117 lines
2.2 KiB
HTML
117 lines
2.2 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3c.org/1999/xhtml">
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<head>
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<title>Canvas box</title>
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<style type='text/css'>
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* {
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margin:0;
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padding:0;
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}
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canvas {
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position:absolute;
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top:50%;
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left:50%;
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margin-top:-200px;
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margin-left:-320px;
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border:1px solid #000;
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}
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</style>
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<script type='text/javascript'>
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function box() {
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var ctx=document.getElementById('canvas').getContext('2d')
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var i
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if (x<0 || x>639 || y<0 || y>399) end=[320,-100]
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else {
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for (i=0;i<pl;i++) {
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if (p[i][0]==x) x++
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if (p[i][1]==y) y++
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}
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end=[x,y]
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}
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if (end[1]>p[0][1]) l*=-1
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var ep=new Array()
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for (i=0;i<pl;i++) ep[i]=[p[i][0]-l/((end[1]-p[i][1])/(end[0]-p[i][0])),p[i][1]-l]
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ctx.clearRect(0,0,640,400)
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ctx.beginPath()
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for (i=0;i<pl;i++) {
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ni=i+1-Math.floor((i+1)/pl)*pl
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ctx.moveTo(p[i][0],p[i][1])
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ctx.lineTo(p[ni][0],p[ni][1])
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ctx.moveTo(p[i][0],p[i][1])
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ctx.lineTo(ep[i][0],ep[i][1])
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ctx.lineTo(ep[ni][0],ep[ni][1])
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}
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ctx.stroke()
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if (p[2][0]>637) a=-1
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else if (p[0][0]<3) a=1
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for (i=0;i<pl;i++) p[i][0]+=a
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if (p[2][0]-p[1][0]==75) z=-1
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else if (p[2][0]-p[1][0]==25) z=1
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p[2][0]+=z
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p[3][0]+=z
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if (p[1][1]>397) b=-.5
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else if (p[0][1]<3) b=.5
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for (i=0;i<pl;i++) p[i][1]+=b
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if (p[1][1]-p[0][1]==75) z=-1
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else if (p[1][1]-p[0][1]==25) z=1
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p[1][1]+=z
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p[2][1]+=z
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if (l==-10) c=.5
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else if (l==40) c=-.5
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l+=c
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setTimeout("box()",10)
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}
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function load() {
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p=new Array()
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p[0]=[2,348]
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p[1]=[2,398]
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p[2]=[52,398]
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p[3]=[52,348]
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pl=p.length
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l=10
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c=.5
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z=-1
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x=-1
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y=-1
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box()
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}
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function getwh() {
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if (self.innerHeight) {
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h=self.innerHeight
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w=self.innerWidth
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}
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else if (document.documentElement && document.documentElement.clientHeight) {
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h=document.documentElement.clientHeight
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w=document.documentElement.clientHeight
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}
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else if (document.body) {
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h=document.body.clientHeight
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w=document.body.clientWidth
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}
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}
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function mm(e) {
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getwh()
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x=Math.floor(e.pageX-(w-642)/2-2)
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y=Math.floor(e.pageY-(h-402)/2-2)
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}
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window.onload=load
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document.onmousemove=mm
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</script>
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</head>
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<body>
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<canvas id='canvas' width='640' height='400'></canvas>
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</body>
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</html>
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