找到两个CG点之间的距离？

Question

我正在使用这些方法和这些变量

CGPoint touchBegan;
CGPoint touchEnd;

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{

}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

}

- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

}

但我无法获得两点之间的距离。例如，用手指画一条线并获取 CGPoint touchBegan 和 CGPoint touchEnd 之间的距离

感谢任何帮助

Answer 1

似乎不存在任何直接执行此操作的方法或函数，您必须取两点坐标的差异并使用勾股定理：

CGPoint touchBegan;
CGPoint touchEnd;

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    UITouch* touch= [touches anyObject];
    touchBegan= [touch locationInView: self.view];
}

- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch* touch= [touches anyObject];
    touchEnd= [touch locationInView: self.view];
    CGFloat dx= touchBegan.x - touchEnd.x;
    CGFloat dy= touchBegan.y - touchEnd.y;
    CGFloat distance= sqrt(dx*dx + dy*dy);
    < Do stuff with distance >
}