]> git.tdb.fi Git - ext/subsurface.git/blobdiff - profile.c
Fix profile and average depth for freedives
[ext/subsurface.git] / profile.c
index e5d8aa9b9065d5cc335e9a74413da3bd2eae1aae..0039867efc29355737294cb1ac02a0cb85743ce6 100644 (file)
--- a/profile.c
+++ b/profile.c
@@ -1,5 +1,5 @@
 /* profile.c */
-/* creates all the necessary data for drawing the dive profile 
+/* creates all the necessary data for drawing the dive profile
  * uses cairo to draw it
  */
 #include <stdio.h>
 #include "dive.h"
 #include "display.h"
 #include "divelist.h"
+#include "color.h"
 
 int selected_dive = 0;
+char zoomed_plot = 0;
 
 typedef enum { STABLE, SLOW, MODERATE, FAST, CRAZY } velocity_t;
+
 /* Plot info with smoothing, velocity indication
  * and one-, two- and three-minute minimums and maximums */
 struct plot_info {
        int nr;
        int maxtime;
        int meandepth, maxdepth;
-       int minpressure, maxpressure;
-       int endpressure; /* start pressure better be max pressure */
+       int maxpressure;
        int mintemp, maxtemp;
        struct plot_data {
                unsigned int same_cylinder:1;
@@ -41,19 +43,76 @@ struct plot_info {
                int avg[3];
        } entry[];
 };
+
 #define SENSOR_PR 0
 #define INTERPOLATED_PR 1
 #define SENSOR_PRESSURE(_entry) (_entry)->pressure[SENSOR_PR]
 #define INTERPOLATED_PRESSURE(_entry) (_entry)->pressure[INTERPOLATED_PR]
+#define GET_PRESSURE(_entry) (SENSOR_PRESSURE(_entry) ? : INTERPOLATED_PRESSURE(_entry))
+
+#define SAC_COLORS_START_IDX SAC_1
+#define SAC_COLORS 9
+#define VELOCITY_COLORS_START_IDX VELO_STABLE
+#define VELOCITY_COLORS 5
+
+typedef enum {
+       /* SAC colors. Order is important, the SAC_COLORS_START_IDX define above. */
+       SAC_1, SAC_2, SAC_3, SAC_4, SAC_5, SAC_6, SAC_7, SAC_8, SAC_9,
 
-/* convert velocity to colors */
-typedef struct { double r, g, b; } rgb_t;
-static const rgb_t rgb[] = {
-       [STABLE]   = {0.0, 0.4, 0.0},
-       [SLOW]     = {0.4, 0.8, 0.0},
-       [MODERATE] = {0.8, 0.8, 0.0},
-       [FAST]     = {0.8, 0.5, 0.0},
-       [CRAZY]    = {1.0, 0.0, 0.0},
+       /* Velocity colors.  Order is still important, ref VELOCITY_COLORS_START_IDX. */
+       VELO_STABLE, VELO_SLOW, VELO_MODERATE, VELO_FAST, VELO_CRAZY,
+
+       /* Other colors */
+       TEXT_BACKGROUND, ALERT_BG, ALERT_FG, EVENTS, SAMPLE_DEEP, SAMPLE_SHALLOW,
+       SMOOTHED, MINUTE, TIME_GRID, TIME_TEXT, DEPTH_GRID, MEAN_DEPTH, DEPTH_TOP,
+       DEPTH_BOTTOM, TEMP_TEXT, TEMP_PLOT, SAC_DEFAULT, BOUNDING_BOX, PRESSURE_TEXT, BACKGROUND
+} color_indice_t;
+
+typedef struct {
+       /* media[0] is screen, and media[1] is printer */
+       struct rgba {
+               double r,g,b,a;
+       } media[2];
+} color_t;
+
+/* [color indice] = {{screen color, printer color}} */
+static const color_t profile_color[] = {
+       [SAC_1]           = {{FUNGREEN1, BLACK1_LOW_TRANS}},
+       [SAC_2]           = {{APPLE1, BLACK1_LOW_TRANS}},
+       [SAC_3]           = {{ATLANTIS1, BLACK1_LOW_TRANS}},
+       [SAC_4]           = {{ATLANTIS2, BLACK1_LOW_TRANS}},
+       [SAC_5]           = {{EARLSGREEN1, BLACK1_LOW_TRANS}},
+       [SAC_6]           = {{HOKEYPOKEY1, BLACK1_LOW_TRANS}},
+       [SAC_7]           = {{TUSCANY1, BLACK1_LOW_TRANS}},
+       [SAC_8]           = {{CINNABAR1, BLACK1_LOW_TRANS}},
+       [SAC_9]           = {{REDORANGE1, BLACK1_LOW_TRANS}},
+
+       [VELO_STABLE]     = {{CAMARONE1, BLACK1_LOW_TRANS}},
+       [VELO_SLOW]       = {{LIMENADE1, BLACK1_LOW_TRANS}},
+       [VELO_MODERATE]   = {{RIOGRANDE1, BLACK1_LOW_TRANS}},
+       [VELO_FAST]       = {{PIRATEGOLD1, BLACK1_LOW_TRANS}},
+       [VELO_CRAZY]      = {{RED1, BLACK1_LOW_TRANS}},
+
+       [TEXT_BACKGROUND] = {{CONCRETE1_LOWER_TRANS, WHITE1}},
+       [ALERT_BG]        = {{BROOM1_LOWER_TRANS, BLACK1_LOW_TRANS}},
+       [ALERT_FG]        = {{BLACK1_LOW_TRANS, BLACK1_LOW_TRANS}},
+       [EVENTS]          = {{REDORANGE1, BLACK1_LOW_TRANS}},
+       [SAMPLE_DEEP]     = {{PERSIANRED1, BLACK1_LOW_TRANS}},
+       [SAMPLE_SHALLOW]  = {{PERSIANRED1, BLACK1_LOW_TRANS}},
+       [SMOOTHED]        = {{REDORANGE1_HIGH_TRANS, BLACK1_LOW_TRANS}},
+       [MINUTE]          = {{MEDIUMREDVIOLET1_HIGHER_TRANS, BLACK1_LOW_TRANS}},
+       [TIME_GRID]       = {{WHITE1, TUNDORA1_MED_TRANS}},
+       [TIME_TEXT]       = {{FORESTGREEN1, BLACK1_LOW_TRANS}},
+       [DEPTH_GRID]      = {{WHITE1, TUNDORA1_MED_TRANS}},
+       [MEAN_DEPTH]      = {{REDORANGE1_MED_TRANS, BLACK1_LOW_TRANS}},
+       [DEPTH_BOTTOM]    = {{GOVERNORBAY1_MED_TRANS, TUNDORA1_MED_TRANS}},
+       [DEPTH_TOP]       = {{MERCURY1_MED_TRANS, WHITE1_MED_TRANS}},
+       [TEMP_TEXT]       = {{GOVERNORBAY2, BLACK1_LOW_TRANS}},
+       [TEMP_PLOT]       = {{ROYALBLUE2_LOW_TRANS, BLACK1_LOW_TRANS}},
+       [SAC_DEFAULT]     = {{WHITE1, BLACK1_LOW_TRANS}},
+       [BOUNDING_BOX]    = {{WHITE1, BLACK1_LOW_TRANS}},
+       [PRESSURE_TEXT]   = {{KILLARNEY1, BLACK1_LOW_TRANS}},
+       [BACKGROUND]      = {{SPRINGWOOD1, BLACK1_LOW_TRANS}},
 };
 
