emis-frontend/src/utils/pdfUtils.js

import { degrees,PageSizes, PDFDocument, rgb, StandardFonts } from 'pdf-lib';
import JsBarcode from 'jsbarcode'
import axios from "axios";
import Buffer from 'vue-buffer'
import * as pdfjs from 'pdfjs-dist';
import * as pdfjsWorker from 'pdfjs-dist/build/pdf.worker.entry';
/**
 * 浏览器打开新页签预览pdf
 * blob（必选）: pdf文件信息（Blob对象）【Blob】
 * docTitle（可选）: 浏览器打开新页签的title  【String】
 * isAddWatermark（可选，默认为false）: 是否需要添加水印 【Boolean】
 * watermark（必选）：水印信息 【Object: { type: string, text: string, image:{ bytes: ArrayBuffer, imageType: string } }】
 * watermark.type（可选）：类型 可选值：text、image、canvas
 * watermark.text（watermark.type为image时不填，否则必填）：水印文本。注意：如果watermark.type值为text，text取值仅支持拉丁字母中的218个字符。详见：https://www.npmjs.com/package/pdf-lib
 * watermark.image（watermark.type为image时必填，否则不填）：水印图片
 * watermark.image.bytes：图片ArrayBuffer
 * watermark.image.imageType：图片类型。可选值：png、jpg
 * Edit By WFT
 */
export default class PdfUtils {
  constructor() {
    const _self = this
  }


  async fillPdfForm(templatePath, outputPath, data) {
    const templateBytes = await fs.promises.readFile(templatePath);
    const fontBytes = await fs.promises.readFile('xxx.ttf');
    pdfDoc = await PDFDocument.load(templateBytes);
    pdfDoc.registerFontkit(fontkit);
    font = await pdfDoc.embedFont(fontBytes);
    const form = pdfDoc.getForm();

    for (const fieldKey in data) {
      const field = form.getTextField(fieldKey);
      if (field) {
        field.setText(data[fieldKey]);
        field.updateAppearances(font)
      }
    }

    const modifiedPdfBytes = await pdfDoc.save();

    await fs.promises.writeFile(outputPath, modifiedPdfBytes);
  }

  async getPdfByTpl(tplStr, params) {
    const tplBase64Str = 'data:application/pdf;base64,' + tplStr
    pdfDoc = await PDFDocument.load(tplBase64Str);
    pdfDoc.registerFontkit(fontkit);
    font = await pdfDoc.embedFont(fontBytes);
    const form = pdfDoc.getForm();
    for (const field in params) {
      const field = form.getTextField(field);
      if (field) {
        field.setText(data[field]);
        field.updateAppearances(font)
      }
    }
    const uint8Array = await newPdf.save();
    let mergeBuffer = Buffer.from(uint8Array);

    var blob=new Blob([mergeBuffer]);

  }






  // 添加 Text 水印
  async addTextWatermark({ pdfDoc, text, docTitle }) {
    // console.log(StandardFonts, 'StandardFonts-->>') // 字体
    const helveticaFont = await pdfDoc.embedFont(StandardFonts.Helvetica)
    const pages = pdfDoc.getPages()
    for(let i = 0; i < pages.length; i++) {
      let page = pages[i]
      let { width, height } = page.getSize()
      for(let i = 0; i < 6; i++) {
        for(let j = 0; j < 6; j++) {
          page.drawText(text, {
            x: j * 100,
            y: height / 5 + i * 100,
            size: 30,
            font: helveticaFont,
            color: rgb(0.95, 0.1, 0.1),
            opacity: 0.2,
            rotate: degrees(-35),
          })
        }
      }
    }
    // 序列化为字节
    const pdfBytes = await pdfDoc.save()
    this.preView(pdfBytes, docTitle)
  }

