Comment compresser ou réduire la taille d'une image avant de l'envoyer à Parse as PFFile? (Rapide)
J'essayais de télécharger un fichier image sur Parse après avoir pris une photo directement sur le téléphone. Mais cela jette une exception:
Arrêt de l'application en raison d'une exception non interceptée 'NSInvalidArgumentException', raison: 'PFFile ne peut pas dépasser 10485760 octets'
Voici mon code:
Dans le premier contrôleur de vue:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if (segue.identifier == "getImage")
{
var svc = segue.destinationViewController as! ClothesDetail
svc.imagePassed = imageView.image
}
}
Dans le contrôleur de vue qui télécharge une image:
let imageData = UIImagePNGRepresentation(imagePassed)
let imageFile = PFFile(name: "\(picName).png", data: imageData)
var userpic = PFObject(className:"UserPic")
userpic["picImage"] = imageFile`
Mais je dois quand même télécharger cette photo dans Parse. Est-il possible de réduire la taille ou la résolution de l'image?
Oui, vous pouvez utiliser UIImageJPEGRepresentation au lieu de UIImagePNGRepresentation pour réduire la taille de votre fichier image. Vous pouvez simplement créer une extension UIImage comme suit:
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)
}
}
éditer/mettre à jour:
Xcode 10 Swift 4.2
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(_ jpegQuality: JPEGQuality) -> Data? {
return jpegData(compressionQuality: jpegQuality.rawValue)
}
}
Usage:
if let imageData = image.jpeg(.lowest) {
print(imageData.count)
}
Si vous voulez limiter la taille de l'image à une valeur concrète, vous pouvez procéder comme suit:
import UIKit
extension UIImage {
// MARK: - UIImage+Resize
func compressTo(_ expectedSizeInMb:Int) -> UIImage? {
let sizeInBytes = expectedSizeInMb * 1024 * 1024
var needCompress:Bool = true
var imgData:Data?
var compressingValue:CGFloat = 1.0
while (needCompress && compressingValue > 0.0) {
if let data:Data = UIImageJPEGRepresentation(self, compressingValue) {
if data.count < sizeInBytes {
needCompress = false
imgData = data
} else {
compressingValue -= 0.1
}
}
}
if let data = imgData {
if (data.count < sizeInBytes) {
return UIImage(data: data)
}
}
return nil
}
}
Jus Fixing pour Xcode 7, testé le 21/09/2015 et fonctionne bien:
Créez simplement une extension UIImage comme suit:
extension UIImage
{
var highestQualityJPEGNSData: NSData { return UIImageJPEGRepresentation(self, 1.0)! }
var highQualityJPEGNSData: NSData { return UIImageJPEGRepresentation(self, 0.75)!}
var mediumQualityJPEGNSData: NSData { return UIImageJPEGRepresentation(self, 0.5)! }
var lowQualityJPEGNSData: NSData { return UIImageJPEGRepresentation(self, 0.25)!}
var lowestQualityJPEGNSData: NSData { return UIImageJPEGRepresentation(self, 0.0)! }
}
Ensuite, vous pouvez l'utiliser comme ceci:
let imageData = imagePassed.lowestQualityJPEGNSData
//image compression
func resizeImage(image: UIImage) -> UIImage {
var actualHeight: Float = Float(image.size.height)
var actualWidth: Float = Float(image.size.width)
let maxHeight: Float = 300.0
let maxWidth: Float = 400.0
var imgRatio: Float = actualWidth / actualHeight
let maxRatio: Float = maxWidth / maxHeight
let compressionQuality: Float = 0.5
//50 percent compression
if actualHeight > maxHeight || actualWidth > maxWidth {
if imgRatio < maxRatio {
//adjust width according to maxHeight
imgRatio = maxHeight / actualHeight
actualWidth = imgRatio * actualWidth
actualHeight = maxHeight
}
else if imgRatio > maxRatio {
//adjust height according to maxWidth
imgRatio = maxWidth / actualWidth
actualHeight = imgRatio * actualHeight
actualWidth = maxWidth
}
else {
actualHeight = maxHeight
actualWidth = maxWidth
}
}
let rect = CGRectMake(0.0, 0.0, CGFloat(actualWidth), CGFloat(actualHeight))
UIGraphicsBeginImageContext(rect.size)
image.drawInRect(rect)
let img = UIGraphicsGetImageFromCurrentImageContext()
let imageData = UIImageJPEGRepresentation(img!,CGFloat(compressionQuality))
UIGraphicsEndImageContext()
return UIImage(data: imageData!)!
