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在 iOS 上将文本转换为图像

发布于 2024-08-08 17:47:19 字数 52 浏览 3 评论 0原文

如何将文本转换为图像并在 UIImageview 中显示。 谁能知道从文本到图像的转换吗？

原文

How to convert Text to Image and show in UIImageview.
Can anyone know the conversion from Text to Image?

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与之呼应 2024-08-15 17:47:19

使用 Swift 5 和 iOS 12，您可以选择以下 6 种方法之一来解决您的问题。

#1.使用 NSString 的 draw(at:withAttributes:) 方法

在最简单的情况下，您要将 String 转换为 UIImage 对于某些属性，您可以使用 draw(at:withAttributes :)。以下 Playground 代码展示了如何使用 draw(at:withAttributes:) 从 String 获取 UIImage：

import UIKit
import PlaygroundSupport

let text = "Hello, world"
let attributes = [
    NSAttributedString.Key.foregroundColor: UIColor.yellow,
    NSAttributedString.Key.font: UIFont.systemFont(ofSize: 22)
]
let textSize = text.size(withAttributes: attributes)

UIGraphicsBeginImageContextWithOptions(textSize, true, 0)
text.draw(at: CGPoint.zero, withAttributes: attributes)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

PlaygroundPage.current.liveView = UIImageView(image: image)

import UIKit
import PlaygroundSupport

let text = "Hello, world"
let attributes = [
    NSAttributedString.Key.foregroundColor: UIColor.yellow,
    NSAttributedString.Key.font: UIFont.systemFont(ofSize: 22)
]
let textSize = text.size(withAttributes: attributes)

let renderer = UIGraphicsImageRenderer(size: textSize)
let image = renderer.image(actions: { context in
    text.draw(at: CGPoint.zero, withAttributes: attributes)
})

PlaygroundPage.current.liveView = UIImageView(image: image)

请注意 NSAttributedString< /code> 有一个类似的方法，称为 draw(at:)。

#2.使用 NSString 的 draw(in:withAttributes:) 方法

作为 draw(at:withAttributes:) 的替代方法，您可以使用 draw(in:withAttributes:)。

import UIKit
import PlaygroundSupport

let text = "Hello, world"
let attributes = [
    NSAttributedString.Key.foregroundColor: UIColor.yellow,
    NSAttributedString.Key.font: UIFont.systemFont(ofSize: 22)
]
let textSize = text.size(withAttributes: attributes)

UIGraphicsBeginImageContextWithOptions(textSize, true, 0)
let rect = CGRect(origin: .zero, size: textSize)
text.draw(in: rect, withAttributes: attributes)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

PlaygroundPage.current.liveView = UIImageView(image: image)

import UIKit
import PlaygroundSupport

let text = "Hello, world"
let attributes = [
    NSAttributedString.Key.foregroundColor: UIColor.yellow,
    NSAttributedString.Key.font: UIFont.systemFont(ofSize: 22)
]
let textSize = text.size(withAttributes: attributes)

let renderer = UIGraphicsImageRenderer(size: textSize)
let image = renderer.image(actions: { context in
    let rect = CGRect(origin: .zero, size: textSize)
    text.draw(in: rect, withAttributes: attributes)
})

PlaygroundPage.current.liveView = UIImageView(image: image)

请注意，NSAttributedString 有一个类似的方法，称为 draw(in:)。

＃3。使用 NSString 的 draw(with:options:attributes:context:) 方法

作为 draw(at:withAttributes:) 和 < code>draw(in:)，您可以使用 draw （带有：选项：属性：上下文：）。请注意，Apple 对 draw(with:options:attributes:context:) 有一些建议：

此方法默认使用基线原点。
如果未指定usesLineFragmentOrigin，则矩形的高度将被忽略，并且该操作被视为单线渲染。

import UIKit
import PlaygroundSupport

let text = "Hello, world"
let attributes = [
    NSAttributedString.Key.foregroundColor: UIColor.yellow,
    NSAttributedString.Key.font: UIFont.systemFont(ofSize: 22)
]
let textSize = text.size(withAttributes: attributes)

