辰年だしドラゴン曲線だよね。という事でjavascriptで。Canvasで。
新年あけましてドラゴン曲線 - jsdo.it - share JavaScript, HTML5 and CSS
ソース
<html>
<script>
window.onload =function(){
var $ = function(id){ return document.getElementById(id); }
var canvas = $("canvas");
var ctx = canvas.getContext('2d');
var clear =function(){
ctx.fillStyle = 'rgb(200, 200, 200)';
ctx.fillRect(0, 0, canvas.width, canvas.height);
}
var line = function(ctx, sx, sy, ex, ey){
ctx.beginPath();
ctx.moveTo(sx, sy);
ctx.lineTo(ex, ey);
ctx.closePath();
ctx.stroke();
}
var dline = function(ctx, sx, sy, ex, ey, cx, cy){
ctx.beginPath();
ctx.moveTo(sx, sy);
ctx.lineTo(cx, cy);
ctx.moveTo(ex, ey);
ctx.lineTo(cx, cy);
ctx.closePath();
ctx.stroke();
};
var dragon = function(ctx, depth, sx, sy, ex, ey, d){
if(depth ==0){
line(ctx,sx,sy,ex,ey);
return;
}
var dx = (ex-sx)/2;
var dy = (ey-sy)/2;
var centerX = ex-dx;
var centerY = ey-dy;
var cx = centerX + (d?dy:-dy);
var cy = centerY + (d?-dx:dx);
if(depth == 1){
dline(ctx,sx,sy,ex,ey,cx,cy);
return;
}
else{
dragon(ctx, depth-1, sx, sy, cx, cy, true);
dragon(ctx, depth-1, cx, cy, ex, ey, false);
}
}
var dragon_call = function(depth){
return function(){
clear();
dragon(ctx, depth, 50, canvas.height/3, canvas.width-100, canvas.height/3,false);
if(depth < 15){
setTimeout(dragon_call(depth+1), 1000);
}
}
};
$("start").onclick = function(){
dragon_call(0)();
}
dragon_call(15)();
}
</script>
<body>
<canvas id="canvas" width=400 height=400 ></canvas>
<br/>
<input type="button" id="start" value="start" ></input>
</body>
</html>
まとめ
今年も頑張る。
