如何在上传到Parse之前压缩缩小图像的大小为PFFile？ （迅速） [英] How to compress of reduce the size of an image before uploading to Parse as PFFile? (Swift)

问题描述

我试图直接在手机上拍照后将图像文件上传到Parse。但它抛出一个异常：

I was trying to upload an image file to Parse after taking photo directly on phone. But it throws an exception:

由于未捕获的异常'NSInvalidArgumentException'终止应用程序，原因：'PFFile不能大于10485760字节'

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'PFFile cannot be larger than 10485760 bytes'

这是我的代码：

在第一个视图控制器中：

In first view controller:

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if (segue.identifier == "getImage")
    {
        var svc = segue.destinationViewController as! ClothesDetail
        svc.imagePassed = imageView.image
    }
}

在上传图像的视图控制器中：

In view controller that uploads image:

let imageData = UIImagePNGRepresentation(imagePassed)
let imageFile = PFFile(name: "\(picName).png", data: imageData)

var userpic = PFObject(className:"UserPic")
userpic["picImage"] = imageFile`

但我仍然需要将该照片上传到Parse。有没有办法减小图像的大小或分辨率？

But I still need to upload that photo to Parse. Is there any way to reduce the size or resolution of the image?

推荐答案

是的，你可以使用 UIImageJPEGRepresentation 而不是 UIImagePNGRepresentation 来减少图像文件的大小。您可以按如下方式创建扩展UIImage：

Yes you can use UIImageJPEGRepresentation instead of UIImagePNGRepresentation to reduce your image file size. You can just create an extension UIImage as follow:

Xcode 8.2•Swift 3.0.2

extension UIImage {
    enum JPEGQuality: CGFloat {
        case lowest  = 0
        case low     = 0.25
        case medium  = 0.5
        case high    = 0.75
        case highest = 1
    }

    /// Returns the data for the specified image in JPEG format.
    /// If the image object’s underlying image data has been purged, calling this function forces that data to be reloaded into memory.
    /// - returns: A data object containing the JPEG data, or nil if there was a problem generating the data. This function may return nil if the image has no data or if the underlying CGImageRef contains data in an unsupported bitmap format.
    func jpeg(_ quality: JPEGQuality) -> Data? {
        return UIImageJPEGRepresentation(self, quality.rawValue)
    }
}

用法：

if let imageData = image.jpeg(.lowest) {
    print(imageData.count)
}

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