[whatwg] Canvas draw quality

[Alfonso Baqueiro]

I wrote this little page to try the canvas

http://guia.sytes.net/notas/javascript/biorritmos.html

Is interesting that the drawed vertical 1px width black lines appear
as 2px width gray lines (in firefox) I suposse that is a colateral
effect caused by the antialiasing, so this simple case makes evident
that we need a method turn on/off the antialiasing.

I suggest:

var canvas = document.getElementById('canvas');
var gc = canvas.getContext('2d');
// some drawing
gc.setAntialiasing(false);
// some drawing
gc.setAntialiasing(true);