如何使文字出现在图像的中心？ [英] How to make text appear in centre of the image?

问题描述

我想在图片上添加文字，我可以按照以下代码所示进行操作。

I want to add a text on an image, and I'm able to do it as shown in below code.

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

    // Setup the font specific variables
    var textColor: UIColor = UIColor.redColor()
    var textFont: UIFont =  UIFont(name: "AmericanTypewriter", size: 75)!
    let textStyle  = NSTextEffectLetterpressStyle

    //Setup the image context using the passed image.
    UIGraphicsBeginImageContext(inImage.size)

    let textFontAttributes = [
        NSFontAttributeName: textFont,
        NSForegroundColorAttributeName: textColor,
        NSTextEffectAttributeName : textStyle
    ]

    inImage.drawInRect(CGRectMake(0, 0, inImage.size.width, inImage.size.height))

    var rect: CGRect = CGRectMake(atPoint.x, atPoint.y, inImage.size.width, inImage.size.height)

    drawText.drawInRect(rect, withAttributes: textFontAttributes)

    var newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()

    UIGraphicsEndImageContext()
    return newImage
}

我调用此函数如下所示

let newImage : UIImage = textToImage(textToAdd!, inImage: imageToSave, atPoint:CGPoint(x: 20, y: 20)) //For now text is displaying at the top in left end for point(x:20 ,y:20)

<但问题是，文本是由用户拍摄的。他们可以给出单个单词或大句子。因此，如果他们只提供一个单词，它应该出现在图像的顶部和中间，或者从左到右顶部。它更像是，我想将文本对齐设置为居中。为了实现它，我应该改变上面给出的CGPoint。但是我没有得到如何改变它以便它在所有情况下看起来都很好。请帮我解决这个问题。

But the problem is, text is taken by user. They can give either single word or big sentence. So if they give only single word, it should appear in top and middle of the image or else in top from left to right. it is more like, I want to set the text alignment to centre. To achieve it, Accordingly I should change the CGPoint given above. But I'm not getting how to change it so that it should look good in all scenarios. Please help me how to achieve this.

推荐答案

添加到@osteven的答案。下面的代码按我的预期工作。希望它能帮助他人。

Added to @osteven answer. Below code works as I expected. Hope it helps others.

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

// Setup the font specific variables
var textColor: UIColor = UIColor.redColor()
var textFont: UIFont =  UIFont(name: "AmericanTypewriter", size: 75)!
let textStyle  = NSTextEffectLetterpressStyle

//Setup the image context using the passed image.
UIGraphicsBeginImageContext(inImage.size)

let textFontAttributes = [
    NSFontAttributeName: textFont,
    NSForegroundColorAttributeName: textColor,
    NSTextEffectAttributeName : textStyle
]

inImage.drawInRect(CGRectMake(0, 0, inImage.size.width, inImage.size.height))

 let textSize = drawText.sizeWithAttributes(textFontAttributes)
    if textSize.width < inImage.size.width {
        println("lesser")
        let textRect = CGRectMake(inImage.size.width / 2 - textSize.width / 2, 0,
        inImage.size.width / 2 + textSize.width / 2, inImage.size.height - textSize.height)
        drawText.drawInRect(textRect, withAttributes: textFontAttributes)
    }
    else {
        println("greater")
        let textRect = CGRectMake(0 , 0,
            inImage.size.width, inImage.size.height)
        drawText.drawInRect(textRect, withAttributes: textFontAttributes)

    }

var newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()

UIGraphicsEndImageContext()
return newImage

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