resize_canvas - setelah di modifikasi untuk Firefox

function resize_canvas(){
var t = getViewport();

innerWidth = t[0];//window.innerWidth;
innerHeight = t[1];//window.innerHeight;

sizeDiffW = innerWidth-canvasWidth;
sizeDiffH = innerHeight-canvasHeight;
chkscaleW = innerWidth/canvasWidth;
chkscaleH = innerHeight/canvasHeight;
scaleFix = Math.min(chkscaleW,chkscaleH);

canvas.width=canvasWidth*scaleFix;
canvas.height=canvasHeight*scaleFix;
context.scale(scaleFix, scaleFix);

canvas.style.left="100px";
canvas.style.top="100px";
canvas.style.marginLeft="100px";
canvas.style.marginTop="100px";


canvas.style.left=((innerWidth-canvasWidth*scaleFix)/2)+"px";
canvas.style.top=((innerHeight-canvasHeight*scaleFix)/2)+"px";

canvas.style.marginLeft=""+((innerWidth-canvasWidth*scaleFix)/2)+"px";
canvas.style.marginTop=""+((innerHeight-canvasHeight*scaleFix)/2)+"px";

}