package com.hzxc.groupactivity.server.util;

import java.awt.image.BufferedImage;

import java.io.*;

import java.math.BigDecimal;

import javax.imageio.ImageIO;

import net.coobird.thumbnailator.Thumbnails;

import org.apache.commons.lang3.StringUtils;

/**

 * Created by hdwang on 2018/12/13.

 */

public class PicUtils {

    public static void main(String[] args) {

        PicUtils.commpressPicForScale("/Users/hdwang/Downloads/1.jpg","/Users/hdwang/Downloads/1_s.jpg", 1000, 0.8,750,1334); // 图片小于1000kb

    }

    /**

      * 根据指定大小和指定精度压缩图片

      *

      * @param srcPath

      *            源图片地址

      * @param desPath

      *            目标图片地址

      * @param desFileSize

      *            指定图片大小，单位kb

      * @param accuracy

      *            精度，递归压缩的比率，建议小于0.9

     *  @param desMaxWidth

     *             目标最大宽度

     *  @param desMaxHeight

     *             目标最大高度

      * @return 目标文件路径

      */

    public static String commpressPicForScale(String srcPath, String desPath,

            long desFileSize, double accuracy,int desMaxWidth,int desMaxHeight) {

        if (StringUtils.isEmpty(srcPath) || StringUtils.isEmpty(srcPath)) {

            return null;

        }

        if (!new File(srcPath).exists()) {

            return null;

        }

        try {

            File srcFile = new File(srcPath);

            long srcFileSize = srcFile.length();

            System.out.println("源图片：" + srcPath + "，大小：" + srcFileSize / 1024

                                        + "kb");

            //获取图片信息

            BufferedImage bim = ImageIO.read(srcFile);

            int srcWidth = bim.getWidth();

            int srcHeight = bim.getHeight();

            //先转换成jpg

            Thumbnails.Builder builder = Thumbnails.of(srcFile).outputFormat("jpg");

            // 指定大小（宽或高超出会才会被缩放）

            if(srcWidth > desMaxWidth || srcHeight > desMaxHeight) {

                builder.size(desMaxWidth, desMaxHeight);

            }else{

                //宽高均小，指定原大小

                builder.size(srcWidth,srcHeight);

            }

            // 写入到内存

            ByteArrayOutputStream baos = new ByteArrayOutputStream(); //字节输出流（写入到内存）

            builder.toOutputStream(baos);

            // 递归压缩，直到目标文件大小小于desFileSize

            byte[] bytes = commpressPicCycle(baos.toByteArray(), desFileSize, accuracy);

            // 输出到文件

            File desFile = new File(desPath);

            FileOutputStream fos = new FileOutputStream(desFile);

            fos.write(bytes);
　　　　　　  fos.close();　

            System.out.println("目标图片：" + desPath + "，大小" + desFile.length() / 1024 + "kb");

            System.out.println("图片压缩完成！");

        } catch (Exception e) {

            e.printStackTrace();

            return null;

        }

        return desPath;

    }

    private static byte[] commpressPicCycle(byte[] bytes, long desFileSize, double accuracy) throws IOException {

       // File srcFileJPG = new File(desPath);

        long srcFileSizeJPG = bytes.length;

        // 2、判断大小，如果小于500kb，不压缩；如果大于等于500kb，压缩

        if (srcFileSizeJPG <= desFileSize * 1024) {

            return bytes;

        }

        // 计算宽高

        BufferedImage bim = ImageIO.read(new ByteArrayInputStream(bytes));

        int srcWdith = bim.getWidth();

        int srcHeigth = bim.getHeight();

        int desWidth = new BigDecimal(srcWdith).multiply(

                                new BigDecimal(accuracy)).intValue();

        int desHeight = new BigDecimal(srcHeigth).multiply(

                                new BigDecimal(accuracy)).intValue();

        ByteArrayOutputStream baos = new ByteArrayOutputStream(); //字节输出流（写入到内存）

        Thumbnails.of(new ByteArrayInputStream(bytes)).size(desWidth, desHeight).outputQuality(accuracy).toOutputStream(baos);

        return commpressPicCycle(baos.toByteArray(), desFileSize, accuracy);

    }

}