  // 添加 image 水印
  async addImageWatermark({ pdfDoc, bytes, imageType, docTitle }) {
    // 嵌入JPG图像字节和PNG图像字节
    let image
    const maps = {
      'jpg': pdfDoc.embedJpg.bind(pdfDoc),
      'png': pdfDoc.embedPng.bind(pdfDoc)
    }
    image = await maps[imageType](bytes)
    // 将JPG图像的宽度/高度缩小到原始大小的50%
    const dims = image.scale(0.5)
    const pages = pdfDoc.getPages()
    for(let i = 0; i < pages.length; i++) {
      let page = pages[i]
      let { width, height } = page.getSize()
      for(let i = 0; i < 6; i++) {
        for(let j = 0; j < 6; j++) {
          page.drawImage(image, {
            x: width / 5 - dims.width / 2 + j * 100,
            y: height / 5 - dims.height / 2 + i * 100,
            width: dims.width,
            height: dims.height,
            rotate: degrees(-35)
          })
        }
      }
    }
    // 序列化为字节
    const pdfBytes = await pdfDoc.save()
    this.preView(pdfBytes, docTitle)
  }

  // 合并文件
  async mergePdf2(urlList, fileName,isNeedDown=false) {
      let startTime = +new Date()
      // console.log(startTime)
      // eslint-disable-next-line
      let promises = [];
      urlList.map((url) => {
        // eslint-disable-next-line no-async-promise-executor
        let tmp = new Promise(async (resolve) => {
          const response = await axios({
            method: "get",
            url,
            responseType: "arraybuffer",
          });
          resolve(Buffer.from(response.data));
        });
        promises.push(tmp);
      });

      const pdfBuffers = await Promise.all(promises);

      const newPdf = await PDFDocument.create();
      for (let buffer of pdfBuffers) {
        const pdfDocument = await PDFDocument.load(buffer);
        const contentPages = await newPdf.copyPages(
          pdfDocument,
          pdfDocument.getPageIndices()
        );
        for (let page of contentPages) {
          newPdf.addPage(page);
        }
      }
      const uint8Array = await newPdf.save();
      let mergeBuffer = Buffer.from(uint8Array);

      var blob=new Blob([mergeBuffer]);

      if(isNeedDown){
        const url = window.URL.createObjectURL(blob);
        const link = document.createElement("a");
        link.href = url;
        link.setAttribute("download", fileName);
        if (typeof link.download === 'undefined') {
          link.setAttribute('target', '_blank')
        }
        // document.body.appendChild(link);
        // link.click();
        document.body.appendChild(link)
        link.click()
        document.body.removeChild(link)
      }else{
        const mergedPdfBlob = new Blob([mergeBuffer], {
          type: "application/pdf",
        });
        return URL.createObjectURL(mergedPdfBlob);;
      }
      // console.log(+new Date() - startTime)
  }

   getPdfnum(url) {
    return new Promise((resolve, reject) => {
      const imgFiles = [];
       //文件读取成功完成时触发
       const loadingTask = pdfjs.getDocument(url);
       loadingTask.promise.then(async (pdf) => {
         const pageNum = pdf.numPages;
         if (pageNum > 10) {
           reject('此pdf页数过多,请线下合并');
         }
         //准备图片
         for (let i = 1; i <= pageNum; i++) {
           imgFiles.push(i);
         }
         resolve(imgFiles);
       });
    });
  }

  /**
   * pdf保存图片
   * @param {Array} newimgList - canvas列表
   * @param {Number} x - 页面展示宽
   * @param {Number} y - 页面展示高
   * @param {String}fileName - 文件名称
   */
  savePdfImage(newimgList, x, y, fileName) {
    return new Promise((resolve, reject) => {

