在iPhone上用手指触摸画出平滑的线条(Draw a smooth line with finger touch on iPhone)

如何在iPhone上用手指滑动/触摸动作绘制平滑线条？我有以下代码，但它不光滑。例如，当我尝试做一个循环时，它会让角落/转弯。我想我必须使用OpenGL。有任何想法吗？示例代码？教程？

谢谢！

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

How do I draw a smooth line with a finger slide/touch motion on the iPhone? I have the following code but it is not smooth. It makes corners/turns for example when I try to do a circle. I think I have to use OpenGL. Any ideas? sample code? tutorials?

Thanks!

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