#define GRAPH_H
struct graph;
+struct graph_label;
-struct graph *graph_new(int xdim, int ydim);
+typedef struct graph_label * graph_label_t;
+
+#define GRAPH_DEFAULT_FONT "Sans 12"
+
+struct graph *graph_new(unsigned int xdim, unsigned int ydim, const char *font);
+/* graph_new() Returns a new graph structure of the given dimensions and font */
+void graph_set_size(struct graph *g, unsigned int xdim, unsigned int ydim);
+/* graph_set_size() Changes the size of a graph to the given dimensions. */
+void graph_set_position(struct graph *g, double xoffset, double yoffset);
+/* graph_set_position() sets the x- and y-offset to translate the graph */
void bar_graph_draw(struct graph *g, cairo_t *cr);
+/* bar_graph_draw() draws the given graph as a bar graph */
void line_graph_draw(struct graph *g, cairo_t *cr);
+/* line_graph_draw draws the given graph as a line graph */
void line_graph_set_data_count_limit(struct graph *g, int per_label_limit);
+/* line_graph_set_data_count_limit() limits the amount of data which can
+ * be added to a line graph. Once the limit is reached, the oldest data
+ * is discarded as new data is added
+ */
+void graph_set_font(struct graph *g, const char *font);
void graph_title(struct graph *g, const char *title);
+/* graph_title() sets the main title of the graph to the given string */
void graph_x_title(struct graph *g, const char *title);
+/* graph_x_title() sets the title of the x axis to the given string */
void graph_y_title(struct graph *g, const char *title);
-void graph_add_label(struct graph *g, const char *label);
-void graph_add_data(struct graph *g, const char *label, const double value);
-void graph_add_xy_data(struct graph *g, const char *label,
- const double x, const double y);
-void graph_set_color(struct graph *g, const char *label,
+/* graph_y_title() sets the title of the y axis to the given string */
+graph_label_t graph_add_label(struct graph *g, const char *label);
+/* graph_add_label() adds a new "stream" of data to be graphed.
+ * For line charts, each label is a separate line on the graph.
+ * For bar charts, each label is a grouping of columns on the x-axis
+ * For example:
+ *
+ * | * | **
+ * | * xxxxxxxx | **
+ * | *** x | ** **
+ * | *x **** | ** ** **
+ * | xxxx* ***** | ** xx ** xx **
+ * | x ** | ** xx ** xx ** xx
+ * | x | ** xx ** xx ** xx
+ * ----------------------- -------------------------
+ * A B C
+ *
+ * For a line graph, the 'x's For a bar graph,
+ * would be on one "label", and 'A', 'B', and 'C'
+ * the '*'s would be on another are the labels.
+ * label.
+ */
+
+int graph_add_data(struct graph *g, graph_label_t label, const double value);
+/* graph_add_data() is used to add data to the labels of a bar graph */
+int graph_add_xy_data(struct graph *g, graph_label_t label,
+ const double x, const double y, const char *tooltip);
+/* graph_add_xy_data is used to add data to the labels of a line graph */
+
+void graph_set_color(struct graph *g, graph_label_t label,
double red, double green, double blue);
+#define INVISIBLE_COLOR (-1.0)
+/* graph_set_color is used to set the color used to plot the data in
+ * a line graph. INVISIBLE_COLOR can be used to plot the data invisibly.
+ * Invisible data will have the same effect on the scaling of the axes
+ * as visible data.
+ */
+
void graph_free(struct graph *bg);
+/* free a graph allocated by graph_new() */
+
+typedef void (*graph_axis_unit_change_callback)(struct graph *g, int power_of_ten);
+void graph_x_axis_unit_change_notify(struct graph *g, graph_axis_unit_change_callback f);
+void graph_y_axis_unit_change_notify(struct graph *g, graph_axis_unit_change_callback f);
+/* The labels used on the x and y axes may be shortened. You can register for callbacks
+ * so that you can know how the labels are shorted, typically used to adjust the axis
+ * titles to display the proper units. The power_of_ten parameter indicates what power
+ * of ten the labels have been divided by (9, 6, 3, or 0, corresponding to billions,
+ * millions, thousands and ones.
+ */
+
+void graph_add_extra_space(struct graph *g, double left_percent, double right_percent,
+ double top_percent, double bottom_percent);
+/* graph_add_extra_space() adds extra space to edges of the the graph
+ * so that the data doesn't go to the very edges.
+ */
+
+extern int graph_has_tooltips(struct graph *g);
+extern const char *graph_find_tooltip(struct graph *g, int x, int y);
+extern int graph_contains_xy(struct graph *p, int x, int y);
+
+extern void graph_set_base_offset(struct graph *g, unsigned int base_offset);
+extern void graph_set_graph_all_zeroes(struct graph *g, unsigned int set);
+extern void graph_clear_values(struct graph *g);
#endif