      // 创建canvas
      var canvas = document.createElement("canvas");
      canvas.width = 100;
      canvas.height = 100;
      canvas.id='d_canvas0';
      document.body.appendChild(canvas)

      let allcanvas = document.getElementById('d_canvas0');
      let allctx = allcanvas.getContext('2d');
      allcanvas.style.width = x;
      allcanvas.style.height = y * newimgList.length;
      const subCanvasWidth = newimgList[0].width;
      const subCanvasHeight = newimgList[0].height;
      allcanvas.width = subCanvasWidth;
      allcanvas.height = subCanvasHeight * newimgList.length;
      newimgList.forEach((subCanvas, index) => {
        // 计算当前图片在Canvas中的垂直位置
        const yPosition = index * subCanvasHeight;
        // 绘制图片
        // 使用drawImage的四个参数版本来指定绘制的源图像区域和目标区域
        allctx.drawImage(subCanvas, 0, yPosition, subCanvasWidth, subCanvasHeight);
        if (index === newimgList.length - 1) {
          let pngData = allcanvas.toDataURL('image/png');
          let obj = {
            url: pngData,
            name: fileName,
            imgWidth:subCanvasWidth,
            imgHeight:subCanvasHeight
          };
          document.body.removeChild(canvas)
          resolve(obj);
        }
      });
    });
  }
  
  pdfToImg(pdfUrl) {
    return new Promise((resolve, reject) => {
      const newimgList = [];
      const fileName = new Date().getTime()+"";
      const loadingTask = pdfjs.getDocument(pdfUrl);
      loadingTask.promise.then(async (pdf) => {
        let pageNum = pdf.numPages;
        console.log(pageNum);
        // 处理
        for (let i = 1; i <= pageNum; i++) {

            // 创建canvas
            var canvas = document.createElement("canvas");
            canvas.width = 100;
            canvas.height = 100;
            canvas.id='vmpdf_canvas_' + i;
            document.body.appendChild(canvas)

          let canvasItem = '';
          pdf.getPage(i).then(async (page) => {
            const canvas = document.getElementById('vmpdf_canvas_' + i);
            const ctx = canvas.getContext('2d');
            const viewport = page.getViewport({ scale: 4 });
            canvas.height = viewport.height;
            canvas.width = viewport.width;
            const destWidth = 298;
            const destheight = destWidth * (viewport.height / viewport.width);
            canvas.style.width = destWidth + 'px';
            canvas.style.height = destWidth * (viewport.height / viewport.width) + 'px';
            newimgList.push(canvas);
            await page.render({ canvasContext: ctx, viewport });
          
            // 使用file对象进行后续操作
            if (i === pageNum) {
              document.body.removeChild(canvas)
              setTimeout(async () => {
                const res = await this.savePdfImage(newimgList, destWidth, destheight, fileName);
                resolve(res);
              }, 500);
            }
          });
        }
      });
    
    });
  }

  getBlobUrl(base64Str, fileName,isNeedDown=false) {
    let blob = this.base64ToBlobNoHeader(base64Str);
    // new Blob([base64Str],{type: 'application/pdf'});
    let pdfurl = window.URL.createObjectURL(blob);
    if(isNeedDown){
      const link = document.createElement("a");
      link.href = pdfurl;
      link.setAttribute("download", fileName);
      if (typeof link.download === 'undefined') {
        link.setAttribute('target', '_blank')
      }
      document.body.appendChild(link)
      link.click()
      document.body.removeChild(link)
    }else{
      return pdfurl;
    }
  }



   base64ToBlobNoHeader(code) {
    //Base64一行不能超过76字符，超过则添加回车换行符。因此需要把base64字段中的换行符，回车符给去掉，有时候因为存在需要把加号空格之类的换回来，取决于base64存取时的规则。
      code = code.replace(/[\n\r]/g, '');
      var raw = window.atob(code);
      let rawLength = raw.length;
    //转换成pdf.js能直接解析的Uint8Array类型
      let uInt8Array = new Uint8Array(rawLength);
      for (let i = 0; i < rawLength; ++i) {
        uInt8Array[i] = raw.charCodeAt(i);
      }
      return new Blob([uInt8Array], {type: 'application/pdf'});//转成pdf类型
  }

