+int selected_dive = 0;
+
+#define ROUND_UP(x,y) ((((x)+(y)-1)/(y))*(y))
+
+/*
+ * When showing dive profiles, we scale things to the
+ * current dive. However, we don't scale past less than
+ * 30 minutes or 90 ft, just so that small dives show
+ * up as such.
+ */
+static int round_seconds_up(int seconds)
+{
+ return MAX(30*60, ROUND_UP(seconds, 60*10));
+}
+
+static int round_feet_up(int feet)
+{
+ return MAX(90, ROUND_UP(feet+5, 15));
+}
+
+/* Scale to 0,0 -> maxx,maxy */
+#define SCALE(x,y) (x)*maxx/scalex+topx,(y)*maxy/scaley+topy
+
+static void plot(cairo_t *cr, int w, int h, struct dive *dive, int samples, struct sample *sample)
+{
+ int i;
+ double topx, topy, maxx, maxy;
+ double scalex, scaley;
+ int maxtime, maxdepth;
+ int begins, sec, depth;
+
+ topx = w / 20.0;
+ topy = h / 20.0;
+ maxx = (w - 2*topx);
+ maxy = (h - 2*topy);
+
+ cairo_set_line_width(cr, 2);
+
+ /* Get plot scaling limits */
+ maxtime = round_seconds_up(dive->duration.seconds);
+ maxdepth = round_feet_up(to_feet(dive->maxdepth));
+
+ /* Depth markers: every 15 ft */
+ scalex = 1.0;
+ scaley = maxdepth;
+ cairo_set_source_rgba(cr, 1, 1, 1, 0.5);
+ for (i = 15; i < maxdepth; i += 15) {
+ cairo_move_to(cr, SCALE(0, i));
+ cairo_line_to(cr, SCALE(1, i));
+ }
+
+ /* Time markers: every 5 min */
+ scalex = maxtime;
+ scaley = 1.0;
+ for (i = 5*60; i < maxtime; i += 5*60) {
+ cairo_move_to(cr, SCALE(i, 0));
+ cairo_line_to(cr, SCALE(i, 1));
+ }
+ cairo_stroke(cr);
+
+ scaley = maxdepth;
+
+ /* Depth profile */
+ cairo_set_source_rgba(cr, 1, 0.2, 0.2, 0.80);
+ begins = sample->time.seconds;
+ cairo_move_to(cr, SCALE(sample->time.seconds, to_feet(sample->depth)));
+ for (i = 1; i < dive->samples; i++) {
+ sample++;
+ sec = sample->time.seconds;
+ depth = to_feet(sample->depth);
+ cairo_line_to(cr, SCALE(sec, depth));
+ }
+ scaley = 1.0;
+ cairo_line_to(cr, SCALE(sec, 0));
+ cairo_line_to(cr, SCALE(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);
+
+ /* Bounding box last */
+ scalex = scaley = 1.0;
+ cairo_set_source_rgb(cr, 1, 1, 1);
+ cairo_move_to(cr, SCALE(0,0));
+ cairo_line_to(cr, SCALE(0,1));
+ cairo_line_to(cr, SCALE(1,1));
+ cairo_line_to(cr, SCALE(1,0));
+ cairo_close_path(cr);
+ cairo_stroke(cr);
+
+}
+