Swift 3.0 中的 IOS 颜色选择器答案

【问题标题】：IOS Color Picker in Swift 3.0Swift 3.0 中的 IOS 颜色选择器
【发布时间】：2016-09-23 08:20:18
【问题描述】：

我正在开发一个与 arduino 通信以控制 RGB LED 灯条的应用程序。我正在尝试实现一个颜色选择器，您可以在其中触摸色谱图像并获取所触摸像素的 UIColor。

我希望用户能够触摸色谱图像上的任何位置，并将颜色更改为他们触摸的颜色。为此，我需要 RGB 数字或它们正在触摸的像素的 UIColor。

我发现以下代码我尝试实施但无济于事。以下是原作者描述：

“这是我制作的一个，它非常简单。它只是一个轻量级的 UIView，允许您指定元素大小以防您想要阻塞区域（elementSize > 1）。它在界面生成器中绘制自己，因此您可以设置元素大小并查看结果。只需将界面构建器中的一个视图设置为此类，然后将自己设置为代表。它会告诉您何时有人点击或拖动它以及该位置的 uicolor。它将绘制自己到自己的范围内，除了这个类之外不需要任何东西，不需要图像。”

import UIKit

internal protocol HSBColorPickerDelegate : NSObjectProtocol {
    func HSBColorColorPickerTouched(sender:HSBColorPicker,     color:UIColor, point:CGPoint, state:UIGestureRecognizerState)
}

@IBDesignable
class HSBColorPicker : UIView {

weak internal var delegate: HSBColorPickerDelegate?
let saturationExponentTop:Float = 2.0
let saturationExponentBottom:Float = 1.3

@IBInspectable var elementSize: CGFloat = 1.0 {
    didSet {
        setNeedsDisplay()
    }
}

private func initialize() {
    self.clipsToBounds = true
    let touchGesture = UILongPressGestureRecognizer(target: self, action: #selector(HSBColorPicker.touchedColor(_:)))
    touchGesture.minimumPressDuration = 0
    touchGesture.allowableMovement = CGFloat.max
    self.addGestureRecognizer(touchGesture)
}

override init(frame: CGRect) {
    super.init(frame: frame)
    initialize()
}

required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    initialize()
}

override func drawRect(rect: CGRect) {
    let context = UIGraphicsGetCurrentContext()

    for y in (0 as CGFloat).stride(to: rect.height, by: elementSize) {

        var saturation = y < rect.height / 2.0 ? CGFloat(2 * y) / rect.height : 2.0 * CGFloat(rect.height - y) / rect.height
        saturation = CGFloat(powf(Float(saturation), y < rect.height / 2.0 ? saturationExponentTop : saturationExponentBottom))
        let brightness = y < rect.height / 2.0 ? CGFloat(1.0) : 2.0 * CGFloat(rect.height - y) / rect.height

        for x in (0 as CGFloat).stride(to: rect.width, by: elementSize) {
            let hue = x / rect.width
            let color = UIColor(hue: hue, saturation: saturation, brightness: brightness, alpha: 1.0)
            CGContextSetFillColorWithColor(context, color.CGColor)
            CGContextFillRect(context, CGRect(x:x, y:y, width:elementSize,height:elementSize))
        }
    }
}

func getColorAtPoint(point:CGPoint) -> UIColor {
    let roundedPoint = CGPoint(x:elementSize * CGFloat(Int(point.x / elementSize)),
        y:elementSize * CGFloat(Int(point.y / elementSize)))
    var saturation = roundedPoint.y < self.bounds.height / 2.0 ? CGFloat(2 * roundedPoint.y) / self.bounds.height
        : 2.0 * CGFloat(self.bounds.height - roundedPoint.y) / self.bounds.height
    saturation = CGFloat(powf(Float(saturation), roundedPoint.y < self.bounds.height / 2.0 ? saturationExponentTop : saturationExponentBottom))
    let brightness = roundedPoint.y < self.bounds.height / 2.0 ? CGFloat(1.0) : 2.0 * CGFloat(self.bounds.height - roundedPoint.y) / self.bounds.height
    let hue = roundedPoint.x / self.bounds.width
    return UIColor(hue: hue, saturation: saturation, brightness: brightness, alpha: 1.0)
}

