+ cairo_stroke(cr);
+
+ move_to(gc, x, y);
+ cairo_rel_move_to(cr, dx, dy);
+
+ cairo_set_source_rgb(cr, tro->r, tro->g, tro->b);
+ cairo_show_text(cr, buffer);
+}
+
+/*
+ * Find the next maximum point in a 10-minute window.
+ *
+ * We exit early if we hit "enough" of a depth reversal,
+ * which is roughly 10 feet.
+ */
+static struct sample *next_minmax(struct sample *sample, struct sample *end, int minmax)
+{
+ const int enough = 3000;
+ struct sample *result;
+ int timelimit, depthlimit;
+
+ if (sample >= end)
+ return 0;
+
+ timelimit = 24*60*60;
+ depthlimit = sample->depth.mm;
+ result = NULL;
+
+ for (;;) {
+ int time, depth;
+
+ sample++;
+ if (sample >= end)
+ return NULL;
+ time = sample->time.seconds;
+ depth = sample->depth.mm;
+ if (time > timelimit)
+ break;
+
+ if (minmax) {
+ if (depth <= depthlimit) {
+ if (depthlimit - depth > enough)
+ break;
+ continue;
+ }
+ } else {
+ if (depth >= depthlimit) {
+ if (depth - depthlimit > enough)
+ break;
+ continue;
+ }
+ }
+
+ result = sample;
+ depthlimit = depth;
+ /* Look up to ten minutes into the future */
+ timelimit = time + 600;
+ }
+ return result;
+}
+
+static void render_depth_sample(struct graphics_context *gc, struct sample *sample)
+{
+ text_render_options_t tro = {1.0, 0.2, 0.2, CENTER};
+ int sec = sample->time.seconds;
+ depth_t depth = sample->depth;
+ const char *fmt;
+ double d;
+
+ switch (output_units.length) {
+ case METERS:
+ d = depth.mm / 1000.0;
+ fmt = "%.1f";
+ break;
+ case FEET:
+ d = to_feet(depth);
+ fmt = "%.0f";
+ break;
+ }
+ plot_text(gc, &tro, sec, depth.mm, fmt, d);
+}
+
+static void plot_text_samples(struct graphics_context *gc, struct sample *a, struct sample *b)
+{
+ struct sample *max, *min;
+
+ if (b < a)
+ return;
+ if (b->time.seconds - a->time.seconds < 3*60)
+ return;
+
+ max = next_minmax(a, b, 1);
+ if (max) {
+ render_depth_sample(gc, max);
+ min = next_minmax(max, b, 0);
+ if (min) {
+ plot_text_samples(gc, min, b);
+ return;
+ }
+ }
+}
+
+static void plot_depth_text(struct dive *dive, struct graphics_context *gc)
+{
+ struct sample *sample, *end;
+ int maxtime, maxdepth;
+
+ /* Get plot scaling limits */
+ maxtime = round_seconds_up(dive->duration.seconds);
+ maxdepth = round_depth_up(dive->maxdepth);
+
+ gc->scalex = maxtime;
+ gc->scaley = maxdepth;
+
+ cairo_set_font_size(gc->cr, 14);
+
+ /*
+ * We never take the last sample into account.
+ * It should be a surface event anyway, although
+ * there are buggy cases where it isn't..
