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：
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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;}@endCRect.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;@endCRect.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;}@endDoCRect.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@endDoCRect.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; }@endmain.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?@"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。