  async mergePdf3(pdfFileList, fileName,isNeedDown=false) {
    let pdfBuffers = [];
    pdfFileList.map((item) => {
      let dateArray=this.base64ToBuffer(item);
      pdfBuffers.push(Buffer.from(dateArray));
    });
    const newPdf = await PDFDocument.create();
    for (let buffer of pdfBuffers) {
      const pdfDocument = await PDFDocument.load(buffer);
      const contentPages = await newPdf.copyPages(
        pdfDocument,
        pdfDocument.getPageIndices()
      );
      for (let page of contentPages) {
        newPdf.addPage(page);
      }
    }
    const uint8Array = await newPdf.save();
    let mergeBuffer = Buffer.from(uint8Array);

    var blob=new Blob([mergeBuffer]);

    if(isNeedDown){
      const url = window.URL.createObjectURL(blob);
      const link = document.createElement("a");
      link.href = url;
      link.setAttribute("download", fileName);
      if (typeof link.download === 'undefined') {
        link.setAttribute('target', '_blank')
      }
      document.body.appendChild(link)
      link.click()
      document.body.removeChild(link)
    }else{
      const mergedPdfBlob = new Blob([mergeBuffer], {
        type: "application/pdf",
      });
      return URL.createObjectURL(mergedPdfBlob);
    }
  }


  async mergePdfToA4(pdfFileList, fileName,isNeedDown=false) {
    let pdfBuffers = [];
    pdfFileList.map((item) => {
      let dateArray=this.base64ToBuffer(item);
      pdfBuffers.push(Buffer.from(dateArray));
    });
    const pdfDoc = await PDFDocument.create();
    const pageA4 = pdfDoc.addPage(PageSizes.A4);
    const drawHeight = pageA4.getHeight()/2;
    const drawWidth = pageA4.getWidth()/2;
    let i=0;
    let x=0;
    let y=0;
    let width=0;
    let height=0;
    let spaceWidth=2;
    for (let buffer of pdfBuffers) {
      const [page] = await pdfDoc.embedPdf(buffer);
      const pageDims = page.scale(1.0);
      // ...pageDims,
      // rotate: degrees(30),
      // opacity: 0.75,
      // Optional blendMode
      // Optional height
      // Optional opacity
      // Optional rotate
      // Optional width
      // Optional x
      // Optional xScale
      // Optional xSkew
      // Optional y
      // Optional yScale
      // Optional ySkew

      // let rateDif=pageDims.width/pageDims.height;
      //  width = drawHeight*rateDif
       width = pageDims.width;
       height = pageDims.height;

       

      if(i==0){
        x=spaceWidth;
        y=pageA4.getHeight()/2;
      }
      else if(i==1){
        x=spaceWidth+pageA4.getWidth()/2;
        y=pageA4.getHeight()/2;
      }
      else if(i==2){
        x=spaceWidth;
        y=spaceWidth;
      }
      else if(i==3){
        x=spaceWidth+pageA4.getWidth()/2;
        y=spaceWidth;
      }

      pageA4.drawPage(page, {
        x: x,
        y: y,
        width:width,
        height:height
      });

      i++;
    }

    const uint8Array = await pdfDoc.save();
    let mergeBuffer = Buffer.from(uint8Array);

    var blob=new Blob([mergeBuffer]);

    if(isNeedDown){
      const url = window.URL.createObjectURL(blob);
      const link = document.createElement("a");
      link.href = url;
      link.setAttribute("download", fileName);
      if (typeof link.download === 'undefined') {
        link.setAttribute('target', '_blank')
      }
      document.body.appendChild(link)
      link.click()
      document.body.removeChild(link)
    }else{
      const mergedPdfBlob = new Blob([mergeBuffer], {
        type: "application/pdf",
      });
      return URL.createObjectURL(mergedPdfBlob);
    }
  }

  downloadBase64(base64Str,fileName) {
    let result = base64Str.replace(/[\r\n]/g, "");
    let pdfBase64 = `data:application/pdf;base64,${result}`;
    let url = URL.createObjectURL(this.base64ToBlob(pdfBase64));
    const link = document.createElement("a");
      link.href = url;
      link.setAttribute("download", fileName);
      if (typeof link.download === 'undefined') {
        link.setAttribute('target', '_blank')
      }
      document.body.appendChild(link)
      link.click()
      document.body.removeChild(link)

