c++判断两个矩形是否相交（判断矩形是否相交）

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：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 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?@"YES":@"NO"); //返回相交矩形 //CRect *inserectRect = [[CRect alloc] init]; CRect *inserectRect = [dorect intersectRect:myrect1 :myrect2]; [inserectRect print]; } return 0; }