CanvasRenderingContext2D: createRadialGradient() method

The CanvasRenderingContext2D.createRadialGradient() method of the Canvas 2D API creates a radial gradient using the size and coordinates of two circles.

This method returns a {{domxref("CanvasGradient")}}. To be applied to a shape, the gradient must first be assigned to the {{domxref("CanvasRenderingContext2D.fillStyle", "fillStyle")}} or {{domxref("CanvasRenderingContext2D.strokeStyle", "strokeStyle")}} properties.

[!NOTE] Gradient coordinates are global, i.e., relative to the current coordinate space. When applied to a shape, the coordinates are NOT relative to the shape's coordinates.

Syntax

js-nolint

createRadialGradient(x0, y0, r0, x1, y1, r1)

The createRadialGradient() method is specified by six parameters, three defining the gradient's start circle, and three defining the end circle.

Parameters

x0
- : The x-axis coordinate of the start circle.
y0
- : The y-axis coordinate of the start circle.
r0
- : The radius of the start circle. Must be non-negative and finite.
x1
- : The x-axis coordinate of the end circle.
y1
- : The y-axis coordinate of the end circle.
r1
- : The radius of the end circle. Must be non-negative and finite.

Return value

A radial {{domxref("CanvasGradient")}} initialized with the two specified circles.

Exceptions

NotSupportedError {{domxref("DOMException")}}
- : Thrown when non-finite values are passed in parameter.
IndexSizeError {{domxref("DOMException")}}
- : Thrown when a negative radius is passed in parameter.

Examples

Filling a rectangle with a radial gradient

This example initializes a radial gradient using the createRadialGradient() method. Three color stops between the gradient's two circles are then created. Finally, the gradient is assigned to the canvas context, and is rendered to a filled rectangle.

HTML

html

<canvas id="canvas" width="200" height="200"></canvas>

JavaScript

const canvas = document.getElementById("canvas");
const ctx = canvas.getContext("2d");

// Create a radial gradient
// The inner circle is at x=110, y=90, with radius=30
// The outer circle is at x=100, y=100, with radius=70
const gradient = ctx.createRadialGradient(110, 90, 30, 100, 100, 70);

// Add three color stops
gradient.addColorStop(0, "pink");
gradient.addColorStop(0.9, "white");
gradient.addColorStop(1, "green");

// Set the fill style and draw a rectangle
ctx.fillStyle = gradient;
ctx.fillRect(20, 20, 160, 160);

Result

{{ EmbedLiveSample('Filling_a_rectangle_with_a_radial_gradient', 700, 240) }}