ios - bezierPathWithRoundedRect 不是完美的圆

Question

画圈有问题:

这段简单的代码演示了:

- (void)drawRect:(CGRect)rect {

    self.layer.sublayers = nil;
    CGFloat radius = self.frame.size.width/2;

    circle = [CAShapeLayer layer];
    circle.path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.width) cornerRadius:radius].CGPath;

    circle.fillColor = [UIColor clearColor].CGColor;
    circle.strokeColor = [UIColor redColor].CGColor;

    circle.lineWidth = 4;

    [self.layer addSublayer:circle];

    CABasicAnimation *drawAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];

    drawAnimation.duration            = 1.0; // "animate over 10 seconds or so.."
    drawAnimation.repeatCount         = 1.0;  // Animate only once..

    drawAnimation.fromValue = [NSNumber numberWithFloat:0];
    drawAnimation.toValue   = [NSNumber numberWithFloat:1];

    drawAnimation.removedOnCompletion = NO;
    drawAnimation.fillMode = kCAFillModeForwards;

    drawAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

    drawAnimation.delegate = self;
    [circle addAnimation:drawAnimation forKey:@"drawCircleAnimation"];

}

我们有结果

前三个圆是用上面的方法画的，最后一个圆是我用PS画的。 如果你能看到 bezierPathWithRoundedRect 绘制的不是完美的圆，我认为它的半径是正确的(一些角被添加到圆上)。如何画出像图片最后一个圆圈一样的圆圈？

PS:我的项目需要使用 bezierPathWithArcCenter，但是当我重新使用 bezierPathWithRoundedRect 时，我遇到了同样的问题!

Answer 1

你需要使用 + (NSBezierPath *)bezierPathWithOvalInRect:(NSRect)aRect 来画一个圆。

根据定义，RoundedRect 是方形的。