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<!DOCTYPE HTML> |
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<html lang=en> |
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<title>Canvas</title> |
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<meta name="viewport" content="width=device-width"> |
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<style> |
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body { |
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margin: 0; |
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padding: 0; |
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background: #C0C0C0; |
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} |
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canvas { |
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width: 240px; |
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background: white; |
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} |
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.mode-viewer canvas { |
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width: 100%; |
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} |
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a { |
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display: inline-block; |
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min-width: 1em; |
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text-align: center; |
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} |
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menu { |
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position: fixed; |
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bottom: 0; |
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width: 100%; |
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margin: 0; |
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padding: 0; |
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font-size: 8px; |
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} |
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.mode-editor menu .viewer-only, |
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.mode-viewer menu .editor-only { |
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display: none; |
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} |
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[hidden] { |
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display: none; |
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} |
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#panel { |
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position: absolute; |
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left: 20px; |
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width: 200px; /* 240px - 20px * 2 */ |
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top: 20px; |
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max-height: 120px; /* 160px - 20px * 2 */ |
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overflow: auto; |
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background-color: #C0C0C0; |
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} |
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#panel p { |
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margin: 0; |
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padding: 0; |
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} |
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</style> |
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|
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<body> |
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|
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<canvas width=240 height=160></canvas> |
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|
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<section id=panel hidden> |
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|
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<p> |
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[<a href="javascript:setProp ('lineWidth', 1); togglePanel ()">1</a> |
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<a href="javascript:setProp ('lineWidth', 2); togglePanel ()">3</a> |
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<a href="javascript:setProp ('lineWidth', 3); togglePanel ()">3</a> |
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<a href="javascript:setProp ('lineWidth', 5); togglePanel ()">5</a> |
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<a href="javascript:setProp ('lineWidth', 10); togglePanel ()">10</a>] |
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</p> |
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|
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<p> |
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[<a href="javascript:setProp ('strokeStyle', 'black'); togglePanel ()" style="color: black">black</a> |
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<a href="javascript:setProp ('strokeStyle', 'red'); togglePanel ()" style="color: red">red</a> |
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<a href="javascript:setProp ('strokeStyle', 'green'); togglePanel ()" style="color: green">green</a> |
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<a href="javascript:setProp ('strokeStyle', 'blue'); togglePanel ()" style="color: blue">blue</a> |
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<a href="javascript:setProp ('strokeStyle', 'orange'); togglePanel ()" style="color: orange">orange</a> |
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<a href="javascript:setProp ('strokeStyle', 'yellow'); togglePanel ()" style="color: yellow">yellow</a> |
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<a href="javascript:setProp ('strokeStyle', 'pink'); togglePanel ()" style="color: pink">pink</a> |
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<a href="javascript:setProp ('strokeStyle', 'purple'); togglePanel ()" style="color: purple">purple</a> |
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<a href="javascript:setProp ('strokeStyle', 'gray'); togglePanel ()" style="color: gray">gray</a> |
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<a href="javascript:setProp ('strokeStyle', 'white'); togglePanel ()" style="color: white">white</a>] |
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</p> |
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|
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</section> |
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|
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<menu><a href="javascript:togglePanel ()" class=editor-only>Panel</a> |
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<a href="client.html?mode=editor" id=edit-link rel=edit class=viewer-only>Edit</a> |
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<a href="client.html?mode=viewer" id=view-link class=editor-only>View</a> |
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<a href="server.cgi?mode=list" rel=index>List</a> |
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<a href="server.cgi?mode=prev" id=prev-link rel=prev>Prev</a> |
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<a href="server.cgi?mode=next" id=next-link rel=next>Next</a> |
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<a href="client.html?mode=editor">New</a></menu> |
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|
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<script> |
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function $ (id) { return document.getElementById (id) } |
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|
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var canvas = document.getElementsByTagName('canvas')[0]; |
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var ctx = canvas.getContext('2d'); |
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ctx.lineCap = 'round'; |
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ctx.lineWidth = 3; |
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ctx.beginPath (); |
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|
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var date; |
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var q = (location.search || '').replace (/^\?/, '').split (/[&;]/); |
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var param = {}; |
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for (var i = 0; i < q.length; i++) { |
