Table of Contents
grammar
parameter
Option key
Example 1: Default appearance of polygonal objects
Example 2: Using the Points attribute
in conclusion
Home Web Front-end JS Tutorial How to add coordinates in a polygon using FabricJS?

How to add coordinates in a polygon using FabricJS?

Aug 24, 2023 pm 02:33 PM

如何使用 FabricJS 在多边形中添加坐标?

We can create a Polygon object by creating an instance of fabric.Polygon. A polygon object can be characterized as any closed shape consisting of a set of connected straight line segments. Since it is one of the basic elements of FabricJS, we can also easily customize it by applying properties such as angle, opacity, etc. We can add coordinates in a polygon using the points property.

grammar

new fabric.Polygon( points: Array, { points: Array }: Object )
Copy after login

parameter

  • points - This parameter accepts an Array, which represents the array of points that make up the polygon object.

  • Options (optional) - This parameter is an object that provides additional customization to our object. Using this parameter, you can change the origin, stroke width, and many other properties associated with the Polygon object for which points is the property.

Option key

  • points - This property accepts an Array which allows us to set an array of points.

Example 1: Default appearance of polygonal objects

Let's look at a code example to see how to add a polygon object to the canvas. In this example, we are not using the points attribute. We have specified an array of points as the first parameter itself, which represents the coordinate values ​​to use.

<!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 Polygon object</h2>
   <p>You can see the Polygon object has been added to 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);
      
      // Initiating a polygon object
      var polygon = new fabric.Polygon(
         [
            { x: -20, y: -35 },
            { x: 20, y: -35 },
            { x: 40, y: 0 },
            { x: 20, y: 35 },
            { x: -20, y: 35 },
            { x: -40, y: 0 },
         ],
         {
            top: 50,
            left: 50,
         }
      );
      
      // Adding it to the canvas
      canvas.add(polygon);
   </script>
</body>
</html> 
Copy after login

Example 2: Using the Points attribute

In this example, we used the point attribute and assigned it an array, which consists of the coordinate values ​​​​of the polygon, where each point is a point with "x" and "y" value object. As you can see, although we have specified the points of the Polygon object, once we use the point properties, it overwrites the values ​​and uses the new coordinates.

<!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 points property</h2>
   <p>You can see the Polygon object's coordinates have changed</p>
   <canvas id="canvas"></canvas>
   <script>
      
      // Initiate a canvas instance
      var canvas = new fabric.Canvas("canvas");
      canvas.setWidth(document.body.scrollWidth);
      canvas.setHeight(250);
      
      // Initiating a points array
      var points = [
         { x: 0, y: 30 },
         { x: 30, y: 30 },
         { x: 30, y: 0 },
         { x: 0, y: 0 },
      ];
      
      // Initiating a polygon object
      var polygon = new fabric.Polygon(points, {
         top: 50,
         left: 50,
         points: [
            { x: 0, y: 70 },
            { x: 70, y: 70 },
            { x: 70, y: 0 },
            { x: 0, y: 0 },
         ],
      });
      
      // Adding it to the canvas
      canvas.add(polygon);
   </script>
</body>
</html>
Copy after login

in conclusion

In this tutorial, we use two simple examples to demonstrate how to add coordinates in a polygon using FabricJS.

The above is the detailed content of How to add coordinates in a polygon using FabricJS?. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

What should I do if I encounter garbled code printing for front-end thermal paper receipts? What should I do if I encounter garbled code printing for front-end thermal paper receipts? Apr 04, 2025 pm 02:42 PM

Frequently Asked Questions and Solutions for Front-end Thermal Paper Ticket Printing In Front-end Development, Ticket Printing is a common requirement. However, many developers are implementing...

Who gets paid more Python or JavaScript? Who gets paid more Python or JavaScript? Apr 04, 2025 am 12:09 AM

There is no absolute salary for Python and JavaScript developers, depending on skills and industry needs. 1. Python may be paid more in data science and machine learning. 2. JavaScript has great demand in front-end and full-stack development, and its salary is also considerable. 3. Influencing factors include experience, geographical location, company size and specific skills.

Demystifying JavaScript: What It Does and Why It Matters Demystifying JavaScript: What It Does and Why It Matters Apr 09, 2025 am 12:07 AM

JavaScript is the cornerstone of modern web development, and its main functions include event-driven programming, dynamic content generation and asynchronous programming. 1) Event-driven programming allows web pages to change dynamically according to user operations. 2) Dynamic content generation allows page content to be adjusted according to conditions. 3) Asynchronous programming ensures that the user interface is not blocked. JavaScript is widely used in web interaction, single-page application and server-side development, greatly improving the flexibility of user experience and cross-platform development.

How to merge array elements with the same ID into one object using JavaScript? How to merge array elements with the same ID into one object using JavaScript? Apr 04, 2025 pm 05:09 PM

How to merge array elements with the same ID into one object in JavaScript? When processing data, we often encounter the need to have the same ID...

How to achieve parallax scrolling and element animation effects, like Shiseido's official website?
or:
How can we achieve the animation effect accompanied by page scrolling like Shiseido's official website? How to achieve parallax scrolling and element animation effects, like Shiseido's official website? or: How can we achieve the animation effect accompanied by page scrolling like Shiseido's official website? Apr 04, 2025 pm 05:36 PM

Discussion on the realization of parallax scrolling and element animation effects in this article will explore how to achieve similar to Shiseido official website (https://www.shiseido.co.jp/sb/wonderland/)...

The difference in console.log output result: Why are the two calls different? The difference in console.log output result: Why are the two calls different? Apr 04, 2025 pm 05:12 PM

In-depth discussion of the root causes of the difference in console.log output. This article will analyze the differences in the output results of console.log function in a piece of code and explain the reasons behind it. �...

Is JavaScript hard to learn? Is JavaScript hard to learn? Apr 03, 2025 am 12:20 AM

Learning JavaScript is not difficult, but it is challenging. 1) Understand basic concepts such as variables, data types, functions, etc. 2) Master asynchronous programming and implement it through event loops. 3) Use DOM operations and Promise to handle asynchronous requests. 4) Avoid common mistakes and use debugging techniques. 5) Optimize performance and follow best practices.

How to implement panel drag and drop adjustment function similar to VSCode in front-end development? How to implement panel drag and drop adjustment function similar to VSCode in front-end development? Apr 04, 2025 pm 02:06 PM

Explore the implementation of panel drag and drop adjustment function similar to VSCode in the front-end. In front-end development, how to implement VSCode similar to VSCode...

See all articles