How to get the complete style declaration of character in IText using FabricJS?

FabricJS Javascript HTML5 Canvas

In this tutorial, we are going to learn about how to get the complete style declaration of character in IText using FabricJS. The IText class was introduced in FabricJS version 1.4, extends fabric.Text and is used to create IText instances. An IText instance gives us the freedom to select, cut, paste or add new text without additional configurations. There are also various supported key combinations and mouse/touch combinations which make text interactive which are not provided in Text.

Textbox, however, which is based on IText allows us to resize the text rectangle and wraps lines automatically. This is not true for IText as height is not adjusted based on the wrapping of lines. We can manipulate our IText object by using various properties. Likewise, we can get the complete style declaration of a character by using the getCompleteStyleDeclaration method.

Syntax

getCompleteStyleDeclaraction(lineIndex: Number, charIndex: Number): Object

Parameters

lineIndex − This parameter accepts a Number which specifies the line number of the required character.
charIndex − This parameter accepts a Number which denotes the position of the character on that line.

Example 1

Using the getCompleteStyleDeclaration method

Let’s see a code example to see how the IText object looks like when the getCompleteStyleDeclaration method is used. In this case, we will be returned the complete style declaration for the 2nd character of the 0th line. The character has been assigned a light yellow text background colour.


<!DOCTYPE html>
<html>
<head>
   <!-- Adding the Fabric JS Library-->
   <script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/510/fabric.min.js"></script>
</head>
<body>
   <h2>Using the getCompleteStyleDeclaration method</h2>
   <p>You can open console from dev tools and see the style declaration for 2nd character of the first line</p>
   <canvas id="canvas"></canvas>
   
   <script>
      // Initiate a canvas instance
      var canvas = new fabric.Canvas("canvas");
      canvas.setWidth(document.body.scrollWidth);
      canvas.setHeight(250);

      // Initiate an itext object
      var itext = new fabric.IText(
         "Add sample text here.
Lorem ipsum dolor sit amet
consectetur adipiscing elit.",{
            width: 300,
            left: 60,
            top: 70,
            fill: "red",
            styles: {
               0: {
                  1: {
                     textBackgroundColor: "rgba(253,255,214,0.9)",
                  },
               },
            },
         }
      );

      // Add it to the canvas
      canvas.add(itext);

      // Using getCompleteStyleDeclaration method
      console.log(
         "The style object is as follows: ",
         itext.getCompleteStyleDeclaration(0, 1)
      );
   </script>
</body>
</html>

Example 2

Using the getCompleteStyleDeclaration method for comparison

Let’s see a code example to compare the style declarations for two characters at the same index in two different lines. In this case, we have selected the second characters from line 1 and 2 and hence they have been highlighted with a different text background colour. Since we have specified a different fill colour, textBackgroundColor and fontSize for both of these characters, those values would be reflected in our console and we will be able to compare those changes.


<!DOCTYPE html>
<html>
<head>
   <!-- Adding the Fabric JS Library-->
   <script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/510/fabric.min.js"></script>
</head>
<body>
   <h2>Using the getCompleteStyleDeclaration method for comparison</h2>
   <p>You can open console from dev tools and see the style declaration for both lines</p>
   <canvas id="canvas"></canvas>

   <script>
      // Initiate a canvas instance
      var canvas = new fabric.Canvas("canvas");
      canvas.setWidth(document.body.scrollWidth);
      canvas.setHeight(250);

      // Initiate an itext object
      var itext = new fabric.IText(
         "Add sample text here.
Lorem ipsum dolor sit amet",{
            width: 300,
            left: 60,
            top: 70,
            fill: "red",
            styles: {
               0: {
                  1: {
                     textBackgroundColor: "rgba(130,111,201,0.6)",
                     fontSize: 30,
                     fill: "black",
                  },
               },
               1: {
                  1: {
                     textBackgroundColor: "rgba(52,235,189,0.5)",
                     fontSize: 90,
                     fill: "green",
                  },
               },
            },
         }
      );

      // Add it to the canvas
      canvas.add(itext);

      // Using getCompleteStyleDeclaration method
      console.log(
         "The style object for 2nd character of 1st line is as follows: ",
         itext.getCompleteStyleDeclaration(0, 1)
      );
      console.log(
         "The style object for 2nd character of 2nd line is as follows: ",
         itext.getCompleteStyleDeclaration(1, 1)
      );
   </script>
</body>
</html>

Rahul Gurung

Updated on: 12-Sep-2022

138 Views

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