JS1k: The JavaScript code golfing competition

var k,j,g,i,p,c,f,m,n,q,h,r=document,o="setAttribute",e="setAttributeNS",d="createElementNS",l="appendChild",b="pageX",a="pageY";g=function(s,t){r.addEventListener(s,t,false)};r.body.innerHTML="";k="http://www.w3.org/2000/svg";j=r[d](k,"svg");j[o]("width",500);j[o]("height",500);j[o]("style","border: 1px solid #666;");r.body[l](j);r.body.style.cursor="crosshair";h=function(t,v){var s,u;u=r[d](k,"line");u[e](null,"stroke","#000");u[e](null,"stroke-width",1);u[e](null,"stroke-linecap","butt");j[l](u);s=function(w,x){u[e](null,"x1",t);u[e](null,"y1",v);u[e](null,"x2",w);u[e](null,"y2",x)};s(t,v);return s};m=function(s,t){p=false;c=false;i=false;f=false};n=function(t,v,s,u){var w=t-s,x=v-u;return(w>=-10&&w<=10&&x>=-10&&x<=10)};g("mousedown",function(t){var s=t[b],u=t[a];if(i){if(n(s,u,p,c)){q(p,c);m();return}}q=h(s,u);p=p||s;c=c||u;f=true});g("mousemove",function(s){if(f){q(s[b],s[a])}});g("mouseup",function(t){var s=t[b],u=t[a];if(!i&&(p===s&&c===u)){i=true;return}if(f){q(s,u)}if(!i){m(s,u)}});

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var svgns,
	paper,
	addListener,
	isPolygon,
	x0,
	y0,
	draw,
	clean,
	snapToPoint,
	currentLine,
	line,
	doc = document,
	setAttribute = "setAttribute",
	setAttributeNS = "setAttributeNS",
	createElementNS = "createElementNS",
	appendChild = "appendChild",
	pageX = "pageX",
	pageY = "pageY";

addListener = function(type, func) {
	doc.addEventListener(type, func, false);
};

doc.body.innerHTML = "";

svgns = "http://www.w3.org/2000/svg";
paper = doc[createElementNS](svgns, "svg");
paper[setAttribute]("width", 500);
paper[setAttribute]("height", 500);
paper[setAttribute]("style", "border: 1px solid #666;");
doc.body[appendChild](paper);
doc.body.style.cursor = "crosshair";


line = function(x, y) {
	var draw, line;

	line = doc[createElementNS](svgns, "line");
	line[setAttributeNS](null, "stroke", "#000");
	line[setAttributeNS](null, "stroke-width", 1);
	line[setAttributeNS](null, "stroke-linecap", "butt");
	paper[appendChild](line);					

	draw = function(x2, y2) {
	
		line[setAttributeNS](null, "x1", x);
		line[setAttributeNS](null, "y1", y);
		line[setAttributeNS](null, "x2", x2);
		line[setAttributeNS](null, "y2", y2);
	}

	draw(x, y);

	return draw;
}

clean = function(x, y) {
	x0 = false;
	y0 = false;
	isPolygon = false;
	draw = false;
};

//	tests if one point is within 5 pixels of another point				
snapToPoint = function(x1, y1, x2, y2) {
	var xd = x1 - x2,
		yd = y1 - y2;
	return (xd >= -10 && xd <= 10 && yd >= -10 && yd <= 10);
};


//	start drawing a new line
addListener("mousedown", function(e) {
	
	var x = e[pageX], y = e[pageY];
	
	//	are we already drawing a polygon
	if(isPolygon) {
		//	if the polygon is closed - finish
		if(snapToPoint(x, y, x0, y0)) {
			currentLine(x0, y0);
			clean();
			return;
		}
		
	}
	//	create a new line
	currentLine = line(x, y)
	x0 = x0 || x;
	y0 = y0 || y;
	draw = true;
});

//	redraw the line as the mouse moves
addListener("mousemove", function(e) {
	if(draw) {
		currentLine(e[pageX], e[pageY]);
	}
});

//	stops drawing a line or switches into polygon mode
addListener("mouseup", function(e) {
	
	var x = e[pageX], y = e[pageY];
	
	//	are we in line mode - and the user has not moved the mouse. go into polygon mode
	if(!isPolygon && (x0 === x && y0 === y)) {
		isPolygon = true;
		return;
	}

	//	draw the line
	if(draw) {
		currentLine(x, y);
	}

	//	clean up
	if(!isPolygon) {
		clean(x, y);
	}

});