CODEWITHSUNDEEP
iosswiftuicolor
user3746428
user3746428

Reputation: 11175

Function to return colour based on value passed

I would like to create a function that will return a colour based on a value that is inserted into it. Ideally what I'm looking to do is have three different colours (e.g. red, green, blue) and a range (e.g. 1 to 100), so that if for example you pass 80 to the function, it will return a colour between green and blue (closer to blue obviously).

Normally I would attempt to write some code before asking for help, but I'm not sure where to start with this one.

Anyone got any suggestions?

Thanks.

Upvotes: 2

Views: 888

Answers (2)

Sruit A.Suk
Sruit A.Suk

Reputation: 7273

Do you mean 0 = Red, 50 = Green and 100 = Blue ?

If number = 40, it's mean It has a lot of Red, some of Green, and none of Blue? am I correct?

I write it in Notepad, please recheck it 

func getColorFromNumber(number: Int) -> UIColor { 
    // case of color between RED and GREEN
    if number <= 50 {
        // get color 1, base on 50 - number
        let rColor1 = 0
        let gColor1 = CGFloat( Double(50 - number) * 157 / 50 )
        let bColor1 = CGFloat( Double(50 - number) * 29 / 50 )

        // get color 2, base on number
        let rColor2 = CGFloat( Double( number ) * 255 / 50 )
        let gColor2 = CGFloat( Double( number ) * 148 / 50 )
        let bColor2 = 0

        let avgR = (rColor1 + rColor2) / 2
        let avgG = (gColor1 + gColor2) / 2
        let avgB = (bColor1 + bColor2) / 2

        return UIColor(red: avgR , green: avgG, blue: avgB, alpha: 1.0)
    }
    // case of color between GREEN and BLUE
    else if number > 50 {
        // get color 2, base on 100 - number 
        let rColor2 = CGFloat( Double( 100 - number ) * 255 / 50 )
        let gColor2 = CGFloat( Double( 100 - number ) * 148 / 50 )
        let bColor2 = 0

        // get color 3, base on number - 50
        let rColor3 = CGFloat( Double( number - 50 ) * 255 / 50 )
        let gColor3 = CGFloat( Double( number - 50 ) * 87 / 50 )
        let bColor3 = CGFloat( Double( number - 50 ) * 29 / 50 )

        let avgR = (rColor2 + rColor3) / 2
        let avgG = (gColor2 + gColor3) / 2
        let avgB = (bColor2 + bColor3) / 2

        return UIColor(red: avgR , green: avgG, blue: avgB, alpha: 1.0)
    }

    // this will never called
    return UIColor(red: 1.0 , green: 1.0, blue: 1.0, alpha: 1.0)
}

Upvotes: 1

dudeman
dudeman

Reputation: 1136

Here's an idea I had:

func colorForNumber(number: Int) -> UIColor {
    let colorLevel = CGFloat(number % 256)
    switch (number / 256) {
    case 0:
        return UIColor(red: colorLevel , green: 0.0, blue: 0.0, alpha: 1.0)
    case 1:
        return UIColor(red: 0.0 , green: colorLevel, blue: 0.0, alpha: 1.0)
    default:
        return UIColor(red: 0.0 , green: 0.0, blue: colorLevel, alpha: 1.0)
    }
}

Upvotes: 0

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