 #define plot_info_size(nr) (sizeof(struct plot_info) + (nr)*sizeof(struct plot_data))
@@ -73,25 +132,28 @@ static void line_to(struct graphics_context *gc, double x, double y)
        cairo_line_to(gc->cr, SCALE(gc, x, y));
 }
 
-static void set_source_rgba(struct graphics_context *gc, double r, double g, double b, double a)
+static void set_source_rgba(struct graphics_context *gc, color_indice_t c)
 {
-       /*
-        * For printers, we still honor 'a', but ignore colors
-        * for now. Black is white and white is black
-        */
-       if (gc->printer) {
-               double sum = r+g+b;
-               if (sum > 0.8)
-                       r = g = b = 0;
-               else
-                       r = g = b = 1;
-       }
+       const color_t *col = &profile_color[c];
+       struct rgba rgb = col->media[gc->printer];
+       double r = rgb.r;
+       double g = rgb.g;
+       double b = rgb.b;
+       double a = rgb.a;
+
        cairo_set_source_rgba(gc->cr, r, g, b, a);
 }
 
-void set_source_rgb(struct graphics_context *gc, double r, double g, double b)
+void init_profile_background(struct graphics_context *gc)
 {
-       set_source_rgba(gc, r, g, b, 1);
+       set_source_rgba(gc, BACKGROUND);
+}
+
+void pattern_add_color_stop_rgba(struct graphics_context *gc, cairo_pattern_t *pat, double o, color_indice_t c)
+{
+       const color_t *col = &profile_color[c];
+       struct rgba rgb = col->media[gc->printer];
+       cairo_pattern_add_color_stop_rgba(pat, o, rgb.r, rgb.g, rgb.b, rgb.a);
 }
 
 #define ROUND_UP(x,y) ((((x)+(y)-1)/(y))*(y))
@@ -102,14 +164,15 @@ static void dump_pi (struct plot_info *pi)
        int i;
 
        printf("pi:{nr:%d maxtime:%d meandepth:%d maxdepth:%d \n"
-               "    minpressure:%d maxpressure:%d endpressure:%d mintemp:%d maxtemp:%d\n",
+               "    maxpressure:%d mintemp:%d maxtemp:%d\n",
                pi->nr, pi->maxtime, pi->meandepth, pi->maxdepth,
-               pi->minpressure, pi->maxpressure, pi->endpressure, pi->mintemp, pi->maxtemp);
+               pi->maxpressure, pi->mintemp, pi->maxtemp);
        for (i = 0; i < pi->nr; i++)
                printf("    entry[%d]:{same_cylinder:%d cylinderindex:%d sec:%d pressure:{%d,%d}\n"
-                       "                temperature:%d depth:%d smoothed:%d}\n",
+                       "                time:%d:%02d temperature:%d depth:%d smoothed:%d}\n",
                        i, pi->entry[i].same_cylinder, pi->entry[i].cylinderindex, pi->entry[i].sec,
                        pi->entry[i].pressure[0], pi->entry[i].pressure[1],
+                       pi->entry[i].sec / 60, pi->entry[i].sec % 60,
                        pi->entry[i].temperature, pi->entry[i].depth, pi->entry[i].smoothed);
        printf("   }\n");
 }
@@ -118,27 +181,45 @@ static void dump_pi (struct plot_info *pi)
  * 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.
- * we also need to add 180 seconds at the end so the min/max
+ * up as such unless zoom is enabled.
+ * We also need to add 180 seconds at the end so the min/max
  * plots correctly
  */
 static int get_maxtime(struct plot_info *pi)
 {
        int seconds = pi->maxtime;
-       /* min 30 minutes, rounded up to 5 minutes, with at least 2.5 minutes to spare */
-       return MAX(30*60, ROUND_UP(seconds+150, 60*5));
+       if (zoomed_plot) {
+               /* Rounded up to one minute, with at least 2.5 minutes to
+                * spare.
+                * For dive times shorter than 10 minutes, we use seconds/4 to
+                * calculate the space dynamically.
+                * This is seamless since 600/4 = 150.
+                */
+               if ( seconds < 600 )
+                       return ROUND_UP(seconds+seconds/4, 60);
+               else
+                       return ROUND_UP(seconds+150, 60);
+       } else {
+               /* min 30 minutes, rounded up to 5 minutes, with at least 2.5 minutes to spare */
+               return MAX(30*60, ROUND_UP(seconds+150, 60*5));
+       }
 }
 
