如何缩放CALayer以适合视频层 [英] How to scale CALayer to fit on the video layer

问题描述

我对CALayer有问题.关键是我想在电影上保存几个UIView.基本上，我正在尝试通过CALayer进行操作.一切正常，该应用会导出具有图层的影片，但带有视图的图层会小于视频帧.

I have a problem with CALayer. The point is that I want to save few UIViews on the movie. Basically I am trying to do it by CALayer. Everything is okay, the app export movie with layers but the layers with views are smaller than video frame.

我尝试手动缩放图层，但是在屏幕上看起来完全不一样.如果我将UIView在电影上移得更高，那么它会更高.

I tried to scale layer manually but at all it is not look like on the screen. If I move UIView higher on movie it is going much higher.

视频具有FullHd框架，UIView的层取决于用户在屏幕上的放置方式.

Video has FullHd frame and layers of UIView depends of it how user place it on the screen.

问题是: -如何呈现具有更好视网膜质量的UIView Context?

The questions are: - How to render UIView Context with better retina quality?

• 如何缩放图层以使其完全适合视频.

有代码:

VideoSaver.saveVideo(videoAsset!) { (composition, size) in
        ////////////////
        //Parent Layer//
        ////////////////

        let parentLayer = CALayer()
        parentLayer.frame = CGRectMake(0, 0, size.width, size.height)

        /////////
        //Sizes//
        /////////
        let xScaleValue = CGRectGetWidth(parentLayer.frame)/CGRectGetWidth(self.view.frame)
        let yScaleValue = CGRectGetHeight(parentLayer.frame)/CGRectGetHeight(self.view.frame)

        ///////////////
        //Video Layer//
        ///////////////
        let videoLayer = CALayer()
        videoLayer.frame = CGRectMake(0, 0, size.width, size.height)

        //////////////////
        //Captions Layer//
        //////////////////

        //Creating UIImage from Captions
        UIGraphicsBeginImageContext(CGSizeMake(self.captionsTextView.bounds.size.width, self.captionsTextView.bounds.size.height+20))
        let currentContext = UIGraphicsGetCurrentContext()

        CGContextTranslateCTM(currentContext, 0, 16)

        self.captionsTextView.layer.renderInContext(currentContext!)
        let captionTextViewImage = UIGraphicsGetImageFromCurrentImageContext()

        UIGraphicsEndImageContext()

        let captionsOverlayLayer = CALayer()
        captionsOverlayLayer.contents = captionTextViewImage.CGImage
        captionsOverlayLayer.frame = CGRectMake(self.captionsTextView.frame.origin.x * xScaleValue,
                                            (size.height - ((self.captionsTextView.frame.origin.y - 20) * yScaleValue)),
                                            CGRectGetWidth(self.captionsTextView.frame) * xScaleValue,
                                            (CGRectGetHeight(self.captionsTextView.frame)+20) * yScaleValue)

        captionsOverlayLayer.masksToBounds = true

        ///////////////////
        //TagFilter Layer//
        ///////////////////
        UIGraphicsBeginImageContext(self.tagView.bounds.size)
        self.tagView.layer.renderInContext(UIGraphicsGetCurrentContext()!)

        let tagViewImage = UIGraphicsGetImageFromCurrentImageContext()

        UIGraphicsEndImageContext()

        let tagOverlayLayer = CALayer()
        tagOverlayLayer.contents = tagViewImage.CGImage
        tagOverlayLayer.frame = CGRectMake(self.tagView.frame.origin.x * xScaleValue,
                                           (size.height - ((self.tagView.frame.origin.y) * yScaleValue)),
                                           CGRectGetWidth(self.tagView.frame) * xScaleValue,
                                           (CGRectGetHeight(self.tagView.frame)) * yScaleValue)
        ///////////////////////////////////////////////

        parentLayer.addSublayer(videoLayer)
        parentLayer.addSublayer(captionsOverlayLayer)
        parentLayer.addSublayer(tagOverlayLayer)

        ///////////////
        //Composition//
        ///////////////
        composition.animationTool = AVVideoCompositionCoreAnimationTool.init(postProcessingAsVideoLayer: videoLayer, inLayer: parentLayer)
    }

我很乐意提供帮助:)

推荐答案

最后，我要放在视频中的所有UIViews都放在一个UIView上.从该UIView中，我正在创建图层并将其缩放为视频大小.如果有人遇到相同的问题，则有一个代码:

At the end all UIViews that I want to have on the video I put to one UIView. From that UIView I am creating the layer and scaling it to video size. There is a code if someone will have the same problem:

VideoSaver.saveVideo(videoAsset!) 
{ 
    (composition, size) in
    ////////////////
    //Parent Layer//
    ////////////////

    let parentLayer = CALayer()
    parentLayer.frame = CGRectMake(0, 0, size.width, size.height)

    ///////////////
    //Video Layer//
    ///////////////
    let videoLayer = CALayer()
    videoLayer.frame = CGRectMake(0, 0, size.width, size.height)

    ///////////////////////
    //Effect Layout Layer//
    ///////////////////////
    UIGraphicsBeginImageContextWithOptions(self.effectLayoutView.bounds.size, false, 0.0)
    self.effectLayoutView.layer.renderInContext(UIGraphicsGetCurrentContext()!)

    let effectLayoutViewImage = UIGraphicsGetImageFromCurrentImageContext()

    UIGraphicsEndImageContext()

    let effectOverlayLayer = CALayer()
    effectOverlayLayer.contents = effectLayoutViewImage.CGImage

    effectOverlayLayer.frame = CGRectMake(0, 0, size.width, size.height)
    effectOverlayLayer.masksToBounds = true

    ///////////////////////////////////////////////

    parentLayer.addSublayer(videoLayer)
    parentLayer.addSublayer(effectOverlayLayer)

    ///////////////
    //Composition//
    ///////////////
    composition.animationTool = AVVideoCompositionCoreAnimationTool.init(postProcessingAsVideoLayer: videoLayer, inLayer: parentLayer)
}

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