swift5 图片压缩 UIImage
2022-04-28 本文已影响0人
杨继磊
//
// UIImage_extension.swift
// F
//
// Created by mac on 2022/3/30.
//
enum ImageCopmpressSize {
//压缩到100KB(1024*100字节)以内
case one
//压缩到200KB(1024*100字节)以内
case two
//压缩到300KB(1024*100字节)以内
case three
}
extension UIImage {
//我们的项目就定不大于200KB
func compressImage()->Data{
compressImage(size: .two)
}
func compressImage(size:ImageCopmpressSize) -> Data{
switch size {
case .one:
return compressImage(maxLength: 1024*100)
case .two:
return compressImage(maxLength: 1024*200)
case .three:
return compressImage(maxLength: 1024*300)
default:
break
}
}
// 图片压缩 byte
func compressImage(maxLength: Int) -> Data {
// let tempMaxLength: Int = maxLength / 8
let tempMaxLength: Int = maxLength
var compression: CGFloat = 1
guard var data = self.jpegData(compressionQuality: compression), data.count > tempMaxLength else { return self.jpegData(compressionQuality: compression)! }
// 压缩大小
var max: CGFloat = 1
var min: CGFloat = 0
for _ in 0..<6 {
compression = (max + min) / 2
data = self.jpegData(compressionQuality: compression)!
if CGFloat(data.count) < CGFloat(tempMaxLength) * 0.9 {
min = compression
} else if data.count > tempMaxLength {
max = compression
} else {
break
}
}
var resultImage: UIImage = UIImage(data: data)!
if data.count < tempMaxLength { return data }
// 压缩大小
var lastDataLength: Int = 0
while data.count > tempMaxLength && data.count != lastDataLength {
lastDataLength = data.count
let ratio: CGFloat = CGFloat(tempMaxLength) / CGFloat(data.count)
print("Ratio =", ratio)
let size: CGSize = CGSize(width: Int(resultImage.size.width * sqrt(ratio)),
height: Int(resultImage.size.height * sqrt(ratio)))
UIGraphicsBeginImageContext(size)
resultImage.draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
resultImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
data = resultImage.jpegData(compressionQuality: compression)!
}
return data
}
}