如何正确地从RGB值初始化UIColor？

Question

我正在使用各种颜色的iPhone应用程序.当用户选择特定颜色按钮时,我相应地设置了绘图颜色.我得到了一些颜色,但在大多数情况下,我得到白色.

这是我的代码:

-(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;
}

谁能告诉我我做错了什么？萨米特

Answer 1

的值是在0.0给1.0的范围内.

例如除以255.,但记住小数点,所以你得到浮点除法而不是整数除法.

喜欢

selectedColor = [UIColor colorWithRed:14.0/255.0 green:114.0/255.0 blue:199.0/255.0 alpha:1];

Answer 2

用Swift实用的方法.

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

你有几个选择

码

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)];

Interface Builder的颜色选择器插件

Panic有一个很好的颜色选择器,适用于IB:http://panic.com/~wade/picker/

Xcode插件

这个为您提供了选择颜色的GUI:http://www.youtube.com/watch？v = eblRfDQM0Go

豆荚和图书馆

有一个很好的pod命名为MPColorTools:https://github.com/marzapower/MPColorTools