JS1k: The JavaScript code golfing competition

var b=[],c=0,d=1,e=1,f,g,h,i,j,k,l=document,m=window,n=l.body.children[0],o=n.getContext("2d"),p=n.width=m.innerWidth-30,q=n.height=m.innerHeight-30,s=p/2,t=q/2,u=Math;o.fillStyle="gray";o.fillRect(0,0,p,q);l.onmousemove=v;l.onmouseup=function(){c=0};l.onmousedown=function(a){c=1;v(a)};l.onkeydown=function(a){a=a.keyCode;a==83&&m.open(n.toDataURL("image/png"),"s");if(a==32)d=!d;if(a==77)e=!e};setInterval(w,33);
function A(a,B,z){o.strokeStyle="black";o.lineWidth=z/7;o.beginPath();c&&o.arc(a,B,z,0,u.PI*2,1);o.closePath();o.fillStyle="white";o.stroke();o.fill()}function v(a){x=a.clientX-n.offsetLeft;y=a.clientY-n.offsetTop;j=s-x;k=t-y;b.push({x:x,y:y,r:u.sqrt(j*j+k*k)+1|0});s=x;t=y}
function w(){if(d)with(o){save();translate(p/2,q/2);scale(1.03,1.03);translate(-p/2,-q/2);drawImage(n,0,0);restore();fillStyle="rgba(0,0,0,0.004)";fillRect(0,0,p,q)}for(b.length==0&&c&&b.push({x:s,y:t,r:1});b.length;)with(b.shift())if(e){f=x%200;g=y%200;for(h=-200;h<=p;h+=200)for(i=-200;i<=q;i+=200)A(h+f,i+g,r)}else A(x,y,r)};

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