;

    CRect   rectResult(0, 0, 300, 300);
    ASSERT(rectResult == rect3);

 

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以上都要注意：执行前的矩形正常化
Note：   Both of the rectangles must be normalized or this function may fail. You can call NormalizeRect to normalize the rectangles before calling this function.