jquery.flot.symbol.js
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/* Flot plugin that adds some extra symbols for plotting points.
Copyright (c) 2007-2014 IOLA and Ole Laursen.
Licensed under the MIT license.
The symbols are accessed as strings through the standard symbol options:
series: {
points: {
symbol: "square" // or "diamond", "triangle", "cross"
}
}
*/
(function ($) {
function processRawData(plot, series, datapoints) {
// we normalize the area of each symbol so it is approximately the
// same as a circle of the given radius
var handlers = {
square: function (ctx, x, y, radius, shadow) {
// pi * r^2 = (2s)^2 => s = r * sqrt(pi)/2
var size = radius * Math.sqrt(Math.PI) / 2;
ctx.rect(x - size, y - size, size + size, size + size);
},
diamond: function (ctx, x, y, radius, shadow) {
// pi * r^2 = 2s^2 => s = r * sqrt(pi/2)
var size = radius * Math.sqrt(Math.PI / 2);
ctx.moveTo(x - size, y);
ctx.lineTo(x, y - size);
ctx.lineTo(x + size, y);
ctx.lineTo(x, y + size);
ctx.lineTo(x - size, y);
},
triangle: function (ctx, x, y, radius, shadow) {
// pi * r^2 = 1/2 * s^2 * sin (pi / 3) => s = r * sqrt(2 * pi / sin(pi / 3))
var size = radius * Math.sqrt(2 * Math.PI / Math.sin(Math.PI / 3));
var height = size * Math.sin(Math.PI / 3);
ctx.moveTo(x - size/2, y + height/2);
ctx.lineTo(x + size/2, y + height/2);
if (!shadow) {
ctx.lineTo(x, y - height/2);
ctx.lineTo(x - size/2, y + height/2);
}
},
cross: function (ctx, x, y, radius, shadow) {
// pi * r^2 = (2s)^2 => s = r * sqrt(pi)/2
var size = radius * Math.sqrt(Math.PI) / 2;
ctx.moveTo(x - size, y - size);
ctx.lineTo(x + size, y + size);
ctx.moveTo(x - size, y + size);
ctx.lineTo(x + size, y - size);
}
};
var s = series.points.symbol;
if (handlers[s])
series.points.symbol = handlers[s];
}
function init(plot) {
plot.hooks.processDatapoints.push(processRawData);
}
$.plot.plugins.push({
init: init,
name: 'symbols',
version: '1.0'
});
})(jQuery);