Is there any idea or better approach do it more nice, elegant way ?
extension UIColor {
static var randomColor: UIColor {
.init(
red: CGFloat(Float.random(in: 0 ... 1.0)),
green: CGFloat(Float.random(in: 0 ... 1.0)),
blue: CGFloat(Float.random(in: 0 ... 1.0)),
alpha: 1.0
)
}
}
Rather than …
CGFloat(Float.random(in: 0 ... 1.0))
… you can use:
CGFloat.random(in: 0...1)
Or, in this context, you can let the compiler infer the type:
extension UIColor {
static var randomColor: UIColor {
.init(
red: .random(in: 0...1),
green: .random(in: 0...1),
blue: .random(in: 0...1),
alpha: 1
)
}
}
Randomize color hue
If you want random red, green, and blue components for your random color, go with #Rob's approach. If you want a randomly selected bright saturated color, randomize the hue.
extension UIColor {
static var randomHue: UIColor {
.init(hue: .random(in: 0...1),
saturation: 1, brightness: 1, alpha: 1)
}
static var randomRGB: UIColor {
.init(red: .random(in: 0...1),
green: .random(in: 0...1),
blue: .random(in: 0...1),
alpha: 1)
}
}
It really depends what mean by "it" in the text describing what you want. Random components tend to yield dull colors.
Related
I am following Stanfords' CS193p Developing Apps for iOS online course.
I'm trying to do the Assignment 6 Memorize.pdf.
It says to use this code below ⬇️, but it gives me always white color. Is there a bug somewhere? Please help.
import SwiftUI
struct RGBAColor: Codable, Equatable, Hashable {
let red: Double
let green: Double
let blue: Double
let alpha: Double
}
extension Color {
init(rgbaColor rgba: RGBAColor) {
self.init(.sRGB, red: rgba.red, green: rgba.green, blue: rgba.blue, opacity: rgba.alpha)
}
}
extension RGBAColor {
init(color: Color) {
var red: CGFloat = 0
var green: CGFloat = 0
var blue: CGFloat = 0
var alpha: CGFloat = 0
if let cgColor = color.cgColor {
UIColor(cgColor: cgColor).getRed(&red, green: &green, blue: &blue, alpha: &alpha)
}
self.init(red: Double(red), green: Double(green), blue: Double(blue), alpha: Double(alpha))
}
}
import SwiftUI
struct ContentView: View {
static let rgbaColorRed = RGBAColor(color: Color.red)
static let thisShouldBeRed = Color(rgbaColor: rgbaColorRed)
var body: some View {
Text("Hello, world!")
.padding()
.foregroundColor(ContentView.thisShouldBeRed) // why white here, not red???
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
As the cgColor property's documentation says:
For a dynamic color, like one you load from an Asset Catalog using init(_:bundle:), or one you create from a dynamic UIKit or AppKit color, this property is nil.
Color.red is actually a dynamic color:
A context-dependent red color suitable for use in UI elements.
So Color.red.cgColor is nil, causing the getRed(_:green:blue:alpha:) call to not run, and the red, green, blue, alpha local variables remain 0. So the color you got is not "white", but "transparent".
You can actually create a UIColor directly from Color, without going through CGColor:
var red: CGFloat = 0
var green: CGFloat = 0
var blue: CGFloat = 0
var alpha: CGFloat = 0
// note here:
UIColor(color).getRed(&red, green: &green, blue: &blue, alpha: &alpha)
self.init(red: Double(red), green: Double(green), blue: Double(blue), alpha: Double(alpha))
I am trying to change the text colour in a UITextField using the following code (RGBA value) however it just appears white, or clear, I'm not too sure as the background is white itself.
passwordTextField.textColor = UIColor(red: CGFloat(202.0), green: CGFloat(228.0), blue: CGFloat(230.0), alpha: CGFloat(100.0))
passwordTextField.returnKeyType = UIReturnKeyType.Done
passwordTextField.placeholder = "Password"
passwordTextField.backgroundColor = UIColor.clearColor()
passwordTextField.borderStyle = UITextBorderStyle.RoundedRect
passwordTextField.font = UIFont(name: "Avenir Next", size: 14)
passwordTextField.textAlignment = NSTextAlignment.Center
passwordTextField.secureTextEntry = true
RGB values for UIColor are between 0 and 1 (see the documentation "specified as a value from 0.0 to 1.0")
You need to divide your numbers by 255:
passwordTextField.textColor = UIColor(red: CGFloat(202.0/255.0), green: CGFloat(228.0/255.0), blue: CGFloat(230.0/255.0), alpha: CGFloat(1.0))
Another thing, you don't need to create CGFloats:
passwordTextField.textColor = UIColor(red:202.0/255.0, green:228.0/255.0, blue:230.0/255.0, alpha:1.0)
Using convenience init ( code like a pro )
Step 1
extension UIColor {
convenience init(r: CGFloat, g: CGFloat, b: CGFloat) {
self.init(red: r/255, green: g/255, blue: b/255, alpha: 1)
}
}
Usage
//let color = UIColor(red: 202/255, green: 228/255, blue: 230/255, alpha: 1) ☠️
let color = UIColor(r: 202, g: 228, b: 230) // 😍
try this instead :
passwordTextField.textColor = UIColor(red: 0.792, green: 0.894, blue: 0.901, alpha: 1.0
Always put substituted values. 202/255 = 0.792
red, green, blue and alpha are supposed to be between 0.0 and 1.0.
