ios - 将 PHAsset 转换为 UIImage 时失去透明度

Question

在我从图像选择器中选择图像并尝试将 PHAsset 转换为 UIImage 图像后，png 图像失去了透明度。 我试着到处搜索，但没有找到任何相关信息。

  func getAssetThumbnail(asset: PHAsset) -> UIImage {
        let manager = PHImageManager.defaultManager()
        let option = PHImageRequestOptions()
        var thumbnail = UIImage()
        option.synchronous = true
        manager.requestImageForAsset(asset, targetSize: CGSize(width: 341.0, height: 182.0), contentMode: .AspectFit, options: option, resultHandler: {(result, info)->Void in
            thumbnail = result!
        })
        return thumbnail
    }

Image before

After selecting and setting it to image view

Answer 1

使用 PHImageRequestOptions.version = 调用 requestImageDataForAsset 获取原始图像数据。原创。然后，您可以从 UIImage(data: data) 创建图像。

例子:

 func getThumbnail(asset: PHAsset) -> UIImage? {

    var thumbnail: UIImage?

    let manager = PHImageManager.defaultManager()

    let options = PHImageRequestOptions()

    options.version = .Original
    options.synchronous = true

    manager.requestImageDataForAsset(asset, options: options) { data, _, _, _ in

        if let data = data {
            thumbnail = UIImage(data: data)
        }
    }

    return thumbnail
}