CanvasRenderingContext2D.createRadialGradient()
The CanvasRenderingContext2D
.createRadialGradient()
method of the Canvas 2D API creates a radial gradient given by the coordinates of the two circles represented by the parameters. This method returns a CanvasGradient
.
Syntax
CanvasGradient <var>ctx.createRadialGradient(x0, y0, r0, x1, y1, r1);</var>
Parameters
x0
- The x axis of the coordinate of the start circle.
y0
- The y axis of the coordinate of the start circle.
- r0
- The radius of the start circle.
x1
- The x axis of the coordinate of the end circle.
y1
- The y axis of the coordinate of the end circle.
- r1
- The radius of the end circle.
Return value
CanvasGradient
- A radial
CanvasGradient
initialized with the two specified circles.
Examples
Using the createRadialGradient
method
This is just a simple code snippet which uses the createRadialGradient
method to create a CanvasGradient
with the specified start and end circles. Once created, you can use the CanvasGradient.addColorStop()
method to define new stops on the gradient with specified offsets and colors. The gradient gets applied if you set it as the current fillStyle
and gets drawn onto the canvas when using the fillRect()
method, for example.
HTML
<canvas id="canvas"></canvas>
JavaScript
var canvas = document.getElementById("canvas"); var ctx = canvas.getContext("2d"); var gradient = ctx.createRadialGradient(100,100,100,100,100,0); gradient.addColorStop(0,"white"); gradient.addColorStop(1,"green"); ctx.fillStyle = gradient; ctx.fillRect(0,0,200,200);
Edit the code below and see your changes update live in the canvas:
Playable code
<canvas id="canvas" width="400" height="200" class="playable-canvas"></canvas> <div class="playable-buttons"> <input id="edit" type="button" value="Edit" /> <input id="reset" type="button" value="Reset" /> </div> <textarea id="code" class="playable-code"> var gradient = ctx.createRadialGradient(100,100,100,100,100,0); gradient.addColorStop(0,"white"); gradient.addColorStop(1,"green"); ctx.fillStyle = gradient; ctx.fillRect(0,0,200,200);</textarea>
var canvas = document.getElementById("canvas"); var ctx = canvas.getContext("2d"); var textarea = document.getElementById("code"); var reset = document.getElementById("reset"); var edit = document.getElementById("edit"); var code = textarea.value; function drawCanvas() { ctx.clearRect(0, 0, canvas.width, canvas.height); eval(textarea.value); } reset.addEventListener("click", function() { textarea.value = code; drawCanvas(); }); edit.addEventListener("click", function() { textarea.focus(); }) textarea.addEventListener("input", drawCanvas); window.addEventListener("load", drawCanvas);
Specifications
Specification | Status | Comment |
---|---|---|
WHATWG HTML Living Standard The definition of 'CanvasRenderingContext2D.createRadialGradient' in that specification. |
Living Standard |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
Gecko-specific notes
- Starting Gecko 2.0 (Firefox 4 / Thunderbird 3.3 / SeaMonkey 2.1), specifying non-finite values now throws
NOT_SUPPORTED_ERR
instead ofSYNTAX_ERR
. - Starting Gecko 5.0 (Firefox 5.0 / Thunderbird 5.0 / SeaMonkey 2.2), specifying a negative radius correctly throws
INDEX_SIZE_ERR
.
See also
- The interface defining it,
CanvasRenderingContext2D
CanvasRenderingContext2D.createLinearGradient()
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/canvasrenderingcontext2d/createradialgradient