如何简化NSBezierPath (或UIBezierPath)代码？

Question

theLen = [NSBezierPath bezierPath];
[theLen moveToPoint:NSMakePoint(_frame.size.width/2 +  base / 2 , _frame.size.height/2 - (diameter / 2))];
[theLen lineToPoint:NSMakePoint(_frame.size.width/2 -  base / 2 , _frame.size.height/2 - (diameter / 2))];
[theLen lineToPoint:NSMakePoint(_frame.size.width/2 - (thickness / 2 ) , _frame.size.height/2)];
[theLen lineToPoint:NSMakePoint(_frame.size.width/2 -  base / 2 , _frame.size.height/2 + (diameter / 2))];
[theLen lineToPoint:NSMakePoint(_frame.size.width/2 + base / 2 , _frame.size.height/2 + (diameter / 2))];
[theLen lineToPoint:NSMakePoint(_frame.size.width/2 + (thickness / 2 ) , _frame.size.height/2)];
[theLen closePath];
theLen.lineWidth = 2;
[theLen stroke];
[theLen fill];

给定这些代码，您将如何简化它？我正在努力学习如何简化代码，我所能想到的就是把它变成……

float commonNSPoint[4];
commonNSPoint[0] = _frame.size.width/2 +  base / 2;
commonNSPoint[1] = _frame.size.width/2 -  base / 2;
commonNSPoint[2] = _frame.size.height/2 - (diameter / 2);
commonNSPoint[3] = _frame.size.height/2 + (diameter / 2);

theLen = [NSBezierPath bezierPath];
[theLen moveToPoint:NSMakePoint( commonNSPoint[0],  commonNSPoint[2])];
[theLen lineToPoint:NSMakePoint(commonNSPoint[1],  commonNSPoint[2])];
[theLen lineToPoint:NSMakePoint(_frame.size.width/2 - (thickness / 2 ) , _frame.size.height/2)];
[theLen lineToPoint:NSMakePoint(commonNSPoint[1],  commonNSPoint[3])];
[theLen lineToPoint:NSMakePoint( commonNSPoint[0], commonNSPoint[3])];
[theLen lineToPoint:NSMakePoint(_frame.size.width/2 + (thickness / 2 ) , _frame.size.height/2)];
[theLen closePath];
[theLen closePath];
theLen.lineWidth = 2;
[theLen stroke];
[theLen fill];

这对我没有什么帮助，因为NSBezierPath或UIBezierPath的点位置并不完全相同。这也使得代码看起来更加混乱。

你们将如何简化这样的NSBezierPath或UIBezierPath。任何东西都会有帮助(因为我的程序是基于不同值的NSPoint和许多NSBezierPath绘图)。

谢谢

Answer 1

首先，提取出通用子表达式，并为它们指定有意义的名称( commonNSPoint不是)。这是一个合理的开始：

    CGFloat xMid = _frame.size.width / 2;
    CGFloat yMid = _frame.size.height / 2;
    CGFloat radius = diameter / 2;
    CGFloat halfBase = base / 2;
    CGFloat halfThick = thickness / 2;

然后创建一个只包含点的数组，而不使用函数和方法调用来使事情变得混乱：

    CGPoint points[] = {
        { xMid + halfBase,  yMid - radius },
        { xMid - halfBase,  yMid - radius },
        { xMid - halfThick, yMid },
        { xMid - halfBase,  yMid + radius },
        { xMid + halfBase,  yMid + radius },
        { xMid + halfThick, yMid },
    };

最后，创建包含这些点的路径：

    theLen = [NSBezierPath bezierPath];
    [theLen appendBezierPathWithPoints:points count:sizeof points / sizeof points[0]];
    [theLen closePath];

或者，让点围绕原点居中，然后在创建路径后平移(滑动)该路径：

    CGFloat radius = diameter / 2;
    CGFloat halfBase = base / 2;
    CGFloat halfThick = thickness / 2;

    CGPoint points[] = {
        { halfBase,  radius },
        { halfBase,  radius },
        { halfThick, 0 },
        { halfBase,  radius },
        { halfBase,  radius },
        { halfThick, 0 },
    };

    theLen = [NSBezierPath bezierPath];
    [theLen appendBezierPathWithPoints:points count:sizeof points / sizeof points[0]];
    [theLen closePath];

    NSAffineTransform *transform = [NSAffineTransform transform];
    [transform translateXBy:_frame.size.width / 2 yBy:_frame.size.height / 2];
    [theLen transformUsingAffineTransform:transform];