swiftxcodeswift3color-picker
IOS Color Picker in Swift 3.0
I'm working on an App that communicates with an arduino to control RGB LED light strips. I am trying to implement a color picker where you touch on an image of a color spectrum and get the UIColor of the pixel that was touched.
I want a user to be able to touch anywhere on the color spectrum image and have the color change to the color they are touching. to do that I either need the RGB numbers or the UIColor of the pixel they are touching.
I have found the following code that I have tried to implement to no avail. here is the Original author description:
"Here's one I made which is as simple as it gets. It's just a lightweight UIView that allows you to specify the element size in case you want blocked regions (elementSize > 1). It draws itself in interface builder so you can set element size and see the consequences. Just set one of your views in interface builder to this class and then set yourself as a delegate. It will tell you when someone either taps or drags on it and the uicolor at that location. It will draw itself to its own bounds and there's no need for anything other than this class, no image required."
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)
}
}
I'm unsure how to get this code to work in swift 3.0. I have ported it over as best I can but I get the following error that I am unsure how to fix:
and
for the first error I seem to have solved it by changing the code to the following but I am unsure if this is correct
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)
}
As for the second errors I am just not sure how to switch to using stride.(from:,to:,by:)
Here is my attempt at porting it over to swift 3.0.
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)
}
}
I would really appreciate any help that you all have to offer. I am also open to entirely different suggestions if you have a better way to achieve my original goal of a color picker the user can touch!
Solution
1) For this line of code to work:
let touchGesture = UILongPressGestureRecognizer(target: self, action: #selector(HSBColorPicker.touchedColor(_:)))
you need to prepend underscore _ character to the parameter in this method:
func touchedColor(_ gestureRecognizer: UILongPressGestureRecognizer){ }
2) When using stride, the right syntax is:
for y in stride(from: 0, to: rect.height, by: elementSize) {
So full for-cycle with additional fixes in Swift 3 version should look like this:
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))
}
}
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