Merge UIImage with UILabel into one UIImage, Swift - ios

Question

I am trying to "merge" an UIImage with a UILabel into one UIImage, for that I wrote a function everything works fine except that the Label does not get added to the Current Graphics Context. I would appreciate your help!
func textToImage(drawText: String, inImage: UIImage, atPoint: CGPoint) -> UIImage{
// Setup the image context using the passed image
UIGraphicsBeginImageContext(inImage.size)
// Put the image into a rectangle as large as the original image
inImage.draw(in: CGRect(origin: CGPoint.zero, size: CGSize(width: inImage.size.width, height: inImage.size.height)))
// Create a point within the space that is as bit as the image
let rectPos = CGPoint(x: atPoint.x, y: atPoint.y)
let rectSize = CGSize(width: inImage.size.width, height: inImage.size.height)
let rect = CGRect(origin: rectPos, size: rectSize)
// Draw the text into an image
let label = UILabel()
label.text = drawText
label.textColor = .white
label.font = UIFont(name: "Helvetica Bold", size: 12)!
label.drawText(in: rect)
// Create a new image out of the images we have created
let newImage = UIGraphicsGetImageFromCurrentImageContext()
// End the context now that we have the image we need
UIGraphicsEndImageContext()
//Pass the image back up to the caller
return newImage!
}

Answer 1

Are u sure that you trying to draw label in correct position? Is rect which you compute as CGRect(origin: CGPoint.zero, size: CGSize(width: inImage.size.width, height: inImage.size.height)) contains atPoint?

Answer 2

The problem seems to be here UIGraphicsBeginImageContext(inImage.size)
The context you are creating is the size of your image. You need to create the context to the size of Image + label height. Then you can add the label accordingly and will be able to see the label inside the image appended.
Also specify the label's frame let label = UILabel().
Suppose you want to append the label at the bottom of the image.
Let the image size be 300 * 400, and you want to put the label at the bottom.
The concept is to create a context with the height of 400 + label height (suppose 40).
Then you set the label frame to be a y of CGRect(0,imagesize.height,100,40).
Hope it helps

Answer 3

Problem with your code is that UIKit (UILabel usage) tries to draw stuff in its own context. You need to draw text + image in same context to get the desired result.
Try this to receive the resulting image:
func textToImage(drawText text: NSString, inImage image: UIImage) -> UIImage
{
UIGraphicsBeginImageContext(image.size)
image.draw(in: CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height))
let font=UIFont(name: "Helvetica-Bold", size: 8)!
let paraStyle=NSMutableParagraphStyle()
paraStyle.alignment=NSTextAlignment.center
let attributes = [NSAttributedStringKey.foregroundColor:UIColor.red, NSAttributedStringKey.font:font, NSAttributedStringKey.paragraphStyle:paraStyle]
let height = font.lineHeight
let y = (image.size.height-height) / 2
let strRect = CGRect(x: 0, y: y, width: image.size.width, height: height)
text.draw(in: strRect.integral, withAttributes: attributes)
let result=UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return result!
}
#IBAction func touchTest(_ sender: Any)
{
let button = sender as! UIButton
let image = self.textToImage(drawText: "my text", inImage: UIImage.init(named: "circle")!)
button.setBackgroundImage(image, for: UIControlState.normal)
}