How to change the font formatting of annotations at runtime in JavaScript Diagram

This article explains how to change the font formatting of annotations at runtime in a JavaScript Diagram. An Annotation is a text label that appears on a node or connector in a JavaScript diagram, allowing you to describe or label the object. An annotation is used to textually represent an object with a string that can be edited at runtime. You can easily customize annotations by adjusting font properties such as bold, italic, underline, size, text color, and background color, enhancing the clarity and appearance of your diagram.

Below is a code example demonstrating how to set the initial font formatting for annotations on nodes and connectors.

// initialize Diagram component
 var diagram = new ej.diagrams.Diagram({
   width: '100%', height: '600px', nodes: [node] ,connectors:[connector]
   }, '#element'); 

//initialize node and connector with annotations
var node = {
   id:'node',
   // Position of the node
   offsetX: 300,
   offsetY: 300,
   // Size of the node
   width: 100,
   height: 100,
   style: { fill: '#6BA5D7', strokeColor: 'white' },
   annotations: [
     {
       content: 'Annotation',
       style: {
         color: 'blue',
         fontFamily: 'TimesNewRoman',
         fill: 'orange',
       },
       visibility:true
     },
    
   ],
 };
 var connector = { id: "connector1",
 type:'Straight',
 sourcePoint: {x: 100,y: 100},
 targetPoint: { x: 200,y: 200},
 annotations: [
   {
     content: 'Annotation',
     style: {
       color: 'blue',
       fontFamily: 'TimesNewRoman',
       fill: 'orange',
     },
     visibility:true
   },
  
 ],
 } 

The code snippet below shows how to dynamically update the annotation font formats for a node and a connector.

document.getElementById('Bold').onclick = () => {
       diagram.nodes[0].annotations[0].style.bold = true;
       diagram.connectors[0].annotations[0].style.bold = true;
   };
   document.getElementById('Italic').onclick = () => {
     diagram.nodes[0].annotations[0].style.italic = true;
     diagram.connectors[0].annotations[0].style.italic = true;
   };
   document.getElementById('textsize').onclick = (args) => {
     diagram.nodes[0].annotations[0].style.fontSize =  Number(args.target.value);
     diagram.connectors[0].annotations[0].style.fontSize =  Number(args.target.value);
   }
   document.getElementById('textcolor').onchange = (args) => {
     diagram.nodes[0].annotations[0].style.color = args.target.value;
     diagram.connectors[0].annotations[0].style.color = args.target.value;
     diagram.dataBind();
   };
   document.getElementById('Underline').onclick = () => {
     diagram.nodes[0].annotations[0].style.textDecoration = 'Underline';
     diagram.connectors[0].annotations[0].style.textDecoration = 'Underline';
   };
   document.getElementById('bgcolor').onchange = (args) => {
     diagram.nodes[0].annotations[0].style.fill = args.target.value;
     diagram.connectors[0].annotations[0].style.fill = args.target.value;
     diagram.dataBind();
   };

Refer to the working sample for additional details and implementation: Sample

Conclusion

We hope you enjoyed learning about how to change the font formatting of annotations at runtime in JavaScript Diagram.

You can refer to our JavaScript Diagram feature tour page to learn about its other groundbreaking feature representations and documentation, as well as how to quickly get started with configuration specifications. You can also explore our JavaScript Diagram example to understand how to create and manipulate data.

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