 static int get_maxdepth(struct plot_info *pi)
 {
        unsigned mm = pi->maxdepth;
-       /* Minimum 30m, rounded up to 10m, with at least 3m to spare */
-       return MAX(30000, ROUND_UP(mm+3000, 10000));
+       if (zoomed_plot) {
+               /* Rounded up to 10m, with at least 3m to spare */
+               return ROUND_UP(mm+3000, 10000);
+       } else {
+               /* Minimum 30m, rounded up to 10m, with at least 3m to spare */
+               return MAX(30000, ROUND_UP(mm+3000, 10000));
+       }
 }
 
 typedef struct {
        int size;
-       double r,g,b;
+       color_indice_t color;
        double hpos, vpos;
 } text_render_options_t;
 
@@ -174,13 +255,13 @@ static void plot_text(struct graphics_context *gc, const text_render_options_t *
        cairo_rel_move_to(cr, dx, dy);
 
        cairo_text_path(cr, buffer);
-       set_source_rgb(gc, 0, 0, 0);
+       set_source_rgba(gc, TEXT_BACKGROUND);
        cairo_stroke(cr);
 
        move_to(gc, x, y);
        cairo_rel_move_to(cr, dx, dy);
 
-       set_source_rgb(gc, tro->r, tro->g, tro->b);
+       set_source_rgba(gc, tro->color);
        cairo_show_text(cr, buffer);
 }
 
@@ -249,14 +330,14 @@ static void plot_one_event(struct graphics_context *gc, struct plot_info *pi, st
        /* draw a little tirangular marker and attach tooltip */
        x = SCALEX(gc, event->time.seconds);
        y = SCALEY(gc, depth);
-       set_source_rgba(gc, 1.0, 1.0, 0.1, 0.8);
+       set_source_rgba(gc, ALERT_BG);
        cairo_move_to(gc->cr, x-15, y+6);
        cairo_line_to(gc->cr, x-3  , y+6);
        cairo_line_to(gc->cr, x-9, y-6);
        cairo_line_to(gc->cr, x-15, y+6);
        cairo_stroke_preserve(gc->cr);
        cairo_fill(gc->cr);
-       set_source_rgba(gc, 0.0, 0.0, 0.0, 0.8);
+       set_source_rgba(gc, ALERT_FG);
        cairo_move_to(gc->cr, x-9, y-3);
        cairo_line_to(gc->cr, x-9, y+1);
        cairo_move_to(gc->cr, x-9, y+4);
@@ -267,7 +348,7 @@ static void plot_one_event(struct graphics_context *gc, struct plot_info *pi, st
 
 static void plot_events(struct graphics_context *gc, struct plot_info *pi, struct dive *dive)
 {
-       static const text_render_options_t tro = {14, 1.0, 0.2, 0.2, CENTER, TOP};
+       static const text_render_options_t tro = {14, EVENTS, CENTER, TOP};
        struct event *event = dive->events;
 
        if (gc->printer)
@@ -291,8 +372,8 @@ static void render_depth_sample(struct graphics_context *gc, struct plot_data *e
 
 static void plot_text_samples(struct graphics_context *gc, struct plot_info *pi)
 {
-       static const text_render_options_t deep = {14, 1.0, 0.2, 0.2, CENTER, TOP};
-       static const text_render_options_t shallow = {14, 1.0, 0.2, 0.2, CENTER, BOTTOM};
+       static const text_render_options_t deep = {14, SAMPLE_DEEP, CENTER, TOP};
+       static const text_render_options_t shallow = {14, SAMPLE_SHALLOW, CENTER, BOTTOM};
        int i;
        int last = -1;
 
@@ -336,7 +417,7 @@ static void plot_smoothed_profile(struct graphics_context *gc, struct plot_info
        int i;
        struct plot_data *entry = pi->entry;
 
-       set_source_rgba(gc, 1, 0.2, 0.2, 0.20);
+       set_source_rgba(gc, SMOOTHED);
        move_to(gc, entry->sec, entry->smoothed);
        for (i = 1; i < pi->nr; i++) {
                entry++;
@@ -346,12 +427,12 @@ static void plot_smoothed_profile(struct graphics_context *gc, struct plot_info
 }
 
 static void plot_minmax_profile_minute(struct graphics_context *gc, struct plot_info *pi,
-                               int index, double a)
+                               int index)
 {
        int i;
        struct plot_data *entry = pi->entry;
 
