PAG动效的使用与执行过程监听

定义：PAG（Portable Animated Graphics）是腾讯自主研发的一套完整的动画工作流解决方案，助力于将 AE 动画方便快捷的应用于各平台终端。

使用过程：
1、引用三方库：import libpag
2、初始化pagview，加载本地pag资源文件，设置循环播放次数，缩放模式，监听动效执行过程等

public lazy var animateView: PAGView = {
        let animate = PAGView(frame: CGRect(x: 0, y: 0, width: UIScreen.main.bounds.size.width, height: UIScreen.main.bounds.size.height))
        animate.setPath(Bundle.main.path(forResource: "test", ofType: "pag"))
        animate.isUserInteractionEnabled = false
        //animate.setRepeatCount(MAXINTERP)//重复播放pag动效
        animate.setRepeatCount(1)//只播放一次
        animate.setScaleMode(PAGScaleModeStretch)
        return animate
    }()

2.1、缩放模式枚举（PAGScaleMode）

typedef enum {
       // The content is not scaled.
       PAGScaleModeNone = 0,
       // The content is stretched to fit.
       PAGScaleModeStretch = 1,
       // The content is scaled with respect to the original unscaled image's aspect ratio. This is the
       // default value.
       PAGScaleModeLetterBox = 2,
       // The content is scaled to fit with respect to the original unscaled image's aspect ratio. This
       // results in cropping
       // on one axis.
       PAGScaleModeZoom = 3,
     } PAGScaleMode;

2.2、遵守PAGViewListener协议，监听动效执行过程

func onAnimationStart(_ pagView: PAGView!) {
        print("动效开始执行")
    }
    func onAnimationCancel(_ pagView: PAGView!) {
        print("动效取消")
    }
    func onAnimationRepeat(_ pagView: PAGView!) {
        print("重复执行")
    }
    func onAnimationEnd(_ pagView: PAGView!) {
        print("动效结束")
    }

3、添加pagview，开始执行

 self.view.addSubview(animateView)
 animateView.play()