将 CVImageBuffer 扭曲到 UIImage

Posted 2023-02-23

【中文标题】将 CVImageBuffer 扭曲到 UIImage

【英文标题】：Distorted CVImageBuffer to UIImage

【发布时间】：2018-05-23 01:20:22

【问题描述】：

我有以下将CVImageBugger 转换为UIImage 的函数。出来的图像总是有点失真。我在UIImageView 中显示了这个函数的返回值，它被设置为'aspect fill'。什么给了？...

private func convert(buffer: CVImageBuffer) -> UIImage? 
    let cmage: CIImage = CIImage(cvPixelBuffer: buffer)
    let context: CIContext = CIContext(options: nil)
    if let cgImage: CGImage = context.createCGImage(cmage, from: cmage.extent) 
        return UIImage(cgImage: cgImage)
    
    return nil

【参考方案1】：

CVImageBuffer 不包含方向信息，可能这就是最终 UIImage 失真的原因。

CVImageBuffer 的默认方向始终是横向（就像 iPhone 的 Home 按钮在右侧），无论您是否以纵向方式拍摄视频。

所以我们需要给图像添加好的方向信息：

extension CIImage 
    func orientationCorrectedImage() -> UIImage? 
        var imageOrientation = UIImageOrientation.up
        switch UIApplication.shared.statusBarOrientation 
        case UIInterfaceOrientation.portrait:
            imageOrientation = UIImageOrientation.right
        case UIInterfaceOrientation.landscapeLeft:
            imageOrientation = UIImageOrientation.down
        case UIInterfaceOrientation.landscapeRight:
            imageOrientation = UIImageOrientation.up
        case UIInterfaceOrientation.portraitUpsideDown:
            imageOrientation = UIImageOrientation.left
        default:
            break;
        

        var w = self.extent.size.width
        var h = self.extent.size.height

        if imageOrientation == .left || imageOrientation == .right || imageOrientation == .leftMirrored || imageOrientation == .rightMirrored 
            swap(&w, &h)
        

        UIGraphicsBeginImageContext(CGSize(width: w, height: h));
        UIImage.init(ciImage: self, scale: 1.0, orientation: imageOrientation).draw(in: CGRect(x: 0, y: 0, width: w, height: h))
        let uiImage:UIImage? = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext();

        return uiImage
    

然后将其与您的代码一起使用：

private func convert(buffer: CVImageBuffer) -> UIImage? 
    let ciImage: CIImage = CIImage(cvPixelBuffer: buffer)
    return ciImage.orientationCorrectedImage()

【讨论】：

谢谢Yun.. 但不幸的是它仍然很长.. 另外我的图像方向没有正确。它只是拉长了..

@7ball，你能提供截图吗？