本文实例讲述了C++判断矩形相交的方法。分享给大家供大家参考。具体如下：

已知2矩形原点和宽高，判断2矩形相交，相交矩形

相交判断原理：

假定矩形是用一对点表达的(minx, miny) (maxx, maxy)，那么两个矩形

rect1{(minx1, miny1)(maxx1, maxy1)}

rect2{(minx2, miny2)(maxx2, maxy2)}

相交的结果一定是个矩形，构成这个相交矩形rect{(minx, miny) (maxx, maxy)}的点对坐标是：

minx   =   max(minx1,   minx2)

miny   =   max(miny1,   miny2)

maxx   =   min(maxx1,   maxx2)

maxy   =   min(maxy1,   maxy2)

如果两个矩形不相交，那么计算得到的点对坐标必然满足：

( minx  >  maxx ) 或者 ( miny  >  maxy )

判定是否相交，以及相交矩形是什么都可以用这个方法一体计算完成

设计3个类：

1. 点类：x，y

2. 矩形类：点，宽，高

3. 判断相交类

程序实现：

CPoint.h

#import

@interface CPoint : NSObject

{

int x; //点坐标

int y;

}

-(void) print;

-(void) setX: (int) vx;

-(void) setY: (int) vy;

-(void) setXY:(int) vx :(int) vy;

-(int) x;

-(int) y;

@end

CPoint.m

#import "CPoint.h"

@implementation CPoint

-(void) print

{

NSLog(@"the point is (%i, %i)",x,y);

}

-(void) setX: (int) vx

{

x = vx;

}

-(void) setY: (int) vy

{

y = vy;

}

-(void) setXY:(int)vx :(int)vy

{

x = vx;

y = vy;

}

-(int) x

{

return x;

}

-(int) y

{

return y;

}

@end

CRect.h

#import

#import "CPoint.h"

@interface CRect : NSObject

{

int w; //矩形长

int h; //矩形高

}

-(void) print;

-(int) w;

-(int) h;

-(void) setW: (int) vw;

-(void) setH: (int) vh;

-(void) setWH: (int) vw :(int) vh;

-(CPoint *) origin;

-(void) setOrigin: (CPoint *) pt;

@end

CRect.m

#import "CRect.h"

@implementation CRect

{

CPoint *origin; //点

}

-(void) print

{

NSLog(@"the rect:(x:%i, y:%i, w:%i,h:%i)",origin.x, origin.y, w, h);

}

-(int) w

{

return w;

}

-(int) h

{

return h;

}

-(void) setW:(int)vw

{

w = vw;

}

-(void) setH:(int)vh

{

h = vh;

}

-(void) setWH:(int)vw :(int)vh

{

w = vw;

h = vh;

}

-(CPoint *) origin

{

return origin;

}

-(void) setOrigin:(CPoint *)pt

{

origin = pt;

}

@end

DoCRect.h

#import

#import "CRect.h"

@interface DoCRect : NSObject

-(BOOL) isIntersect:(CRect *) rect1 :(CRect *) rect2; //矩形相交否

-(CRect *) intersectRect: (CRect *) rect1 :(CRect *) rect2; //相交矩形

@end

DoCRect.m

#import "DoCRect.h"

@implementation DoCRect

//矩形是否相交

-(BOOL) isIntersect:(CRect *)rect1 :(CRect *)rect2

{

int minx = MAX(rect1.origin.x, rect2.origin.x);

int miny = MAX(rect1.origin.y, rect2.origin.y);

int maxx = MIN(rect1.origin.x+rect1.w, rect2.origin.x+rect2.w);

int maxy = MIN(rect1.origin.y+rect1.h, rect2.origin.y+rect2.h);

if (minx>maxx || miny>maxy)

{

return NO;

}

return YES;

}

-(CRect *) intersectRect:(CRect *)rect1 :(CRect *)rect2

{

int minx = MAX(rect1.origin.x, rect2.origin.x);

int miny = MAX(rect1.origin.y, rect2.origin.y);

int maxx = MIN(rect1.origin.x+rect1.w, rect2.origin.x+rect2.w);

int maxy = MIN(rect1.origin.y+rect1.h, rect2.origin.y+rect2.h);

CRect * rect = [[CRect alloc] init];

CPoint *p = [[CPoint alloc] init];

if (NO == [self isIntersect:rect1 :rect2])//no isIntersect

{

[p setXY:minx :miny];

[rect setOrigin:p];

rect.w = 0;

rect.h = 0;

return rect;

}

[p setXY:minx :miny];

[rect setOrigin:p];

rect.w = ABS(maxx-minx);

rect.h = ABS(maxy - miny);

return rect;

}

@end

main.m 测试

#import

#import "DoCRect.h"

int main(int argc, const char * argv[])

{

@autoreleasepool

{

NSLog(@"Hello,判断矩形相交，返回矩形的原点和长高");

//初始化对象

CRect *myrect1 = [[CRect alloc] init];

CRect *myrect2 = [[CRect alloc] init];

CPoint *p1 = [[CPoint alloc] init];

CPoint *p2 = [[CPoint alloc] init];

DoCRect *dorect = [[DoCRect alloc] init];

//原点变量

[p1 setXY:200 :420];

[p2 setXY:400 :300];

//设置矩形原点

[myrect1 setOrigin:p1];

[myrect1 setWH:250 :75];

[myrect1 print];

[myrect2 setOrigin:p2];

[myrect2 setWH:100 :180];

[myrect2 print];

//判断2矩形是否相交

BOOL insersect = [dorect isIntersect:myrect1 :myrect1];

NSLog(@" two rect is :%@",insersect?@"YES":@"NO");

//返回相交矩形

//CRect *inserectRect = [[CRect alloc] init];

CRect *inserectRect = [dorect intersectRect:myrect1 :myrect2];

[inserectRect print];

}

return 0;

}

希望本文所述对大家的C++程序设计有所帮助。