ios 在 Swift 中使用纯色创建 UIImage

Create UIImage with solid color in Swift

提问by Henry Pham

I want to programmatically create an UIImage filled by a solid color. Anyone have an idea of how to do this in Swift?

我想以编程方式创建一个由纯色填充的 UIImage。任何人都知道如何在 Swift 中做到这一点？

回答by Luca Davanzo

Another nice solution, Swift 2.2compatible, is to create another constructor in UIImage, in this way:

另一个与Swift 2.2兼容的不错的解决方案是在 UIImage 中创建另一个构造函数，如下所示：

public extension UIImage {
    public convenience init?(color: UIColor, size: CGSize = CGSize(width: 1, height: 1)) {
        let rect = CGRect(origin: .zero, size: size)
        UIGraphicsBeginImageContextWithOptions(rect.size, false, 0.0)
        color.setFill()
        UIRectFill(rect)
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        guard let cgImage = image?.CGImage else { return nil }
        self.init(CGImage: cgImage)
    }  
}

In this way you can create the custom colored-image in this way:

通过这种方式，您可以以这种方式创建自定义彩色图像：

let redImage = UIImage(color: .redColor())

Or, optionally, create the image with a custom size:

或者，可以选择使用自定义大小创建图像：

let redImage200x200 = UIImage(color: .redColor(), size: CGSize(width: 200, height: 200))

Swift 3.0

斯威夫特 3.0

public extension UIImage {
  public convenience init?(color: UIColor, size: CGSize = CGSize(width: 1, height: 1)) {
    let rect = CGRect(origin: .zero, size: size)
    UIGraphicsBeginImageContextWithOptions(rect.size, false, 0.0)
    color.setFill()
    UIRectFill(rect)
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    guard let cgImage = image?.cgImage else { return nil }
    self.init(cgImage: cgImage)
  }
}

回答by anthonyliao

Here's another option. I believe you wanted an exact UIImage object.

这是另一种选择。我相信你想要一个确切的 UIImage 对象。

func getImageWithColor(color: UIColor, size: CGSize) -> UIImage {
    let rect = CGRectMake(0, 0, size.width, size.height)
    UIGraphicsBeginImageContextWithOptions(size, false, 0)
    color.setFill()
    UIRectFill(rect)
    let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image
}

Stick this in your Swift code and call it

将其粘贴到您的 Swift 代码中并调用它

Swift 3.1:

斯威夫特 3.1：

func getImageWithColor(color: UIColor, size: CGSize) -> UIImage {
    let rect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
    UIGraphicsBeginImageContextWithOptions(size, false, 0)
    color.setFill()
    UIRectFill(rect)
    let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()
    return image
}

回答by neoneye

Swift 4 version:

斯威夫特 4 版本：

extension UIColor {
    func image(_ size: CGSize = CGSize(width: 1, height: 1)) -> UIImage {
        return UIGraphicsImageRenderer(size: size).image { rendererContext in
            self.setFill()
            rendererContext.fill(CGRect(origin: .zero, size: size))
        }
    }
}

Usage:

用法：

let image0 = UIColor.orange.image(CGSize(width: 128, height: 128))
let image1 = UIColor.yellow.image()

回答by Zorayr

A cleaner approach would be to encapsulate the logic inside an UIImageextension:

更简洁的方法是将逻辑封装在UIImage扩展中：

import UIKit

extension UIImage {
  class func imageWithColor(color: UIColor) -> UIImage {
    let rect: CGRect = CGRectMake(0, 0, 1, 1)
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(1, 1), false, 0)
    color.setFill()
    UIRectFill(rect)
    let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image
  }
}

Now the consumer can call, UIImage.imageWithColor(UIColor.blackColor())to create an image with black background.

现在消费者可以调用，UIImage.imageWithColor(UIColor.blackColor())创建一个黑色背景的图像。

回答by Steve Rosenberg

class ViewController: UIViewController {

    @IBOutlet weak var imageView: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        imageView.backgroundColor = UIColor.redColor()
    }
}

Similar method if you want draw the image yourself vs. connecting one via IBOutlet.