-       set_source_rgba(gc, 1, 0.2, 1, a);
+       set_source_rgba(gc, MINUTE);
        move_to(gc, entry->sec, entry->min[index]->depth);
        for (i = 1; i < pi->nr; i++) {
                entry++;
@@ -369,9 +450,9 @@ static void plot_minmax_profile(struct graphics_context *gc, struct plot_info *p
 {
        if (gc->printer)
                return;
-       plot_minmax_profile_minute(gc, pi, 2, 0.1);
-       plot_minmax_profile_minute(gc, pi, 1, 0.1);
-       plot_minmax_profile_minute(gc, pi, 0, 0.1);
+       plot_minmax_profile_minute(gc, pi, 2);
+       plot_minmax_profile_minute(gc, pi, 1);
+       plot_minmax_profile_minute(gc, pi, 0);
 }
 
 static void plot_depth_profile(struct graphics_context *gc, struct plot_info *pi)
@@ -381,20 +462,21 @@ static void plot_depth_profile(struct graphics_context *gc, struct plot_info *pi
        int sec, depth;
        struct plot_data *entry;
        int maxtime, maxdepth, marker;
-       int increments[4] = { 5*60, 10*60, 15*60, 30*60 };
+       int increments[8] = { 10, 20, 30, 60, 5*60, 10*60, 15*60, 30*60 };
 
        /* Get plot scaling limits */
        maxtime = get_maxtime(pi);
        maxdepth = get_maxdepth(pi);
 
-       /* Time markers: at most every 5 min, but no more than 12 markers
-        * and for convenience we do 5, 10, 15 or 30 min intervals.
+       /* Time markers: at most every 10 seconds, but no more than 12 markers.
+        * We start out with 10 seconds and increment up to 30 minutes,
+        * depending on the dive time.
         * This allows for 6h dives - enough (I hope) for even the craziest
         * divers - but just in case, for those 8h depth-record-breaking dives,
         * we double the interval if this still doesn't get us to 12 or fewer
         * time markers */
        i = 0;
-       while (maxtime / increments[i] > 12 && i < 4)
+       while (maxtime / increments[i] > 12 && i < 8)
                i++;
        incr = increments[i];
        while (maxtime / incr > 12)
@@ -402,18 +484,26 @@ static void plot_depth_profile(struct graphics_context *gc, struct plot_info *pi
 
        gc->leftx = 0; gc->rightx = maxtime;
        gc->topy = 0; gc->bottomy = 1.0;
-       set_source_rgba(gc, 1, 1, 1, 0.5);
+       set_source_rgba(gc, TIME_GRID);
+       cairo_set_line_width(gc->cr, 2);
+
        for (i = incr; i < maxtime; i += incr) {
                move_to(gc, i, 0);
                line_to(gc, i, 1);
        }
        cairo_stroke(cr);
 
-       /* now the text on every second time marker */
-       text_render_options_t tro = {10, 0.2, 1.0, 0.2, CENTER, TOP};
-       for (i = incr; i < maxtime; i += 2 * incr)
-               plot_text(gc, &tro, i, 1, "%d", i/60);
-
+       /* now the text on the time markers */
+       text_render_options_t tro = {10, TIME_TEXT, CENTER, TOP};
+       if (maxtime < 600) {
+               /* Be a bit more verbose with shorter dives */
+               for (i = incr; i < maxtime; i += incr)
+                       plot_text(gc, &tro, i, 1, "%02d:%02d", i/60, i%60);
+       } else {
+               /* Only render the time on every second marker for normal dives */
+               for (i = incr; i < maxtime; i += 2 * incr)
+                       plot_text(gc, &tro, i, 1, "%d", i/60);
+       }
        /* Depth markers: every 30 ft or 10 m*/
        gc->leftx = 0; gc->rightx = 1.0;
        gc->topy = 0; gc->bottomy = maxdepth;
@@ -422,7 +512,7 @@ static void plot_depth_profile(struct graphics_context *gc, struct plot_info *pi
        case FEET: marker = 9144; break;        /* 30 ft */
        }
 
-       set_source_rgba(gc, 1, 1, 1, 0.5);
+       set_source_rgba(gc, DEPTH_GRID);
        for (i = marker; i < maxdepth; i += marker) {
                move_to(gc, 0, i);
                line_to(gc, 1, i);
@@ -431,7 +521,7 @@ static void plot_depth_profile(struct graphics_context *gc, struct plot_info *pi
 
        /* Show mean depth */
        if (! gc->printer) {
-               set_source_rgba(gc, 1, 0.2, 0.2, 0.40);
+               set_source_rgba(gc, MEAN_DEPTH);
                move_to(gc, 0, pi->meandepth);
                line_to(gc, 1, pi->meandepth);
                cairo_stroke(cr);
@@ -448,24 +538,24 @@ static void plot_depth_profile(struct graphics_context *gc, struct plot_info *pi
                plot_minmax_profile(gc, pi);
        }
 
-       set_source_rgba(gc, 1, 0.2, 0.2, 0.80);
-
        /* Do the depth profile for the neat fill */
        gc->topy = 0; gc->bottomy = maxdepth;
-       set_source_rgba(gc, 1, 0.2, 0.2, 0.20);
+
+       cairo_pattern_t *pat;
+       pat = cairo_pattern_create_linear (0.0, 0.0,  0.0, 256.0);
+       pattern_add_color_stop_rgba (gc, pat, 1, DEPTH_BOTTOM);
+       pattern_add_color_stop_rgba (gc, pat, 0, DEPTH_TOP);
+
+       cairo_set_source(gc->cr, pat);
+       cairo_pattern_destroy(pat);
+       cairo_set_line_width(gc->cr, 2);
 
        entry = pi->entry;
        move_to(gc, 0, 0);
        for (i = 0; i < pi->nr; i++, entry++)
                line_to(gc, entry->sec, entry->depth);
        cairo_close_path(gc->cr);
-       if (gc->printer) {
-               set_source_rgba(gc, 1, 1, 1, 0.2);
-               cairo_fill_preserve(cr);
-               set_source_rgb(gc, 1, 1, 1);
-               cairo_stroke(cr);
-               return;
-       }
+
        cairo_fill(gc->cr);
 
