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f0982d7d9a
将 electron.js 中的 PDF 导出、渲染器辅助函数和工具函数拆分为独立模块： - electron/lib/pdf-export.js: PDF 导出相关功能 - electron/lib/renderer.js: 渲染器辅助函数 - electron/lib/other.js: 平台检测和 URL 验证常量 此重构提高了代码可维护性，减少了主文件的复杂度。
440 lines
18 KiB
JavaScript
Vendored
440 lines
18 KiB
JavaScript
Vendored
const path = require('path')
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const {BrowserWindow, ipcMain} = require('electron')
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const loger = require("electron-log");
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const crc = require("crc");
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const zlib = require('zlib');
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const PDFDocument = require('pdf-lib').PDFDocument;
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const config = require('../package.json');
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const MICRON_TO_PIXEL = 264.58 //264.58 micron = 1 pixel
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const PIXELS_PER_INCH = 100.117 // Usually it is 100 pixels per inch but this give better results
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const PNG_CHUNK_IDAT = 1229209940;
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const LARGE_IMAGE_AREA = 30000000;
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const pdfExport = {
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//NOTE: Key length must not be longer than 79 bytes (not checked)
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writePngWithText(origBuff, key, text, compressed, base64encoded) {
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let isDpi = key == 'dpi';
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let inOffset = 0;
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let outOffset = 0;
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let data = text;
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let dataLen = isDpi ? 9 : key.length + data.length + 1; //we add 1 zeros with non-compressed data, for pHYs it's 2 of 4-byte-int + 1 byte
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//prepare compressed data to get its size
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if (compressed) {
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data = zlib.deflateRawSync(encodeURIComponent(text));
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dataLen = key.length + data.length + 2; //we add 2 zeros with compressed data
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}
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let outBuff = Buffer.allocUnsafe(origBuff.length + dataLen + 4); //4 is the header size "zTXt", "tEXt" or "pHYs"
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try {
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let magic1 = origBuff.readUInt32BE(inOffset);
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inOffset += 4;
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let magic2 = origBuff.readUInt32BE(inOffset);
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inOffset += 4;
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if (magic1 != 0x89504e47 && magic2 != 0x0d0a1a0a) {
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throw new Error("PNGImageDecoder0");
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}
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outBuff.writeUInt32BE(magic1, outOffset);
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outOffset += 4;
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outBuff.writeUInt32BE(magic2, outOffset);
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outOffset += 4;
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} catch (e) {
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loger.error(e.message, {stack: e.stack});
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throw new Error("PNGImageDecoder1");
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}
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try {
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while (inOffset < origBuff.length) {
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let length = origBuff.readInt32BE(inOffset);
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inOffset += 4;
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let type = origBuff.readInt32BE(inOffset)
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inOffset += 4;
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if (type == PNG_CHUNK_IDAT) {
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// Insert zTXt chunk before IDAT chunk
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outBuff.writeInt32BE(dataLen, outOffset);
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outOffset += 4;
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let typeSignature = isDpi ? 'pHYs' : (compressed ? "zTXt" : "tEXt");
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outBuff.write(typeSignature, outOffset);
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outOffset += 4;
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if (isDpi) {
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let dpm = Math.round(parseInt(text) / 0.0254) || 3937; //One inch is equal to exactly 0.0254 meters. 3937 is 100dpi
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outBuff.writeInt32BE(dpm, outOffset);
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outBuff.writeInt32BE(dpm, outOffset + 4);
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outBuff.writeInt8(1, outOffset + 8);
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outOffset += 9;
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data = Buffer.allocUnsafe(9);
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data.writeInt32BE(dpm, 0);
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data.writeInt32BE(dpm, 4);
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data.writeInt8(1, 8);
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} else {
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outBuff.write(key, outOffset);
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outOffset += key.length;
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outBuff.writeInt8(0, outOffset);
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outOffset++;
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if (compressed) {
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outBuff.writeInt8(0, outOffset);
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outOffset++;
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data.copy(outBuff, outOffset);
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} else {
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outBuff.write(data, outOffset);
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}
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outOffset += data.length;
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}
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let crcVal = 0xffffffff;
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crcVal = crc.crcjam(typeSignature, crcVal);
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crcVal = crc.crcjam(data, crcVal);
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// CRC
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outBuff.writeInt32BE(crcVal ^ 0xffffffff, outOffset);
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outOffset += 4;
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// Writes the IDAT chunk after the zTXt
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outBuff.writeInt32BE(length, outOffset);
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outOffset += 4;
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outBuff.writeInt32BE(type, outOffset);
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outOffset += 4;
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origBuff.copy(outBuff, outOffset, inOffset);
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// Encodes the buffer using base64 if requested
