The CanvasRenderingContext2D.shadowOffsetY property of the Canvas 2D API specifies the distance that shadows will be offset vertically.

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.


ctx.shadowOffsetY = offset;
A float specifying the distance that shadows will be offset vertically. Positive values are down, and negative are up. The default value is 0 (no vertical offset). Infinity and NaN values are ignored.


Moving a shadow vertically

This example adds a blurred shadow to a rectangle. The shadowColor property sets its color, shadowOffsetY sets its offset 25 units towards the bottom, and shadowBlur gives it a blur level of 10.


<canvas id="canvas"></canvas>


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

// Shadow
ctx.shadowColor = 'red';
ctx.shadowOffsetY = 25;
ctx.shadowBlur = 10;

// Rectangle
ctx.fillStyle = 'blue';
ctx.fillRect(20, 20, 150, 80);



Specification Status Comment
HTML Living Standard
The definition of 'CanvasRenderingContext2D.shadowOffsetY' in that specification.
Living Standard

Browser compatibility

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See also