As others mentioned, UIColor components are normalized in the range 0.0 ~ 1.0 (I think wide color gamuts are the exception, but haven't researched that yet).
A conveninet extension to the UIColor class will let you use values in the 0~255 range (like those obtained from various inspectors and image editing tools):
import UIKit
extension UIColor {
convenience init(
redByte red:UInt8,
greenByte green:UInt8,
blueByte blue:UInt8,
alphaByte alpha:UInt8
) {
self.init(
red: CGFloat(red )/255.0,
green: CGFloat(green)/255.0,
blue: CGFloat(blue )/255.0,
alpha: CGFloat(alpha)/255.0
)
}
}
UIColor convenient methods, from Integers, or from Hex.
extension UIColor {
convenience init(red: Int, green: Int, blue: Int, alpha: CGFloat) {
assert(red >= 0 && red <= 255, "Invalid red component")
assert(green >= 0 && green <= 255, "Invalid green component")
assert(blue >= 0 && blue <= 255, "Invalid blue component")
self.init(red: CGFloat(red) / 255.0, green: CGFloat(green) / 255.0, blue: CGFloat(blue) / 255.0, alpha: alpha)
}
convenience init(rgb: Int, alpha: CGFloat = 1) {
self.init(
red: (rgb >> 16) & 0xFF,
green: (rgb >> 8) & 0xFF,
blue: rgb & 0xFF,
alpha: alpha
)
}
}
I've created NSWindow and made it's background colour absolutely blue (#0000FF). But when the window is rendered, the colour is "lighter" than it should be (#0F3FFB).
class LilWindow: NSViewController {
override func viewDidLoad() {
self.view.window?.backgroundColor =
NSColor.init(red: 0, green: 0, blue: 1, alpha: 1)
}
Does anyone know why it is happening and how to fix this? (screenshot attached)
Okay, so after a couple of hours fiddling with code and #KenThomases help, I figured out that if you want your RGB colours to looks correctly on NSImages and NSWindows, you must convert it into NSDeviceRGBColorSpace colorspace. To do this I've written a simple function:
func toScreenColor(color:NSColor) -> NSColor {
var red: CGFloat = 0, green: CGFloat = 0, blue: CGFloat = 0, alpha: CGFloat = 0
color
.colorUsingColorSpaceName(NSCalibratedRGBColorSpace)!
.getRed(&red, green: &green, blue: &blue, alpha: &alpha)
return NSColor(deviceRed: red, green: green, blue: blue, alpha: alpha)
}
How I can make a random color function using Swift?
import UIKit
class ViewController: UIViewController {
var randomNumber = arc4random_uniform(20)
var randomColor = arc4random()
//Color Background randomly
func colorBackground() {
// TODO: set a random color
view.backgroundColor = UIColor.yellow
}
}
You're going to need a function to produce random CGFloats in the range 0 to 1:
extension CGFloat {
static func random() -> CGFloat {
return CGFloat(arc4random()) / CGFloat(UInt32.max)
}
}
Then you can use this to create a random colour:
extension UIColor {
static func random() -> UIColor {
return UIColor(
red: .random(),
green: .random(),
blue: .random(),
alpha: 1.0
)
}
}
If you wanted a random alpha, just create another random number for that too.
You can now assign your view's background colour like so:
self.view.backgroundColor = .random()
For Swift 4.2
extension UIColor {
static var random: UIColor {
return UIColor(
red: .random(in: 0...1),
green: .random(in: 0...1),
blue: .random(in: 0...1),
alpha: 1.0
)
}
}
For Swift 3 and above:
extension CGFloat {
static var random: CGFloat {
return CGFloat(arc4random()) / CGFloat(UInt32.max)
}
}
extension UIColor {
static var random: UIColor {
return UIColor(red: .random, green: .random, blue: .random, alpha: 1.0)
}
}
Usage:
let myColor: UIColor = .random
Make a function to generate random color:
func getRandomColor() -> UIColor {
//Generate between 0 to 1
let red:CGFloat = CGFloat(drand48())
let green:CGFloat = CGFloat(drand48())
let blue:CGFloat = CGFloat(drand48())
return UIColor(red:red, green: green, blue: blue, alpha: 1.0)
}
Now, you can call this function whenever you need random color.
