java 图片水印

首先需要引入该jar
implementation "com.drewnoakes:metadata-extractor:2.14.0"

直接上代码

package com.example.lib

import com.drew.imaging.ImageMetadataReader
import com.drew.metadata.Directory
import sun.java2d.pipe.DrawImage
import java.awt.Color
import java.awt.Font
import java.awt.Graphics2D
import java.awt.image.BufferedImage
import java.io.File
import java.io.FileInputStream
import java.io.FileOutputStream
import java.util.*
import javax.imageio.ImageIO
import javax.naming.directory.DirContext
import kotlin.collections.HashMap

/**
 * 2023/8/21
 * ..╭︿︿︿╮
 * {/ .  . /}
 * .( (oo) )    create by cps
 *  .︶︶︶
 * 为照片添加时间戳
 */
class AddTimeUtil {

    fun readFile(dirPath: String) {
        val dirFile = File(dirPath)
        val fileList = dirFile.listFiles()?.filter {
            it.name.endsWith(".png") || it.name.endsWith(".jpg")
        }?.toList()

        val hashMap = HashMap<String, String>()
        fileList?.forEach { file ->
            println("===================================================")
            println(file.name)
            hashMap.clear()
            val readMetadata = ImageMetadataReader.readMetadata(file)
            readMetadata.directories.forEach { directory: Directory? ->
                directory?.let { di ->
                    di.tags.forEach {
                        hashMap[it.tagName] = it.description
                        println("${it.tagName} ${it.description}")
                    }
                }
            }

            var width: Int = 0
            hashMap.entries.firstOrNull { hm ->
                hm.key.toLowerCase().contains("width".toLowerCase())
            }?.let {
                width = it.value.split(" ")[0].toInt()
            }

            //星期一 八月 21 14:39:51 +08:00 2023
            var timeStr: String = hashMap.entries.firstOrNull { hm ->
                hm.key.toLowerCase().contains("Modified Date".toLowerCase())
            }?.value ?: getTodayStr()
            timeStr.split(" ").let {
                timeStr = "${it[5]}-${it[1]}-${it[2]} "
            }

            println("$width  $timeStr")

            addTimeMark(file, timeStr)

        }

    }


    fun getTodayStr(): String {
        return with(Calendar.getInstance()) {

            "${get(Calendar.YEAR)}-${get(Calendar.MONTH) + 1}-${get(Calendar.DAY_OF_MONTH)}"
        }

    }


    fun addTimeMark(file: File, contentStr: String) {
        val ivFile: BufferedImage = ImageIO.read(FileInputStream(file))
        val width = ivFile.getWidth()
        val height = ivFile.getHeight()
        val bufferedImage = BufferedImage(width, height, BufferedImage.TYPE_INT_RGB)
        val graphicsIv = bufferedImage.createGraphics()

        with(graphicsIv) {
            drawImage(ivFile, 0, 0, width, height, null)
            color = Color(250,0,250)
            font = Font("宋体", Font.BOLD, 50)
        }
        val fontSize = getFontSizeByWidth(width, contentStr, graphicsIv)
        println("最适合的文本大小$fontSize")
        graphicsIv.font = Font("宋体", Font.BOLD, fontSize)
        val tvWidth = getContentWidth(contentStr, fontSize, graphicsIv)
        val tvHeight = getContentHeight(fontSize, graphicsIv)
        graphicsIv.drawString(contentStr, width - tvWidth, height - tvHeight)

        val fileOutputStream =
            FileOutputStream("${file.parent}/${file.nameWithoutExtension}_back.png")
        ImageIO.write(bufferedImage, "png", fileOutputStream)
        fileOutputStream.flush()
        fileOutputStream.close()
    }

    fun getFontSizeByWidth(picWidth: Int, contentStr: String, g: Graphics2D): Int {
        val fontSize: Int = (100 downTo 0 step 2).first {
            getContentWidth(contentStr, it, g) < picWidth / 3
        }.run {
            this
        }
        return fontSize

    }

    fun getContentWidth(contentStr: String, fontSize: Int, g: Graphics2D): Int {
        val font = Font("宋体", Font.BOLD, fontSize)
        val charsWidth =
            g.getFontMetrics(font).charsWidth(contentStr.toCharArray(), 0, contentStr.length)
        val height = g.getFontMetrics(font).height
        return charsWidth
    }

    fun getContentHeight(fontSize: Int, g: Graphics2D): Int {
        val font = Font("宋体", Font.BOLD, fontSize)
        return g.getFontMetrics(font).height

    }

}

todo
本代码段，未实现角度旋转的问题。有空再研究。
为啥会有此篇。因为我的R10打印照片没有水印。我觉得，照片作为一种保存记忆的载体，应该有时间来铭刻。