<canvas width="600" height="400"> </canvas>
<script>
var colores = ["blue", "red", "green"];
var colorRef = 0;
var pantalla = document.querySelector("canvas");
var pincel = pantalla.getContext("2d");
pincel.fillStyle = "grey";
pincel.fillRect(0,0,600,400);
function dibujarCirculo(evento) {
var x = evento.pageX - pantalla.offsetLeft; //pos x
var y = evento.pageY - pantalla.offsetTop; //pos y
pincel.fillStyle = colores[colorRef];
pincel.beginPath();
pincel.arc(x,y,10,0,2*(Math.PI));
pincel.fill();
console.log(x+" - "+y);
}
pantalla.onclick = dibujarCirculo;
function alterarColor() {
colorRef++;
if(colorRef >= colores.length) {
colorRef = 0;
}
return false;
}
pantalla.oncontextmenu = alterarColor;
</script>