Created
August 26, 2012 19:05
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canvas demo
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <script src="http://code.jquery.com/jquery-latest.min.js"></script> | |
| </head> | |
| <body> | |
| <h1>canvas</h1> | |
| <canvas width="400" height="400" id="canvasElement"></canvas> | |
| <script type="text/javascript"> | |
| var ctx = canvasElement.getContext('2d'); | |
| var speedX = 2; | |
| var speedY = 3; | |
| var currentX = 100; | |
| var currentY = 350; | |
| function drawAtXY(x,y) { | |
| ctx.clearRect(0,0,400,400) | |
| ctx.fillStyle = 'red'; | |
| ctx.fillRect(x,y,30,30); | |
| } | |
| function redraw() { | |
| currentX += speedX; | |
| currentY += speedY; | |
| drawAtXY(currentX, currentY); | |
| if (currentX > 370) speedX = -2; | |
| if (currentX < 0) speedX = 2; | |
| if (currentY > 370) speedY = -3; | |
| if (currentY < 0) speedY = 3; | |
| } | |
| setInterval(redraw,30); | |
| $(canvasElement).on('click', checkClick); | |
| function checkClick(event) { | |
| var x = event.offsetX; | |
| var y = event.offsetY; | |
| console.log('there was a click at x: '+x+' y: '+y); | |
| var rightOfBox = currentX+30 | |
| var bottomOfBox = currentY+30 | |
| if (x > currentX && x < rightOfBox) { | |
| if (y > currentY && y < bottomOfBox) { | |
| alert('hit') | |
| } | |
| } | |
| } | |
| </script> | |
| </body> | |
| </html> |
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