        /* Now do it again for the velocity colors */
@@ -476,9 +566,8 @@ static void plot_depth_profile(struct graphics_context *gc, struct plot_info *pi
                /* we want to draw the segments in different colors
                 * representing the vertical velocity, so we need to
                 * chop this into short segments */
-               rgb_t color = rgb[entry->velocity];
                depth = entry->depth;
-               set_source_rgb(gc, color.r, color.g, color.b);
+               set_source_rgba(gc, VELOCITY_COLORS_START_IDX + entry->velocity);
                move_to(gc, entry[-1].sec, entry[-1].depth);
                line_to(gc, sec, depth);
                cairo_stroke(cr);
@@ -513,7 +602,7 @@ static void plot_single_temp_text(struct graphics_context *gc, int sec, int mkel
 {
        double deg;
        const char *unit;
-       static const text_render_options_t tro = {12, 0.2, 0.2, 1.0, LEFT, TOP};
+       static const text_render_options_t tro = {12, TEMP_TEXT, LEFT, TOP};
 
        deg = get_temp_units(mkelvin, &unit);
 
@@ -523,7 +612,7 @@ static void plot_single_temp_text(struct graphics_context *gc, int sec, int mkel
 static void plot_temperature_text(struct graphics_context *gc, struct plot_info *pi)
 {
        int i;
-       int last = 0, sec = 0;
+       int last = -300, sec = 0;
        int last_temperature = 0, last_printed_temp = 0;
 
        if (!setup_temperature_limits(gc, pi))
@@ -537,14 +626,23 @@ static void plot_temperature_text(struct graphics_context *gc, struct plot_info
                        continue;
                last_temperature = mkelvin;
                sec = entry->sec;
-               if (sec < last + 300)
+               /* don't print a temperature
+                * if it's been less than 5min and less than a 2K change OR
+                * if it's been less than 2min OR if the change from the
+                * last print is less than .4K (and therefore less than 1F */
+               if (((sec < last + 300) && (abs(mkelvin - last_printed_temp) < 2000)) ||
+                       (sec < last + 120) ||
+                       (abs(mkelvin - last_printed_temp) < 400))
                        continue;
                last = sec;
                plot_single_temp_text(gc,sec,mkelvin);
                last_printed_temp = mkelvin;
        }
-       /* it would be nice to print the end temperature, if it's different */
-       if (abs(last_temperature - last_printed_temp) > 500)
+       /* it would be nice to print the end temperature, if it's
+        * different or if the last temperature print has been more
+        * than a quarter of the dive back */
+       if ((abs(last_temperature - last_printed_temp) > 500) ||
+               ((double)last / (double)sec < 0.75))
                plot_single_temp_text(gc, sec, last_temperature);
 }
 
@@ -557,7 +655,8 @@ static void plot_temperature_profile(struct graphics_context *gc, struct plot_in
        if (!setup_temperature_limits(gc, pi))
                return;
 
-       set_source_rgba(gc, 0.2, 0.2, 1.0, 0.8);
+       cairo_set_line_width(gc->cr, 2);
+       set_source_rgba(gc, TEMP_PLOT);
        for (i = 0; i < pi->nr; i++) {
                struct plot_data *entry = pi->entry + i;
                int mkelvin = entry->temperature;
@@ -586,55 +685,101 @@ static int get_cylinder_pressure_range(struct graphics_context *gc, struct plot_
        return pi->maxpressure != 0;
 }
 
-static void plot_pressure_helper(struct graphics_context *gc, struct plot_info *pi, int type)
+/* set the color for the pressure plot according to temporary sac rate
+ * as compared to avg_sac; the calculation simply maps the delta between
+ * sac and avg_sac to indexes 0 .. (SAC_COLORS - 1) with everything
+ * more than 6000 ml/min below avg_sac mapped to 0 */
+
+static void set_sac_color(struct graphics_context *gc, int sac, int avg_sac)
+{
+       int sac_index = 0;
+       int delta = sac - avg_sac + 7000;
+
+       if (!gc->printer) {
+               sac_index = delta / 2000;
+               if (sac_index < 0)
+                       sac_index = 0;
+               if (sac_index > SAC_COLORS - 1)
+                       sac_index = SAC_COLORS - 1;
+               set_source_rgba(gc, SAC_COLORS_START_IDX + sac_index);
+       } else {
+               set_source_rgba(gc, SAC_DEFAULT);
+       }
+}
+
+/* calculate the current SAC in ml/min and convert to int */
+#define GET_LOCAL_SAC(_entry1, _entry2, _dive) (int)                           \
+       ((GET_PRESSURE((_entry1)) - GET_PRESSURE((_entry2))) *                  \
+               (_dive)->cylinder[(_entry1)->cylinderindex].type.size.mliter /  \
+               (((_entry2)->sec - (_entry1)->sec) / 60.0) /                    \
+               (1 + ((_entry1)->depth + (_entry2)->depth) / 20000.0) /         \
+               1000.0)
+
+#define SAC_WINDOW 45  /* sliding window in seconds for current SAC calculation */
+
+static void plot_cylinder_pressure(struct graphics_context *gc, struct plot_info *pi,
+                               struct dive *dive)
 {
        int i;
+       int last = -1;
        int lift_pen = FALSE;
+       int first_plot = TRUE;
+       int sac = 0;
+       struct plot_data *last_entry = NULL;
+
+       if (!get_cylinder_pressure_range(gc, pi))
+               return;
+
+       cairo_set_line_width(gc->cr, 2);
 
        for (i = 0; i < pi->nr; i++) {
                int mbar;
                struct plot_data *entry = pi->entry + i;
 
