How to find the complexity of a Line instance using FabricJS?

FabricJS Javascript HTML5 Canvas

In this tutorial, we are going to learn about how to find the complexity of a Line 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 get the complexity of a Line object, we use the complexity method. This method will return 1 if the current object is directly inherited from a base class and not from a subclass.

Syntax

 complexity(): Number

Using the complexity method

Example

Let’s see a code example to see the logged output when we use the complexity method to obtain the complexity of the Line instance. The complexity is 1 unless sub-classed.


<!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 complexity method</h2>
   <p>You can open console from dev tools and see the logged output</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([70, 100, 150, 200], {
         stroke: "blue",
      });
      
      // Add it to the canvas
      canvas.add(line);
      
      // Using the complexity method
      console.log("The complexity of Line instance is: ", line.complexity());
   </script>
</body>
</html>

Using the complexity method to compare different objects

Example

In this example, we have used the complexity method to compare the complexities of a line instance and a polygon instance. You can open the console from dev tools to see that the complexities are different.


<!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 complexity method to compare different objects</h2>
   <p>You can open console from dev tools and see that the complexities are different
   </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([70, 100, 150, 200], {
         stroke: "blue",
      });
      
      // Initiate a Polygon object
      var polygon = new fabric.Polyline(
         [
            { x: 50, y: 30 },
            { x: 105, y: 10 },
            { x: 160, y: 30 },
            { x: 100, y: 150 },
         ],
            {
               fill: "red",
               left: 300,
               top: 70,
            }
      );
      
      // Add both to the canvas
      canvas.add(line);
      canvas.add(polygon);
      
      // Using the complexity method
      console.log("The complexity of Line instance is: ", line.complexity());
      console.log(
         "The complexity of Polygon instance is: ",
         polygon.complexity()
      );
   </script>
</body>
</html>

Rahul Gurung

Updated on: 21-Oct-2022

136 Views

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