How to scale a Line object to a given width using FabricJS?

In this tutorial, we are going to learn how to scale a Line object to a given width 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 scale a Line object to a given width we use the scaleToWidth method.

Syntax

scaleToWidth(value: Number, absolute: Boolean): fabric.Object

Parameters

  • value − This parameter accepts a Number which determines the new width value of our line object.

  • absolute − This parameter accepts a Boolean value which determines whether the viewport is to be ignored or not.

Default appearance of the Line object

Example

Let’s see a code example to see how our line object looks when the scaleToWidth method is not used. In this case, our line object will not be scaled in horizontal or vertical directions.

<!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>Default appearance of the Line object</h2>
   <p>
      You can see that the object has not been scaled in horizontal or vertical direction
   </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);
   </script>
</body>
</html>

Passing the scaleToWidth method with a custom value

Example

In this example, we will see how assigning a value to the scaleToWidth method scales our line object to a given width. Since we have passed the value as 200, that will be the new width of our line object.

<!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>Passing the scaleToWidth method with a custom value</h2>
    <p>
       You can see that the new width of our line object is 200
    </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,
      });

      // Using the scaleToWidth method
      line.scaleToWidth(200, false);

      // Add it to the canvas
      canvas.add(line);
   </script>
</body>
</html>

Updated on: 25-Oct-2022

155 Views

Kickstart Your Career

Get certified by completing the course

Get Started
Advertisements