在swift中以编程方式获取图像文件类型

Question

我正在使用文件手提包PNG和JPEG从解析下载图像.

当图像下载到应用程序时,我需要确定文件类型是什么,所以我可以相应地处理图像.

看了一下uiimageview的API并进行了搜索,但在swift中找不到任何解决方案.

任何输入赞赏

试图从PFFIle获取网址§:

let imageURLFromParse = NSURL(string : caseImageFile2.url);

// Error here: 'NSURL?' does not have a member named 'pathExtension'                   
if(imageURLFromParse.pathExtension!.lowercaseString == ".jpg" || imageURLFromParse.pathExtension.lowercaseString == ".jpeg"){

  println("Parse image ext is a jpg: \(imageURLFromParse.pathExtension.lowercaseString)");

  fileExtenion = ".jpg";

} else {                        
  println("Parse image is a png: \(imageURLFromParse.pathExtension.lowercaseString)");

  fileExtenion = ".png";                           
}

Answer 1

Swift 3.0.2的更新

基于Hoa的答案和Kingfisher图书馆

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
        }
    }
}

用法

let imageURLFromParse = NSURL(string : "https://i.stack.imgur.com/R64uj.jpg")
let imageData = NSData(contentsOf: imageURLFromParse! as URL)
print(imageData!.imageFormat)

您可以将其与本地和在线图像一起使用.

Answer 2

您可以在项目https://github.com/bonyadmitr/ImageFormat中进行测试

添加到项目

import Foundation

/// can be done "heic", "heix", "hevc", "hevx"
enum ImageFormat: String {
    case png, jpg, gif, tiff, webp, heic, unknown
}

extension ImageFormat {
    static func get(from data: Data) -> ImageFormat {
        switch data[0] {
        case 0x89:
            return .png
        case 0xFF:
            return .jpg
        case 0x47:
            return .gif 
        case 0x49, 0x4D:
            return .tiff 
        case 0x52 where data.count >= 12:
            let subdata = data[0...11]

            if let dataString = String(data: subdata, encoding: .ascii),
                dataString.hasPrefix("RIFF"),
                dataString.hasSuffix("WEBP")
            {    
                return .webp
            }

        case 0x00 where data.count >= 12 :
            let subdata = data[8...11]

            if let dataString = String(data: subdata, encoding: .ascii),
                Set(["heic", "heix", "hevc", "hevx"]).contains(dataString)
                ///OLD: "ftypheic", "ftypheix", "ftyphevc", "ftyphevx"
            {    
                return .heic
            }
        default:
            break
        }
        return .unknown
    } 

    var contentType: String {
        return "image/\(rawValue)"
    }
}

使用

for file in ["1.jpg", "2.png", "3.gif", "4.svg", "5.TIF", "6.webp", "7.HEIC"] {
    if let data = Data(bundleFileName: file) {
        print(file, ImageFormat.get(from: data))
    }
}

/// Result
/// 1.jpg jpg
/// 2.png png
/// 3.gif gif
/// 4.svg unknown
/// 5.TIF tiff
/// 6.webp webp
/// 7.HEIC heic