}
Swift 4 approche binaire pour compresser l'image
Je pense qu'il est assez tard pour répondre à cette question, mais voici ma solution à la question qui est optimisée. J'utilise recherche binaire pour trouver la valeur optimale. Ainsi, par exemple, si l’approche de soustraction normale atteint 62%, il faudrait 38 tentatives de compression, l’approche * Recherche binaire ** atteindrait la solution requise en log max (100) = environ 7 tentatives.
Toutefois, tenez également à vous informer que la fonction UIImageJPEGRepresentation ne se comporte pas linéairement, en particulier lorsque le nombre atteint presque 1. Voici la capture d'écran dans laquelle nous pouvons voir que l'image cesse de se compresser lorsque la valeur de flottant est> 0,995. Le comportement est assez imprévisible, il est donc préférable d’avoir un tampon delta capable de gérer de tels cas.
Voici le code pour cela
extension UIImage {
func resizeToApprox(sizeInMB: Double, deltaInMB: Double = 0.2) -> Data {
let allowedSizeInBytes = Int(sizeInMB * 1024 * 1024)
let deltaInBytes = Int(deltaInMB * 1024 * 1024)
let fullResImage = UIImageJPEGRepresentation(self, 1.0)
if (fullResImage?.count)! < Int(deltaInBytes + allowedSizeInBytes) {
return fullResImage!
}
var i = 0
var left:CGFloat = 0.0, right: CGFloat = 1.0
var mid = (left + right) / 2.0
var newResImage = UIImageJPEGRepresentation(self, mid)
while (true) {
i += 1
if (i > 13) {
print("Compression ran too many times ") // ideally max should be 7 times as log(base 2) 100 = 6.6
break
}
print("mid = \(mid)")
if ((newResImage?.count)! < (allowedSizeInBytes - deltaInBytes)) {
left = mid
} else if ((newResImage?.count)! > (allowedSizeInBytes + deltaInBytes)) {
right = mid
} else {
print("loop ran \(i) times")
return newResImage!
}
mid = (left + right) / 2.0
newResImage = UIImageJPEGRepresentation(self, mid)
}
return UIImageJPEGRepresentation(self, 0.5)!
}
}
Dans Swift 4, j'ai créé cette extension qui recevra la taille attendue et tentera de l'atteindre.
extension UIImage {
enum CompressImageErrors: Error {
case invalidExSize
case sizeImpossibleToReach
}
func compressImage(_ expectedSizeKb: Int, completion : (UIImage,CGFloat) -> Void ) throws {
let minimalCompressRate :CGFloat = 0.4 // min compressRate to be checked later
if expectedSizeKb == 0 {
throw CompressImageErrors.invalidExSize // if the size is equal to zero throws
}
let expectedSizeBytes = expectedSizeKb * 1024
let imageToBeHandled: UIImage = self
var actualHeight : CGFloat = self.size.height
var actualWidth : CGFloat = self.size.width
var maxHeight : CGFloat = 841 //A4 default size I'm thinking about a document
var maxWidth : CGFloat = 594
var imgRatio : CGFloat = actualWidth/actualHeight
let maxRatio : CGFloat = maxWidth/maxHeight
var compressionQuality : CGFloat = 1
var imageData:Data = UIImageJPEGRepresentation(imageToBeHandled, compressionQuality)!
while imageData.count > expectedSizeBytes {
if (actualHeight > maxHeight || actualWidth > maxWidth){
if(imgRatio < maxRatio){
imgRatio = maxHeight / actualHeight;
actualWidth = imgRatio * actualWidth;
actualHeight = maxHeight;
}
else if(imgRatio > maxRatio){
imgRatio = maxWidth / actualWidth;
actualHeight = imgRatio * actualHeight;
actualWidth = maxWidth;
}
else{
actualHeight = maxHeight;
actualWidth = maxWidth;
compressionQuality = 1;
}
}
let rect = CGRect(x: 0.0, y: 0.0, width: actualWidth, height: actualHeight)
UIGraphicsBeginImageContext(rect.size);
imageToBeHandled.draw(in: rect)
let img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
if let imgData = UIImageJPEGRepresentation(img!, compressionQuality) {
if imgData.count > expectedSizeBytes {
if compressionQuality > minimalCompressRate {
compressionQuality -= 0.1
} else {
maxHeight = maxHeight * 0.9
maxWidth = maxWidth * 0.9
}
}
imageData = imgData
}
}
completion(UIImage(data: imageData)!, compressionQuality)
}
}
Utiliser
do {
try UiImageView.image?.compressImage(100, completion: { (image, compressRatio) in
print(image.size)
imageData = UIImageJPEGRepresentation(image, compressRatio)
base64data = imageData?.base64EncodedString()
})
} catch {
print("Error")
}
Swift 4.2mise à jour. J'ai créé cette extension pour réduire la taille de UIImage.
