如何在iOS Swift中为图像添加文本？

Question

我已经环顾四周,并没有成功地弄清楚如何拍摄文字,将其叠加在图像上,然后将两者合并为一个UIImage.

我使用我能想到的搜索字词已经让Google筋疲力尽了,所以如果有人有解决方案或者至少提示他们可以指出它将会非常感激.

Answer 1

好的......我明白了:

func textToImage(drawText: NSString, inImage: UIImage, atPoint: CGPoint) -> UIImage{

    // Setup the font specific variables
    var textColor = UIColor.whiteColor()
    var textFont = UIFont(name: "Helvetica Bold", size: 12)!

    // Setup the image context using the passed image
    let scale = UIScreen.mainScreen().scale
    UIGraphicsBeginImageContextWithOptions(inImage.size, false, scale)

    // Setup the font attributes that will be later used to dictate how the text should be drawn
    let textFontAttributes = [
        NSFontAttributeName: textFont,
        NSForegroundColorAttributeName: textColor,
    ]

    // Put the image into a rectangle as large as the original image
    inImage.drawInRect(CGRectMake(0, 0, inImage.size.width, inImage.size.height))

    // Create a point within the space that is as bit as the image
    var rect = CGRectMake(atPoint.x, atPoint.y, inImage.size.width, inImage.size.height)

    // Draw the text into an image
    drawText.drawInRect(rect, withAttributes: textFontAttributes)

    // Create a new image out of the images we have created
    var newImage = UIGraphicsGetImageFromCurrentImageContext()

    // End the context now that we have the image we need
    UIGraphicsEndImageContext()

    //Pass the image back up to the caller
    return newImage

}

要调用它,您只需传入一个图像:

textToImage("000", inImage: UIImage(named:"thisImage.png")!, atPoint: CGPointMake(20, 20))

以下链接帮助我顺利完成:

Swift - 使用drawInRect绘制文本:withAttributes:

如何在Objective-C(iOS)中的图像上写文字？

最初的目标是创建一个动态图像,我可以使用它,AnnotaionView例如在地图上的给定位置定价,这对它很有用.希望这有助于某人尝试做同样的事情.

对于swift 3:

 func textToImage(drawText text: NSString, inImage image: UIImage, atPoint point: CGPoint) -> UIImage {
    let textColor = UIColor.white
    let textFont = UIFont(name: "Helvetica Bold", size: 12)!

    let scale = UIScreen.main.scale
    UIGraphicsBeginImageContextWithOptions(image.size, false, scale)

    let textFontAttributes = [
        NSFontAttributeName: textFont,
        NSForegroundColorAttributeName: textColor,
        ] as [String : Any]
    image.draw(in: CGRect(origin: CGPoint.zero, size: image.size))

    let rect = CGRect(origin: point, size: image.size)
    text.draw(in: rect, withAttributes: textFontAttributes)

    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    return newImage!
 }

对于快速4:

 func textToImage(drawText text: String, inImage image: UIImage, atPoint point: CGPoint) -> UIImage {
    let textColor = UIColor.white
    let textFont = UIFont(name: "Helvetica Bold", size: 12)!

    let scale = UIScreen.main.scale
    UIGraphicsBeginImageContextWithOptions(image.size, false, scale)

    let textFontAttributes = [
        NSAttributedStringKey.font: textFont,
        NSAttributedStringKey.foregroundColor: textColor,
        ] as [NSAttributedStringKey : Any]
    image.draw(in: CGRect(origin: CGPoint.zero, size: image.size))

    let rect = CGRect(origin: point, size: image.size)
    text.draw(in: rect, withAttributes: textFontAttributes)

    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    return newImage!
 }

Answer 2

我的简单方案:

func generateImageWithText(text: String) -> UIImage? {
    let image = UIImage(named: "imageWithoutText")!

    let imageView = UIImageView(image: image)
    imageView.backgroundColor = UIColor.clear
    imageView.frame = CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height)

    let label = UILabel(frame: CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height))
    label.backgroundColor = UIColor.clear
    label.textAlignment = .center
    label.textColor = UIColor.white
    label.text = text

    UIGraphicsBeginImageContextWithOptions(label.bounds.size, false, 0)
    imageView.layer.render(in: UIGraphicsGetCurrentContext()!)
    label.layer.render(in: UIGraphicsGetCurrentContext()!)
    let imageWithText = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    return imageWithText
}

Answer 3

您也可以执行CATextLayer.

    // 1
let textLayer = CATextLayer()
textLayer.frame = someView.bounds

// 2
var string = ""
for _ in 1...20 {
  string += "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce auctor arcu quis velit congue dictum. "
}

textLayer.string = string

// 3
let fontName: CFStringRef = "Noteworthy-Light"
textLayer.font = CTFontCreateWithName(fontName, fontSize, nil)

// 4
textLayer.foregroundColor = UIColor.darkGrayColor().CGColor
textLayer.wrapped = true
textLayer.alignmentMode = kCAAlignmentLeft
textLayer.contentsScale = UIScreen.mainScreen().scale
someView.layer.addSublayer(textLayer)

http://www.raywenderlich.com/90488/calayer-in-ios-with-swift-10-examples

Answer 4

我已经创建了一个扩展，可以在任何地方使用它：

import Foundation
import UIKit
extension UIImage {

    class func createImageWithLabelOverlay(label: UILabel,imageSize: CGSize, image: UIImage) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(CGSize(width: imageSize.width, height: imageSize.height), false, 2.0)
        let currentView = UIView.init(frame: CGRect(x: 0, y: 0, width: imageSize.width, height: imageSize.height))
        let currentImage = UIImageView.init(image: image)
        currentImage.frame = CGRect(x: 0, y: 0, width: imageSize.width, height: imageSize.height)
        currentView.addSubview(currentImage)
        currentView.addSubview(label)
        currentView.layer.render(in: UIGraphicsGetCurrentContext()!)
        let img = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return img!
    }

}

用法：在ViewController上您要添加大小和标签的任何地方，请按以下方式使用它-

let newImageWithOverlay = UIImage.createImageWithLabelOverlay(label: labelToAdd, imageSize: size, image: editedImage)