使用RGB值创建NSColor

Question

如何从RGB值创建NSColor？

Answer 1

每NSColor文档：

NSColor *myColor = [NSColor colorWithCalibratedRed:redValue green:greenValue blue:blueValue alpha:1.0f]; 

Answer 2

float red = 0.5f; 
float green = 0.2f; 
float blue = 0.4f; 
float alpha = 0.8f; 

NSColor *rgb = [NSColor colorWithDeviceRed:red green:green blue:blue alpha:alpha]; 

Answer 3

另外不要忘记从你的实际RGB值做下面的转换，让我们从Photoshop说...

的RGB （226,226,226）可以被实例化为使用以下值的NSColor：

Red: 226/255 = 0.886... 
Green: 226/255 = 0.886... 
Blue: 226/255 = 0.886... 

[NSColor colorWithDeviceRed:0.886f green:0.886f blue:0.886f alpha:1.0f]; 

为什么255？ 8位颜色通道的范围从0到255（含）。标准化时，这将缩放到[0,1]（含）范围内。请参阅从标准化值到非标准化值的转换参考，反之亦然。

参考

• OpenGL ES Full Specification，请参阅表2.7页38
• Unreal Engine Color Conversion

Answer 4

扩展斯威夫特2

extension NSObject { 
    func RGB(r:CGFloat, g:CGFloat, b:CGFloat, alpha:CGFloat? = 1) -> NSColor { 
     return NSColor(red: r/255, green: g/255, blue: b/255, alpha: alpha!) 
    } 
} 

然后只需调用

RGB(r: 16, g: 105, b: 125) 

或

RGB(r: 16, g: 105, b: 125, alpha: 0.5)