Created
September 16, 2019 15:16
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fun with circles
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<canvas> | |
</canvas> | |
<script> | |
(function() | |
{ | |
var canvas = document.getElementsByTagName("canvas")[0]; | |
var ctx = canvas.getContext("2d"); | |
canvas.width = window.innerWidth; | |
canvas.height = window.innerHeight; | |
var started=true; | |
var DEG2RAD = Math.PI / 180; | |
var mouse = [window.innerWidth/2,window.innerHeight/2]; | |
function draw_line(s,e) | |
{ | |
ctx.beginPath(); | |
ctx.moveTo(s[0],s[1]); | |
ctx.lineTo(e[0],e[1]); | |
ctx.stroke(); | |
ctx.closePath(); | |
} | |
var nl = 3; | |
var rot = []; | |
var list = []; | |
var rinc=[1,4,1,1]; | |
var lens=[50,100,150,10]; | |
for(var i = 0; i < nl; ++i) | |
{ | |
list[i]=[]; | |
rot[i]=0; | |
} | |
setInterval(function() | |
{ | |
ctx.fillStyle="#fff"; | |
ctx.fillRect(0,0,canvas.width,canvas.height); | |
for(var itx in list) | |
{ | |
for(var litx in list[itx]) | |
{ | |
if(litx == 0) continue; | |
var it = list[itx][litx]; | |
draw_line(list[itx][litx-1],it); | |
} | |
} | |
if(!started) | |
return; | |
var orgs=[]; | |
for(var i = 0; i < nl; i++) | |
{ | |
var beg = mouse; | |
if(i>0) | |
beg=orgs[i-1]; | |
var l =[beg[0] + Math.cos(DEG2RAD * rot[i]) * lens[i], beg[1] + Math.sin(DEG2RAD * rot[i]) * lens[i]]; | |
draw_line(beg,l); | |
list[i].push(l); | |
rot[i]+=rinc[i]; | |
orgs[i]=l; | |
} | |
}, 10); | |
document.onkeydown=function(ev) | |
{ | |
switch(ev.key) | |
{ | |
case "f": | |
started^=1; | |
break; | |
} | |
}; | |
document.onmousemove=function(ev) | |
{ | |
//mouse=[ev.clientX,ev.clientY]; | |
}; | |
})(); | |
</script> |
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