self.view.backgroundColor = getRandomColor()
For random solid colors you can use UIColor HSB initializer and randomize only the hue:
extension UIColor {
static var random: UIColor {
return .init(hue: .random(in: 0...1), saturation: 1, brightness: 1, alpha: 1)
}
}
let color1: UIColor = .random
let color2: UIColor = .random
let color3: UIColor = .random
let color4: UIColor = .random
let color5: UIColor = .random
SwiftUI - Swift 5
import SwiftUI
extension Color {
static var random: Color {
return Color(red: .random(in: 0...1),
green: .random(in: 0...1),
blue: .random(in: 0...1))
}
}
Usage:
let randomColor: Color = .random
With Swift 4.2, you can simplify this by using the new random functions which have been added:
extension UIColor {
static func random () -> UIColor {
return UIColor(
red: CGFloat.random(in: 0...1),
green: CGFloat.random(in: 0...1),
blue: CGFloat.random(in: 0...1),
alpha: 1.0)
}
}
There are more details here.
Swift 4.2 🔸
I'm adding this answer because it uses a different approach, and because many of the previous answers requires additional syntactic sugar, which in my opinion shouldn't be preferred. Vanilla Swift for the win.
extension UIColor {
/**
* Returns random color
* ## Examples:
* self.backgroundColor = UIColor.random
*/
static var random: UIColor {
let r:CGFloat = .random(in: 0...1)
let g:CGFloat = .random(in: 0...1)
let b:CGFloat = .random(in: 0...1)
return UIColor(red: r, green: g, blue: b, alpha: 1)
}
}
Swift 4.2 Extension
extension UIColor {
convenience init(red: Int, green: Int, blue: Int) {
assert(red >= 0 && red <= 255, "Invalid red component")
assert(green >= 0 && green <= 255, "Invalid green component")
assert(blue >= 0 && blue <= 255, "Invalid blue component")
self.init(red: CGFloat(red) / 255.0, green: CGFloat(green) / 255.0, blue: CGFloat(blue) / 255.0, alpha: 1.0)
}
convenience init(rgb: Int) {
self.init(
red: (rgb >> 16) & 0xFF,
green: (rgb >> 8) & 0xFF,
blue: rgb & 0xFF
)
}
static func random() -> UIColor {
return UIColor(rgb: Int(CGFloat(arc4random()) / CGFloat(UINT32_MAX) * 0xFFFFFF))
}
}
Usage:
let color = UIColor.random()
Swift 5.1
Make This function and generate Random color.
e.g. view.backgroundColor = random()
func random() -> UIColor {
return UIColor(red: .random(in: 0...1),
green: .random(in: 0...1),
blue: .random(in: 0...1),
alpha: 1.0)
}
Using an extension with an inline function to generate randoms
extension UIColor {
static func random() -> UIColor {
func random() -> CGFloat { return .random(in:0...1) }
return UIColor(red: random(),
green: random(),
blue: random(),
alpha: 1.0)
}
}
func anotherGetRandomColor()->UIColor{
let newRed = Double(arc4random_uniform(256))/255.0
let newGreen = Double(arc4random_uniform(256))/255.0
let newBlue = Double(arc4random_uniform(256))/255.0
return UIColor(red: CGFloat(newRed), green: CGFloat(newGreen), blue: CGFloat(newBlue), alpha: 1.0)
}
Trying to create the colors of the rectangle using variables
import UIKit
class Color: UIView
{
var colors = ViewController()
override func drawRect(rect: CGRect)
{
let swiftColor = UIColor(red: 1, green: 165/255, blue: 0, alpha: 1);
let context = UIGraphicsGetCurrentContext()
CGContextSetLineWidth(context, 5.0)
CGContextSetStrokeColorWithColor(context,
UIColor(red: CGFloat(colors.red1), green: CGFloat(colors.green1), blue: CGFloat(colors.blue1), alpha: 1.0))
let rectangle = CGRectMake(60,170,200,80)
CGContextAddRect(context, rectangle)
CGContextStrokePath(context)
CGContextSetFillColorWithColor(context,
UIColor(red: CGFloat(colors.red1), green: CGFloat(colors.green1), blue: CGFloat(colors.blue1), alpha: 1.0))
CGContextFillRect(context, rectangle)
}
}
getting an error that says there is an extra argument 'green' in call
the variables are floats from a different class and should work fine
CGContextSetStrokeColorWithColor takes CGColor arguments, not UIColor. From the docs:
func CGContextSetStrokeColorWithColor(c: CGContext!, color: CGColor!)
v // Just delete this extra parenthesis and you will be fine
UIColor(red: CGFloat(colors.red1), green: CGFloat(colors.green1), blue: CGFloat(colors.blue1), alpha: 1.0))
It should be like this:
UIColor(red: CGFloat(colors.red1), green: CGFloat(colors.green1), blue: CGFloat(colors.blue1), alpha: 1.0)