WDP_AUTO, "graph_legend", 0, 0,

	WC_GRAPH_LEGEND, WC_NONE,

	0,

	_nested_graph_legend_widgets, lengthof(_nested_graph_legend_widgets)

);

static void ShowGraphLegend()

{

	AllocateWindowDescFront<GraphLegendWindow>(&_graph_legend_desc, 0);

}

/** Contains the interval of a graph's data. */

struct ValuesInterval {

	OverflowSafeInt64 highest; ///< Highest value of this interval. Must be zero or greater.

	OverflowSafeInt64 lowest;  ///< Lowest value of this interval. Must be zero or less.

};

/******************/

/* BASE OF GRAPHS */

/*****************/

struct BaseGraphWindow : Window {

protected:

	static const int GRAPH_MAX_DATASETS     =  64;

	static const int GRAPH_NUM_MONTHS       =  24; ///< Number of months displayed in the graph.

	static const int MIN_GRAPH_NUM_LINES_Y  =   9; ///< Minimal number of horizontal lines to draw.

	static const int MIN_GRID_PIXEL_SIZE    =  20; ///< Minimum distance between graph lines.

	uint64 excluded_data; ///< bitmask of the datasets that shouldn't be displayed.

	byte num_dataset;

	byte num_on_x_axis;

	byte num_vert_lines;

	static const TextColour graph_axis_label_colour = TC_BLACK; ///< colour of the graph axis label.

	/* The starting month and year that values are plotted against. If month is

	 * 0xFF, use x_values_start and x_values_increment below instead. */

	byte month;

	Year year;

	/* These values are used if the graph is being plotted against values

	 * rather than the dates specified by month and year. */

	uint16 x_values_start;

	uint16 x_values_increment;

	int graph_widget;

	StringID format_str_y_axis;

	byte colours[GRAPH_MAX_DATASETS];

			Dimension d = GetStringBoundingBox(STR_GRAPH_Y_LABEL);

			if (d.width > max_width) max_width = d.width;

			y_label -= y_label_separation;

		}

		return max_width;

	}

	/**

	 * Actually draw the graph.

	 * @param r the rectangle of the data field of the graph

	 */

	void DrawGraph(Rect r) const

	{

		uint x, y;               ///< Reused whenever x and y coordinates are needed.

		ValuesInterval interval; ///< Interval that contains all of the graph data.

		int x_axis_offset;       ///< Distance from the top of the graph to the x axis.

		/* the colours and cost array of GraphDrawer must accommodate

		 * both values for cargo and companies. So if any are higher, quit */

		static_assert(GRAPH_MAX_DATASETS >= (int)NUM_CARGO && GRAPH_MAX_DATASETS >= (int)MAX_COMPANIES);

		assert(this->num_vert_lines > 0);

		/* Rect r will be adjusted to contain just the graph, with labels being

		 * placed outside the area. */

		r.top    += 5 + GetCharacterHeight(FS_SMALL) / 2;

		r.bottom -= (this->month == 0xFF ? 1 : 3) * GetCharacterHeight(FS_SMALL) + 4;

		r.left   += 9;

		r.right  -= 5;

		/* Initial number of horizontal lines. */

		int num_hori_lines = 160 / MIN_GRID_PIXEL_SIZE;

		/* For the rest of the height, the number of horizontal lines will increase more slowly. */

		int resize = (r.bottom - r.top - 160) / (2 * MIN_GRID_PIXEL_SIZE);

		if (resize > 0) num_hori_lines += resize;

		interval = GetValuesInterval(num_hori_lines);

		int label_width = GetYLabelWidth(interval, num_hori_lines);

		r.left += label_width;

		int x_sep = (r.right - r.left) / this->num_vert_lines;

		int y_sep = (r.bottom - r.top) / num_hori_lines;

		/* Redetermine right and bottom edge of graph to fit with the integer

		/* Draw the vertical grid lines. */

		/* Don't draw the first line, as that's where the axis will be. */

		x = r.left + x_sep;

		for (int i = 0; i < this->num_vert_lines; i++) {

			GfxFillRect(x, r.top, x, r.bottom, grid_colour);

			x += x_sep;

		}

		/* Draw the horizontal grid lines. */

		y = r.bottom;

		for (int i = 0; i < (num_hori_lines + 1); i++) {

			GfxFillRect(r.left - 3, y, r.left - 1, y, GRAPH_AXIS_LINE_COLOUR);

			GfxFillRect(r.left, y, r.right, y, grid_colour);

			y -= y_sep;

		}

		/* Draw the y axis. */

		GfxFillRect(r.left, r.top, r.left, r.bottom, GRAPH_AXIS_LINE_COLOUR);

		/* Draw the x axis. */

		y = x_axis_offset + r.top;

		/* Find the largest value that will be drawn. */

		if (this->num_on_x_axis == 0) return;

		assert(this->num_on_x_axis > 0);

		assert(this->num_dataset > 0);

		/* draw text strings on the y axis */

		int64 y_label = interval.highest;

		int64 y_label_separation = abs(interval.highest - interval.lowest) / num_hori_lines;

		y = r.top - GetCharacterHeight(FS_SMALL) / 2;

		for (int i = 0; i < (num_hori_lines + 1); i++) {

			SetDParam(0, this->format_str_y_axis);

			SetDParam(1, y_label);

			DrawString(r.left - label_width - 4, r.left - 4, y, STR_GRAPH_Y_LABEL, graph_axis_label_colour, SA_RIGHT);

			y_label -= y_label_separation;

			y += y_sep;

		}

		/* draw strings on the x axis */

		if (this->month != 0xFF) {