HTML and CSS Reference
In-Depth Information
You can specify the bitmap pixel dimensions using attributes on the canvas element,
either in the markup or with a setAttribute(...) call. You can also resize the canvas
element by using CSS styling on the width/height, but this has the effect of shrinking
or stretching the canvas element while keeping the existing pixel dimensions, rather
than actually changing them.
For instance, let's say you wanted a full-page canvas element that resized itself with the
window. If you want that sizing to be achieved by stretching or shrinking the canvas
element while maintaining the same pixel dimensions, use CSS, like this:
#mycanvas { width:100%; height:100%; }
However, if you want a canvas element that keeps resizing its bitmap pixel dimensions
along with the dimensions of the browser window, you need to use JavaScript:
window.onresize = function() {
mycanvas .width = document.documentElement.clientWidth;
mycanvas .height = document.documentElement.clientHeight;
You can resize the canvas element as often as you like. However, each time you resize
it, the drawing space will be cleared. This is actually a useful trick, as you can quickly
clear the canvas by simply setting its width to be the same as its current width:
function clear(mycanvas) {
mycanvas.width = mycanvas.width;
See Also
For more information on how to use canvas , see this canvas tutorial on MDC: https:// .
9.4 Using Gradients, Patterns, and Line Styles
You want to create gradients and other drawing styles.
Each time you render a path to the canvas element, the color and style for that drawing
are picked up from the currently set stroke and fill styles.
For instance, to vary the way that line segments are drawn on paths, you can control
the stroke styles with lineWidth , lineCap , and lineJoin :
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