ios 如何在 swift 编程中在 UIimage 中设置背景颜色

how to set a background color in UIimage in swift programming

提问by Rizwan Shaikh

I draw an image using drawInRect()method.

我使用drawInRect()方法绘制图像。

My rectangle is size of 120*120 and my image is 100 * 100.

我的矩形大小为 120 * 120，我的图像为 100 * 100。

How i can set a background color to my image in swift?

如何快速为我的图像设置背景颜色？

回答by Egghead

You can also use this extension:

你也可以使用这个扩展：

    extension UIImage {
        func imageWithColor(tintColor: UIColor) -> UIImage {
            UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)

            let context = UIGraphicsGetCurrentContext()!
            context.translateBy(x: 0, y: self.size.height)
            context.scaleBy(x: 1.0, y: -1.0);
            context.setBlendMode(.normal)

            let rect = CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height) as CGRect
            context.clip(to: rect, mask: self.cgImage!)
            tintColor.setFill()
            context.fill(rect)

            let newImage = UIGraphicsGetImageFromCurrentImageContext()!
            UIGraphicsEndImageContext()

            return newImage
        }
    }

And then

进而

image.imageWithColor("#1A6BAE".UIColor)

EDIT: 2019-11: Updated to Swift 5 by @Yuto

编辑：2019-11：由@Yuto 更新到 Swift 5

回答by Dili

Updated @Egghead's solution for Swift 3

更新了@Egghead 的 Swift 3 解决方案

extension UIImage {
   static func imageWithColor(tintColor: UIColor) -> UIImage {
        let rect = CGRect(x: 0, y: 0, width: 1, height: 1)
        UIGraphicsBeginImageContextWithOptions(rect.size, false, 0)
        tintColor.setFill()
        UIRectFill(rect)
        let image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
        UIGraphicsEndImageContext()
        return image
    }
}

Usage :

用法 ：

UIImage.imageWithColor(tintColor: <Custom color>)

回答by dimpiax

Swift 5, 4

斯威夫特 5、4

If you need to draw the background of an image, for optimization and decorative purposes, you can draw the image in a specific way:

如果您需要绘制图像的背景，出于优化和装饰的目的，您可以通过特定方式绘制图像：

UIImage(named: "someImage")?.withBackground(color: .white)

UIImage(named: "someImage")?.withBackground(color: .white)

---

---

Extension

延期

extension UIImage {
    func withBackground(color: UIColor, opaque: Bool = true) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(size, opaque, scale)

        guard let ctx = UIGraphicsGetCurrentContext() else { return self }
        defer { UIGraphicsEndImageContext() }

        let rect = CGRect(origin: .zero, size: size)
        ctx.setFillColor(color.cgColor)
        ctx.fill(rect)
        ctx.concatenate(CGAffineTransform(a: 1, b: 0, c: 0, d: -1, tx: 0, ty: size.height))
        ctx.draw(cgImage!, in: rect)

        return UIGraphicsGetImageFromCurrentImageContext() ?? self
    }
}

回答by Woodstock

It's probably best to use the backgroundColor property of your UIImageView. You can do this as follows -

最好使用 UIImageView 的 backgroundColor 属性。您可以按如下方式执行此操作 -

self.imageView.backgroundColor = UIColor.redColor()

The following preset colors exist:

存在以下预设颜色：

blackColor
darkGrayColor
lightGrayColor
whiteColor
grayColor
redColor
greenColor
blueColor
cyanColor
yellowColor
magentaColor
orangeColor
purpleColor
brownColor
clearColor

If you instead want to programmatically create a UIImage with a given color, you can do this as follows:

如果您想以编程方式创建具有给定颜色的 UIImage，您可以按如下方式执行此操作：

var rect = CGRectMake(0, 0, size.width, size.height)
UIGraphicsBeginImageContextWithOptions(size, false, 0)
color.setFill()
UIRectFill(rect)
var image: UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

Where the var'image' is your colored UIImage.

其中var“图像”是您的彩色 UIImage。

回答by Domenico

An other way to obtain an image with a background color with an extension is: (Swift 3)

获取带有扩展名的背景颜色图像的另一种方法是：（Swift 3）

extension UIImage {

    /**
        Returns an UIImage with a specified background color.
        - parameter color: The color of the background
     */
    convenience init(withBackground color: UIColor) {

        let rect: CGRect = CGRect(x: 0, y: 0, width: 1, height: 1)
        UIGraphicsBeginImageContext(rect.size);
        let context:CGContext = UIGraphicsGetCurrentContext()!;
        context.setFillColor(color.cgColor);
        context.fill(rect)

        let image:UIImage = UIGraphicsGetImageFromCurrentImageContext()!
        UIGraphicsEndImageContext()

        self.init(ciImage: CIImage(image: image)!)

    }
}

And then:

进而：

// change UIColor.white with your color
let image = UIImage(withBackground: UIColor.white)

回答by Irfan

Solution for swift 4 based on the already acepted answer:

基于已经接受的答案的 swift 4 解决方案：

func imageWithColor(tintColor: UIColor) -> UIImage {
    UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)

    let context = UIGraphicsGetCurrentContext() as! CGContext
    context.translateBy(x: 0, y: size.height)
    context.scaleBy(x: 1, y: -1)
    context.setBlendMode(.normal)

    let rect = CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height) as CGRect
    context.clip(to: rect, mask: self.cgImage!)
    tintColor.setFill()
    context.fill(rect)
    let newImage = UIGraphicsGetImageFromCurrentImageContext() as! UIImage
    UIGraphicsEndImageContext()

    return newImage
}

Usage:

用法：

image.imageWithColor("#1A6BAE".UIColor)