Saved Transparent Images在Swift中以黑色背景返回

Question

我使用以下函数在View控制器中保存和检索图像。但是，检索到的保存图像的图像(是一个透明的.png文件(返回黑色背景。如果有人能告诉我如何解决这个问题，我将不胜感激？谢谢你的帮助！

func saveImage(image: UIImage) -> Bool {
guard let data = image.jpegData(compressionQuality: 1) ?? image.pngData() else {
return false
}
guard let directory = try? FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false) as NSURL else {
return false
}
do {
try data.write(to: directory.appendingPathComponent("fileName.png")!)
return true
} catch {
print(error.localizedDescription)
return false
}
}
func getSavedImage(named: String) -> UIImage? {
if let dir = try? FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false) {
return UIImage(contentsOfFile: URL(fileURLWithPath: dir.absoluteString).appendingPathComponent(named).path)
}
return nil
}

Answer 1

JPEG无法支持透明度，因为它使用RGB颜色空间。这样你就可以在不妥协的情况下保存png图像。

func saveImage(image: UIImage) -> Bool {
guard let data = image.pngData()
guard let directory = try? FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false) as NSURL else {
return false
}
do {
try data.write(to: directory.appendingPathComponent("fileName.png")!)
return true
} catch {
print(error.localizedDescription)
return false
}
}

func getSavedImage(named: String) -> UIImage? {
if let dir = try? FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false) {
return UIImage(contentsOfFile: URL(fileURLWithPath: dir.absoluteString).appendingPathComponent(named).path)
}
return nil
}