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var p = q[i].split (/=/); |
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param[p[0]] = p[1]; |
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} |
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date = parseInt (param.date) || new Date ().valueOf (); |
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var url = 'server.cgi?date=' + date; |
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|
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$('edit-link').href += ';date=' + date; |
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$('view-link').href += ';date=' + date; |
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$('prev-link').href += ';date=' + date; |
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$('next-link').href += ';date=' + date; |
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|
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param.mode = param.mode || 'editor'; |
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document.body.className = 'mode-' + param.mode; |
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|
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if (param.mode == 'viewer') { |
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readRemoteImage (); |
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setInterval (readRemoteImage, 2000); |
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} else { |
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var drawing = false; |
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canvas.onmousedown = function (ev) { |
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drawing = true; |
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ctx.beginPath (); |
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var x = ev.clientX; |
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var y = ev.clientY; |
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ctx.moveTo (x, y); |
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write ('moveTo', x, y); |
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}; |
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canvas.onmousemove = function (ev) { |
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if (drawing) { |
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var x = ev.clientX; |
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var y = ev.clientY; |
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ctx.lineTo (x, y); |
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write ('lineTo', x, y); |
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ctx.stroke (); |
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// ctx.closePath (); |
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// ctx.beginPath (); |
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// ctx.moveTo (x, y); |
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} |
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}; |
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window.onmouseup = function (ev) { |
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if (!drawing) return; |
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ctx.stroke (); |
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ctx.closePath (); |
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drawing = false; |
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}; |
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|
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var newEvents = []; |
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function write () { |
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newEvents.push (Array.prototype.join.call (arguments, ',')); |
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} |
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|
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readRemoteImage (); |
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setInterval (function () { |
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if (newEvents.length) { |
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var xhr = new XMLHttpRequest (); |
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xhr.open ('POST', url, true); |
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xhr.setRequestHeader ('Content-Type', 'text/plain'); |
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xhr.send (newEvents.join (';')); |
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newEvents = []; |
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} |
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}, 2000); |
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} |
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|
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function setProp (n, v) { |
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ctx[n] = v; |
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write (n, v); |
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} |
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|
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function readRemoteImage () { |
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var xhr = new XMLHttpRequest (); |
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xhr.open ('GET', url, false); |
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xhr.setRequestHeader ('Cache-Control', 'no-cache'); |
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xhr.send (null); |
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if (xhr.responseText) { |
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var events = xhr.responseText.split (/\x0A/); |
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if (events.length) { |
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canvas.width = canvas.width; // clear |
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processEvents(events); |
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} |
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} |
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} |
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|
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function processEvents (events) { |
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for (var i = 0; i < events.length; i++) { |
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var ev = events[i].split (/,/); |
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if (ev[0] == 'lineTo') { |
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var x = parseFloat (ev[1]); |
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var y = parseFloat (ev[2]); |
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ctx.lineTo (x, y); |
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ctx.stroke (); |
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// ctx.closePath (); |
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// ctx.beginPath (); |
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// ctx.moveTo (x, y); |
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} else if (ev[0] == 'moveTo') { |
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var x = parseFloat (ev[1]); |
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var y = parseFloat (ev[2]); |
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ctx.moveTo (x, y); |
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} else if (ev[0] == 'strokeStyle' || ev[0] == 'lineWidth') { |
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ctx.closePath (); |
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ctx.beginPath (); |
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ctx[ev[0]] = ev[1]; |
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} |
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} |
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} |
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|
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function togglePanel () { |
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if ($('panel').hasAttribute ('hidden')) { |
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$('panel').removeAttribute ('hidden'); |
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} else { |
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$('panel').setAttribute ('hidden', ''); |
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} |
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} |
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</script> |