func getPointForColor(color:UIColor) -> CGPoint {
    var hue:CGFloat=0;
    var saturation:CGFloat=0;
    var brightness:CGFloat=0;
    color.getHue(&hue, saturation: &saturation, brightness: &brightness, alpha: nil);

    var yPos:CGFloat = 0
    let halfHeight = (self.bounds.height / 2)

    if (brightness >= 0.99) {
        let percentageY = powf(Float(saturation), 1.0 / saturationExponentTop)
        yPos = CGFloat(percentageY) * halfHeight
    } else {
        //use brightness to get Y
        yPos = halfHeight + halfHeight * (1.0 - brightness)
    }

    let xPos = hue * self.bounds.width

    return CGPoint(x: xPos, y: yPos)
}

func touchedColor(gestureRecognizer: UILongPressGestureRecognizer){
    let point = gestureRecognizer.locationInView(self)
    let color = getColorAtPoint(point)

    self.delegate?.HSBColorColorPickerTouched(self, color: color, point: point, state:gestureRecognizer.state)
}
}

我不确定如何让这段代码在 swift 3.0 中运行。我已尽我所能将其移植过来，但出现以下错误，我不确定如何修复：

和

对于第一个错误，我似乎已经通过将代码更改为以下来解决它，但我不确定这是否正确

private func initialize() {
    self.clipsToBounds = true
    let touchGesture = UILongPressGestureRecognizer(target: self, action: #selector(HSBColorPicker.touchedColor(gestureRecognizer:)))
    touchGesture.minimumPressDuration = 0
    touchGesture.allowableMovement = CGFloat.greatestFiniteMagnitude
    self.addGestureRecognizer(touchGesture)
}

至于第二个错误，我只是不确定如何切换到使用 stride。(from:,to:,by:)

这是我将其移植到 swift 3.0 的尝试。

import UIKit

internal protocol HSBColorPickerDelegate : NSObjectProtocol {
    func HSBColorColorPickerTouched(sender:HSBColorPicker, color:UIColor,    point:CGPoint, state:UIGestureRecognizerState)
}

@IBDesignable
class HSBColorPicker : UIView {

weak internal var delegate: HSBColorPickerDelegate?
let saturationExponentTop:Float = 2.0
let saturationExponentBottom:Float = 1.3

@IBInspectable var elementSize: CGFloat = 1.0 {
    didSet {
        setNeedsDisplay()
    }
}

private func initialize() {
    self.clipsToBounds = true
    let touchGesture = UILongPressGestureRecognizer(target: self, action: #selector(HSBColorPicker.touchedColor(gestureRecognizer:)))
    touchGesture.minimumPressDuration = 0
    touchGesture.allowableMovement = CGFloat.greatestFiniteMagnitude
    self.addGestureRecognizer(touchGesture)
}

override init(frame: CGRect) {
    super.init(frame: frame)
    initialize()
}

required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    initialize()
}

override func draw(_ rect: CGRect) {
    let context = UIGraphicsGetCurrentContext()

    for y in (0 as CGFloat).stride(to: rect.height, by: elementSize) {

        var saturation = y < rect.height / 2.0 ? CGFloat(2 * y) / rect.height : 2.0 * CGFloat(rect.height - y) / rect.height
        saturation = CGFloat(powf(Float(saturation), y < rect.height / 2.0 ? saturationExponentTop : saturationExponentBottom))
        let brightness = y < rect.height / 2.0 ? CGFloat(1.0) : 2.0 * CGFloat(rect.height - y) / rect.height

        for x in (0 as CGFloat).stride(to: rect.width, by: elementSize) {
            let hue = x / rect.width
            let color = UIColor(hue: hue, saturation: saturation, brightness: brightness, alpha: 1.0)
            context!.setFillColor(color.cgColor)
            context!.fill(CGRect(x:x, y:y, width:elementSize,height:elementSize))
        }
    }
}

