How to flip a Triangle vertically using FabricJS?


In this tutorial, we are going to learn how we can flip a Triangle object vertically using FabricJS. Triangle is one of the various shapes provided by FabricJS. In order to create a triangle, we will have to create an instance of fabric.Triangle class and add it to the canvas. We can flip a triangle object vertically using the flipY property.

Syntax

new fabric.Triangle({ flipY: Boolean }: Object)

Parameters

  • Options (optional) − This parameter is an Object which provides additional customizations to our triangle. Using this parameter, properties such as colour, cursor, stroke width, and a lot of other properties can be changed related to the object of which flipY is a property.

Options Keys

  • flipY − This property accepts a Boolean value which allows us to flip an object vertically.

Example 1

Passing flipY as key with a 'false' value

Let's see a code example that shows us the default orientation of a triangle object in FabricJS. Since we are passing the flipY property a False value, the triangle object will not be flipped vertically.

<!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 flipY as key with a 'false' value</h2>
   <p>You can see that the triangle object has not been flipped vertically.</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 triangle object
         var triangle = new fabric.Triangle({
         left: 75,
         top: 45,
         width: 180,
         height: 109,
         stroke: "#e3f988",
         strokeWidth: 5,
         flipY: false,
      });

      // Create gradient fill
      triangle.set(
         "fill",
         new fabric.Gradient({
            type: "linear",
            coords: { x1: 0, y1: 0, x2: 0, y2: 100 },
            colorStops: [
                  { offset: 0, color: "#545a2c" },
                  { offset: 1, color: "#6495ed" },
            ],
         })
      );
      // Add it to the canvas
      canvas.add(triangle);
   </script>
</body>
</html>

Example 2

Passing the flipY property as key with a 'true' value

In this example, we have a triangle object of width 180px and height 109px with a vertical linear gradient fill. As we apply the flipY property to the triangle object, it flips vertically and thus we see that the triangle has flipped as well.

<!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 flipY property as key with a 'true' value</h2>
   <p>You can see that the triangle object has been flipped vertically</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 triangle object
      var triangle = new fabric.Triangle({
         left: 75,
         top: 45,
         width: 180,
         height: 109,
         stroke: "#e3f988",
         strokeWidth: 5,
         flipY: true,
      });

      // Create gradient fill
      triangle.set(
         "fill",
         new fabric.Gradient({
            type: "linear",
            coords: { x1: 0, y1: 0, x2: 0, y2: 100 },
            colorStops: [
               { offset: 0, color:"#545a2c" },
               { offset: 1, color: "#6495ed" },
            ],
         })
      );

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

Updated on: 24-Jun-2022

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