Draw text in the right corner of the image

There is a simple function call to get the "bounding box" for a string. You can use this to position the text to be drawn in the image:

    // get the bounding-box for the string
    let stringSize = drawText.size(attributes: textFontAttributes)

    // position the bounding-box at the bottom-right corner of the image
    let x = self.size.width - ceil(stringSize.width)
    let y = self.size.height - ceil(stringSize.height)

    let rect = CGRect(x: x, y: y, width: stringSize.width, height: stringSize.height)

    // Draw the text into an image
    drawText.draw(in: rect, withAttributes: textFontAttributes)

      

        
        
        
      

    

Note that this code example places text in the lower right corner - ignores the parameter atPoint

. You will probably change this to a type parameter whichCorner

and then compute the position x

and accordingly y

.

By the way ... drawText

- a terrible name for a variable - it sounds like a function. It is much more convenient to use something like textToDraw

.

---

Following is the modified function using a parameter atCorner

where the values ​​are:

        +-----------+ 
        | 0       1 | 
        |           | 
        |           | 
        | 3       2 |
        +-----------+

      

        
        
        
      

    

---

Edit: Using the right-align style (as suggested by Tilina Chamin Hewagama) has some advantages. This edited version even handles text with "\n"

embedded line breaks.

extension UIImage {

    func addText(textToDraw: NSString, atCorner: Int, textColor: UIColor?, textFont: UIFont?) -> UIImage {

        // Setup the font specific variables
        var _textColor: UIColor
        if textColor == nil {
            _textColor = UIColor.white
        } else {
            _textColor = textColor!
        }

        var _textFont: UIFont
        if textFont == nil {
            _textFont = UIFont.systemFont(ofSize: 50)
        } else {
            _textFont = textFont!
        }

        // Setup the image context using the passed image
        UIGraphicsBeginImageContext(size)

        // Put the image into a rectangle as large as the original image
        draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))

        let titleParagraphStyle = NSMutableParagraphStyle()

        // Setup the font attributes that will be later used to dictate how the text should be drawn
        let textFontAttributes = [
            NSFontAttributeName: _textFont,
            NSForegroundColorAttributeName: _textColor,
            NSParagraphStyleAttributeName: titleParagraphStyle
            ] as [String : Any]

        // get the bounding-box for the string
        var stringSize = textToDraw.size(attributes: textFontAttributes)

        // draw in rect functions like whole numbers
        stringSize.width = ceil(stringSize.width)
        stringSize.height = ceil(stringSize.height)

        var rect = CGRect(origin: CGPoint.zero, size: self.size)

        switch atCorner {

        case 1:
            // top-right
            titleParagraphStyle.alignment = .right

        case 2:
            // bottom-right
            rect.origin.y = self.size.height - stringSize.height
            titleParagraphStyle.alignment = .right

        case 3:
            // bottom-left
            rect.origin.y = self.size.height - stringSize.height

        default:
            // top-left
            // don't need to change anything here
            break

        }

        // Draw the text into an image
        textToDraw.draw(in: rect, withAttributes: textFontAttributes)

        // 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!
    }

}