问题描述
我见过人们在Objective-c中这样做,但我很快就遇到了麻烦。我从图片中获得了一个像素的颜色,但现在我需要采用单独的红色,绿色和蓝色值。这是我所拥有的(h,w和rgb是整数,image.getPixelColor(CGPoint)返回一个UIColor):
I have seen people do this in objective-c, but I am having trouble with this in swift. I have gotten the color of a pixel from a picture, but now I need to take the individual red, green, and blue values. Here is what I have (h, w, and rgb are integers and image.getPixelColor(CGPoint) returns a UIColor):
xArry[h][w][rgb] = image.getPixelColor(CGPoint(x: w, y: h))
如何将此UIColor更改为红色,绿色和蓝色值?谢谢!
How do I change this UIColor into the red, green, and blue values? Thanks!
推荐答案
您可以将UIColor转换为CIColor,然后从中提取颜色成分,如下所示:
You can convert UIColor to CIColor and then extract the color components from it as follow:
更新: Xcode 8.3.2•Swift 3.1
extension UIColor {
var coreImageColor: CIColor {
return CIColor(color: self)
}
var components: (red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat) {
let coreImageColor = self.coreImageColor
return (coreImageColor.red, coreImageColor.green, coreImageColor.blue, coreImageColor.alpha)
}
}
用法:
let myColor = UIColor(red: 0.5, green: 1, blue: 0.25, alpha: 0.5)
let myCIColor = myColor.coreImageColor
let greencomponent = myColor.components.green
let myColorComponents = myColor.components
print(myColorComponents.red) // 0.5
print(myColorComponents.green) // 1.0
print(myColorComponents.blue) // 0.25
print(myColorComponents.alpha) // 0.5
你也可以使用函数getRed()并创建一个扩展来提取组件,如下所示,但结果是可选的:
You can also use the function getRed() and create an extension to extract the components as follow but the result would be optional:
extension UIColor {
var components: (red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat)? {
var r: CGFloat = 0, g: CGFloat = 0, b: CGFloat = 0, a: CGFloat = 0
return getRed(&r, green: &g, blue: &b, alpha: &a) ? (r,g,b,a) : nil
}
}
用法
Usage
let myColor = UIColor(red: 0.5, green: 1, blue: 0.25, alpha: 0.5)
if let myColorComponents = myColor.components {
print(myColorComponents.red) // 0.5
print(myColorComponents.green) // 1.0
print(myColorComponents.blue) // 0.25
print(myColorComponents.alpha) // 0.5
}
这篇关于从UIColor中提取RGB值的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!