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return base64encoded ? outBuff.toString('base64') : outBuff;
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}
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outBuff.writeInt32BE(length, outOffset);
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outOffset += 4;
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outBuff.writeInt32BE(type, outOffset);
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outOffset += 4;
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origBuff.copy(outBuff, outOffset, inOffset, inOffset + length + 4);// +4 to move past the crc
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inOffset += length + 4;
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outOffset += length + 4;
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}
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} catch (e) {
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loger.error(e.message, {stack: e.stack});
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throw e;
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}
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},
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//TODO Create a lightweight html file similar to export3.html for exporting to vsdx
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exportVsdx(event, args, directFinalize) {
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let win = new BrowserWindow({
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width: 1280,
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height: 800,
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show: false,
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webPreferences: {
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preload: path.join(__dirname, 'electron-preload.js'),
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webSecurity: true,
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nodeIntegration: true,
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contextIsolation: true,
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},
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})
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let loadEvtCount = 0;
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function loadFinished() {
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loadEvtCount++;
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if (loadEvtCount == 2) {
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win.webContents.send('export-vsdx', args);
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ipcMain.once('export-vsdx-finished', (evt, data) => {
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let hasError = false;
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if (data == null) {
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hasError = true;
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}
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//Set finalize here since it is call in the reply below
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function finalize() {
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win.destroy();
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}
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if (directFinalize === true) {
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event.finalize = finalize;
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} else {
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//Destroy the window after response being received by caller
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ipcMain.once('export-finalize', finalize);
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}
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if (hasError) {
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event.reply('export-error');
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} else {
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event.reply('export-success', data);
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}
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});
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}
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}
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//Order of these two events is not guaranteed, so wait for them async.
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//TOOD There is still a chance we catch another window 'app-load-finished' if user created multiple windows quickly
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ipcMain.once('app-load-finished', loadFinished);
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win.webContents.on('did-finish-load', loadFinished);
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},
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async mergePdfs(pdfFiles, xml) {
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//Pass throgh single files
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if (pdfFiles.length == 1 && xml == null) {
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return pdfFiles[0];
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}
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try {
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const pdfDoc = await PDFDocument.create();
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pdfDoc.setCreator(config.name);
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if (xml != null) {
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//Embed diagram XML as file attachment
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await pdfDoc.attach(Buffer.from(xml).toString('base64'), config.name + '.xml', {
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mimeType: 'application/vnd.jgraph.mxfile',
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description: config.name + ' Content'
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});
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}
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for (let i = 0; i < pdfFiles.length; i++) {
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const pdfFile = await PDFDocument.load(pdfFiles[i].buffer);
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const pages = await pdfDoc.copyPages(pdfFile, pdfFile.getPageIndices());
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pages.forEach(p => pdfDoc.addPage(p));
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}
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const pdfBytes = await pdfDoc.save();
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return Buffer.from(pdfBytes);
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} catch (e) {
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throw new Error('Error during PDF combination: ' + e.message);
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}
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},
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exportDiagram(event, args, directFinalize) {
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if (args.format == 'vsdx') {
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pdfExport.exportVsdx(event, args, directFinalize);
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return;
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}
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let browser = null;
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try {
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browser = new BrowserWindow({
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webPreferences: {
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preload: path.join(__dirname, 'electron-preload.js'),
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backgroundThrottling: false,
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contextIsolation: true,
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disableBlinkFeatures: 'Auxclick' // Is this needed?