-               mbar = entry->pressure[type];
-               if (!entry->same_cylinder)
+               mbar = GET_PRESSURE(entry);
+               if (!entry->same_cylinder) {
                        lift_pen = TRUE;
+                       last_entry = NULL;
+               }
                if (!mbar) {
                        lift_pen = TRUE;
                        continue;
                }
+               if (!last_entry) {
+                       last = i;
+                       last_entry = entry;
+                       sac = GET_LOCAL_SAC(entry, pi->entry + i + 1, dive);
+               } else {
+                       int j;
+                       sac = 0;
+                       for (j = last; j < i; j++)
+                               sac += GET_LOCAL_SAC(pi->entry + j, pi->entry + j + 1, dive);
+                       sac /= (i - last);
+                       if (entry->sec - last_entry->sec >= SAC_WINDOW) {
+                               last++;
+                               last_entry = pi->entry + last;
+                       }
+               }
+               set_sac_color(gc, sac, dive->sac);
                if (lift_pen) {
-                       if (i > 0 && entry->same_cylinder) {
+                       if (!first_plot && 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 */
+                                * draw at least a short line */
                                int prev_pr;
-                               prev_pr = (entry-1)->pressure[type] ? : (entry-1)->pressure[1 - type];
+                               prev_pr = GET_PRESSURE(entry - 1);
                                move_to(gc, (entry-1)->sec, prev_pr);
                                line_to(gc, entry->sec, mbar);
-                       } else
+                       } else {
+                               first_plot = FALSE;
                                move_to(gc, entry->sec, mbar);
+                       }
                        lift_pen = FALSE;
-               }
-               else
+               } else {
                        line_to(gc, entry->sec, mbar);
+               }
+               cairo_stroke(gc->cr);
+               move_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,
@@ -644,7 +789,7 @@ static void plot_pressure_value(struct graphics_context *gc, int mbar, int sec,
        const char *unit;
 
        pressure = get_pressure_units(mbar, &unit);
-       text_render_options_t tro = {10, 0.2, 1.0, 0.2, xalign, yalign};
+       text_render_options_t tro = {10, PRESSURE_TEXT, xalign, yalign};
        plot_text(gc, &tro, sec, mbar, "%d %s", pressure, unit);
 }
 
@@ -660,14 +805,21 @@ static void plot_cylinder_pressure_text(struct graphics_context *gc, struct plot
        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++) {
+       /* only loop over the actual events from the dive computer
+        * plus the second synthetic event at the start (to make sure
+        * we get "time=0" right)
+        * sadly with a recent change that first entry may no longer
+        * have any pressure reading - in that case just grab the
+        * pressure from the second entry */
+       if (GET_PRESSURE(pi->entry + 1) == 0 && GET_PRESSURE(pi->entry + 2) !=0)
+               INTERPOLATED_PRESSURE(pi->entry + 1) = GET_PRESSURE(pi->entry + 2);
+       for (i = 1; 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);
+                               mbar = GET_PRESSURE(entry);
                                plot_pressure_value(gc, mbar, entry->sec, LEFT, BOTTOM);
                                seen_cyl[cyl] = TRUE;
                        }
@@ -675,14 +827,14 @@ static void plot_cylinder_pressure_text(struct graphics_context *gc, struct plot
                                /* 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_pressure[cyl] = GET_PRESSURE(entry - 1);
                                last_time[cyl] = (entry - 1)->sec;
                        }
                }
        }
        cyl = entry->cylinderindex;
-       last_pressure[cyl] = SENSOR_PRESSURE(entry) ? : INTERPOLATED_PRESSURE(entry);
+       if (GET_PRESSURE(entry))
+               last_pressure[cyl] = GET_PRESSURE(entry);
        last_time[cyl] = entry->sec;
 
        for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) {
@@ -747,7 +899,7 @@ static velocity_t velocity(int speed)
        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 
+                               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 */
@@ -769,12 +921,10 @@ static struct plot_info *analyze_plot_info(struct plot_info *pi)
        /* 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 pressure = GET_PRESSURE(entry);
                int temperature = entry->temperature;
 
                if (pressure) {
-                       if (!pi->minpressure || pressure < pi->minpressure)
-                               pi->minpressure = pressure;
                        if (pressure > pi->maxpressure)
                                pi->maxpressure = pressure;
                }
@@ -805,7 +955,7 @@ static struct plot_info *analyze_plot_info(struct plot_info *pi)
                                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->velocity = velocity((entry[0].depth - entry[past].depth) /
                                                        (entry[0].sec - entry[past].sec));
                        }
                } else
@@ -817,7 +967,7 @@ static struct plot_info *analyze_plot_info(struct plot_info *pi)
                struct plot_data *entry = pi->entry +i;
                analyze_plot_info_minmax(entry, pi->entry, pi->entry+nr);
        }
-       
+
        return pi;
 }
 
@@ -875,8 +1025,22 @@ static void list_free(pr_track_t *list)
        free(list);
 }
 
