从函数返回 CGPoints

Question

我还有一个关于在交汇处传递 CGPoint 的问题：

(CGPoint[]) displayPoints:(CGPoint) startPoint 
                        withEnd:(CGPoint) endPoint
                 withBaseRotate:(Boolean) baseRotate {

// do some stuf with four or six points
// create a array of the points and return - it


    CGPoint ourPoints[] = {
        CGPointMake(point1.x, point1.y),
        CGPointMake(point2.x, point2.y),
        CGPointMake(point3.x, point3.y),
        //... some more points
    } ;

  return ourPoints[];
}

为什么这不起作用？

Answer 1

必须返回一个指向它在内存中存储位置的指针

(const CGPoint *) displayPoints:(CGPoint) startPoint 
                  withEnd:(CGPoint) endPoint
           withBaseRotate:(Boolean) baseRotate {

    CGPoint ourPoints[] = {
        CGPointMake(point1.x, point1.y),
        CGPointMake(point2.x, point2.y),
        CGPointMake(point3.x, point3.y),
        //... some more points
    } ;

  return ourPoints;
}

如果您查看 CFContextAddLines 的签名，您会发现这就是他们正在使用的。现在编译器会抛出一个警告，要求返回内存指针...所以我不确定这是否是首选方式，但它回答了您的问题。