func getColorAtPoint(point:CGPoint) -> UIColor {
    let roundedPoint = CGPoint(x:elementSize * CGFloat(Int(point.x / elementSize)),
        y:elementSize * CGFloat(Int(point.y / elementSize)))
    var saturation = roundedPoint.y < self.bounds.height / 2.0 ? CGFloat(2 * roundedPoint.y) / self.bounds.height
        : 2.0 * CGFloat(self.bounds.height - roundedPoint.y) / self.bounds.height
    saturation = CGFloat(powf(Float(saturation), roundedPoint.y < self.bounds.height / 2.0 ? saturationExponentTop : saturationExponentBottom))
    let brightness = roundedPoint.y < self.bounds.height / 2.0 ? CGFloat(1.0) : 2.0 * CGFloat(self.bounds.height - roundedPoint.y) / self.bounds.height
    let hue = roundedPoint.x / self.bounds.width
    return UIColor(hue: hue, saturation: saturation, brightness: brightness, alpha: 1.0)
}

func getPointForColor(color:UIColor) -> CGPoint {
    var hue:CGFloat=0;
    var saturation:CGFloat=0;
    var brightness:CGFloat=0;
    color.getHue(&hue, saturation: &saturation, brightness: &brightness, alpha: nil);

    var yPos:CGFloat = 0
    let halfHeight = (self.bounds.height / 2)

    if (brightness >= 0.99) {
        let percentageY = powf(Float(saturation), 1.0 / saturationExponentTop)
        yPos = CGFloat(percentageY) * halfHeight
    } else {
        //use brightness to get Y
        yPos = halfHeight + halfHeight * (1.0 - brightness)
    }

    let xPos = hue * self.bounds.width

    return CGPoint(x: xPos, y: yPos)
}

func touchedColor(gestureRecognizer: UILongPressGestureRecognizer){
    let point = gestureRecognizer.location(in: self)
    let color = getColorAtPoint(point: point)

    self.delegate?.HSBColorColorPickerTouched(sender: self, color: color, point: point, state:gestureRecognizer.state)
}
}

非常感谢大家提供的任何帮助。如果您有更好的方法来实现我最初的目标，即用户可以触摸的颜色选择器，我也愿意接受完全不同的建议！

【问题讨论】：

标签： swift xcode swift3 color-picker

【解决方案1】：

1) 要使这行代码起作用：

let touchGesture = UILongPressGestureRecognizer(target: self, action: #selector(HSBColorPicker.touchedColor(_:)))

您需要在此方法的参数前加上下划线_：

func touchedColor(_ gestureRecognizer: UILongPressGestureRecognizer){ }

2) 使用 stride 时，正确的语法是：

for y in stride(from: 0, to: rect.height, by: elementSize) {

如此完整的for-cycle 以及 Swift 3 版本中的附加修复应该如下所示：

for y in stride(from: 0, to: rect.height, by: elementSize) {
    var saturation = y < rect.height / 2.0 ? CGFloat(2 * y) / rect.height : 2.0 * CGFloat(rect.height - y) / rect.height
    saturation = CGFloat(powf(Float(saturation), y < rect.height / 2.0 ? saturationExponentTop : saturationExponentBottom))
    let brightness = y < rect.height / 2.0 ? CGFloat(1.0) : 2.0 * CGFloat(rect.height - y) / rect.height

    for x in stride(from: 0, to: rect.width, by: elementSize) {
        let hue = x / rect.width
        let color = UIColor(hue: hue, saturation: saturation, brightness: brightness, alpha: 1.0)
        context!.setFillColor(color.cgColor)
        context!.fill(CGRect(x:x, y:y, width:elementSize,height:elementSize))
    }
}

【讨论】：

完美！这正是让我束手无策的原因！还有一个问题，我有一个红色、绿色和蓝色值的变量。如何根据上面的代码将这些变量设置为被触摸的颜色？
我假设您的意思是 let color = UIColor() 行：所以很简单 let color = UIColor(red: green: white:) 方法。我的回答对你有帮助吗？ :)