Created
August 23, 2014 22:31
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RGBs
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| <html> | |
| <head> | |
| <title>Get some RGBA data from canvas!</title> | |
| </head> | |
| <body> | |
| <h1>Get RGBs from canvas</h1> | |
| <canvas id="acanvas" width="300" height="300"></canvas> | |
| </body> | |
| <script type="text/javascript"> | |
| ;(function() { | |
| var getColorAtPos = function (x,y) { | |
| var pos = ((y * can.width) + x)*4; | |
| var imgData = con.getImageData(0,0,can.height,can.width).data; | |
| if(can.width >= x && can.height >= y) { | |
| return { r:imgData[pos], g:imgData[pos+1], b:imgData[pos+2], a:imgData[pos+3] }; | |
| } else { | |
| return {r:0, g:0,b:0,a:0 }; | |
| } | |
| }; | |
| var can = document.getElementById('acanvas'); | |
| var con = can.getContext('2d'); | |
| con.rect(0,0,can.height,can.width); | |
| con.fillStyle = "#00ff00" | |
| con.fill() | |
| con.fillStyle = "#ff0000" | |
| con.fillRect(0,0,100,100); | |
| var imageData = con.getImageData(0,0,can.height,can.width); | |
| can.addEventListener("click",function(e) { | |
| console.log("Mouse event",e.clientX,e.clientY); | |
| console.log(getColorAtPos(e.clientX,e.clientY)); | |
| }, false); | |
| })(); | |
| </script> | |
| </html> |
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