-static void fill_missing_tank_pressures(struct dive *dive, struct plot_info *pi,
-                                       pr_track_t **track_pr)
+static void dump_pr_track(pr_track_t **track_pr)
+{
+       int cyl;
+       pr_track_t *list;
+
+       for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) {
+               list = track_pr[cyl];
+               while (list) {
+                       printf("cyl%d: start %d end %d t_start %d t_end %d pt %6.3f\n", cyl,
+                               list->start, list->end, list->t_start, list->t_end, list->pressure_time);
+                       list = list->next;
+               }
+       }
+}
+
+static void fill_missing_tank_pressures(struct plot_info *pi, pr_track_t **track_pr)
 {
        pr_track_t *list = NULL;
        pr_track_t *nlist = NULL;
@@ -885,12 +1049,17 @@ static void fill_missing_tank_pressures(struct dive *dive, struct plot_info *pi,
        struct plot_data *entry;
        int cur_pr[MAX_CYLINDERS];
 
+       if (0) {
+               /* another great debugging tool */
+               dump_pr_track(track_pr);
+       }
        for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) {
                cur_pr[cyl] = track_pr[cyl]->start;
        }
 
-       /* The first two are "fillers" */
-       for (i = 2; i < pi->nr; i++) {
+       /* The first two are "fillers", but in case we don't have a sample
+        * at time 0 we need to process the second of them here */
+       for (i = 1; i < pi->nr; i++) {
                entry = pi->entry + i;
                if (SENSOR_PRESSURE(entry)) {
                        cur_pr[entry->cylinderindex] = SENSOR_PRESSURE(entry);
@@ -905,31 +1074,36 @@ static void fill_missing_tank_pressures(struct dive *dive, struct plot_info *pi,
                                /* there may be multiple segments - so
                                 * let's assemble the length */
                                nlist = list;
-                               pt = list->pressure_time;
-                               while (!nlist->end) {
-                                       nlist = nlist->next;
-                                       if (!nlist) {
-                                               /* oops - we have no end pressure,
-                                                * so this means this is a tank without
-                                                * gas consumption information */
-                                               break;
+                               if (list) {
+                                       pt = list->pressure_time;
+                                       while (!nlist->end) {
+                                               nlist = nlist->next;
+                                               if (!nlist) {
+                                                       /* oops - we have no end pressure,
+                                                        * so this means this is a tank without
+                                                        * gas consumption information */
+                                                       break;
+                                               }
+                                               pt += nlist->pressure_time;
                                        }
-                                       pt += nlist->pressure_time;
                                }
                                if (!nlist) {
                                        /* just continue without calculating
                                         * interpolated values */
+                                       INTERPOLATED_PRESSURE(entry) = cur_pr[entry->cylinderindex];
                                        list = NULL;
                                        continue;
                                }
-                               magic = (nlist->end - cur_pr[entry->cylinderindex]) / pt;                               }
+                               magic = (nlist->end - cur_pr[entry->cylinderindex]) / pt;
+                       }
                        if (pt != 0.0) {
                                double cur_pt = (entry->sec - (entry-1)->sec) *
-                                       (1 + entry->depth / 10000.0);
+                                       (1 + (entry->depth + (entry-1)->depth) / 20000.0);
                                INTERPOLATED_PRESSURE(entry) =
-                                       cur_pr[entry->cylinderindex] + cur_pt * magic;
+                                       cur_pr[entry->cylinderindex] + cur_pt * magic + 0.5;
                                cur_pr[entry->cylinderindex] = INTERPOLATED_PRESSURE(entry);
-                       }
+                       } else
+                               INTERPOLATED_PRESSURE(entry) = cur_pr[entry->cylinderindex];
                }
        }
 }
@@ -1063,8 +1237,13 @@ static struct plot_info *create_plot_info(struct dive *dive, int nr_samples, str
                while (ev && ev->time.seconds < sample->time.seconds) {
                        /* insert two fake plot info structures for the end of
                         * the old tank and the start of the new tank */
-                       entry->sec = ev->time.seconds;
-                       (entry+1)->sec = ev->time.seconds + 1;
+                       if (ev->time.seconds == sample->time.seconds - 1) {
+                               entry->sec = ev->time.seconds - 1;
+                               (entry+1)->sec = ev->time.seconds;
+                       } else {
+                               entry->sec = ev->time.seconds;
+                               (entry+1)->sec = ev->time.seconds + 1;
+                       }
                        /* we need a fake depth - let's interpolate */
                        if (i) {
                                entry->depth = sample->depth.mm -
@@ -1094,7 +1273,7 @@ static struct plot_info *create_plot_info(struct dive *dive, int nr_samples, str
                entry->temperature = sample->temperature.mkelvin;
 
                if (depth || lastdepth)
-                       lastindex = i+pi_idx;
+                       lastindex = i + pi_idx;
 
                lastdepth = depth;
                if (depth > pi->maxdepth)
@@ -1109,14 +1288,14 @@ static struct plot_info *create_plot_info(struct dive *dive, int nr_samples, str
                entry = pi->entry + i + pi_idx;
                ev = get_next_gaschange(ev->next);
        }
-       nr_samples += pi_idx - 2;
+       nr = nr_samples + pi_idx - 2;
        check_gas_change_events(dive, pi);
 
        for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) /* initialize the start pressures */
                track_pr[cyl] = pr_track_alloc(dive->cylinder[cyl].start.mbar, -1);
        current = track_pr[pi->entry[2].cylinderindex];
-       for (i = 0; i < nr_samples; i++) {
-               entry = pi->entry + i + 2;
+       for (i = 0; i < nr + 1; i++) {
+               entry = pi->entry + i + 1;
 
                entry->same_cylinder = entry->cylinderindex == cylinderindex;
                cylinderindex = entry->cylinderindex;
@@ -1140,7 +1319,7 @@ static struct plot_info *create_plot_info(struct dive *dive, int nr_samples, str
                }
                /* finally, do the discrete integration to get the SAC rate equivalent */
                current->pressure_time += (entry->sec - (entry-1)->sec) *
-                                               (1 + entry->depth / 10000.0);
+                       (1 + (entry->depth + (entry-1)->depth) / 20000.0);
                missing_pr |= !SENSOR_PRESSURE(entry);
        }
 
