+}
+
+/* gets both the actual start and end pressure as well as the scaling factors */
+static int get_cylinder_pressure_range(struct graphics_context *gc, struct plot_info *pi)
+{
+ gc->leftx = 0;
+ gc->rightx = get_maxtime(pi);
+
+ gc->bottomy = 0; gc->topy = pi->maxpressure * 1.5;
+ return pi->maxpressure != 0;
+}
+
+static void plot_pressure_helper(struct graphics_context *gc, struct plot_info *pi, int type)
+{
+ int i;
+ int lift_pen = FALSE;
+
+ for (i = 0; i < pi->nr; i++) {
+ int mbar;
+ struct plot_data *entry = pi->entry + i;
+
+ mbar = entry->pressure[type];
+ if (!entry->same_cylinder)
+ lift_pen = TRUE;
+ if (!mbar) {
+ lift_pen = TRUE;
+ continue;
+ }
+ if (lift_pen) {
+ if (i > 0 && entry->same_cylinder) {
+ /* if we have a previous event from the same tank,
+ * draw at least a short line .
+ * This uses the implementation detail that the
+ * type is either 0 or 1 */
+ int prev_pr;
+ prev_pr = (entry-1)->pressure[type] ? : (entry-1)->pressure[1 - type];
+ move_to(gc, (entry-1)->sec, prev_pr);
+ line_to(gc, entry->sec, mbar);
+ } else
+ move_to(gc, entry->sec, mbar);
+ lift_pen = FALSE;
+ }
+ else
+ line_to(gc, entry->sec, mbar);
+ }
+ cairo_stroke(gc->cr);
+
+}
+
+static void plot_cylinder_pressure(struct graphics_context *gc, struct plot_info *pi)
+{
+ if (!get_cylinder_pressure_range(gc, pi))
+ return;
+
+ /* first plot the pressure readings we have from the dive computer */
+ set_source_rgba(gc, 0.2, 1.0, 0.2, 0.80);
+ plot_pressure_helper(gc, pi, SENSOR_PR);
+
+ /* then, in a different color, the interpolated values */
+ set_source_rgba(gc, 1.0, 1.0, 0.2, 0.80);
+ plot_pressure_helper(gc, pi, INTERPOLATED_PR);
+}
+
+static void plot_pressure_value(struct graphics_context *gc, int mbar, int sec,
+ int xalign, int yalign)
+{
+ int pressure;
+ const char *unit;
+
+ pressure = get_pressure_units(mbar, &unit);
+ text_render_options_t tro = {10, 0.2, 1.0, 0.2, xalign, yalign};
+ plot_text(gc, &tro, sec, mbar, "%d %s", pressure, unit);
+}
+
+static void plot_cylinder_pressure_text(struct graphics_context *gc, struct plot_info *pi)
+{
+ int i;
+ int mbar, cyl;
+ int seen_cyl[MAX_CYLINDERS] = { FALSE, };
+ int last_pressure[MAX_CYLINDERS] = { 0, };
+ int last_time[MAX_CYLINDERS] = { 0, };
+ struct plot_data *entry;
+
+ if (!get_cylinder_pressure_range(gc, pi))
+ return;
+
+ /* only loop over the actual events from the dive computer */
+ for (i = 2; i < pi->nr; i++) {
+ entry = pi->entry + i;
+
+ if (!entry->same_cylinder) {
+ cyl = entry->cylinderindex;
+ if (!seen_cyl[cyl]) {
+ mbar = SENSOR_PRESSURE(entry) ? : INTERPOLATED_PRESSURE(entry);
+ plot_pressure_value(gc, mbar, entry->sec, LEFT, BOTTOM);
+ seen_cyl[cyl] = TRUE;
+ }
+ if (i > 2) {
+ /* remember the last pressure and time of
+ * the previous cylinder */
+ cyl = (entry - 1)->cylinderindex;
+ last_pressure[cyl] =
+ SENSOR_PRESSURE(entry - 1) ? : INTERPOLATED_PRESSURE(entry - 1);
+ last_time[cyl] = (entry - 1)->sec;
+ }
+ }
+ }
+ cyl = entry->cylinderindex;
+ last_pressure[cyl] = SENSOR_PRESSURE(entry) ? : INTERPOLATED_PRESSURE(entry);
+ last_time[cyl] = entry->sec;
+
+ for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) {
+ if (last_time[cyl]) {
+ plot_pressure_value(gc, last_pressure[cyl], last_time[cyl], CENTER, TOP);
+ }
+ }
+}
+
+static void analyze_plot_info_minmax_minute(struct plot_data *entry, struct plot_data *first, struct plot_data *last, int index)
+{
+ struct plot_data *p = entry;
+ int time = entry->sec;
+ int seconds = 90*(index+1);