  }



  async urlToBlob(url) {
    const response = await fetch(url);
    const arrayBuffer = await response.arrayBuffer();
    const byteArray = new Uint8Array(arrayBuffer);
    return new Blob([byteArray], {type: response.headers.get('content-type')});
  }
    
   blobToBase64(blob) {
    return new Promise((resolve, reject) => {
    const reader = new FileReader();
    reader.onload = () => resolve(reader.result);
    reader.onerror = reject;
    reader.readAsDataURL(blob);
    });
  }

  fileTobase64(file) {
    let reader = new FileReader();
    reader.readAsDataURL(file)
  }

  blobToArrayBuffer(blob, callback) {
    let reader = new FileReader();
    reader.readAsArrayBuffer(blob);
    reader.onload = function () {
        return callback(this.result);
    }
  }

// let blob = new Blob([1, 2, 3, 4, 5]);
// blobToArrayBuffer(blob, (arrayBuffer) => { console.log(arrayBuffer) })



  base64ToFile(base64Data, filename) { // 64转file
    if (typeof base64Data != 'string') {
      // this.$toast("urlData不是字符串")
      return;
    }
    var arr = base64Data.split(',')
    var type = arr[0].match(/:(.*?);/)[1]
    var fileExt = type.split('/')[1]
    var bstr = atob(arr[1])
    var n = bstr.length
    var u8arr = new Uint8Array(n)
    while (n--) {
      u8arr[n] = bstr.charCodeAt(n);
    }
    return new File([u8arr], filename +'.' + fileExt, {
      type: type
    });
  }

  base64ToBlob(base64Data) {
    let arr = base64Data.split(','),
    fileType = arr[0].match(/:(.*?);/)[1],
    bstr = atob(arr[1]),
    l = bstr.length,
    u8Arr = new Uint8Array(l);
    while (l--) {
        u8Arr[l] = bstr.charCodeAt(l);
    }
    return new Blob([u8Arr], {
        type: fileType
    });
  }

  base64ToBuffer(base64Str){
    const padding = '='.repeat((4 - base64Str.length % 4) % 4);
    const base64 = (base64Str + padding).replace(/\-/g, '+').replace(/_/g, '/');
    const rawData = window.atob(base64);
    const outputArray = new Uint8Array(rawData.length);
    for (let i = 0; i < rawData.length; ++i) {
        outputArray[i] = rawData.charCodeAt(i);
    }
    return outputArray;
  }


  // base64ToArrayBuffer(base64Str) {
  //   let arr = base64Data.split(','),
  //   fileType = arr[0].match(/:(.*?);/)[1],
  //   bstr = atob(result),
  //   l = bstr.length,
  //   u8Arr = new Uint8Array(l);
  //   while (l--) {
  //       u8Arr[l] = bstr.charCodeAt(l);
  //   }
  //   let blob = new Blob([u8Arr], {
  //     type: fileType
  //    });
  //   let reader = new FileReader();
  //   reader.onload = function(result) {
  //       console.log(result);
  //   }

