itextPdf超长图片转pdf文件

echarts生成的超长图片使用itextPdf转换为pdf

引入依赖

		<dependency>
            <groupId>com.itextpdf</groupId>
            <artifactId>itextpdf</artifactId>
            <version>5.5.10</version>
        </dependency>

注：使用的图片为竖版图片，要将echarts生成的图片顺时针旋转90度

图片旋转方法借鉴于此

package com.snow.imageutils.utils;

import com.itextpdf.text.BadElementException;
import com.itextpdf.text.Document;
import com.itextpdf.text.Image;

import com.itextpdf.text.Rectangle;
import com.itextpdf.text.pdf.PdfWriter;


import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import java.io.IOException;
import java.math.BigDecimal;

/**
 * @title: ImageToPdfUtil
 * @Author Qiao
 * @Date: 2023/2/22 0022 10:48
 * @Version 1.0
 */
public class ImageToPdfUtil {
	//itextPd 中pdf页面高度宽度最大值都不能超过14400
    private static int PAGE_MAX_HEIGHT=14400;
    private static int DECIMAL_POINT_NUM=2;
    private static int ONE_HUNDRED=100;

    //
    public static void imageConvertPDF(Image image,String filePath){
        Document document = new Document();
        //设置文档页边距
        document.setMargins(0, 0, 0, 0);
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(filePath);
            PdfWriter.getInstance(document, fos);
            //打开文档
            document.open();
            //获取图片高度
            float scaledHeight = image.getScaledHeight();
            //判断图片高度是否大于最高高度14400
            if (scaledHeight > PAGE_MAX_HEIGHT){
                //图片高度除以页面最大高度14400乘以100等于图片缩小比例
                BigDecimal bigDecimal = BigDecimal.valueOf(scaledHeight);
                BigDecimal bigDecimal1 = BigDecimal.valueOf(PAGE_MAX_HEIGHT);
                BigDecimal divide = bigDecimal1.divide(bigDecimal, DECIMAL_POINT_NUM, BigDecimal.ROUND_DOWN);
                BigDecimal multiply = divide.multiply(BigDecimal.valueOf(ONE_HUNDRED));
                //multiply 计算的图片缩放比例
                image.scalePercent(multiply.intValue());
            }
            float imageHeight = image.getScaledHeight();
            float imageWidth = image.getScaledWidth();
            //设置页面宽高与图片一致 最大为14400
            Rectangle rectangle = new Rectangle(imageWidth, imageHeight);
            document.setPageSize(rectangle);
            //图片居中
            image.setAlignment(Image.ALIGN_CENTER);
            //新建一页添加图片
            document.newPage();
            document.add(image);
        }catch (Exception e){

        }finally {
            //关闭文档
            document.close();
            try {
                fos.flush();
                fos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /*
     * @description: 将图片转换为BufferedImage
     * @author: qiaohui
     * @date: 2023/2/21 0021 14:46
     * @param:
     * @return:
     **/
    private static BufferedImage toBufferedImage(java.awt.Image image) {
        if (image instanceof BufferedImage) {
            return (BufferedImage) image;
        }
        image = new ImageIcon(image).getImage();
        BufferedImage bimage = null;
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        try {
            int transparency = Transparency.OPAQUE;
            GraphicsDevice gs = ge.getDefaultScreenDevice();
            GraphicsConfiguration gc = gs.getDefaultConfiguration();
            bimage = gc.createCompatibleImage(
                    image.getWidth(null), image.getHeight(null), transparency);
        } catch (HeadlessException e) {
            //........
        }

        if (bimage == null) {
            int type = BufferedImage.TYPE_INT_RGB;
            bimage = new BufferedImage(image.getWidth(null), image.getHeight(null), type);
        }
        Graphics g = bimage.createGraphics();

        g.drawImage(image, 0, 0, null);
        g.dispose();

        return bimage;

    }


    public static void main(String[] args) {
        try {
            Image image = Image.getInstance("E:/imageServer/6.png");
            imageConvertPDF(image,"E:/imageServer/6.pdf");
        } catch (BadElementException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

不压缩图片高度直接转换为pdf会出现以下错误，只需要将页面最大尺寸限制再14400以内即可

Exception in thread "main" ExceptionConverter: com.itextpdf.text.DocumentException: The page size must be smaller than 14400 by 14400. It's 694.0 by 17900.0.
	at com.itextpdf.text.pdf.PdfPage.<init>(PdfPage.java:96)
	at com.itextpdf.text.pdf.PdfDocument.endPage(PdfDocument.java:1021)
	at com.itextpdf.text.pdf.PdfDocument.close(PdfDocument.java:881)
	at com.itextpdf.text.Document.close(Document.java:415)
	at com.snow.imageutils.utils.ImageToPdfUtil.imageConvertPDF(ImageToPdfUtil.java:67)
	at com.snow.imageutils.utils.ImageToPdfUtil.main(ImageToPdfUtil.java:118)