+ struct plot_data *min, *max;
+ int avg, nr;
+
+ /* Go back 'seconds' in time */
+ while (p > first) {
+ if (p[-1].sec < time - seconds)
+ break;
+ p--;
+ }
+
+ /* Then go forward until we hit an entry past the time */
+ min = max = p;
+ avg = p->depth;
+ nr = 1;
+ while (++p < last) {
+ int depth = p->depth;
+ if (p->sec > time + seconds)
+ break;
+ avg += depth;
+ nr ++;
+ if (depth < min->depth)
+ min = p;
+ if (depth > max->depth)
+ max = p;
+ }
+ entry->min[index] = min;
+ entry->max[index] = max;
+ entry->avg[index] = (avg + nr/2) / nr;
+}
+
+static void analyze_plot_info_minmax(struct plot_data *entry, struct plot_data *first, struct plot_data *last)
+{
+ analyze_plot_info_minmax_minute(entry, first, last, 0);
+ analyze_plot_info_minmax_minute(entry, first, last, 1);
+ analyze_plot_info_minmax_minute(entry, first, last, 2);
+}
+
+static velocity_t velocity(int speed)
+{
+ velocity_t v;
+
+ if (speed < -304) /* ascent faster than -60ft/min */
+ v = CRAZY;
+ else if (speed < -152) /* above -30ft/min */
+ v = FAST;
+ else if (speed < -76) /* -15ft/min */
+ v = MODERATE;
+ else if (speed < -25) /* -5ft/min */
+ v = SLOW;
+ else if (speed < 25) /* very hard to find data, but it appears that the recommendations
+ for descent are usually about 2x ascent rate; still, we want
+ stable to mean stable */
+ v = STABLE;
+ else if (speed < 152) /* between 5 and 30ft/min is considered slow */
+ v = SLOW;
+ else if (speed < 304) /* up to 60ft/min is moderate */
+ v = MODERATE;
+ else if (speed < 507) /* up to 100ft/min is fast */
+ v = FAST;
+ else /* more than that is just crazy - you'll blow your ears out */
+ v = CRAZY;
+
+ return v;
+}
+static struct plot_info *analyze_plot_info(struct plot_info *pi)
+{
+ int i;
+ int nr = pi->nr;
+
+ /* Do pressure min/max based on the non-surface data */
+ for (i = 0; i < nr; i++) {
+ struct plot_data *entry = pi->entry+i;
+ int pressure = SENSOR_PRESSURE(entry) ? : INTERPOLATED_PRESSURE(entry);
+ int temperature = entry->temperature;
+
+ if (pressure) {
+ if (!pi->minpressure || pressure < pi->minpressure)
+ pi->minpressure = pressure;
+ if (pressure > pi->maxpressure)
+ pi->maxpressure = pressure;
+ }
+
+ if (temperature) {
+ if (!pi->mintemp || temperature < pi->mintemp)
+ pi->mintemp = temperature;
+ if (temperature > pi->maxtemp)
+ pi->maxtemp = temperature;
+ }
+ }
+
+ /* Smoothing function: 5-point triangular smooth */
+ for (i = 2; i < nr; i++) {
+ struct plot_data *entry = pi->entry+i;
+ int depth;
+
+ if (i < nr-2) {
+ depth = entry[-2].depth + 2*entry[-1].depth + 3*entry[0].depth + 2*entry[1].depth + entry[2].depth;
+ entry->smoothed = (depth+4) / 9;
+ }
+ /* vertical velocity in mm/sec */
+ /* Linus wants to smooth this - let's at least look at the samples that aren't FAST or CRAZY */
+ if (entry[0].sec - entry[-1].sec) {
+ entry->velocity = velocity((entry[0].depth - entry[-1].depth) / (entry[0].sec - entry[-1].sec));
+ /* if our samples are short and we aren't too FAST*/
+ if (entry[0].sec - entry[-1].sec < 15 && entry->velocity < FAST) {
+ int past = -2;
+ while (i+past > 0 && entry[0].sec - entry[past].sec < 15)
+ past--;
+ entry->velocity = velocity((entry[0].depth - entry[past].depth) /
+ (entry[0].sec - entry[past].sec));
+ }
+ } else
+ entry->velocity = STABLE;
+ }
+
+ /* One-, two- and three-minute minmax data */
+ for (i = 0; i < nr; i++) {
+ struct plot_data *entry = pi->entry +i;
+ analyze_plot_info_minmax(entry, pi->entry, pi->entry+nr);
+ }
+
+ return pi;
+}