/* 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);