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 <Foundation/Foundation.h> @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 <Foundation/Foundation.h> #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 <Foundation/Foundation.h> #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 <Foundation/Foundation.h> #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"); //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。