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我想是什么让我的问题/问题与其他帖子不同的是我不是在缩放视图，而是资产层指令（AVMutableVideoCompositionLayerInstruction）。所以设置锚点、view.center、CG Rect 缩放都不起作用。

除了使用 CGAffineTransformMakeTranslation 移动资产以使其看起来像居中但高度不准确之外，我无法弄清楚如何使其从中心缩放。有没有我失踪的财产？文档和指南不是很有帮助，但也许我错过了一些东西。

代码如下。谢谢大家！！！:)

此外，对于那些正在寻找使用 CGTransforms 导出 avasset 的方法的人，下面的代码是到达那里的所有步骤；当然需要填写诸如 CMTimeRanges 之类的详细信息，但希望这可以帮助某人弄清楚这个令人困惑的事情。

-(void) goAssetsExport {
    AVMutableComposition *composition = [[AVMutableComposition alloc] init];

    AVMutableCompositionTrack *firstTrack = [composition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];

    AVMutableVideoComposition *videoComposition = [AVMutableVideoComposition videoComposition];
    videoComposition.frameDuration = CMTimeMake(1,30);
    videoComposition.renderScale = 1.0;
    videoComposition.renderSize = CGSizeMake(self.view.bounds.size.width, self.view.bounds.size.height);

    NSURL *movieURL = [[NSBundle mainBundle] URLForResource:[NSString stringWithFormat:@"%@",   [preloadEffectsArray objectAtIndex:i]]  withExtension:@"mov"];
    AVURLAsset *firstAsset = [AVURLAsset URLAssetWithURL:movieURL options:nil];
    AVAssetTrack *firstAssetTrack = [[firstAsset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];

    [firstTrack insertTimeRange:CMTimeRangeMake(firstTrackRangeMin, duration) ofTrack:firstAssetTrack atTime:firstTrackRangeMin error:nil];

    AVMutableVideoCompositionInstruction *transitionInstruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];

    AVMutableVideoCompositionLayerInstruction *fromLayer = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstructionWithAssetTrack:firstTrack];


    //**This is where problem might be?**//
    CGAffineTransform Scaler = CGAffineTransformMakeScale(scaleNumber,scaleNumber);
    CGAffineTransform Mover = CGAffineTransformMakeTranslation(scaleNumber * -100, scaleNumber * -150);

    [fromLayer setTransform:CGAffineTransformConcat(Scaler,Mover) atTime:firstTrackRangeMin];

    transitionInstruction.layerInstructions = [NSArray arrayWithObject:fromLayer];

    videoComposition.instructions = instructionArray;

    [self exportVideo:composition withInstructionComposition:videoComposition];
}
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1 回答 1

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CGAffineTransform在 Quartz 坐标系中工作，这就是你应该开始的点：

CGAffineTransform  translate = CGAffineTransformMakeTranslation((x,y);
CGAffineTransform  scale = CGAffineTransformMakeScale(q,z);
CGAffineTransform finalTransform = CGAffineTransformConcat(scale, CGAffineTransformConcat(translate, assetTrackForVideo1.preferredTransform));
        [layerInstructionForVideo setTransform:finalTransform atTime:kCMTimeZero];
        [layerInstructions addObject:layerInstructionForVideo];

对我来说，这种改造工作。

编辑：我的错误，忘记编辑所有代码！

于 2014-05-15T16:24:44.770 回答