Ici vous avez deux méthodes, la première prend un pourcentage et la seconde réduit l’image à 1Mo.
Bien sûr, vous pouvez changer la seconde méthode pour devenir 1Ko ou n’importe quelle taille souhaitée.
import UIKit
extension UIImage {
func resized(withPercentage percentage: CGFloat) -> UIImage? {
let canvasSize = CGSize(width: size.width * percentage, height: size.height * percentage)
UIGraphicsBeginImageContextWithOptions(canvasSize, false, scale)
defer { UIGraphicsEndImageContext() }
draw(in: CGRect(Origin: .zero, size: canvasSize))
return UIGraphicsGetImageFromCurrentImageContext()
}
func resizedTo1MB() -> UIImage? {
guard let imageData = self.pngData() else { return nil }
let megaByte = 1000.0
var resizingImage = self
var imageSizeKB = Double(imageData.count) / megaByte // ! Or devide for 1024 if you need KB but not kB
while imageSizeKB > megaByte { // ! Or use 1024 if you need KB but not kB
guard let resizedImage = resizingImage.resized(withPercentage: 0.5),
let imageData = resizedImage.pngData() else { return nil }
resizingImage = resizedImage
imageSizeKB = Double(imageData.count) / megaByte // ! Or devide for 1024 if you need KB but not kB
}
return resizingImage
}
}
C'est très simple avec l'extension UIImage
extension UIImage {
func resizeByByte(maxByte: Int, completion: @escaping (Data) -> Void) {
var compressQuality: CGFloat = 1
var imageData = Data()
var imageByte = UIImageJPEGRepresentation(self, 1)?.count
while imageByte! > maxByte {
imageData = UIImageJPEGRepresentation(self, compressQuality)!
imageByte = UIImageJPEGRepresentation(self, compressQuality)?.count
compressQuality -= 0.1
}
if maxByte > imageByte! {
completion(imageData)
} else {
completion(UIImageJPEGRepresentation(self, 1)!)
}
}
utiliser
// max 300kb
image.resizeByByte(maxByte: 300000) { (resizedData) in
print("image size: \(resizedData.count)")
}
En rapide
func ResizeImageOriginalSize(targetSize: CGSize) -> UIImage {
var actualHeight: Float = Float(self.size.height)
var actualWidth: Float = Float(self.size.width)
let maxHeight: Float = Float(targetSize.height)
let maxWidth: Float = Float(targetSize.width)
var imgRatio: Float = actualWidth / actualHeight
let maxRatio: Float = maxWidth / maxHeight
var compressionQuality: Float = 0.5
//50 percent compression
if actualHeight > maxHeight || actualWidth > maxWidth {
if imgRatio < maxRatio {
//adjust width according to maxHeight
imgRatio = maxHeight / actualHeight
actualWidth = imgRatio * actualWidth
actualHeight = maxHeight
}
else if imgRatio > maxRatio {
//adjust height according to maxWidth
imgRatio = maxWidth / actualWidth
actualHeight = imgRatio * actualHeight
actualWidth = maxWidth
}
else {
actualHeight = maxHeight
actualWidth = maxWidth
compressionQuality = 1.0
}
}
let rect = CGRect(x: 0.0, y: 0.0, width: CGFloat(actualWidth), height: CGFloat(actualHeight))
UIGraphicsBeginImageContextWithOptions(rect.size, false, CGFloat(compressionQuality))
self.draw(in: rect)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
}
Swift 3
@ réponse leo-dabus révisée pour Swift 3
extension UIImage {
var uncompressedPNGData: Data? { return UIImagePNGRepresentation(self) }
var highestQualityJPEGNSData: Data? { return UIImageJPEGRepresentation(self, 1.0) }
var highQualityJPEGNSData: Data? { return UIImageJPEGRepresentation(self, 0.75) }
var mediumQualityJPEGNSData: Data? { return UIImageJPEGRepresentation(self, 0.5) }
var lowQualityJPEGNSData: Data? { return UIImageJPEGRepresentation(self, 0.25) }
var lowestQualityJPEGNSData:Data? { return UIImageJPEGRepresentation(self, 0.0) }
}