请教下：做缩放动画时，画面会有抖动的感觉，不流畅，如何解决呢？

[yinghuochong]

demo.mp4

demo代码如下：

    func scaleAnimationDemo() -> VideoLab {
        // 1. LayerGroup
        var timeRange = CMTimeRange(start: CMTime.zero, duration: CMTime(seconds: 5, preferredTimescale: 600))
        let keyTimes = [CMTime(seconds: 0, preferredTimescale: 600),
                        CMTime(seconds: 5, preferredTimescale: 600)]
        let animation1 = KeyframeAnimation(keyPath: "scale",
                                           values: [1, 1.2],
                                           keyTimes: keyTimes,
                                           timingFunctions: [.quadraticEaseInOut])
        var transform = Transform.identity
        transform.animations = [animation1]
        
        
        // Add sub-renderLayer1
        let image = UIImage(named: "image2.HEIC")
        let imageSource = ImageSource(cgImage: image?.cgImage)
        imageSource.selectedTimeRange = CMTimeRange(start: CMTime.zero, duration: timeRange.duration)
        timeRange = imageSource.selectedTimeRange
        let renderLayer1 = RenderLayer(timeRange: timeRange, source: imageSource)
        renderLayer1.transform = transform
        
        // 2. Composition
        let composition = RenderComposition()
        composition.renderSize = CGSize(width: 2016, height: 1512)
        composition.layers = [renderLayer1]
        
        // 3. VideoLab
        let videoLab = VideoLab(renderComposition: composition)
        
        return videoLab
    }