UIGraphicsBeginImageContextWithOptions(textSize, true, 0)
let rect = CGRect(origin: .zero, size: textSize)
text.draw(with: rect, options: [.usesLineFragmentOrigin], attributes: attributes, context: nil)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

PlaygroundPage.current.liveView = UIImageView(image: image)

import UIKit
import PlaygroundSupport

let text = "Hello, world"
let attributes = [
    NSAttributedString.Key.foregroundColor: UIColor.yellow,
    NSAttributedString.Key.font: UIFont.systemFont(ofSize: 22)
]
let textSize = text.size(withAttributes: attributes)

let renderer = UIGraphicsImageRenderer(size: textSize)
let image = renderer.image(actions: { context in
    text.draw(with: .zero, options: [.usesLineFragmentOrigin], attributes: attributes, context: nil)
})

PlaygroundPage.current.liveView = UIImageView(image: image)

请注意，NSAttributedString 有一个类似的方法，称为 draw(with:options:context:)。

＃4。使用CALayer的render(in:)方法

如果你想捕获UILabel、UITextField的文本或 UITextView 到 UIImage，您可以使用 渲染（in:)。以下 Playground 代码展示了如何使用 render(in:) 对 UILabel 的内容文本进行快照：

import UIKit
import PlaygroundSupport

let label = UILabel(frame: .zero)
label.textColor = .yellow
label.font = UIFont.systemFont(ofSize: 22)
label.text = "Hello, world"
label.sizeToFit()

UIGraphicsBeginImageContextWithOptions(label.frame.size, true, 0)
guard let context = UIGraphicsGetCurrentContext() else { exit(0) }
label.layer.render(in: context)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

PlaygroundPage.current.liveView = UIImageView(image: image)

import UIKit
import PlaygroundSupport

let label = UILabel(frame: .zero)
label.textColor = .yellow
label.font = UIFont.systemFont(ofSize: 22)
label.text = "Hello, world"
label.sizeToFit()

let renderer = UIGraphicsImageRenderer(size: label.frame.size)
let image = renderer.image(actions: { context in
    label.layer.render(in: context.cgContext)
})

PlaygroundPage.current.liveView = UIImageView(image: image)

#5。使用 UIView 的 drawHierarchy(in:afterScreenUpdates:) 方法

如果您想捕获 UILabel、UITextField 的文本code> 或 UITextView 到 UIImage，您可以使用 drawHierarchy(in:afterScreenUpdates:)。请注意，Apple 对 drawHierarchy(in:afterScreenUpdates:) 有一些建议：

当您想要对视图快照应用图形效果（例如模糊）时，请使用此方法。此方法不如 snapshotView(afterScreenUpdates:) 方法快。

import UIKit
import PlaygroundSupport

let label = UILabel(frame: .zero)
label.textColor = .yellow
label.font = UIFont.systemFont(ofSize: 22)
label.text = "Hello, world"
label.sizeToFit()

UIGraphicsBeginImageContextWithOptions(label.frame.size, true, 0)    
_ = label.drawHierarchy(in: label.bounds, afterScreenUpdates: true)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

PlaygroundPage.current.liveView = UIImageView(image: image)

import UIKit
import PlaygroundSupport

let label = UILabel(frame: .zero)
label.textColor = .yellow
label.font = UIFont.systemFont(ofSize: 22)
label.text = "Hello, world"
label.sizeToFit()

let renderer = UIGraphicsImageRenderer(size: label.frame.size)
let image = renderer.image(actions: { context in
    _ = label.drawHierarchy(in: label.bounds, afterScreenUpdates: true)
})

PlaygroundPage.current.liveView = UIImageView(image: image)

