+/*
+ * Return air usage (in liters).
+ */
+static double calculate_airuse(struct dive *dive)
+{
+ double airuse = 0;
+ int i;
+
+ for (i = 0; i < MAX_CYLINDERS; i++) {
+ cylinder_t *cyl = dive->cylinder + i;
+ int size = cyl->type.size.mliter;
+ double kilo_atm;
+
+ if (!size)
+ continue;
+
+ kilo_atm = (cyl->start.mbar - cyl->end.mbar) / 1013250.0;
+
+ /* Liters of air at 1 atm == milliliters at 1k atm*/
+ airuse += kilo_atm * size;
+ }
+ return airuse;
+}
+
+static void plot_info(struct dive *dive, cairo_t *cr,
+ double maxx, double maxy)
+{
+ text_render_options_t tro = {0.2, 1.0, 0.2, LEFT};
+ const double liters_per_cuft = 28.317;
+ const char *unit;
+ double airuse;
+
+ airuse = calculate_airuse(dive);
+ if (!airuse)
+ return;
+
+ /* I really need to start addign some unit setting thing */
+ switch (output_units.volume) {
+ case LITER:
+ unit = "l";
+ break;
+ case CUFT:
+ unit = "cuft";
+ airuse /= liters_per_cuft;
+ break;
+ }
+ plot_text(cr, &tro, maxx*0.8, maxy*0.8, "vol: %4.2f %s", airuse, unit);
+ if (dive->duration.seconds) {
+ double pressure = 1 + (dive->meandepth.mm / 10000.0);
+ double sac = airuse / pressure * 60 / dive->duration.seconds;
+ plot_text(cr, &tro, maxx*0.8, maxy*0.85, "SAC: %4.2f %s/min", sac, unit);
+ }
+}
+
+static void plot_cylinder_pressure_text(struct dive *dive, cairo_t *cr,
+ double maxx, double maxy)
+{
+ double scalex, scaley;
+ pressure_t startp, endp;
+
+ cairo_set_font_size(cr, 10);
+
+ if (get_cylinder_pressure_range(dive, &scalex, &scaley,
+ &startp, &endp)) {
+ int start, end;
+ const char *unit = "bar";
+
+ switch (output_units.pressure) {
+ case PASCAL:
+ start = startp.mbar * 100;
+ end = startp.mbar * 100;
+ unit = "pascal";
+ break;
+ case BAR:
+ start = (startp.mbar + 500) / 1000;
+ end = (endp.mbar + 500) / 1000;
+ unit = "bar";
+ break;
+ case PSI:
+ start = to_PSI(startp);
+ end = to_PSI(endp);
+ unit = "psi";
+ break;
+ }
+
+ text_render_options_t tro = {0.2, 1.0, 0.2, LEFT};
+ plot_text(cr, &tro, SCALE(0, startp.mbar), "%d %s", start, unit);
+ plot_text(cr, &tro, SCALE(dive->duration.seconds, endp.mbar),
+ "%d %s", end, unit);
+ }
+}
+