Picture handling: change data structure to store offset instead timestamp

It makes no sense to store a 64bit time stamp with every picture. Even the
32bit offset (in seconds) from the dive start is WAY overkill. But
switching to that makes the code much more simple in a number of spots.
And makes what is saved to the XML file easier to read, too.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

5 files changed, 13 insertions, 12 deletions

diff --git a/dive.c b/dive.c
index a04c92198..c1b5cae87 100644
--- a/dive.c
+++ b/dive.c
@@ -2283,13 +2283,14 @@ static bool new_picture_for_dive(struct dive *d, char *filename)
 
 void dive_create_picture(struct dive *d, char *filename, int shift_time)
 {
+	timestamp_t timestamp;
 	if (!new_picture_for_dive(d, filename))
 		return;
 	struct picture *p = alloc_picture();
 	p->filename = filename;
-	picture_load_exif_data(p);
-	if (p->timestamp)
-		p->timestamp += shift_time;
+	picture_load_exif_data(p, &timestamp);
+	if (timestamp)
+		p->offset = timestamp - d->when + shift_time;
 	dive_add_picture(d, p);
 	dive_set_geodata_from_picture(d, p);
 }
@@ -2298,7 +2299,7 @@ void dive_add_picture(struct dive *d, struct picture *newpic)
 {
 	struct picture **pic_ptr = &d->picture_list;
 	/* let's keep the list sorted by time */
-	while( *pic_ptr && (*pic_ptr)->timestamp < newpic->timestamp )
+	while( *pic_ptr && (*pic_ptr)->offset < newpic->offset )
 		pic_ptr = &(*pic_ptr)->next;
 	newpic->next = *pic_ptr;
 	*pic_ptr = newpic;
diff --git a/dive.h b/dive.h
index 279a2944c..23278d4a3 100644
--- a/dive.h
+++ b/dive.h
@@ -289,7 +289,7 @@ struct dive {
 /* picture list and methods related to dive picture handling */
 struct picture {
 	char *filename;
-	time_t timestamp;
+	int32_t offset;
 	degrees_t latitude;
 	degrees_t longitude;
 	struct picture *next;
@@ -305,7 +305,7 @@ extern void dive_create_picture(struct dive *d, char *filename, int shift_time);
 extern void dive_add_picture(struct dive *d, struct picture *newpic);
 extern void dive_remove_picture(struct dive *d, struct picture *pic);
 extern unsigned int dive_get_picture_count(struct dive *d);
-extern void picture_load_exif_data(struct picture *p);
+extern void picture_load_exif_data(struct picture *p, timestamp_t *timestamp);
 extern void dive_set_geodata_from_picture(struct dive *d, struct picture *pic);
 
 
diff --git a/qt-ui/profile/profilewidget2.cpp b/qt-ui/profile/profilewidget2.cpp
index 8374006bc..c709e9389 100644
--- a/qt-ui/profile/profilewidget2.cpp
+++ b/qt-ui/profile/profilewidget2.cpp
@@ -1307,13 +1307,13 @@ void ProfileWidget2::plotPictures()
 		struct picture *pic  = (struct picture*) m->index(i,1).data(Qt::UserRole).value<void*>();
 		// it's a correct picture, but doesn't have a timestamp: only show on the widget near the
 		// information area.
-		if (!pic->timestamp)
+		if (!pic->offset)
 			continue;
 		DivePictureItem *item = new DivePictureItem();
 		item->setPixmap(m->index(i,0).data(Qt::DecorationRole).value<QPixmap>());
 		// let's put the picture at the correct time, but at a fixed "depth" on the profile
 		// not sure this is ideal, but it seems to look right.
-		x = timeAxis->posAtValue(pic->timestamp - current_dive->when);
+		x = timeAxis->posAtValue(pic->offset);
 		if (i == 0)
 			y = 10;
 		else
diff --git a/qthelper.cpp b/qthelper.cpp
index 1dd25e241..7eba936a6 100644
--- a/qthelper.cpp
+++ b/qthelper.cpp
@@ -264,7 +264,7 @@ extern "C" xsltStylesheetPtr get_stylesheet(const char *name)
 	return xslt;
 }
 
-extern "C" void picture_load_exif_data(struct picture *p)
+extern "C" void picture_load_exif_data(struct picture *p, timestamp_t *timestamp)
 {
 	EXIFInfo exif;
 	memblock mem;
@@ -273,7 +273,7 @@ extern "C" void picture_load_exif_data(struct picture *p)
 		goto picture_load_exit;
 	if (exif.parseFrom((const unsigned char *)mem.buffer, (unsigned)mem.size) != PARSE_EXIF_SUCCESS)
 		goto picture_load_exit;
-	p->timestamp = exif.epoch();
+	*timestamp = exif.epoch();
 	p->longitude.udeg= lrint(1000000.0 * exif.GeoLocation.Longitude);
 	p->latitude.udeg  = lrint(1000000.0 * exif.GeoLocation.Latitude);
 	picture_load_exit:
diff --git a/save-xml.c b/save-xml.c
index 17f463a93..037fc45cb 100644
--- a/save-xml.c
+++ b/save-xml.c
@@ -333,8 +333,8 @@ static void save_picture(struct membuffer *b, struct picture *pic)
 	put_string(b, "  <picture filename='");
 	put_string(b, pic->filename);
 	put_string(b, "'");
-	if (pic->timestamp)
-		put_format(b, " timestamp='%ld'", pic->timestamp);
+	if (pic->offset)
+		put_format(b, " offset='%d'", pic->offset);
 	if (pic->latitude.udeg || pic->longitude.udeg) {
 		put_degrees(b, pic->latitude, " gps='", " ");
 		put_degrees(b, pic->longitude, "", "'");