package com.....util;

import lombok.extern.slf4j.Slf4j;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.rendering.ImageType;
import org.apache.pdfbox.rendering.PDFRenderer;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.ArrayList;
 
import java.util.List;

@Slf4j
public class PdfUtil {

    //經過測試,dpi為96,100,105,120,150,200中,105顯示效果較為清晰,體積穩定,dpi越高圖片體積越大,一般電腦顯示解析度為96
    public static final float DEFAULT_DPI = 105;
    //預設轉換的圖片格式為jpg
    public static final String DEFAULT_FORMAT = "jpg";

    public static void main(String[] args) throws IOException {
        PdfUtil.pdfToImage(
 
"D:\\test.pdf", "D:\\test");
    }

    public static void pdfToImage(String pdfPath, String imgPath) {
        try {
            //影象合併使用引數
            // 總寬度
            int width = 0;
            // 儲存一張圖片中的RGB資料
            int[] singleImgRGB;
            int shiftHeight = 0;
            //儲存每張圖片的畫素值
            BufferedImage imageResult = null
 
;
            //利用PdfBox生成影象
            PDDocument pdDocument = PDDocument.load(new File(pdfPath));
            PDFRenderer renderer = new PDFRenderer(pdDocument);
            //迴圈每個頁碼
            for (int i = 0, len = pdDocument.getNumberOfPages(); i < len; i++) {
                BufferedImage image = renderer.renderImageWithDPI(i, DEFAULT_DPI, ImageType.RGB);
                int imageHeight = image.getHeight();
                int imageWidth = image.getWidth();
                //計算高度和偏移量
                //使用第一張圖片寬度;
                width = imageWidth;
                //儲存每頁圖片的畫素值
                imageResult = new BufferedImage(width, imageHeight, BufferedImage.TYPE_INT_RGB);
                //這裡有高度，可以將imageHeight*len，我這裡值提取一頁所以不需要
                singleImgRGB = image.getRGB(0, 0, width, imageHeight, null, 0, width);
                // 寫入流中
                imageResult.setRGB(0, shiftHeight, width, imageHeight, singleImgRGB, 0, width);
                // 寫圖片
                File f = new File(imgPath, "test_" + i + ".png");
                if (!f.exists()) {
                    f.createNewFile();
                }
                ImageIO.write(imageResult, DEFAULT_FORMAT, f);
            }
            pdDocument.close();

        } catch (Exception e) {
            e.printStackTrace();
        }
        //OVER
    }

    public static List<byte[]> pdfToImage(String pdfPath) {
        List<byte[]> result = new ArrayList<>();
        try {
            //影象合併使用引數
            // 總寬度
            int width = 0;
            // 儲存一張圖片中的RGB資料
            int[] singleImgRGB;
            int shiftHeight = 0;
            //儲存每張圖片的畫素值
            BufferedImage imageResult = null;
            //利用PdfBox生成影象
            PDDocument pdDocument = PDDocument.load(new File(pdfPath));
            PDFRenderer renderer = new PDFRenderer(pdDocument);
            //迴圈每個頁碼
            for (int i = 0, len = pdDocument.getNumberOfPages(); i < len; i++) {
                BufferedImage image = renderer.renderImageWithDPI(i, DEFAULT_DPI, ImageType.RGB);
                int imageHeight = image.getHeight();
                int imageWidth = image.getWidth();
                //計算高度和偏移量
                //使用第一張圖片寬度;
                width = imageWidth;
                //儲存每頁圖片的畫素值
                imageResult = new BufferedImage(width, imageHeight, BufferedImage.TYPE_INT_RGB);
                //這裡有高度，可以將imageHeight*len，我這裡值提取一頁所以不需要
                singleImgRGB = image.getRGB(0, 0, width, imageHeight, null, 0, width);
                // 寫入流中
                imageResult.setRGB(0, shiftHeight, width, imageHeight, singleImgRGB, 0, width);
                // 寫圖片
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                ImageIO.write(imageResult, DEFAULT_FORMAT, out);
                result.add(out.toByteArray());
            }
            pdDocument.close();

        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }
}