在我的应用中，我允许用户将其图像上传到我的Amazon s3存储桶。用户从手机中捕获照片后，我便立即将其显示在屏幕上，然后开始上传。此时，我开始显示进度栏，该进度栏告诉用户现在的体育场。但是，是否有一种方法可以使图像在上传时变灰，并在上传完成后恢复原始颜色？
到目前为止，我的代码如下：
func imagePickerController(picker: UIImagePickerController, didFinishPickingImage image: UIImage, editingInfo: [String : AnyObject]?) {
let path = NSTemporaryDirectory().stringByAppendingString("image.jpeg")
if let data = UIImageJPEGRepresentation(image, 0.8) {
data.writeToFile(path, atomically: true)
}
self.dismissViewControllerAnimated(true, completion: {})
let credentialsProvider = AWSCognitoCredentialsProvider(regionType:CognitoRegionType,
identityPoolId:CognitoIdentityPoolId)
let configuration = AWSServiceConfiguration(region:CognitoRegionType, credentialsProvider:credentialsProvider)
AWSServiceManager.defaultServiceManager().defaultServiceConfiguration = configuration
let ext = "jpeg"
let uploadRequest = AWSS3TransferManagerUploadRequest()
uploadRequest.body = NSURL(string: "file://"+path)
uploadRequest.key = NSProcessInfo.processInfo().globallyUniqueString + "." + ext
uploadRequest.bucket = S3BucketName
uploadRequest.contentType = "image/" + ext
//here I would like to present a greyed out photo until it's fully uploaded:
imageView.image = image
progressBar.hidden = false
uploadRequest.uploadProgress = { (bytesSent, totalBytesSent, totalBytesExpectedToSend) -> Void in
dispatch_async(dispatch_get_main_queue(), { () -> Void in
if totalBytesExpectedToSend > 0 {
self.progressBar.progress = Float(Double(totalBytesSent) / Double(totalBytesExpectedToSend))
}
})
}
let transferManager = AWSS3TransferManager.defaultS3TransferManager()
transferManager.upload(uploadRequest).continueWithBlock { (task) -> AnyObject! in
if let error = task.error {
print("Upload failed ❌ (\(error))")
}
if let exception = task.exception {
print("Upload failed ❌ (\(exception))")
}
if task.result != nil {
let s3URL = NSURL(string: "http://s3-eu-west-1.amazonaws.com/\(S3BucketName)/\(uploadRequest.key!)")!
//print("Uploaded to:\n\(s3URL)")
self.photoURL = s3URL.absoluteString
print(self.photoURL)
}
else {
print("Unexpected empty result.")
}
return nil
}
}
最佳答案
您可以通过多种方式执行此操作。一种简单的方法是将UIView放置在图像视图的顶部，并设置为opaque = false，并使用深灰色的背景色，其alpha值约为50％。这会使图像变暗并使它看起来暗淡和低对比度。
您还可以在图像视图下放置100％不透明的黑色UIView，然后将图像视图上的alpha设置为50％。
您可以将CALayer放置在图像视图层的顶部，背景颜色为50％不透明的深灰色。
所有这些方法都会产生类似的效果。
请注意，您还可以将图像视图放在为UIBlurEffect设置的UIVisualEffectView的内容视图中。那会使图像模糊而不是变灰。
关于ios - 如何快速将uiImage暂时变灰？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/35959378/