iphone - CGContext画线: CGContextFillPath not working?

Question

有人知道为什么 CGContextFillPath 在下面的代码片段中不起作用吗？我使用以下代码绘制 UIImageView。它正确地抚摸路径，但忽略 CGContextFillPath。

UIGraphicsBeginImageContext(self.frame.size);
[drawingView.image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 5.0);
CGContextSetAllowsAntialiasing(UIGraphicsGetCurrentContext(), YES);
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 1.0, 0.0, 0.0, 1.0);
CGContextSetRGBFillColor(UIGraphicsGetCurrentContext(), 1.0, 0.0, 0.0, 1.0);
CGContextBeginPath(UIGraphicsGetCurrentContext());
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), firstMovedTouch.x, firstMovedTouch.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
CGContextFillPath(UIGraphicsGetCurrentContext());
drawingView.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

Answer 1

要解决此问题，请使用以下代码:

CGContextRef context = UIGraphicsGetCurrentContext(); 

CGContextSetRGBStrokeColor(context, 0.0, 0.0, 0.0, 1.0);
CGContextSetRGBFillColor(context, 0.0, 0.0, 0.0, 1.0);
CGContextSetLineJoin(context, kCGLineJoinRound);
CGContextSetLineWidth(context, 8.0);

CGMutablePathRef pathRef = CGPathCreateMutable();

/* do something with pathRef. For example:*/
CGPathMoveToPoint(pathRef, NULL, x, y);
CGPathAddLineToPoint(pathRef, NULL, x, y+100);
CGPathAddLineToPoint(pathRef, NULL, x+100, y+100);
CGPathAddLineToPoint(pathRef, NULL, x+100, y);
CGPathCloseSubpath(pathRef);

CGContextAddPath(context, pathRef);
CGContextFillPath(context);

CGContextAddPath(context, pathRef);
CGContextStrokePath(context);

CGPathRelease(pathRef);