TraceView: Center traces vertically after view creation

[pulseview.git] / pv / view / view.cpp

diff --git a/pv/view/view.cpp b/pv/view/view.cpp
index a086d23de523f07e2be1192cbfc3b4bd2a028b09..08dc8828357d0e704a45dc6782411024968a7381 100644 (file)
--- a/pv/view/view.cpp
+++ b/pv/view/view.cpp
@@ -14,8 +14,7 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifdef ENABLE_DECODE
@@ -155,7 +154,10 @@ View::View(Session &session, QWidget *parent) :
        cursors_(new CursorPair(*this)),
        next_flag_text_('A'),
        trigger_markers_(),
-       hover_point_(-1, -1)
+       hover_point_(-1, -1),
+       scroll_needs_defaults_(false),
+       saved_v_offset_(0),
+       size_finalized_(false)
 {
        connect(scrollarea_.horizontalScrollBar(), SIGNAL(valueChanged(int)),
                this, SLOT(h_scroll_value_changed(int)));
@@ -280,6 +282,8 @@ const Viewport* View::viewport() const
 void View::save_settings(QSettings &settings) const
 {
        settings.setValue("scale", scale_);
+       settings.setValue("v_offset",
+               scrollarea_.verticalScrollBar()->sliderPosition());
 
        std::stringstream ss;
        boost::archive::text_oarchive oa(ss);
@@ -295,6 +299,9 @@ void View::save_settings(QSettings &settings) const
 
 void View::restore_settings(QSettings &settings)
 {
+       // Note: It is assumed that this function is only called once,
+       // immediately after restoring a previous session.
+
        if (settings.contains("scale"))
                set_scale(settings.value("scale").toDouble());
 
@@ -314,6 +321,13 @@ void View::restore_settings(QSettings &settings)
                signal->restore_settings(settings);
                settings.endGroup();
        }
+
+       if (settings.contains("v_offset")) {
+               saved_v_offset_ = settings.value("v_offset").toInt();
+               set_v_offset(saved_v_offset_);
+               scroll_needs_defaults_ = false;
+               // Note: see resizeEvent() for additional information
+       }
 }
 
 vector< shared_ptr<TimeItem> > View::time_items() const
@@ -798,7 +812,7 @@ void View::update_scroll()
                vscrollbar->setRange(extents.first - areaSize.height(),
                        extents.second);
 
-       if (scroll_needs_defaults)
+       if (scroll_needs_defaults_)
                set_scroll_default();
 }
 
@@ -815,11 +829,11 @@ void View::set_scroll_default()
 
        // Special case: when starting up and the window isn't visible yet,
        // areaSize is [0, 0]. In this case we want to be called again later
-       if (areaSize.height() == 0) {
-               scroll_needs_defaults = true;
+       if ((areaSize.height() == 0) || (!size_finalized_)) {
+               scroll_needs_defaults_ = true;
                return;
        } else {
-               scroll_needs_defaults = false;
+               scroll_needs_defaults_ = false;
        }
 
        const pair<int, int> extents = v_extents();
@@ -956,6 +970,27 @@ bool View::eventFilter(QObject *object, QEvent *event)
 void View::resizeEvent(QResizeEvent*)
 {
        update_layout();
+
+       // This is somewhat of a hack, unfortunately. We cannot use
+       // set_v_offset() from within restore_settings() as the view
+       // at that point is neither visible nor properly sized.
+       // This is the least intrusive workaround I could come up
+       // with: set the vertical offset (or scroll defaults) when
+       // the view is visible and resized to its final size.
+       // Resize events that are sent when the view is not visible
+       // must be ignored as they have wrong sizes, potentially
+       // preventing the v offset from being set successfully.
+
+       if (isVisible())
+               size_finalized_ = true;
+
+       if (size_finalized_ && saved_v_offset_) {
+               set_v_offset(saved_v_offset_);
+               saved_v_offset_ = 0;
+       }
+
+       if (size_finalized_ && scroll_needs_defaults_)
+               set_scroll_default();
 }
 
 void View::row_item_appearance_changed(bool label, bool content)