C++ method to determine the intersection of rectangles
- 2020-04-02 03:10:54
- OfStack
This paper illustrates the method of C++ to judge the intersection of rectangles. Share with you for your reference. The details are as follows:
Given the origin and width and height of 2 rectangles, judge that 2 rectangles intersect
Intersection judgment principle:
Suppose the rectangle is represented by a pair of points (minx, miny) (maxx, maxy), then two rectangles
Rect1 {(minx1 miny1) (maxx1 maxy1)}
Rect2 {(minx2 miny2) (maxx2 maxy2)}
The result of intersection must be a rectangle. The point pair coordinate of rect{(minx, miny) (maxx, maxy)} is:
minx
=
Max (minx1,
Minx2)
miny
=
Max (miny1,
Miny2)
maxx
=
Min (maxx1,
Maxx2)
maxy
=
Min (maxy1,
Maxy2)
If the two rectangles do not intersect, then the calculated point pair coordinates must satisfy:
(minx
>
Maxx) or (miny
>
Maxy)
You can use this method to determine if the rectangle intersects, and what the intersecting rectangle is. Okay
Design 3 classes:
1. Point class: x, y
2. Rectangle: point, width and height
3. Judge the intersection class
Program implementation:
CPoint.h
#import <Foundation/Foundation.h>
@interface CPoint : NSObject
{
int x; //Point coordinates
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; //Long rectangle
int h; //High rectangle
}
-(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; //point
}
-(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; //Intersection of rectangles
-(CRect *) intersectRect: (CRect *) rect1 :(CRect *) rect2; //Intersection of the rectangle
@end
DoCRect.m
#import "DoCRect.h"
@implementation DoCRect
//Whether the rectangles intersect or not
-(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 test
#import <Foundation/Foundation.h>
#import "DoCRect.h"
int main(int argc, const char * argv[])
{
@autoreleasepool
{
NSLog(@"Hello, Determines that the rectangle intersects, and returns the original rectangle point And grow ");
//Initialize object
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];
// The original point variable
[p1 setXY:200 :420];
[p2 setXY:400 :300];
// Set the rectangle point
[myrect1 setOrigin:p1];
[myrect1 setWH:250 :75];
[myrect1 print];
[myrect2 setOrigin:p2];
[myrect2 setWH:100 :180];
[myrect2 print];
// judge 2Whether the rectangles intersect or not
BOOL insersect = [dorect isIntersect:myrect1 :myrect1];
NSLog(@" two rect is :%@",insersect?@"YES":@"NO");
// return Intersection of the rectangle
//CRect *inserectRect = [[CRect alloc] init];
CRect *inserectRect = [dorect intersectRect:myrect1 :myrect2];
[inserectRect print];
}
return 0;
}
Hope that the article described in the C++ programming to help you.