对于IOS点、线、角的计算

2019独角兽企业重金招聘Python工程师标准>>>

//计算两个点之间的距离

CGFloat distanceBetweenPoints (CGPoint first, CGPoint second) {
    CGFloat deltaX = second.x - first.x;
    CGFloat deltaY = second.y - first.y;
    return sqrt(deltaX*deltaX + deltaY*deltaY );
};

计算两个点与X轴线的夹角：

/**
 *  计算角度
 *  @param edge 线
 *  @return 角度
 */
-(CGFloat)angleForStartPoint:(CGPoint)startPoint EndPoint:(CGPoint)endPoint{
    
    CGPoint Xpoint = CGPointMake(startPoint.x + 100, startPoint.y);
    
    CGFloat a = endPoint.x - startPoint.x;
    CGFloat b = endPoint.y - startPoint.y;
    CGFloat c = Xpoint.x - startPoint.x;
    CGFloat d = Xpoint.y - startPoint.y;
    
    CGFloat rads = acos(((a*c) + (b*d)) / ((sqrt(a*a + b*b)) * (sqrt(c*c + d*d))));
    
    if (startPoint.y>endPoint.y) {
        rads = -rads;
    }
    return rads;
}

对于一个View进行旋转之后，通过view的frame不能准确找到四个角点位置。方法是将四个角点也进行变换，获取到对应的点

-(void)click:(UIButton *)btn{           //获取_view的原点旋转40°后的点的位置     CGPoint roP = [self rotePoint:40 center: _view.center point: _view.frame.origin scale:1];     CGAffineTransform rotation = CGAffineTransformMakeRotation(90*M_PI/180);           [_view setTransform:rotation];       }     /**  *  旋转后点的计算  *  *  @param angle        旋转角度  *  @param center       旋转中心点  *  @param initialPoint 旋转前点的位置  *  @param scale        旋转变形比例  *  *  @return 旋转后点的位置  */ - (CGPoint)rotePoint:(CGFloat)angle center:(CGPoint)center point:(CGPoint)initialPoint scale:(CGFloat)scale {     CGFloat x = [self angleForStartPoint:center EndPoint:initialPoint];     x = -x;           if (x > 0) {         x = M_PI-x;     }else{         x = - M_PI - x;     }           CGFloat length = distanceBetweenPoints(center, initialPoint) * scale;     CGFloat ang = x + angle / 180.0 * M_PI;       NSLog(@"ang = %f",ang * 180/M_PI);     CGPoint rotatedPoint;           rotatedPoint.x = center.x - length * cos(ang);     rotatedPoint.y = center.y - length * sin(ang);           return rotatedPoint; }

转载于:https://my.oschina.net/iceTear/blog/1505757