  //   reader.readAsArrayBuffer(blob);
  // }

  base64File(base64Str,fileName){
    var fileExt=".pdf";

    var bstr = atob(base64Str)
    var n = bstr.length
    var u8arr = new Uint8Array(n)
    while (n--) {
      u8arr[n] = bstr.charCodeAt(n);
    }
    return new File([u8arr], fileName +'.' + fileExt, {
      type: type
    });
  }

  getObjectURL(file) {
    let url = null;
    if (window.createObjectURL != undefined) { // basic
        url = window.createObjectURL(file);
    } else if (window.webkitURL != undefined) { // webkit or chrome
        url = window.webkitURL.createObjectURL(file);
    } else if (window.URL != undefined) { // mozilla(firefox)
        url = window.URL.createObjectURL(file);
    }
    return url;
  }

  // 添加 canvas 水印
  addCanvasWatermark({ pdfDoc, text, docTitle }) {
    // 旋转角度大小
    const rotateAngle = Math.PI / 6;

    // labels是要显示的水印文字，垂直排列
    let labels = new Array();
    labels.push(text);

    const pages = pdfDoc.getPages()

    const size = pages[0].getSize()

    let pageWidth = size.width
    let pageHeight = size.height

    let canvas = document.createElement('canvas');
    let canvasWidth = canvas.width = pageWidth;
    let canvasHeight = canvas.height = pageHeight;

    const context = canvas.getContext('2d');
    context.font = "15px Arial";

    // 先平移到画布中心
    context.translate(pageWidth / 2, pageHeight / 2 - 250);
    // 在绕画布逆方向旋转30度
    context.rotate(-rotateAngle);
    // 在还原画布的坐标中心
    context.translate(-pageWidth / 2, -pageHeight / 2);

    // 获取文本的最大长度
    let textWidth = Math.max(...labels.map(item => context.measureText(item).width));

    let lineHeight = 15, fontHeight = 12, positionY, i
    i = 0, positionY = 0
    while (positionY <= pageHeight) {
      positionY = positionY + lineHeight * 5
      i++
    }
    canvasWidth += Math.sin(rotateAngle) * (positionY + i * fontHeight) // 给canvas加上画布向左偏移的最大距离
    canvasHeight = 2 * canvasHeight
    for (positionY = 0, i = 0; positionY <= canvasHeight; positionY = positionY + lineHeight * 5) {
      // 进行画布偏移是为了让画布旋转之后水印能够左对齐;
      context.translate(-(Math.sin(rotateAngle) * (positionY + i * fontHeight)), 0);
      for (let positionX = 0; positionX < canvasWidth; positionX += 2 * textWidth) {
        let spacing = 0;
        labels.forEach(item => {
          context.fillText(item, positionX, positionY + spacing);
          context.fillStyle = 'rgba(187, 187, 187, .8)'; // 字体颜色
          spacing = spacing + lineHeight;
        })
      }
      context.translate(Math.sin(rotateAngle) * (positionY + i * fontHeight), 0);
      context.restore();
      i++
    }
    // 图片的base64编码路径
    let dataUrl = canvas.toDataURL('image/png');
    // 使用Xhr请求获取图片Blob
    let xhr = new XMLHttpRequest();
    xhr.open("get", dataUrl, true);
    xhr.responseType = "blob";
    xhr.onload = res => {
      const imgBlob = res.target.response
      // 获取Blob图片Buffer
      imgBlob.arrayBuffer().then(async buffer => {
        const pngImage = await pdfDoc.embedPng(buffer)
        for(let i = 0; i < pages.length; i++) {
          pages[i].drawImage(pngImage)
        }
        // 序列化为字节
        const pdfBytes = await pdfDoc.save()
        this.preView(pdfBytes, docTitle)
      })
    }
    xhr.send();
  }

  // 预览
  preView(stream, docTitle) {
    const URL = window.URL || window.webkitURL;
    const href = URL.createObjectURL(new Blob([stream], { type: 'application/pdf;charset=utf-8' }))
    const wo = window.open(href)
    // 设置新打开的页签 document title
    let timer = setInterval(() => {
      if(wo.closed) {
        clearInterval(timer)
      } else {
        wo.document.title = docTitle
      }
    }, 500)
  }
}