The CanvasRenderingContext2D.strokeStyle
property of the Canvas 2D API specifies the color, gradient, or pattern to use for the strokes (outlines) around shapes. The default is #000
(black).
This example applies a blue stroke color to a rectangle.
HTML
<canvas id="canvas"></canvas>
JavaScript
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
ctx.strokeStyle = 'blue';
ctx.strokeRect(10, 10, 100, 100);
Result
In this example, we use two for
loops and the arc()
method to draw a grid of circles, each having a different stroke color. To achieve this, we use the two variables i
and j
to generate a unique RGB color for each circle, and only modify the green and blue values. (The red channel has a fixed value.)
var ctx = document.getElementById('canvas').getContext('2d');
for (let i = 0; i < 6; i++) {
for (let j = 0; j < 6; j++) {
ctx.strokeStyle = `rgb(
0,
${Math.floor(255 - 42.5 * i)},
${Math.floor(255 - 42.5 * j)})`;
ctx.beginPath();
ctx.arc(12.5 + j * 25, 12.5 + i * 25, 10, 0, Math.PI * 2, true);
ctx.stroke();
}
}
The result looks like this:
In WebKit- and Blink-based browsers, the non-standard and deprecated method ctx.setStrokeColor()
is implemented in addition to this property.
setStrokeColor(color, optional alpha);
setStrokeColor(grayLevel, optional alpha);
setStrokeColor(r, g, b, a);
setStrokeColor(c, m, y, k, a);