How do I add text to an image in iOS Swift?
My simple solution:
func generateImageWithText(text: String) -> UIImage? {
let image = UIImage(named: "imageWithoutText")!
let imageView = UIImageView(image: image)
imageView.backgroundColor = UIColor.clear
imageView.frame = CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height)
let label = UILabel(frame: CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height))
label.backgroundColor = UIColor.clear
label.textAlignment = .center
label.textColor = UIColor.white
label.text = text
UIGraphicsBeginImageContextWithOptions(label.bounds.size, false, 0)
imageView.layer.render(in: UIGraphicsGetCurrentContext()!)
label.layer.render(in: UIGraphicsGetCurrentContext()!)
let imageWithText = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return imageWithText
}
Ok... I figured it out:
func textToImage(drawText: NSString, inImage: UIImage, atPoint: CGPoint) -> UIImage{
// Setup the font specific variables
var textColor = UIColor.whiteColor()
var textFont = UIFont(name: "Helvetica Bold", size: 12)!
// Setup the image context using the passed image
let scale = UIScreen.mainScreen().scale
UIGraphicsBeginImageContextWithOptions(inImage.size, false, scale)
// Setup the font attributes that will be later used to dictate how the text should be drawn
let textFontAttributes = [
NSFontAttributeName: textFont,
NSForegroundColorAttributeName: textColor,
]
// Put the image into a rectangle as large as the original image
inImage.drawInRect(CGRectMake(0, 0, inImage.size.width, inImage.size.height))
// Create a point within the space that is as bit as the image
var rect = CGRectMake(atPoint.x, atPoint.y, inImage.size.width, inImage.size.height)
// Draw the text into an image
drawText.drawInRect(rect, withAttributes: textFontAttributes)
// Create a new image out of the images we have created
var newImage = UIGraphicsGetImageFromCurrentImageContext()
// End the context now that we have the image we need
UIGraphicsEndImageContext()
//Pass the image back up to the caller
return newImage
}
To call it, you just pass in an image:
textToImage("000", inImage: UIImage(named:"thisImage.png")!, atPoint: CGPointMake(20, 20))
The following links helped me get this straight:
Swift - Drawing text with drawInRect:withAttributes:
How to write text on image in Objective-C (iOS)?
The original goal was to create a dynamic image that I could use in an AnnotaionView
such as putting a price at a given location on a map and this worked out great for it. Hope this helps someone trying to do the same thing.
For Swift 3:
func textToImage(drawText text: NSString, inImage image: UIImage, atPoint point: CGPoint) -> UIImage {
let textColor = UIColor.white
let textFont = UIFont(name: "Helvetica Bold", size: 12)!
let scale = UIScreen.main.scale
UIGraphicsBeginImageContextWithOptions(image.size, false, scale)
let textFontAttributes = [
NSFontAttributeName: textFont,
NSForegroundColorAttributeName: textColor,
] as [String : Any]
image.draw(in: CGRect(origin: CGPoint.zero, size: image.size))
let rect = CGRect(origin: point, size: image.size)
text.draw(in: rect, withAttributes: textFontAttributes)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
}
For Swift 4:
func textToImage(drawText text: String, inImage image: UIImage, atPoint point: CGPoint) -> UIImage {
let textColor = UIColor.white
let textFont = UIFont(name: "Helvetica Bold", size: 12)!
let scale = UIScreen.main.scale
UIGraphicsBeginImageContextWithOptions(image.size, false, scale)
let textFontAttributes = [
NSAttributedStringKey.font: textFont,
NSAttributedStringKey.foregroundColor: textColor,
] as [NSAttributedStringKey : Any]
image.draw(in: CGRect(origin: CGPoint.zero, size: image.size))
let rect = CGRect(origin: point, size: image.size)
text.draw(in: rect, withAttributes: textFontAttributes)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
}
For Swift 5:
func textToImage(drawText text: String, inImage image: UIImage, atPoint point: CGPoint) -> UIImage {
let textColor = UIColor.white
let textFont = UIFont(name: "Helvetica Bold", size: 12)!
let scale = UIScreen.main.scale
UIGraphicsBeginImageContextWithOptions(image.size, false, scale)
let textFontAttributes = [
NSAttributedString.Key.font: textFont,
NSAttributedString.Key.foregroundColor: textColor,
] as [NSAttributedString.Key : Any]
image.draw(in: CGRect(origin: CGPoint.zero, size: image.size))
let rect = CGRect(origin: point, size: image.size)
text.draw(in: rect, withAttributes: textFontAttributes)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage!
}