gojs
Version:
Interactive diagrams, charts, and graphs, such as trees, flowcharts, orgcharts, UML, BPMN, or business diagrams
180 lines (156 loc) • 7.45 kB
HTML
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Minimal GoJS Sample Generating PDF</title>
<meta name="description" content="A simple demonstration of generating a PDF file in the browser, showing it in the page, and downloading it as a file." />
<!-- Copyright 1998-2023 by Northwoods Software Corporation. -->
<meta charset="UTF-8">
<script src="https://unpkg.com/gojs"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/require.js/2.3.6/require.min.js"></script>
<script src="https://unpkg.com/svg-to-pdfkit"></script>
<script id="code">
// This just creates and initializes a Diagram.
// The details do not really matter for this demo.
var myDiagram = null;
function init() {
const $ = go.GraphObject.make;
myDiagram =
new go.Diagram("myDiagramDiv",
{
"grid.visible": true,
"undoManager.isEnabled": true
});
myDiagram.nodeTemplate =
$(go.Node, "Auto",
$(go.Shape, "RoundedRectangle",
{ strokeWidth: 0, fill: "white" },
new go.Binding("fill", "color")),
$(go.TextBlock,
{ margin: 8 },
new go.Binding("text", "key"))
);
myDiagram.model = new go.GraphLinksModel(
[
{ key: "Alpha", color: "lightblue" },
{ key: "Beta", color: "orange" },
{ key: "Gamma", color: "lightgreen" },
{ key: "Delta", color: "pink" }
],
[
{ from: "Alpha", to: "Beta" },
{ from: "Alpha", to: "Gamma" },
{ from: "Beta", to: "Beta" },
{ from: "Gamma", to: "Delta" },
{ from: "Delta", to: "Alpha" }
]);
}
// This common function is called both when showing the PDF in an iframe and when downloading a PDF file.
// The options include:
// "pageSize", either "A4" or "LETTER" (the default)
// "layout", either "portrait" (the default) or "landscape"
// "margin" for the uniform page margin on each page (default is 36 pt)
// "padding" instead of the Diagram.padding when adjusting the Diagram.documentBounds for the area to render
// "imgWidth", size of diagram image for one page; defaults to the page width minus margins
// "imgHeight", size of diagram image for one page; defaults to the page height minus margins
// "parts", "background", "showTemporary", "showGrid", all are passed to Diagram.makeSvg
function generatePdf(action, diagram, options) {
if (!(diagram instanceof go.Diagram)) throw new Error("no Diagram provided when calling generatePdf");
if (!options) options = {};
const pageSize = (options.pageSize || "LETTER").toUpperCase();
if (pageSize !== "LETTER" && pageSize !== "A4") throw new Error("unknown page size: " + pageSize);
// LETTER: 612x792 pt == 816x1056 CSS units
// A4: 595.28x841.89 pt == 793.71x1122.52 CSS units
let pageWidth = (pageSize === "LETTER" ? 612 : 595.28) * 96 / 72; // convert from pt to CSS units
let pageHeight = (pageSize === "LETTER" ? 792 : 841.89) * 96 / 72;
const layout = (options.layout || "portrait").toLowerCase();
if (layout !== "portrait" && layout !== "landscape") throw new Error("unknown layout: " + layout);
if (layout === "landscape") {
const temp = pageWidth;
pageWidth = pageHeight;
pageHeight = temp;
}
const margin = options.margin !== undefined ? options.margin : 36; // pt: 0.5 inch margin on each side
const padding = options.padding !== undefined ? options.padding : diagram.padding; // CSS units
const imgWidth = options.imgWidth !== undefined ? options.imgWidth : (pageWidth-margin/72*96*2); // CSS units
const imgHeight = options.imgHeight !== undefined ? options.imgHeight : (pageHeight-margin/72*96*2); // CSS units
const pageOptions = {
size: pageSize,
margin: margin, // unit is pt
layout: layout
};
require(["blob-stream", "pdfkit"], (blobStream, PDFDocument) => {
const doc = new PDFDocument(pageOptions);
const stream = doc.pipe(blobStream());
const bnds = diagram.documentBounds;
// add some descriptive text
//doc.text(diagram.nodes.count + " nodes, " + diagram.links.count + " links Diagram size: " + bnds.width.toFixed(2) + " x " + bnds.height.toFixed(2));
const db = diagram.documentBounds.copy().subtractMargin(diagram.padding).addMargin(padding);
const p = db.position;
// iterate over page areas of document bounds
for (let j = 0; j < db.height; j += imgHeight) {
for (let i = 0; i < db.width; i += imgWidth) {
// if any page has no Parts partially or fully in it, skip rendering that page
const r = new go.Rect(p.x + i, p.y + j, imgWidth, imgHeight);
if (diagram.findPartsIn(r, true, false).count === 0) continue;
if (i > 0 || j > 0) doc.addPage(pageOptions);
const makeOptions = {};
if (options.parts !== undefined) makeOptions.parts = options.parts;
if (options.background !== undefined) makeOptions.background = options.background;
if (options.showTemporary !== undefined) makeOptions.showTemporary = options.showTemporary;
if (options.showGrid !== undefined) makeOptions.showGrid = options.showGrid;
makeOptions.scale = 1;
makeOptions.position = new go.Point(p.x + i, p.y + j);
makeOptions.size = new go.Size(imgWidth, imgHeight);
const svg = diagram.makeSvg(makeOptions);
SVGtoPDF(doc, svg, margin, margin, null);
}
}
doc.end();
stream.on('finish', () => action(stream.toBlob('application/pdf')));
});
}
// Two different uses of generatePdf: one shows the PDF document in the page,
// the other downloads it as a file and the user specifies where to save it.
const pdfOptions = // shared by both ways of generating PDF
{
showTemporary: true, // default is false
// layout: "landscape", // instead of "portrait"
// pageSize: "A4" // instead of "LETTER"
};
function showPdf() {
generatePdf(blob => {
const datauri = window.URL.createObjectURL(blob);
const frame = document.getElementById("myFrame");
if (frame) {
frame.style.display = "block";
frame.src = datauri;
setTimeout(() => window.URL.revokeObjectURL(datauri), 1);
}
}, myDiagram, pdfOptions);
}
function downloadPdf() {
generatePdf(blob => {
const datauri = window.URL.createObjectURL(blob);
const a = document.createElement("a");
a.style = "display: none";
a.href = datauri;
a.download = "myDiagram.pdf";
document.body.appendChild(a);
requestAnimationFrame(() => {
a.click();
window.URL.revokeObjectURL(datauri);
document.body.removeChild(a);
});
}, myDiagram, pdfOptions);
}
</script>
</head>
<body onload="init()">
<div id="sample">
<div id="myDiagramDiv" style="border: solid 1px black; width:400px; height:400px"></div>
<div><button onclick="showPdf()">Show PDF</button> <button onclick="downloadPdf()">Download PDF</button></div>
<iframe id="myFrame" style="display:none; width:1000px; height:1000px"></iframe>
</div>
</body>
</html>