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},
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show: false,
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frame: false,
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enableLargerThanScreen: true,
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transparent: args.format == 'png' && (args.bg == null || args.bg == 'none'),
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});
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if (serverUrl) {
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browser.loadURL(serverUrl + 'drawio/webapp/export3.html').then(_ => { }).catch(_ => { })
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} else {
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browser.loadFile('./public/drawio/webapp/export3.html').then(_ => { }).catch(_ => { })
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}
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const contents = browser.webContents;
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let pageByPage = (args.format == 'pdf' && !args.print), from, to, pdfs;
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if (pageByPage) {
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from = args.allPages ? 0 : parseInt(args.from || 0);
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to = args.allPages ? 1000 : parseInt(args.to || 1000) + 1; //The 'to' will be corrected later
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pdfs = [];
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args.from = from;
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args.to = from;
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args.allPages = false;
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}
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contents.on('did-finish-load', function () {
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//Set finalize here since it is call in the reply below
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function finalize() {
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browser.destroy();
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}
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if (directFinalize === true) {
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event.finalize = finalize;
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} else {
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//Destroy the window after response being received by caller
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ipcMain.once('export-finalize', finalize);
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}
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function renderingFinishHandler(evt, renderInfo) {
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if (renderInfo == null) {
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event.reply('export-error');
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return;
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}
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let pageCount = renderInfo.pageCount, bounds = null;
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//For some reason, Electron 9 doesn't send this object as is without stringifying. Usually when variable is external to function own scope
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try {
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bounds = JSON.parse(renderInfo.bounds);
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} catch (e) {
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bounds = null;
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}
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let pdfOptions = {pageSize: 'A4'};
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let hasError = false;
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if (bounds == null || bounds.width < 5 || bounds.height < 5) //very small page size never return from printToPDF
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{
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//A workaround to detect errors in the input file or being empty file
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hasError = true;
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} else {
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pdfOptions = {
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printBackground: true,
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pageSize: {
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width: bounds.width / PIXELS_PER_INCH,
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height: (bounds.height + 2) / PIXELS_PER_INCH //the extra 2 pixels to prevent adding an extra empty page
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},
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margins: {
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top: 0,
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bottom: 0,
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left: 0,
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right: 0
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} // no margin
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}
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}
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let base64encoded = args.base64 == '1';
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if (hasError) {
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event.reply('export-error');
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} else if (args.format == 'png' || args.format == 'jpg' || args.format == 'jpeg') {
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//Adds an extra pixel to prevent scrollbars from showing
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let newBounds = {
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width: Math.ceil(bounds.width + bounds.x) + 1,
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height: Math.ceil(bounds.height + bounds.y) + 1
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};
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browser.setBounds(newBounds);
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//TODO The browser takes sometime to show the graph (also after resize it takes some time to render)
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// 1 sec is most probably enough (for small images, 5 for large ones) BUT not a stable solution
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setTimeout(function () {
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browser.capturePage().then(function (img) {
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//Image is double the given bounds, so resize is needed!
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let tScale = 1;
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//If user defined width and/or height, enforce it precisely here. Height override width
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if (args.h) {
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tScale = args.h / newBounds.height;
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} else if (args.w) {
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tScale = args.w / newBounds.width;
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}
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newBounds.width *= tScale;
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newBounds.height *= tScale;
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img = img.resize(newBounds);
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let data = args.format == 'png' ? img.toPNG() : img.toJPEG(args.jpegQuality || 90);
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if (args.dpi != null && args.format == 'png') {
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data = pdfExport.writePngWithText(data, 'dpi', args.dpi);
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}
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if (args.embedXml == "1" && args.format == 'png') {
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data = pdfExport.writePngWithText(data, "mxGraphModel", args.xml, true,
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base64encoded);
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} else {
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if (base64encoded) {
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data = data.toString('base64');
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}
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}
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event.reply('export-success', data);
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});
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}, bounds.width * bounds.height < LARGE_IMAGE_AREA ? 1000 : 5000);
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} else if (args.format == 'pdf') {
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if (args.print) {
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pdfOptions = {
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scaleFactor: args.pageScale,
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printBackground: true,
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pageSize: {
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width: args.pageWidth * MICRON_TO_PIXEL,
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//This height adjustment fixes the output. TODO Test more cases
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height: (args.pageHeight * 1.025) * MICRON_TO_PIXEL
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},
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marginsType: 1 // no margin
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};
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contents.print(pdfOptions, (success, errorType) => {
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//Consider all as success
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event.reply('export-success', {});
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});
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} else {
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contents.printToPDF(pdfOptions).then(async (data) => {
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pdfs.push(data);
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to = to > pageCount ? pageCount : to;
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from++;
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if (from < to) {
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args.from = from;
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args.to = from;
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ipcMain.once('render-finished', renderingFinishHandler);
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contents.send('render', args);
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} else {
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data = await pdfExport.mergePdfs(pdfs, args.embedXml == '1' ? args.xml : null);
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event.reply('export-success', data);
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}
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})
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.catch((error) => {
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event.reply('export-error', error);
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});
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}
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} else if (args.format == 'svg') {
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contents.send('get-svg-data');
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ipcMain.once('svg-data', (evt, data) => {
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event.reply('export-success', data);
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});
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} else {
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event.reply('export-error', 'Error: Unsupported format');
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}
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}
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ipcMain.once('render-finished', renderingFinishHandler);
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if (args.format == 'xml') {
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ipcMain.once('xml-data', (evt, data) => {
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event.reply('export-success', data);
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});
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ipcMain.once('xml-data-error', () => {
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event.reply('export-error');
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});
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}
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args.border = args.border || 0;
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args.scale = args.scale || 1;
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contents.send('render', args);
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});
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} catch (e) {
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if (browser != null) {
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browser.destroy();
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}
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event.reply('export-error', e);
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console.log('export-error', e);
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}
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},
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}
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const onExport = () => {
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ipcMain.on('export', pdfExport.exportDiagram);
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}
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module.exports = {pdfExport, onExport};
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