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sparkline.js
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sparkline.js
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var sparkline = function(canvas_id, data, endpoint, color, style) {
if (window.HTMLCanvasElement) {
var c = document.getElementById(canvas_id),
ctx = c.getContext('2d'),
color = (color ? color : 'rgba(0,0,0,0.5)'),
style = (style == 'bar' ? 'bar' : 'line'),
height = c.height - 2,
width = c.width,
total = data.length,
max = Math.max.apply(Math, data),
xstep = width/total,
ystep = max/height,
x = 0,
y = height - data[0]/ystep,
i;
ctx.clearRect(0, 0, width, height);
ctx.beginPath();
ctx.strokeStyle = color;
ctx.moveTo(x, y);
for (i = 1; i < total; i = i + 1) {
x = x + xstep;
y = height - data[i]/ystep + 1;
if (style == 'bar') { ctx.moveTo(x,height); }
ctx.lineTo(x, y);
}
ctx.stroke();
if (endpoint && style == 'line') {
ctx.beginPath();
ctx.fillStyle = 'rgba(255,0,0,0.5)';
ctx.arc(x, y, 1.5, 0, Math.PI*2);
ctx.fill();
}
}
};