FabricJS – How to center a Line object vertically on canvas?


In this tutorial, we are going to learn how to center a Line vertically on canvas 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 center the line object vertically on the canvas we use the centerV method.

Syntax

 centerV() 

Default appearance of the Line object

Example

Let’s see a code example to see how our line object looks when the centerV method is not used. In this case, the line object will not be centered vertically on the canvas.

<!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 line object has not been centered vertically on the canvas </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>

Using the centerV method

Example

In this example, we will see how by using the centerV method, we are able to place the line object exactly at the vertical center of the canvas. In this case, the object is centered 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>Using the centerV method</h2> <p> You can see that the line object has been centered vertically on the canvas </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 centerV() method to center line object vertically line.centerV(); </script> </body> </html>

Updated on: 20-Oct-2022

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