How to convert a View (Not ddisplayed) to JPEG image? - ios

Question

I have this code to convert a view to image. But i want my image to be in jpeg format.What chnages do i need to make in this code to get my image as JPEG format. I am not showing my view in device.
extension UIView{
func createTransparentImage() -> UIImage {
let renderFormat = UIGraphicsImageRendererFormat.default()
renderFormat.opaque = false
self.isOpaque = false
self.layer.isOpaque = true
self.backgroundColor = UIColor.clear
self.layer.backgroundColor = UIColor.clear.cgColor
let renderer = UIGraphicsImageRenderer(size: bounds.size, format: renderFormat)
return renderer.image{
(context) in
layer.render(in: context.cgContext)
}
}
}

Answer 1

So with your extension you get back a UIImage if you want you can save it as JPEG or PNG, by converting it to Data or NSData in Objective C:
let viewSnapshot = view.createTransparentImage()
//save as JPEG
if let data = viewSnapshot.jpegData(compressionQuality: 0.8) {
//variable data has the JPEG image with quality of 80%
}
//save as PNG
if let data = viewSnapshot.pngData() {
//variable data has the PNG data of the snapshot
}
If you wanted to save this image you can just do the following inside of the if let data
let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
if let documentsDirectory = paths.first {
let fileName = documentsDirectory.appendingPathComponent("myImage.jpg")
try? data.write(to: fileName)
}
Given that you do not need UIImage but only JPEG data just do a slight modification on your extension as follows:
extension UIView{
func createImageData(quality: CGFloat = 0.8) -> Data {
let renderFormat = UIGraphicsImageRendererFormat.default()
renderFormat.opaque = false
self.isOpaque = false
self.layer.isOpaque = true
self.backgroundColor = UIColor.clear
self.layer.backgroundColor = UIColor.clear.cgColor
let renderer = UIGraphicsImageRenderer(size: bounds.size, format: renderFormat)
return renderer.jpegData(withCompressionQuality: quality, actions: { context in
layer.render(in: context.cgContext)
})
}
}
Notice the final line was changed to:
return renderer.jpegData(withCompressionQuality: quality, actions: { context in
Thus to use this you can simply do:
let viewSnapshotData = view.createImageData(quality: 0.9)
As per LeoDabus you can use the following extension to get snapshot of a UIView with alpha transparency if it is needed:
extension UIView {
var snapshot: UIImage {
isOpaque = false
backgroundColor = .clear
let format = UIGraphicsImageRendererFormat.default()
format.opaque = false
return UIGraphicsImageRenderer(size: bounds.size, format: format).image { _ in
drawHierarchy(in: bounds, afterScreenUpdates: true)
}
}
}

Answer 2

extension UIView{
func captureViewAsImage() -> UIImage? {
var screenshotImage :UIImage?
let layer = self.layer
UIGraphicsBeginImageContextWithOptions(layer.frame.size, false, UIScreen.main.scale);
guard let context = UIGraphicsGetCurrentContext() else {return nil}
layer.render(in:context)
screenshotImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return screenshotImage
}
}
and use this function as
let img = view.captureViewAsImage()