I’m trying to generate a gojs diagram image using server side nodejs.
Here is my script below, but I can’t figure out why makeImageData
just returns null? How can I make it return base64 image data.
const go = require("gojs");
var $ = go.GraphObject.make; // for conciseness in defining templates
const myDiagram =
$(go.Diagram, '', // No DOM, so there can be no DIV!
{
viewSize: new go.Size(400,400), // Set this property in DOM-less environments
layout: $(go.LayeredDigraphLayout)
});
myDiagram.nodeTemplate =
$(go.Node, "Auto", // the Shape will go around the TextBlock
$(go.Shape, "RoundedRectangle", { strokeWidth: 0, fill: "white" },
// Shape.fill is bound to Node.data.color
new go.Binding("fill", "color")),
$(go.TextBlock,
{ margin: 8, font: "bold 14px sans-serif", stroke: '#333' }, // Specify a margin to add some room around the text
// TextBlock.text is bound to Node.data.key
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" }
]);
myDiagram.addDiagramListener('InitialLayoutCompleted', function() {
console.log(myDiagram.makeImageData({
background:'white',
scale:1,
type: 'image/png',
}));
});