＃6。使用 UIView 的 snapshotView(afterScreenUpdates:) 方法

如果您可以获取 UIView 而不是 UIImage > 在快照操作中，您可以使用 snapshotView(afterScreenUpdates:)。以下 Playground 代码展示了如何使用 snapshotView(afterScreenUpdates:) 将 UILabel 的内容文本快照到 UIView 中：

import UIKit
import PlaygroundSupport

let label = UILabel(frame: .zero)
label.textColor = .yellow
label.font = UIFont.systemFont(ofSize: 22)
label.text = "Hello, world"
label.sizeToFit()

let view = label.snapshotView(afterScreenUpdates: true)
PlaygroundPage.current.liveView = view

With Swift 5 and iOS 12, you can choose one the 6 following ways in order to solve your problem.

#1. Using NSString's draw(at:withAttributes:) method

In the simplest case where you want to convert a String to a UIImage with some attributes, you can use draw(at:withAttributes:). The following Playground codes show how to get an UIImage from a String using draw(at:withAttributes:):

import UIKit
import PlaygroundSupport

let text = "Hello, world"
let attributes = [
    NSAttributedString.Key.foregroundColor: UIColor.yellow,
    NSAttributedString.Key.font: UIFont.systemFont(ofSize: 22)
]
let textSize = text.size(withAttributes: attributes)

UIGraphicsBeginImageContextWithOptions(textSize, true, 0)
text.draw(at: CGPoint.zero, withAttributes: attributes)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

PlaygroundPage.current.liveView = UIImageView(image: image)

import UIKit
import PlaygroundSupport

let text = "Hello, world"
let attributes = [
    NSAttributedString.Key.foregroundColor: UIColor.yellow,
    NSAttributedString.Key.font: UIFont.systemFont(ofSize: 22)
]
let textSize = text.size(withAttributes: attributes)

let renderer = UIGraphicsImageRenderer(size: textSize)
let image = renderer.image(actions: { context in
    text.draw(at: CGPoint.zero, withAttributes: attributes)
})

PlaygroundPage.current.liveView = UIImageView(image: image)

Note that NSAttributedString has a similar method called draw(at:).

#2. Using NSString's draw(in:withAttributes:) method

As an alternative to draw(at:withAttributes:), you can use draw(in:withAttributes:).

import UIKit
import PlaygroundSupport

let text = "Hello, world"
let attributes = [
    NSAttributedString.Key.foregroundColor: UIColor.yellow,
    NSAttributedString.Key.font: UIFont.systemFont(ofSize: 22)
]
let textSize = text.size(withAttributes: attributes)

UIGraphicsBeginImageContextWithOptions(textSize, true, 0)
let rect = CGRect(origin: .zero, size: textSize)
text.draw(in: rect, withAttributes: attributes)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

PlaygroundPage.current.liveView = UIImageView(image: image)

import UIKit
import PlaygroundSupport

let text = "Hello, world"
let attributes = [
    NSAttributedString.Key.foregroundColor: UIColor.yellow,
    NSAttributedString.Key.font: UIFont.systemFont(ofSize: 22)
]
let textSize = text.size(withAttributes: attributes)

let renderer = UIGraphicsImageRenderer(size: textSize)
let image = renderer.image(actions: { context in
    let rect = CGRect(origin: .zero, size: textSize)
    text.draw(in: rect, withAttributes: attributes)
})

PlaygroundPage.current.liveView = UIImageView(image: image)

Note that NSAttributedString has a similar method called draw(in:).

