How to flip a Circle vertically using FabricJS?

fabricjsjavascripthtml5 canvas更新于 2025/2/3 21:32:17

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

语法

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

Parameters

options (optional) − This parameter is an Object which provides additional customizations to our circle. 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. It allows us to flip an object vertically.

Example 1

Passing flipY as key with a 'false' value

Let's see an example that shows us the default orientation of a circle object in FabricJS. Since we are passing the flipY property a false value, the circle 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>How to flip a Circle vertically using FabricJS?</h2>
      <p>This is the default orientation of the object. We have set <b>flipY</b> as False, but even if we don't use it, <b>flipY</b> will be by default set to False. </p>
      <canvas id="canvas"></canvas>

      <script>
         // 启动一个canvas实例
         var canvas = new fabric.Canvas("canvas");
         var circle = new fabric.Circle({
            left: 215,
            top: 50,
            fill: "green",
            radius: 80,
            stroke: "#228b22",
            strokeWidth: 2,
            flipY: false
         });

         // 创建渐变填充
         circle.set("fill", new fabric.Gradient({
            type: "linear",
            coords: {
               x1: 0,
               y1: 0,
               x2: 0,
               y2: 50
            },
            colorStops: [{
               offset: 0,
               color: "red"
            }, {
               offset: 1,
               color: "green"
            }, ],
         }));

         // 将它们添加到画布
         canvas.add(circle);
         canvas.setWidth(document.body.scrollWidth);
         canvas.setHeight(250);
      </script>
   </body>
</html>

示例 2

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

In this example, we have a circle object of radius 80px with a vertical linear gradient fill. As we apply the flipY property to the circle object, it flips vertically and thus we see that the gradient 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>How to flip a Circle vertically using FabricJS?</h2>
      <p>Here observe that the circle has flipped vertically (see the gradient), as we have set <b>flipY</b> to True.</p>
      <canvas id="canvas"></canvas>

      <script>
         // 启动一个canvas实例
         var canvas = new fabric.Canvas("canvas");
         var circle = new fabric.Circle({
            left: 215,
            top: 50,
            fill: "green",
            radius: 80,
            stroke: "#228b22",
            strokeWidth: 2,
            flipY: true
         });

         // 创建渐变填充
         circle.set("fill", new fabric.Gradient({
            type: "linear",
            coords: {
               x1: 0,
               y1: 0,
               x2: 0,
               y2: 50
            },
            colorStops: [{
               offset: 0,
               color: "red"
            }, {
               offset: 1,
               color: "green"
            }, ],
         }));

         // 将它们添加到画布
         canvas.add(circle);
         canvas.setWidth(document.body.scrollWidth);
         canvas.setHeight(250);
      </script>
   </body>
</html>