I am trying to create an UIImage
that I will use to set the background for a UICollectionViewCell
. I found this function to convert a UIView
to UIImage
:
func imageWithView(view: UIView) -> UIImage? {
UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.isOpaque, 0.0)
view.drawHierarchy(in: view.bounds, afterScreenUpdates: true)
let snapshotImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return snapshotImage
}
In my collection view cell function I do:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! VideoCell
//creating view
let colour1 = UIColor.yellow.cgColor
let colour2 = UIColor.red.cgColor
let gradientLayer = CAGradientLayer()
gradientLayer.frame = contentView.bounds
gradientLayer.colors = [colour1, colour2]
gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.5)
gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.5)
let gradientView = UIView(frame: contentView.bounds)
gradientView.layer.addSublayer(gradientLayer)
//converting UIView to UIImage
let ccimage = imageWithView(view: gradientView)
}
However, I keep getting this error:
View (0x7fe876e2d940, UIView) drawing with afterScreenUpdates:YES inside CoreAnimation commit is not supported
If I make afterScreenUpdates: false
, then I get this error:
[Snapshotting] Drawing a view that has not been rendered at least once requires afterScreenUpdates: YES.
I'am really confused on how to approach this error. Am I calling the function in the wrong place?
Try this one it's working code for (swift 4)
In UICollectionView cellForItemAt
method.
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! VideoCell
//creating view
let colour1 = UIColor.yellow.cgColor
let colour2 = UIColor.red.cgColor
let gradientLayer = CAGradientLayer()
gradientLayer.frame = contentView.bounds
gradientLayer.colors = [colour1, colour2]
gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.5)
gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.5)
let gradientView = UIView(frame: contentView.bounds)
gradientView.layer.addSublayer(gradientLayer)
//converting UIView to UIImage
if cell.backgroundColor == nil{
cell.backgroundColor = UIColor(patternImage:gradientView.gradient_image!)
}
return cell
}
Extension fro convert UIView
to UIImage
extension UIView {
var gradient_image: UIImage? {
if #available(iOS 10.0, *) {
let renderer = UIGraphicsImageRenderer(bounds: bounds)
return renderer.image { rendererContext in
layer.render(in: rendererContext.cgContext)
}
} else {
// If Swift version is lower than 4.2,
UIGraphicsBeginImageContextWithOptions(self.bounds.size, self.isOpaque, 0.0)
defer { UIGraphicsEndImageContext() }
guard let currentContext = UIGraphicsGetCurrentContext() else {
return nil
}
self.layer.render(in: currentContext)
return UIGraphicsGetImageFromCurrentImageContext()
}
}
}
Output :
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.