The stroke() function
Summary: The stroke() function is a path function that draws your path to the canvas using the current strokeStyle color
The stroke()
function is used to draw a path on to the canvas
(but not filling it). To fill the path you will need
to use
the fill()
function
. The order in which you call the fill()
and stroke()
functions does matter - by using the fill
function after the stroke()
function the fill can obscure half of the
stroke. This leads to your lines appearing
thinner than the lineWidth setting. This can be desirable though - and it also
may be avoided depending on
what you do for anti-aliasing. If, for example, you translate by half a pixel
before you do any drawing your lines
will be drawn thinner and the fill will not overwrite half the line. You can see
this by looking at
the isPointInStroke()
demonstration
.
As you'll see half of the stroke is outside of the fill.
Arguments to the function
-
Optionally you can specify a Path2D object to be stroked. If not given the
default path is stroked.
Stroke the default path:context.stroke();
Stroke the given Path2D object:context.stroke(path);
An example
Stroking the default path:
<script>
window.onload = function ()
{
var canvas = document.getElementById("cvs");
var context = canvas.getContext('2d');
context.beginPath();
context.rect(5,5,90,90);
context.stroke();
}
</script>
Stroking a Path2D object:
<script>
window.onload = function ()
{
var canvas = document.getElementById("cvs");
var context = canvas.getContext('2d');
var path = new Path2D();
path.rect(5,5,90,90);
context.stroke(path);
}
</script>