如果您想自己绘制图像而不是通过 IBOutlet 连接图像，则使用类似的方法。

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        var frame = CGRectMake(100,100,100,100)
        var imageView2 = UIImageView(frame: frame)
        imageView2.backgroundColor = UIColor.redColor()
        self.view.addSubview(imageView2)
    }
}

Third method borrowing from anthonyliao. A little more complicated:

借鉴 anthonylio 的第三种方法。稍微复杂一点：

class ViewController: UIViewController {

    func getImageWithColor(color: UIColor, size: CGSize) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(size, false, 0)
        color.setFill()
        UIRectFill(CGRectMake(0, 0, 100, 100))
        var image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return image
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        var imageView = UIImageView(frame: CGRectMake(100,100,100,100))
        let screenImage = getImageWithColor(UIColor.redColor(), size: CGSize(width: 100, height: 100))
        imageView.image = screenImage
        self.view.addSubview(imageView)
    }
}

回答by Moustafa Baalbaki

You can use the new iOS 10UIGraphicsImageRendererAPI.

您可以使用新的iOS 10 UIGraphicsImageRendererAPI。

Here is an extension on UIColor in Swift 3.1

这是Swift 3.1 中UIColor 的扩展

extension UIColor {
func getImage(size: CGSize) -> UIImage {
    let renderer = UIGraphicsImageRenderer(size: size)
    return renderer.image(actions: { rendererContext in
        self.setFill()
        rendererContext.fill(CGRect(x: 0, y: 0, width: size.width, height: size.height))
    })
}}

回答by drew..

A minor tweak to @neoneye's excellent answer, allowing the calling code not to need to create the CGSize, and altered the name to not collide with numerous others:

对@neoneye 的优秀答案稍作调整，允许调用代码不需要创建 CGSize，并将名称更改为不与许多其他人发生冲突：

Swift 4

斯威夫特 4

extension UIColor {
    func imageWithColor(width: Int, height: Int) -> UIImage {
        let size = CGSize(width: width, height: height)
        return UIGraphicsImageRenderer(size: size).image { rendererContext in
            self.setFill()
            rendererContext.fill(CGRect(origin: .zero, size: size))
        }
    }
}

回答by iOSGeek

A nice way is to have a computed property like this:

一个很好的方法是拥有一个像这样的计算属性：

extension UIColor {
    var imageRepresentation : UIImage {
      let rect = CGRect(x: 0.0, y: 0.0, width: 1.0, height: 1.0)
      UIGraphicsBeginImageContext(rect.size)
      let context = UIGraphicsGetCurrentContext()

      context?.setFillColor(self.cgColor)
      context?.fill(rect)

      let image = UIGraphicsGetImageFromCurrentImageContext()
      UIGraphicsEndImageContext()

    return image!
  }
}

Usage:

用法：

let redImage = UIColor.red.imageRepresentation

回答by Ayman Ibrahim

Swift 3 version of @anthonyliao Accepted answer:

Swift 3 版本的@anthonyliao 接受的答案：

class func getImageWithColor(color: UIColor, size: CGSize) -> UIImage
{
    let rect = CGRect(origin: CGPoint(x: 0, y: 0), size: CGSize(width: size.width, height: size.height))
    UIGraphicsBeginImageContextWithOptions(size, false, 0)
    color.setFill()
    UIRectFill(rect)
    let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()
    return image
}

回答by droid

Rect with rounded corners

带圆角的矩形

extension UIImage {
convenience init?(color: UIColor) {
    let rect = CGRect(x: 0, y: 0, width: 10, height: 2)
    UIGraphicsBeginImageContextWithOptions(CGSize(width: 10, height: 2), false, 0)
    let bezierPath = UIBezierPath(roundedRect: rect, cornerRadius: 8)
    color.setFill()
    bezierPath.fill()
    let image = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()

    guard  let cgImage = image.cgImage else {
        return nil
    }
    self.init(cgImage: cgImage)
}

}

}