JS1k: The JavaScript code golfing competition

eval('g=Math;q=256;s=b=128;R=24;A="setAttribute";B="addColorStop";F="getImageData";_l(d){return g.round(g.min(g.max(d,0),q-1))}_a(d,e){return(e*q+d)*4}_u(d){for(y=q;y--;)for(x=q;x--;)d(x,y)}_L(d,e,k,n,o){if(o){r=d.createRadialGradient(e,k,0,e,k,R);z="rgba(0,0,"+(b?"255":"0")+",0";r[B](0,z+".2)");r[B](1,z+")");d.fillStyle=r;d.fillRect(e-R,k-R,R*2,R*2)}r=d[F](0,0,q,q).data;v=d[F](0,0,q,q);u(_(f,j){t=l(n[l(r[a(f,j+1)+2]-r[a(f,j-1)+2]-j+k+s)*q+l(r[a(f+1,j)+2]-r[a(f-1,j)+2]-f+e+s)]);for(i=3;i--;)v.data[a(f,j)+i]=t;v.data[a(f,j)+3]=q-1});d.putImageData(v,q,0)}M=[];u(_(d,e){V=(d-s)/s;W=(e-s)/s;M[e*q+d]=g.max(0,1-g.sqrt(V*V+W*W))*q});H=I=m=0;h=document.body.children.c;h[A]("width",q*2);h[A]("height",q);c=h.getContext("2d");c.fillRect(0,0,512,q);c.fillStyle="#004";c.font="80px Arial";c.fillText("JS1k",40,s+R);onmousedown=_(){m=1};onmouseup=_(){m=0};onmousemove=_(d){H=d.clientX-8;I=d.clientY-8};onkeyup=_(d){G=d.which-48;b=G==-16?!b:b;R=G>-1&G<10?G*4:R};setInterval("L(c,H,I,M,m)",5);'.replace(/_/g,"function "))

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