iOS原生、Android 原生， flutter 三种方式给照片流添加文字（水印）

效果图：三中代码实现的效果差不多

Swift：代码

import UIKit

class ImageWatermarking: NSObject {
    
    static func textToImage(drawText text: String, inImage initImage: UIImage, atPoint point: CGPoint) -> UIImage {
        let textColor = UIColor.white
        let textFont = UIFont(name:"Helvetica", size: 26)!

        
        // 新建底部拼接区域
        let rect: CGRect = CGRect(x: 0, y: 0, width: initImage.size.width, height: 220)
        UIGraphicsBeginImageContext(rect.size)
        let context: CGContext = UIGraphicsGetCurrentContext()!
        context.setFillColor(UIColor.kHexRGBA(0x000000,0.3).cgColor)
        context.fill(rect)
        let imagebottom = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsGetCurrentContext()
        

        let style = NSMutableParagraphStyle()
        style.lineSpacing = 6
        style.lineBreakMode = NSLineBreakMode.byTruncatingTail
        // 在底部拼接区域添加文字
        let textFontAttributes = [
            NSAttributedString.Key.font: textFont,
            NSAttributedString.Key.foregroundColor: textColor,
            NSAttributedString.Key.paragraphStyle: style
            
            ] as [NSAttributedString.Key : Any]
        imagebottom!.draw(in: CGRect(origin: CGPoint.zero, size: imagebottom!.size))
        let rectText = CGRect(origin: point, size: initImage.size)
        text.draw(in: rectText, withAttributes: textFontAttributes)
        let newTextImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        

        // 拼接原图和新建的底部区域
        let topImage = initImage
        let bottomImage = newTextImage
        
        let allSize = CGSize(width: topImage.size.width, height: topImage.size.height )
        UIGraphicsBeginImageContext(allSize)
        
        let areaSizeTop = CGRect(x: 0, y: 0, width: topImage.size.width, height: topImage.size.height)
        topImage.draw(in: areaSizeTop)

        let areaSizeBottom = CGRect(x: 0, y: areaSizeTop.size.height-220, width: bottomImage!.size.width, height: bottomImage!.size.height)
        bottomImage!.draw(in: areaSizeBottom)

        let newImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()!
        UIGraphicsEndImageContext()
        
        return newImage

    }


}

Swift 调用：

        
let contentStr :String =  currentTime &