如何在 iOS Swift 中向图像添加文本? [英] How do I add text to an image in iOS Swift?

问题描述

我环顾四周，并没有成功弄清楚如何获取文本，将其叠加在图像上，然后将两者合并为一个 UIImage.

I have looked around and have been unsuccessful at figuring out how take text, overlay it on an image, and then combine the two into a single UIImage.

我已经用我能想到的搜索词用尽了谷歌，所以如果有人有解决方案或至少是他们可以指出的提示，我们将不胜感激.

I have exhausted Google using the search terms I can think of so if anyone has a solution or at least a hint they can point to it would be greatly appreciated.

推荐答案

好的...我想通了:

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

}

调用它，你只需传入一个图像:

To call it, you just pass in an image:

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

以下链接帮助我明白了这一点:

The following links helped me get this straight:

Swift - 使用 drawInRect:withAttributes 绘制文本:

如何在Objective-C (iOS)?

最初的目标是创建一个动态图像，我可以在 AnnotionView 中使用它，例如在地图上的给定位置标出价格，这对它来说效果很好.希望这对尝试做同样事情的人有所帮助.

The original goal was to create a dynamic image that I could use in an AnnotaionView such as putting a price at a given location on a map and this worked out great for it. Hope this helps someone trying to do the same thing.

 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 Swift 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!
 }

对于 Swift 5:

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 = [
        NSAttributedString.Key.font: textFont,
        NSAttributedString.Key.foregroundColor: textColor,
        ] as [NSAttributedString.Key : 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!
}

这篇关于如何在 iOS Swift 中向图像添加文本?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！