You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
58 lines
2.1 KiB
HTML
58 lines
2.1 KiB
HTML
<!doctype html>
|
|
<html>
|
|
<head>
|
|
<meta charset="utf-8">
|
|
<title>Spray Paint</title>
|
|
<link rel="stylesheet" href="../include/style.css">
|
|
</head>
|
|
<body>
|
|
<header>
|
|
Example from <a href="http://amzn.com/1430236655?tag=html5anim-20"><em>Foundation HTML5 Animation with JavaScript</em></a>
|
|
</header>
|
|
<canvas id="canvas" width="400" height="400"></canvas>
|
|
<aside>Click and draw with the mouse.</aside>
|
|
|
|
<script src="../include/utils.js"></script>
|
|
<script>
|
|
window.onload = function () {
|
|
var canvas = document.getElementById('canvas'),
|
|
context = canvas.getContext('2d'),
|
|
mouse = utils.captureMouse(canvas),
|
|
imagedata = context.getImageData(0, 0, canvas.width, canvas.height),
|
|
pixels = imagedata.data,
|
|
brush_size = 25,
|
|
brush_density = 50,
|
|
brush_color;
|
|
|
|
canvas.addEventListener('mousedown', function () {
|
|
brush_color = utils.parseColor(Math.random() * 0xffffff, true); //to number
|
|
canvas.addEventListener('mousemove', onMouseMove, false);
|
|
}, false);
|
|
|
|
canvas.addEventListener('mouseup', function () {
|
|
canvas.removeEventListener('mousemove', onMouseMove, false);
|
|
}, false);
|
|
|
|
function onMouseMove () {
|
|
//loop over each brush bristle
|
|
for (var i = 0; i < brush_density; i++) {
|
|
var angle = Math.random() * Math.PI * 2,
|
|
radius = Math.random() * brush_size,
|
|
xpos = (mouse.x + Math.cos(angle) * radius) | 0,
|
|
ypos = (mouse.y + Math.sin(angle) * radius) | 0,
|
|
offset = (xpos + ypos * imagedata.width) * 4; //array index of canvas coordinate
|
|
|
|
//set the color of a pixel using its component colors: r,g,b,a (0-255)
|
|
pixels[offset] = brush_color >> 16 & 0xff; //red
|
|
pixels[offset + 1] = brush_color >> 8 & 0xff; //green
|
|
pixels[offset + 2] = brush_color & 0xff; //blue
|
|
pixels[offset + 3] = 255; //alpha
|
|
}
|
|
|
|
context.putImageData(imagedata, 0, 0);
|
|
}
|
|
};
|
|
</script>
|
|
</body>
|
|
</html>
|