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November 30, 2015 01:49
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HTML Canvas boilerplate
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<!DOCTYPE HTML> | |
<html> | |
<body> | |
<canvas id="myCanvas" width="1000" height="1000"></canvas> | |
<script> | |
function drawImage() { | |
var canvas = document.getElementById('myCanvas'); | |
var context = canvas.getContext('2d'); | |
var imageWidth = canvas.width = Math.min(canvas.width, window.innerWidth); | |
var imageHeight = canvas.height = Math.min(canvas.height, window.innerHeight); | |
var imageData = context.createImageData(imageWidth, imageHeight); | |
// iterate over all pixels based on x and y coordinates | |
for(var y = 0; y < imageHeight; y++) { | |
// loop through each column | |
for(var x = 0; x < imageWidth; x++) { | |
imageData.data[(imageWidth*y + x) * 4 + 0] = y/imageHeight * 255; | |
imageData.data[(imageWidth*y + x) * 4 + 1] = y/imageHeight * 255; | |
imageData.data[(imageWidth*y + x) * 4 + 2] = x/imageWidth * 255; | |
imageData.data[(imageWidth*y + x) * 4 + 3] = 255; | |
} | |
} | |
context.putImageData(imageData, 0, 0); | |
} | |
drawImage(); | |
</script> | |
</body> | |
</html> |
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