The CanvasRenderingContext2D
.shadowBlur
property of the Canvas 2D API specifies the amount of blur applied to shadows. The default is 0
(no blur).
Note: Shadows are only drawn if the shadowColor
property is set to a non-transparent value. One of the shadowBlur
, shadowOffsetX
, or shadowOffsetY
properties must be non-zero, as well.
Syntax
ctx.shadowBlur = level;
level
- A non-negative float specifying the level of shadow blur, where
0
represents no blur and larger numbers represent increasingly more blur. This value doesn't correspond to a number of pixels, and is not affected by the current transformation matrix. The default value is0
. Negative,Infinity
, andNaN
values are ignored.
Examples
Adding a shadow to a shape
This example adds a blurred shadow to a rectangle. The shadowColor
property sets its color, and shadowBlur
sets its level of bluriness.
HTML
<canvas id="canvas"></canvas>
JavaScript
const canvas = document.getElementById('canvas'); const ctx = canvas.getContext('2d'); // Shadow ctx.shadowColor = 'red'; ctx.shadowBlur = 15; // Rectangle ctx.fillStyle = 'blue'; ctx.fillRect(20, 20, 150, 100);
Result
Specifications
Specification | Status | Comment |
---|---|---|
HTML Living Standard The definition of 'CanvasRenderingContext2D.shadowBlur' in that specification. |
Living Standard |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
shadowBlur | Chrome Full support Yes | Edge Full support 12 | Firefox Full support 1.5 | IE Full support Yes | Opera Full support Yes | Safari Full support Yes | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 4 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
Legend
- Full support
- Full support
WebKit/Blink-specific notes
In WebKit- and Blink-based browsers, the non-standard and deprecated method ctx.setShadow()
is implemented besides this property.
setShadow(width, height, blur, color, alpha); setShadow(width, height, blur, graylevel, alpha); setShadow(width, height, blur, r, g, b, a); setShadow(width, height, blur, c, m, y, k, a);
See also
- The interface defining this property:
CanvasRenderingContext2D
CanvasRenderingContext2D.shadowColor