How to set font size of SKLabelNode to fit in fixed size (Swift)

Question

I have a square (200X200) with a SKLabelNode in it. The label shows score and it my be reach a large number. I want fit the number in the square.

How c

Answer 1

This expansion of mike663's answer worked for me, and gets there much quicker than going 1 pixel at a time.

// Find the right size by trial & error...
var testingSize: CGFloat = 0    // start from here
var currentStep: CGFloat = 16   // go up by this much. It will be reduced each time we overshoot.
var foundMatch = false

while !foundMatch {
    var overShot = false
    while !overShot {
        testingSize += currentStep
        labelNode.fontSize = testingSize
        // How much bigger the text should be to perfectly fit in the given rectangle.
        let scalingFactor = min(rect.width / labelNode.frame.width, rect.height / labelNode.frame.height)

        if scalingFactor < 1         { overShot   = true }  // Never go over the space
        else if scalingFactor < 1.01 { foundMatch = true }  // Stop when over 99% of the space is filled
    }
    testingSize -= currentStep  // go back to the last one that didn't overshoot
    currentStep /= 4
}
labelNode.fontSize = testingSize // go back to the one we were happy with