Fix profile and average depth for freedives

Freedives can easily exceed the assumed ascent/descent rate, which
results in wacky dive profiles.  Add a check to make the ascent and
descent fit within the duration of the dive.

2 files changed, 7 insertions, 4 deletions

diff --git a/dive.c b/dive.c
index aee09d53a..54784cdba 100644
--- a/dive.c
+++ b/dive.c
@@ -478,11 +478,12 @@ struct dive *fixup_dive(struct dive *dive)
 		int asc_desc_time = depth*60/9000;
 		int duration = dive->duration.seconds;
 
-		/* Protect against insane dives - make mean be half of max */
-		if (duration <= asc_desc_time) {
+		/* Some sanity checks against insane dives */
+		if (duration < 2)
 			duration = 2;
-			asc_desc_time = 1;
-		}
+		if (asc_desc_time * 2 >= duration)
+			asc_desc_time = duration/2;
+
 		dive->meandepth.mm = depth*(duration-asc_desc_time)/duration;
 		return dive;
 	}
diff --git a/profile.c b/profile.c
index d4e88c02c..0039867ef 100644
--- a/profile.c
+++ b/profile.c
@@ -1387,6 +1387,8 @@ void plot(struct graphics_context *gc, cairo_rectangle_int_t *drawing_area, stru
 		int duration = dive->duration.seconds;
 		int maxdepth = dive->maxdepth.mm;
 		int asc_desc_time = dive->maxdepth.mm*60/9000;
+		if (asc_desc_time * 2 >= duration)
+			asc_desc_time = duration / 2;
 		sample = fake;
 		fake[1].time.seconds = asc_desc_time;
 		fake[1].depth.mm = maxdepth;