How to create a String representation of a Line object using FabricJS?

FabricJS Javascript HTML5 Canvas

In this tutorial, we are going to learn about how to create a String representation of a Line object using FabricJS. A Line element is one of the basic elements provided in FabricJS. It is used for creating straight lines. Because line elements are geometrically one-dimensional and do not contain an interior, they are never filled. We can create a line object by creating an instance of fabric.Line, specifying the x and y coordinates of the line and adding it to the canvas. In order to create a String representation of a Line object, we use the toString method.

Syntax

 toString(): String

Using the toString method

Example

Let’s see a code example to see the logged output when the toString method is used. In this case, a String representation of the line instance will be returned.


<!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 toString method</h2>
   <p>
      You can open console from dev tools and see that the logged output contains the String representation of the line instance
   </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 a Line object
      var line = new fabric.Line([200, 100, 100, 40], {
         stroke: "blue",
         strokeWidth: 20,
      });
      
      // Add it to the canvas
      canvas.add(line);
      
      // Using the toString method
      console.log(
         "String representation of the Line instance is: ",
         line.toString()
      );
   </script>
</body>
</html>

Using toString method to compare two different elements

Example

Let’s see a code example to see how we can compare two objects by viewing their respective String representations. Here, we have initialized a line instance and a rectangle instance. On applying the toString method on each of them we can see their respective string representations in the console.


<!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 toString method to compare two different elements</h2>
   <p>
      You can open console from dev tools and see that the logged output contains the String representation of the line instance and the rectangle instance
   </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 a Line object
      var line = new fabric.Line([200, 100, 100, 40], {
         stroke: "blue",
         strokeWidth: 20,
      });
      // Initiate a Rectangle object
      var rect = new fabric.Rect( {
         stroke: "red",
         strokeWidth: 20,
         width:20,
         height: 50,
         left: 400,
         top: 55
      });
      // Add them to the canvas
      canvas.add(line);
      canvas.add(rect)
      // Using the toString method
      console.log(
         "String representation of the Line instance is: ", line.toString()
      );
      console.log(
         "String representation of the Rectangle instance is: ",
         rect.toString()
      );
   </script>
</body>
</html>

Rahul Gurung

Updated on: 20-Oct-2022

139 Views

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