#3. Using NSString's draw(with:options:attributes:context:) method

As an alternative to draw(at:withAttributes:) and draw(in:), you can use draw(with:options:attributes:context:). Note that Apple has some recommendations for draw(with:options:attributes:context:):

This method uses the baseline origin by default.
If usesLineFragmentOrigin is not specified, the rectangle’s height will be ignored and the operation considered to be single-line rendering.

import UIKit
import PlaygroundSupport

let text = "Hello, world"
let attributes = [
    NSAttributedString.Key.foregroundColor: UIColor.yellow,
    NSAttributedString.Key.font: UIFont.systemFont(ofSize: 22)
]
let textSize = text.size(withAttributes: attributes)

UIGraphicsBeginImageContextWithOptions(textSize, true, 0)
let rect = CGRect(origin: .zero, size: textSize)
text.draw(with: rect, options: [.usesLineFragmentOrigin], attributes: attributes, context: nil)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

PlaygroundPage.current.liveView = UIImageView(image: image)

import UIKit
import PlaygroundSupport

let text = "Hello, world"
let attributes = [
    NSAttributedString.Key.foregroundColor: UIColor.yellow,
    NSAttributedString.Key.font: UIFont.systemFont(ofSize: 22)
]
let textSize = text.size(withAttributes: attributes)

let renderer = UIGraphicsImageRenderer(size: textSize)
let image = renderer.image(actions: { context in
    text.draw(with: .zero, options: [.usesLineFragmentOrigin], attributes: attributes, context: nil)
})

PlaygroundPage.current.liveView = UIImageView(image: image)

Note that NSAttributedString has a similar method called draw(with:options:context:).

#4. Using CALayer's render(in:) method

If you want to capture the text of a UILabel, UITextField or UITextView to a UIImage, you can use render(in:). The following Playground codes show how to snapshot the content text of a UILabel using render(in:):

import UIKit
import PlaygroundSupport

let label = UILabel(frame: .zero)
label.textColor = .yellow
label.font = UIFont.systemFont(ofSize: 22)
label.text = "Hello, world"
label.sizeToFit()

UIGraphicsBeginImageContextWithOptions(label.frame.size, true, 0)
guard let context = UIGraphicsGetCurrentContext() else { exit(0) }
label.layer.render(in: context)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

PlaygroundPage.current.liveView = UIImageView(image: image)

import UIKit
import PlaygroundSupport

let label = UILabel(frame: .zero)
label.textColor = .yellow
label.font = UIFont.systemFont(ofSize: 22)
label.text = "Hello, world"
label.sizeToFit()

let renderer = UIGraphicsImageRenderer(size: label.frame.size)
let image = renderer.image(actions: { context in
    label.layer.render(in: context.cgContext)
})

PlaygroundPage.current.liveView = UIImageView(image: image)

#5. Using UIView's drawHierarchy(in:afterScreenUpdates:) method

If you want to capture the text of a UILabel, UITextField or UITextView to a UIImage, you can use drawHierarchy(in:afterScreenUpdates:). Note that Apple has some recommendations for drawHierarchy(in:afterScreenUpdates:):

Use this method when you want to apply a graphical effect, such as a blur, to a view snapshot. This method is not as fast as the snapshotView(afterScreenUpdates:) method.

import UIKit
import PlaygroundSupport

let label = UILabel(frame: .zero)
label.textColor = .yellow
label.font = UIFont.systemFont(ofSize: 22)
label.text = "Hello, world"
label.sizeToFit()

UIGraphicsBeginImageContextWithOptions(label.frame.size, true, 0)    
_ = label.drawHierarchy(in: label.bounds, afterScreenUpdates: true)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

PlaygroundPage.current.liveView = UIImageView(image: image)

import UIKit
import PlaygroundSupport

let label = UILabel(frame: .zero)
label.textColor = .yellow
label.font = UIFont.systemFont(ofSize: 22)
label.text = "Hello, world"
label.sizeToFit()

let renderer = UIGraphicsImageRenderer(size: label.frame.size)
let image = renderer.image(actions: { context in
    _ = label.drawHierarchy(in: label.bounds, afterScreenUpdates: true)
})

PlaygroundPage.current.liveView = UIImageView(image: image)

