metanohi-misc-subsites/subsites/projects/canvas/dl.htm

106 lines
1.9 KiB
HTML

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3c.org/1999/xhtml">
<head>
<title>CanvasDraw :: Lines</title>
<style type='text/css'>
* {
margin:0;
padding:0;
}
canvas {
position:absolute;
top:50%;
left:50%;
margin-top:-200px;
margin-left:-320px;
border:1px solid #000;
}
</style>
<script type='text/javascript'>
click=false
coor=false
function getwh() {
if (self.innerHeight) {
h=self.innerHeight
w=self.innerWidth
}
else if (document.documentElement && document.documentElement.clientHeight) {
h=document.documentElement.clientHeight
w=document.documentElement.clientHeight
}
else if (document.body) {
h=document.body.clientHeight
w=document.body.clientWidth
}
}
function ld(num,d) {
if (d==0) num=Math.floor(num/10)
else num=Math.ceil(num/10)
return num
}
function load() {
l=new Array()
ctx=document.getElementById('canvas').getContext('2d')
}
function mm(e) {
getwh()
x=Math.floor(e.pageX-(w-642)/2-2)
y=Math.floor(e.pageY-(h-402)/2-2)
if (click) {
ctx.clearRect(0,0,640,400)
ctx.beginPath()
for (var i=0;i<l.length;i++) {
ctx.moveTo(l[i][0][0],l[i][0][1])
ctx.lineTo(l[i][1][0],l[i][1][1])
}
ctx.moveTo(ox,oy)
ctx.lineTo(x,y)
ctx.stroke()
}
coor=true
}
function mc() {
if (coor) {
if (click) {
if (ld(x,0)==ld(sx,0) && ld(y,0)==ld(sy,0) || ld(x,1)==ld(sx,1) && ld(y,1)==ld(sy,1)) {
click=false
l[l.length]=[[ox,oy],[sx,sy]]
ctx.clearRect(0,0,640,400)
ctx.beginPath()
for (var i=0;i<l.length;i++) {
ctx.moveTo(l[i][0][0],l[i][0][1])
ctx.lineTo(l[i][1][0],l[i][1][1])
}
ctx.stroke()
}
else l[l.length]=[[ox,oy],[x,y]]
}
else {
sx=x
sy=y
click=true
}
ox=x
oy=y
}
}
window.onload=load
document.onmousemove=mm
document.onclick=mc
</script>
</head>
<body>
<canvas id='canvas' width='640' height='400'></canvas>
</body>
</html>