How to initialize UIColor from RGB values properly? - uibutton

Question

I am working on an iPhone application which uses various colors. When user selects the particular color button I set drawing color accordingly. I am getting the color for some but in the most of the cases I am getting white color.
Here is my code:
-(IBAction)colorSelected:(UIButton *)sender
{
switch (sender.tag)
{
case 1:
self.drawcolor= [UIColor colorWithRed:200 green:191 blue:231 alpha:1];
break;
case 2:
self.drawcolor= [UIColor colorWithRed:163 green:73 blue:164 alpha:1];
break;
case 3:
self.drawcolor= [UIColor colorWithRed:112 green:146 blue:76 alpha:1];
break;
case 4:
self.drawcolor= [UIColor colorWithRed:63 green:72 blue:204 alpha:1];
break;
case 5:
self.drawcolor= [UIColor colorWithRed:153 green:217 blue:234 alpha:1];
break;
case 6:
self.drawcolor= [UIColor colorWithRed:0 green:162 blue:232 alpha:1];
break;
case 7:
self.drawcolor= [UIColor colorWithRed:181 green:230 blue:29 alpha:1];
break;
case 8:
self.drawcolor= [UIColor colorWithRed:34 green:177 blue:76 alpha:1];
break;
case 9:
self.drawcolor= [UIColor colorWithRed:239 green:228 blue:176 alpha:1];
break;
case 10:
self.drawcolor= [UIColor colorWithRed:255 green:201 blue:0 alpha:1];
break;
case 11:
self.drawcolor= [UIColor colorWithRed:255 green:201 blue:14 alpha:1];
break;
case 12:
self.drawcolor= [UIColor colorWithRed:237 green:28 blue:36 alpha:1];
break;
case 13:
self.drawcolor= [UIColor colorWithRed:255 green:127 blue:39 alpha:1];
break;
case 14:
self.drawcolor= [UIColor colorWithRed:255 green:174 blue:201 alpha:1];
break;
case 15:
self.drawcolor= [UIColor colorWithRed:185 green:122 blue:87 alpha:1];
break;
case 16:
self.drawcolor= [UIColor colorWithRed:136 green:0 blue:21 alpha:1];
break;
case 17:
self.drawcolor= [UIColor colorWithRed:195 green:195 blue:195 alpha:1];
break;
case 18:
self.drawcolor= [UIColor colorWithRed:127 green:127 blue:127 alpha:1];
break;
case 19:
self.drawcolor= [UIColor colorWithRed:255 green:255 blue:255 alpha:1];
break;
case 20:
self.drawcolor= [UIColor colorWithRed:0 green:0 blue:0 alpha:1];
break;
default:
break;
}
self.preColor=self.drawcolor;
self.lineWidth=self.prelineWidth;
}
Can any one tell me what I am doing wrong ?
Sumit

Answer 1

The values are in the 0.0 to 1.0 range.
E.g. divide by 255., but remember the decimal dot so you get floating point division and not integer division.
Like
selectedColor = [UIColor colorWithRed:14.0/255.0 green:114.0/255.0 blue:199.0/255.0 alpha:1];

Answer 2

Pragmatic approach with Swift.
extension UIColor {
convenience init(rgbColorCodeRed red: Int, green: Int, blue: Int, alpha: CGFloat) {
let redPart: CGFloat = CGFloat(red) / 255
let greenPart: CGFloat = CGFloat(green) / 255
let bluePart: CGFloat = CGFloat(blue) / 255
self.init(red: redPart, green: greenPart, blue: bluePart, alpha: alpha)
}
}

Answer 3

You got several options
Code
CGFloat red = 16.0;
CGFloat green = 97.0;
CGFloat blue = 5.0;
CGFloat alpha = 255.0;
UIColor *color = [UIColor colorWithRed:(red/255.0) green:(green/255.0) blue:(blue/255.0) alpha:(alpha/255.0)];
Color picker plugin for Interface Builder
There's a nice color picker from Panic which works well with IB: http://panic.com/~wade/picker/
Xcode plugin
This one gives you a GUI for choosing colors: http://www.youtube.com/watch?v=eblRfDQM0Go
Pods and libraries
There's a nice pod named MPColorTools: https://github.com/marzapower/MPColorTools

Answer 4

Here is a method that you can easily turn into a category on UIColor that will allow you to specify a color based on RGBA values of 0 - 255.
+ (UIColor *)colorFromRGBAWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue alpha:(CGFloat)alpha {
return [UIColor colorWithRed:red/255.0 green:green/255.0 blue:blue/255.0 alpha:alpha/255.0];
}
If you make it a UIColor category extension, you can use it like so:
UIColor *myAwesomeColor = [UIColor colorFromRGBAWithRed:48 green:119 blue:167 alpha:255];

Answer 5

In Swift you can easily set your Background-Color for example of a cell like this:
cell.backgroundColor = UIColor.init(red: 14.0/255.0, green: 114.0/255.0, blue: 199.0/255.0, alpha: 1)
:-)

Answer 6

(ContentView.Layer.BorderColor) //CG Object
= UIColor.LightGray.CGColor;