How to get a screenshot of the View (Drawing View) used for drawing using UIBezeir path - ios

Question

I have a Drawing View which is on a Scroll View. After drawing is completed I need a screenshot of the drawing which I will be uploading to the server.
I am using UIBezeir path to draw on the view.
let path = UIBezierPath()
for i in self.drawView.path{
path.append(i)
}
self.drawView.path is an NSArray with all the bezeir paths of the drawing.
But when I use the bounding box of this path and get max and min values of coordinates and try to capture a screenshot I get this
var rect:CGRect = CGRect(x: path.bounds.minX, y: path.bounds.minY, width: path.bounds.maxX, height: path.bounds.maxY)
I also tried to give the bounds of the path itself
let rect:CGRect = CGRect(x: path.bounds.origin.x - 5, y: path.bounds.origin.y - 5, width: path.bounds.size.width + 5, height: path.bounds.size.height + 5)
Just for reference I tried using this rect and create a view (clear color with border layer) and placed it over the Drawing, it work pretty fine but when I try to capture an image it goes out of bounds
This is the function I am using to capture the screen
func imgScreenShot(bounds:CGRect) -> UIImage{
let rect: CGRect = bounds
self.drawView.isOpaque = false
self.drawView.backgroundColor = UIColor.clear
UIGraphicsBeginImageContextWithOptions(rect.size, false, 0.0)
var context: CGContext? = UIGraphicsGetCurrentContext()
if let aContext = context {
self.drawView.layer.render(in: aContext)
}
var capturedImage: UIImage? = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
//let finalImage = scaleImage(image: capturedImage)
return capturedImage!
}
I am also tried getting a UIView with this function
let vw = self.drawView.resizableSnapshotView(from: rect, afterScreenUpdates: true, withCapInsets: UIEdgeInsets.zero)
This gives me a perfect UIView with the drawing in that, but again when I try to convert the UIView to UIImage using the function giving the views bounds, I get a blank image.
Can anyone suggest what I am doing wrong or any other solution for how I can get this, bounds of image starting right exactly at the bounds of the drawing
let vw = self.drawView.resizableSnapshotView(from: rect2, afterScreenUpdates: true, withCapInsets: UIEdgeInsets.zero)
vw?.frame = CGRect(x: 50, y: 50, width: 100, height: 100)
vw?.layer.borderColor = UIColor.red.cgColor
vw?.layer.borderWidth = 1
self.drawView.addSubview(vw!)
let image = vw?.snapshotImage
let imgView = UIImageView(frame: CGRect(x: 250, y: 50, width: 100, height: 100))
imgView.layer.borderColor = UIColor.gray.cgColor
imgView.layer.borderWidth = 1
self.drawView.addSubview(imgView)

Answer 1

Make an extension of UIView and UIImage , so in whole application lifecycle you can use those methods(which one i will be describe at below) for capture the screenshort of any perticular UIView and resize the existing image(if needed).
Here is the extension of UIView :-
extension UIView {
var snapshotImage : UIImage? {
var snapShotImage:UIImage?
UIGraphicsBeginImageContext(self.frame.size)
if let context = UIGraphicsGetCurrentContext() {
self.layer.render(in: context)
if let image = UIGraphicsGetImageFromCurrentImageContext() {
UIGraphicsEndImageContext()
snapShotImage = image
}
}
return snapShotImage
}
}
Here is the extension of UIImage :-
extension UIImage {
func resizeImage(newSize:CGSize) -> UIImage? {
var newImage:UIImage?
let horizontalRatio = newSize.width / size.width
let verticalRatio = newSize.height / size.height
let ratio = max(horizontalRatio, verticalRatio)
let newSize = CGSize(width: size.width * ratio, height: size.height * ratio)
UIGraphicsBeginImageContext(newSize)
if let _ = UIGraphicsGetCurrentContext() {
draw(in: CGRect(origin: CGPoint(x: 0, y: 0), size: newSize))
if let image = UIGraphicsGetImageFromCurrentImageContext() {
UIGraphicsEndImageContext()
newImage = image
}
}
return newImage
}
}
How to use those functions in our desired class ?
if let snapImage = yourUIView.snapshotImage {
///... snapImage is the desired image you want and its dataType is `UIImage`.
///... Now resize the snapImage into desired size by using this one
if let resizableImage = snapImage.resizeImage(newSize: CGSize(width: 150.0, height: 150.0)) {
print(resizableImage)
}
}
here yourUIView means , the one you have taken for drawing some inputs. it can be IBOutlet as well as your UIView (which you have taken programmatically)