如何在swift中从UIImage获取图像扩展名/格式？
如何在swift中从UIImage获取图像扩展名/格式？
提问于 2017-12-21 08:26:28
我正在尝试上传一张图片到我的服务器上，但是在上传之前，我需要检查图片的格式是否有效。
假设我只想要.jpeg和.png，所以如果用户从他们的手机上选择.gif格式的图像，我会显示一些警告。
我从用户图库/相机获取图像，然后我想检查格式，但我不知道如何检查格式
@IBAction func selectPictureButtonDidPressed(_ sender: Any) {
let imagePickerController = UIImagePickerController()
imagePickerController.delegate = self
imagePickerController.allowsEditing = true
let actionSheet = UIAlertController(title: "Photo Source", message: "please choose your source", preferredStyle: .actionSheet)
// action camera
let actionCamera = UIAlertAction(title: "Camera", style: .default) { (action) in
if UIImagePickerController.isSourceTypeAvailable(.camera) {
imagePickerController.sourceType = .camera
self.present(imagePickerController, animated: true, completion: nil)
} else {
self.showAlert(alertTitle: "Opppss", alertMessage: "camera can't be used / not available", actionTitle: "OK")
print("camera can't be used / not available")
}
}
// action photo library
let actionPhotoLibrary = UIAlertAction(title: "Photo Library", style: .default) { (action) in
imagePickerController.sourceType = .photoLibrary
self.present(imagePickerController, animated: true, completion: nil)
}
//action cancel
let actionCancel = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
actionSheet.addAction(actionCamera)
actionSheet.addAction(actionPhotoLibrary)
actionSheet.addAction(actionCancel)
self.present(actionSheet, animated: true, completion: nil)
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
let image = info[UIImagePickerControllerOriginalImage] as! UIImage
postImage.image = image
picker.dismiss(animated: true, completion: nil)
doesItHasImage = true
}
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
picker.dismiss(animated: true, completion: nil)
}如何检查该格式？
我曾尝试在谷歌上寻找，但我只是得到了图像格式，如果它是从URL派生的。不是像这样直接从UIImage
import UIKit
import ImageIO
struct ImageHeaderData{
static var PNG: [UInt8] = [0x89]
static var JPEG: [UInt8] = [0xFF]
static var GIF: [UInt8] = [0x47]
static var TIFF_01: [UInt8] = [0x49]
static var TIFF_02: [UInt8] = [0x4D]
}
enum ImageFormat{
case Unknown, PNG, JPEG, GIF, TIFF
}
extension NSData{
var imageFormat: ImageFormat{
var buffer = [UInt8](repeating: 0, count: 1)
self.getBytes(&buffer, range: NSRange(location: 0,length: 1))
if buffer == ImageHeaderData.PNG
{
return .PNG
} else if buffer == ImageHeaderData.JPEG
{
return .JPEG
} else if buffer == ImageHeaderData.GIF
{
return .GIF
} else if buffer == ImageHeaderData.TIFF_01 || buffer == ImageHeaderData.TIFF_02{
return .TIFF
} else{
return .Unknown
}
}
}
// USAGE
let imageURLFromParse = NSURL(string : "https://i.stack.imgur.com/R64uj.jpg")
let imageData = NSData(contentsOf: imageURLFromParse! as URL)
print(imageData!.imageFormat)Stack Overflow用户
发布于 2020-10-26 19:54:31
如果您更喜欢使用URL，在swift 5.2中，您可以使用
enum ImageFormat {
case png
case jpeg
case gif
case tiff
case unknown
init(byte: UInt8) {
switch byte {
case 0x89:
self = .png
case 0xFF:
self = .jpeg
case 0x47:
self = .gif
case 0x49, 0x4D:
self = .tiff
default:
self = .unknown
}
}
}
extension Data {
var imageFormat: ImageFormat{
guard let header = map({ $0 as UInt8 })[safe: 0] else {
return .unknown
}
return ImageFormat(byte: header)
}
}
extension Collection {
/// Returns the element at the specified index iff it is within bounds, otherwise nil.
/// - Parameters:
/// - Parameter index: The index of the item to get safely the element
/// - Returns: The element if available or nil otherwise
subscript(safe index: Index) -> Element? {
return indices.contains(index) ? self[index] : nil
}
}我发现：
jpegData(compressionQuality: CGFloat)
pngData()总是成功，而且内存效率不高。在一个例子中，我看到一个1.6Mb的图像因为pngData()而变成了6MB。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/47916207
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