Use a recursive (instead of iterative) minmax depth finder

This is a bit more natural, and makes it much easier to do scale
independence.  In particular, I want to make it possible to grow and
shrink the graph, and this should make it particularly simple to react
by giving more or fewer minmax points.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2011-09-07 13:51:35 -07:00
parent d1ce430878
commit 96f5bea1ac

View file

@ -67,7 +67,7 @@ static void plot_text(cairo_t *cr, text_render_options_t *tro,
* We exit early if we hit "enough" of a depth reversal,
* which is roughly 10 feet.
*/
static struct sample *next_minmax(struct dive *dive, struct sample *sample, struct sample *end, int minmax)
static struct sample *next_minmax(struct sample *sample, struct sample *end, int minmax)
{
const int enough = 3000;
struct sample *result;
@ -116,6 +116,50 @@ static struct sample *next_minmax(struct dive *dive, struct sample *sample, stru
/* Scale to 0,0 -> maxx,maxy */
#define SCALE(x,y) (x)*maxx/scalex,(y)*maxy/scaley
void plot_text_samples(struct dive *dive, cairo_t *cr,
double maxx, double maxy,
double scalex, double scaley,
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) {
text_render_options_t tro = {1.0, 0.2, 0.2, CENTER};
int sec = max->time.seconds;
depth_t depth = max->depth;
const char *fmt;
double d;
min = next_minmax(max, b, 0);
plot_text_samples(dive, cr, maxx, maxy, scalex, scaley, a, max);
if (min) {
plot_text_samples(dive, cr, maxx, maxy, scalex, scaley, max, min);
plot_text_samples(dive, cr, maxx, maxy, scalex, scaley, min, b);
} else
plot_text_samples(dive, cr, maxx, maxy, scalex, scaley, max, b);
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(cr, &tro, SCALE(sec, depth.mm), fmt, d);
return;
}
}
static void plot_depth_text(struct dive *dive, cairo_t *cr,
double maxx, double maxy)
{
@ -141,29 +185,7 @@ static void plot_depth_text(struct dive *dive, cairo_t *cr,
sample = dive->sample;
end = dive->sample + dive->samples - 1;
while ((sample = next_minmax(dive, sample, end, 1)) != NULL) {
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(cr, &tro, SCALE(sec, depth.mm), fmt, d);
sample = next_minmax(dive, sample, end, 0);
if (!sample)
break;
}
plot_text_samples(dive, cr, maxx, maxy, scalex, scaley, sample, end);
}
static void plot_depth_profile(struct dive *dive, cairo_t *cr,