@@ -1154,22 +1333,39 @@ static struct plot_info *create_plot_info(struct dive *dive, int nr_samples, str
                        pr_track->end = pr;
                }
        }
-       /* Fill in the last two entries with empty values but valid times */
-       i = nr_samples + 2;
+       /* Fill in the last two entries with empty values but valid times
+        * without creating a false cylinder change event */
+       i = nr + 2;
        pi->entry[i].sec = sec + 20;
+       pi->entry[i].same_cylinder = 1;
+       pi->entry[i].cylinderindex = pi->entry[i-1].cylinderindex;
+       INTERPOLATED_PRESSURE(pi->entry + i) = GET_PRESSURE(pi->entry + i - 1);
        pi->entry[i+1].sec = sec + 40;
-       /* the number of actual entries - we may have allocated more if there
-        * were gas change events, but this is how many were filled */
+       pi->entry[i+1].same_cylinder = 1;
+       pi->entry[i+1].cylinderindex = pi->entry[i-1].cylinderindex;
+       INTERPOLATED_PRESSURE(pi->entry + i + 1) = GET_PRESSURE(pi->entry + i - 1);
+       /* the number of actual entries - some computers have lots of
+        * depth 0 samples at the end of a dive, we want to make sure
+        * we have exactly one of them at the end */
        pi->nr = lastindex+1;
+       while (pi->nr <= i+2 && pi->entry[pi->nr-1].depth > 0)
+               pi->nr++;
        pi->maxtime = pi->entry[lastindex].sec;
 
-       pi->endpressure = pi->minpressure = dive->cylinder[0].end.mbar;
-       pi->maxpressure = dive->cylinder[0].start.mbar;
+       /* Analyze_plot_info() will do the sample max pressures,
+        * this handles the manual pressures
+        */
+       pi->maxpressure = 0;
+       for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) {
+               unsigned int mbar = dive->cylinder[cyl].start.mbar;
+               if (mbar > pi->maxpressure)
+                       pi->maxpressure = mbar;
+       }
 
        pi->meandepth = dive->meandepth.mm;
 
        if (missing_pr) {
-               fill_missing_tank_pressures(dive, pi, track_pr);
+               fill_missing_tank_pressures(pi, track_pr);
        }
        for (cyl = 0; cyl < MAX_CYLINDERS; cyl++)
                list_free(track_pr[cyl]);
@@ -1186,12 +1382,17 @@ void plot(struct graphics_context *gc, cairo_rectangle_int_t *drawing_area, stru
        int nr = dive->samples;
 
        if (!nr) {
+               /* The dive has no samples, so create a few fake ones.  This assumes an
+               ascent/descent rate of 9 m/min, which is just below the limit for FAST. */
                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 = duration * 0.05;
+               fake[1].time.seconds = asc_desc_time;
                fake[1].depth.mm = maxdepth;
-               fake[2].time.seconds = duration * 0.95;
+               fake[2].time.seconds = duration - asc_desc_time;
                fake[2].depth.mm = maxdepth;
                fake[3].time.seconds = duration * 1.00;
                nr = 4;
@@ -1200,7 +1401,7 @@ void plot(struct graphics_context *gc, cairo_rectangle_int_t *drawing_area, stru
        pi = create_plot_info(dive, nr, sample);
 
        cairo_translate(gc->cr, drawing_area->x, drawing_area->y);
-       cairo_set_line_width(gc->cr, 2);
+       cairo_set_line_width(gc->cr, 1);
        cairo_set_line_cap(gc->cr, CAIRO_LINE_CAP_ROUND);
        cairo_set_line_join(gc->cr, CAIRO_LINE_JOIN_ROUND);
 
@@ -1214,15 +1415,15 @@ void plot(struct graphics_context *gc, cairo_rectangle_int_t *drawing_area, stru
        gc->maxx = (drawing_area->width - 2*drawing_area->x);
        gc->maxy = (drawing_area->height - 2*drawing_area->y);
 
+       /* Depth profile */
+       plot_depth_profile(gc, pi);
+       plot_events(gc, pi, dive);
+
        /* Temperature profile */
        plot_temperature_profile(gc, pi);
 
        /* Cylinder pressure plot */
-       plot_cylinder_pressure(gc, pi);
-
-       /* Depth profile */
-       plot_depth_profile(gc, pi);
-       plot_events(gc, pi, dive);
+       plot_cylinder_pressure(gc, pi, dive);
 
        /* Text on top of all graphs.. */
        plot_temperature_text(gc, pi);
@@ -1233,7 +1434,8 @@ void plot(struct graphics_context *gc, cairo_rectangle_int_t *drawing_area, stru
        gc->leftx = 0; gc->rightx = 1.0;
        gc->topy = 0; gc->bottomy = 1.0;
 
-       set_source_rgb(gc, 1, 1, 1);
+       set_source_rgba(gc, BOUNDING_BOX);
+       cairo_set_line_width(gc->cr, 1);
        move_to(gc, 0, 0);
        line_to(gc, 0, 1);
        line_to(gc, 1, 1);