#6. Using UIView's snapshotView(afterScreenUpdates:) method

If it's OK for you to get a UIView instead of a UIImage from your snapshot operation, you can use snapshotView(afterScreenUpdates:). The following Playground code shows how to snapshot the content text of a UILabel into a UIView using snapshotView(afterScreenUpdates:):

import UIKit
import PlaygroundSupport

let label = UILabel(frame: .zero)
label.textColor = .yellow
label.font = UIFont.systemFont(ofSize: 22)
label.text = "Hello, world"
label.sizeToFit()

let view = label.snapshotView(afterScreenUpdates: true)
PlaygroundPage.current.liveView = view
回复 原文
蓝颜夕 2024-08-15 17:47:19

您可以开始尝试这样的事情：

NSString *string = @"Some text";
UIGraphicsBeginImageContext(CGSizeMake(80, 50));
[string drawAtPoint:CGPointMake(10, 20)
           withFont:[UIFont systemFontOfSize:12]];
UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

result 包含带有文本的 UIImage，您可以将其分配给 UIImageView image 属性。

You can start playing around with something like this:

NSString *string = @"Some text";
UIGraphicsBeginImageContext(CGSizeMake(80, 50));
[string drawAtPoint:CGPointMake(10, 20)
           withFont:[UIFont systemFontOfSize:12]];
UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

result contains the UIImage with the text in it, and you can assign it to the UIImageView image property.

回复 原文
送君千里 2024-08-15 17:47:19

SWIFT 3 ：

为 UIImage 创建一个扩展，以便您可以在任何地方使用它：

extension UIImage {
    class func imageWithLabel(label: UILabel) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(label.bounds.size, false, 0.0)
        label.layer.render(in: UIGraphicsGetCurrentContext()!)
        let img = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return img!
   }
}

现在无论您在哪里需要使用它从文本创建图像：

// 这种标签的自定义是根据您的需要，您需要哪种字体，什么背景颜色。随意改变。

let label = UILabel(frame: CGRect(x: 0, y: 0, width: 300, height: 20))
label.numberOfLines = 0
label.textAlignment = .center
label.textColor = UIColor.white
label.backgroundColor = UIColor.black
label.font = UIFont(name: "Montserrat", size: 17)
label.text = "YOUR TEXT HERE"
label.sizeToFit()
let image = UIImage.imageWithLabel(label: label)

SWIFT 3 :

Create an extension for UIImage so that you can use it everywhere:

extension UIImage {
    class func imageWithLabel(label: UILabel) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(label.bounds.size, false, 0.0)
        label.layer.render(in: UIGraphicsGetCurrentContext()!)
        let img = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return img!
   }
}

Now where ever you need to use this to create an image from Text :

// This customisation of label is according to your needs which font , what background color you need. Feel free to change.

let label = UILabel(frame: CGRect(x: 0, y: 0, width: 300, height: 20))
label.numberOfLines = 0
label.textAlignment = .center
label.textColor = UIColor.white
label.backgroundColor = UIColor.black
label.font = UIFont(name: "Montserrat", size: 17)
label.text = "YOUR TEXT HERE"
label.sizeToFit()
let image = UIImage.imageWithLabel(label: label)
回复 原文
黯淡〆 2024-08-15 17:47:19

[yourImageView addSubview:textView];
[canvas addSubview:passingImageView];

UIGraphicsBeginImageContext(canvas.bounds.size);
[canvas.layer renderInContext:UIGraphicsGetCurrentContext()];

UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();
return resultingImage;

你应该采用一个 UIView 并在内部采用 UIImageview ，上面的代码应该可以解决问题。这里的画布是 UIView。

[yourImageView addSubview:textView];
[canvas addSubview:passingImageView];

UIGraphicsBeginImageContext(canvas.bounds.size);
[canvas.layer renderInContext:UIGraphicsGetCurrentContext()];

UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();
return resultingImage;

you should take a UIView and inside take UIImageview and the above code should do the trick.Here canvas is UIView.

回复 原文
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