在Xcode 8 beta 6中,一些添加路径的函数发生了变化,包括添加弧线的函数:
func addArc(center: CGPoint, radius: CGFloat, startAngle: CGFloat, endAngle: CGFloat, clockwise: Bool, transform: CGAffineTransform = default)
除了函数定义之外,在苹果网站上没有其他文档。我无法从该函数获取实际弧形,并一直依赖于使用切线的第二个版本。有人能提供一个可用的示例吗?这可能只是一个错误吗?
以下是受此更改破坏的函数:
public class func createHorizontalArcPath(_ startPoint:CGPoint, width:CGFloat, arcHeight:CGFloat, closed:Bool = false) -> CGMutablePath
{
// http://www.raywenderlich.com/33193/core-graphics-tutorial-arcs-and-paths
let arcRect = CGRect(x: startPoint.x, y: startPoint.y-arcHeight, width: width, height: arcHeight)
let arcRadius = (arcRect.size.height/2) + (pow(arcRect.size.width, 2) / (8*arcRect.size.height));
let arcCenter = CGPoint(x: arcRect.origin.x + arcRect.size.width/2, y: arcRect.origin.y + arcRadius);
let angle = acos(arcRect.size.width / (2*arcRadius));
let startAngle = CGFloat(M_PI)+angle // (180 degrees + angle)
let endAngle = CGFloat(M_PI*2)-angle // (360 degrees - angle)
let path = CGMutablePath();
path.addArc(center: arcCenter, radius: arcRadius, startAngle: startAngle, endAngle: endAngle, clockwise: true)
if(closed == true)
{path.addLine(to: startPoint)}
return path;
}