ios - 动画绘制 CAShapeLayer 的填充

Question

我一直在尝试使用 CAShapeLayer 绘制路径，如这篇精彩文章 http://oleb.net/blog/2010/12/animating-drawing-of-cgpath-with-cashapelayer 中所述。 ，但我想知道是否有办法为图层的填充设置动画。

例如，我想在屏幕上绘制一些文本，但我只能绘制文本的描边，而不能绘制填充。另一个例子，我有一个星形，我想为其填充动画。

这可以使用 CAShapeLayer 或其他对象吗？

谢谢!

Answer 1

大部分时间都是相同的代码，您只需为 CABasicAnimation 的 fromValue 和 toValue 设置不同的值。我创建了一个类别，它返回一个 CABasicAnimation:

StrokeEnd 动画

+ (CABasicAnimation *)animStrokeEndWithDuration:(CGFloat)dur
                                       delegate:(id)target{
    CABasicAnimation *animLine = 
     [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    [animLine setDuration:dur];
    [animLine setFromValue:[NSNumber numberWithFloat:0.0f]];
    [animLine setToValue:[NSNumber numberWithFloat:1.0f]];
    [animLine setRemovedOnCompletion:NO];
    [animLine setFillMode:kCAFillModeBoth];
    [animLine setDelegate:target];
    [animLine setTimingFunction:
     [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];

    return animLine;
}

填充颜色的动画

+ (CABasicAnimation *)animFillColorWithDur:(CGFloat)dur
                                  startCol:(UIColor *)start
                                  endColor:(UIColor *)end
                                  delegate:(id)target{

    CABasicAnimation *animFill = 
     [CABasicAnimation animationWithKeyPath:@"fillColor"];
    [animFill setDuration:dur];
    [animFill setFromValue:(id)start.CGColor];
    [animFill setToValue:(id)end.CGColor];
    [animFill setRemovedOnCompletion:NO];
    [animFill setDelegate:target];
    [animFill setFillMode:kCAFillModeBoth];

    return animFill;
}

返回的 CABasicAnimation 只需添加到 CAShapeLayer 中:

[_myShapeLayer addAnimation:returnedAnimation forKey:@"animKey"]