+ */
+ sample = dive->sample;
+ end = dive->sample + dive->samples - 1;
+
+ plot_text_samples(gc, sample, end);
+}
+
+static void plot_depth_profile(struct dive *dive, struct graphics_context *gc)
+{
+ cairo_t *cr = gc->cr;
+ int begins, sec, depth;
+ int i, samples;
+ struct sample *sample;
+ int maxtime, maxdepth, marker;
+
+ samples = dive->samples;
+ if (!samples)
+ return;
+
+ cairo_set_line_width(gc->cr, 2);
+
+ /* Get plot scaling limits */
+ maxtime = round_seconds_up(dive->duration.seconds);
+ maxdepth = round_depth_up(dive->maxdepth);
+
+ /* Time markers: every 5 min */
+ gc->scalex = maxtime;
+ gc->scaley = 1.0;
+ for (i = 5*60; i < maxtime; i += 5*60) {
+ move_to(gc, i, 0);
+ line_to(gc, i, 1);
+ }
+
+ /* Depth markers: every 30 ft or 10 m*/
+ gc->scalex = 1.0;
+ gc->scaley = maxdepth;
+ switch (output_units.length) {
+ case METERS: marker = 10000; break;
+ case FEET: marker = 9144; break; /* 30 ft */
+ }
+
+ cairo_set_source_rgba(cr, 1, 1, 1, 0.5);
+ for (i = marker; i < maxdepth; i += marker) {
+ move_to(gc, 0, i);
+ line_to(gc, 1, i);
+ }
+ cairo_stroke(cr);
+
+ /* Show mean depth */
+ cairo_set_source_rgba(cr, 1, 0.2, 0.2, 0.40);
+ move_to(gc, 0, dive->meandepth.mm);
+ line_to(gc, 1, dive->meandepth.mm);
+ cairo_stroke(cr);
+
+ gc->scalex = maxtime;
+
+ sample = dive->sample;
+ cairo_set_source_rgba(cr, 1, 0.2, 0.2, 0.80);
+ begins = sample->time.seconds;
+ move_to(gc, sample->time.seconds, sample->depth.mm);
+ for (i = 1; i < dive->samples; i++) {
+ sample++;
+ sec = sample->time.seconds;
+ if (sec <= maxtime) {
+ depth = sample->depth.mm;
+ line_to(gc, sec, depth);
+ }
+ }
+ gc->scaley = 1.0;
+ line_to(gc, MIN(sec,maxtime), 0);
+ line_to(gc, begins, 0);
+ cairo_close_path(cr);
+ cairo_set_source_rgba(cr, 1, 0.2, 0.2, 0.20);
+ cairo_fill_preserve(cr);
+ cairo_set_source_rgba(cr, 1, 0.2, 0.2, 0.80);
+ cairo_stroke(cr);
+}
+
+/* gets both the actual start and end pressure as well as the scaling factors */
+static int get_cylinder_pressure_range(struct dive *dive, struct graphics_context *gc,
+ pressure_t *startp, pressure_t *endp)
+{
+ int i;
+ int min, max;
+
+ gc->scalex = round_seconds_up(dive->duration.seconds);
+
+ max = 0;
+ min = 5000000;
+ if (startp)
+ startp->mbar = endp->mbar = 0;
+
+ for (i = 0; i < dive->samples; i++) {
+ int mbar;
+ struct sample *sample = dive->sample + i;
+
+ /* FIXME! We only track cylinder 0 right now */
+ if (sample->cylinderindex)
+ continue;
+ mbar = sample->cylinderpressure.mbar;
+ if (!mbar)
+ continue;
+ if (mbar < min)
+ min = mbar;
+ if (mbar > max)
+ max = mbar;
+ }
+ if (startp)
+ startp->mbar = max;
+ if (endp)
+ endp->mbar = min;
+ if (!max)
+ return 0;
+ gc->scaley = max * 1.5;
+ return 1;
+}
+
+static void plot_cylinder_pressure(struct dive *dive, struct graphics_context *gc)
+{
+ int i, sec = -1;
+
+ if (!get_cylinder_pressure_range(dive, gc, NULL, NULL))
+ return;
+
+ cairo_set_source_rgba(gc->cr, 0.2, 1.0, 0.2, 0.80);
+
+ move_to(gc, 0, dive->cylinder[0].start.mbar);
+ for (i = 1; i < dive->samples; i++) {
+ int mbar;
+ struct sample *sample = dive->sample + i;
+
+ mbar = sample->cylinderpressure.mbar;
+ if (!mbar)
+ continue;
+ sec = sample->time.seconds;
+ if (sec <= dive->duration.seconds)
+ line_to(gc, sec, mbar);
+ }
+ /*
+ * We may have "surface time" events, in which case we don't go
+ * back to dive duration
+ */
+ if (sec < dive->duration.seconds)
+ line_to(gc, dive->duration.seconds, dive->cylinder[0].end.mbar);
+ cairo_stroke(gc->cr);
+}
+
+/*
+ * 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, struct graphics_context *gc)
+{
+ 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(gc, &tro, 0.8, 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(gc, &tro, 0.8, 0.85, "SAC: %4.2f %s/min", sac, unit);
+ }
+}
+
+static void plot_cylinder_pressure_text(struct dive *dive, struct graphics_context *gc)
+{
+ pressure_t startp, endp;
+
+ cairo_set_font_size(gc->cr, 10);
+
+ if (get_cylinder_pressure_range(dive, gc, &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;