Created
May 22, 2011 13:14
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example on how to handle mouse and touch events - http://sebcode.github.com/touchevents/
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| <!doctype html> | |
| <title>touchevents</title> | |
| <canvas id="canvas" width="500" height="300"></canvas> | |
| <script> | |
| function isTouchDevice() { | |
| var el = document.createElement('div') | |
| el.setAttribute('ongesturestart', 'return;') | |
| return typeof el.ongesturestart == "function" | |
| } | |
| var canvas = document.getElementById('canvas') | |
| ,ctx = canvas.getContext('2d') | |
| ,w = canvas.width | |
| ,h = canvas.height | |
| ,istouch = isTouchDevice() | |
| /* circle's x, y position */ | |
| ,x = w / 2, y = h / 2 | |
| /* pointer's x, y position */ | |
| ,px = 0, py = 0 | |
| /* offset x, y */ | |
| ,ox = 0, oy = 0 | |
| /* pointer is over circle */ | |
| ,pointover = false | |
| /* pointer is grabbing circle */ | |
| ,grabbing = false | |
| /* user is touching or holding mouse button down */ | |
| ,isdown = false | |
| setInterval(function() { | |
| ctx.fillStyle = "black" | |
| ctx.fillRect(0, 0, w, h) | |
| ctx.fillStyle = 'white' | |
| ctx.font = '20px sans-serif' | |
| ctx.fillText( | |
| 'px:' + px + | |
| ' py:' + py + | |
| ' g:' + (grabbing ? '1' : '0') + | |
| ' po:' + (pointover ? '1' : '0') + | |
| ' id:' + (isdown ? '1' : '0') + | |
| ' istouchdevice:' + (istouch ? '1' : '0') | |
| , 10, 30) | |
| ctx.fillStyle = grabbing ? "red" : "white" | |
| ctx.beginPath() | |
| ctx.arc(x, y, 30, Math.PI * 2, 0, true) | |
| ctx.fill() | |
| pointover = ctx.isPointInPath(px, py) | |
| ctx.closePath() | |
| if (isdown && pointover) { | |
| grabbing = true | |
| } | |
| if (grabbing) { | |
| x = px - ox | |
| y = py - oy | |
| } | |
| }, 1000 / 60) | |
| if (!istouch) { | |
| canvas.addEventListener('mousemove', function(e) { | |
| px = e.clientX - canvas.offsetLeft | |
| py = e.clientY - canvas.offsetTop | |
| }, true) | |
| canvas.addEventListener('mousedown', function(e) { | |
| px = e.clientX - canvas.offsetLeft | |
| py = e.clientY - canvas.offsetTop | |
| ox = px - x | |
| oy = py - y | |
| isdown = true | |
| }, true) | |
| canvas.addEventListener('mouseup', function(e) { | |
| isdown = false | |
| grabbing = false | |
| }, true) | |
| } | |
| else { | |
| canvas.addEventListener('touchmove', function(e) { | |
| px = e.targetTouches[0].pageX - canvas.offsetLeft | |
| py = e.targetTouches[0].pageY - canvas.offsetTop | |
| e.preventDefault() | |
| }, true) | |
| canvas.addEventListener('touchstart', function(e) { | |
| px = e.touches[0].clientX - canvas.offsetLeft | |
| py = e.touches[0].clientY - canvas.offsetTop | |
| ox = px - x | |
| oy = py - y | |
| isdown = true | |
| }, true) | |
| canvas.addEventListener('touchend', function(e) { | |
| isdown = false | |
| grabbing = false | |
| }, true) | |
| canvas.addEventListener('touchcancel', function(e) { | |
| isdown = false | |
| grabbing = false | |
| }, true) | |
| } | |
| </script> |
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