View: Adjust top margin when needed

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

diff --git a/pv/view/view.cpp b/pv/view/view.cpp
index 772a95e07156f3232f24fd19fd46796b0711a7f3..2fc14d2b64c9e777827650f7565125d1fe351aae 100644 (file)
--- a/pv/view/view.cpp
+++ b/pv/view/view.cpp
@@ -149,8 +149,7 @@ View::View(Session &session, bool is_main_view, QWidget *parent) :
        trigger_markers_(),
        hover_point_(-1, -1),
        scroll_needs_defaults_(false),
-       saved_v_offset_(0),
-       size_finalized_(false)
+       saved_v_offset_(0)
 {
        GlobalSettings settings;
        coloured_bg_ = settings.value(GlobalSettings::Key_View_ColouredBG).toBool();
@@ -319,7 +318,7 @@ void View::restore_settings(QSettings &settings)
                saved_v_offset_ = settings.value("v_offset").toInt();
                set_v_offset(saved_v_offset_);
                scroll_needs_defaults_ = false;
-               // Note: see resizeEvent() for additional information
+               // Note: see eventFilter() for additional information
        }
 }
 
@@ -747,6 +746,30 @@ void View::calculate_tick_spacing()
        set_tick_precision(tick_precision);
 }
 
+void View::adjust_top_margin()
+{
+       assert(viewport_);
+
+       const QSize areaSize = viewport_->size();
+
+       const pair<int, int> extents = v_extents();
+       const int top_margin = owner_visual_v_offset() + extents.first;
+       const int trace_bottom = owner_visual_v_offset() + extents.first + extents.second;
+
+       // Do we have empty space at the top while the last trace goes out of screen?
+       if ((top_margin > 0) && (trace_bottom > areaSize.height())) {
+               const int trace_height = extents.second - extents.first;
+
+               // Center everything vertically if there is enough space
+               if (areaSize.height() >= trace_height)
+                       set_v_offset(extents.first -
+                               ((areaSize.height() - trace_height) / 2));
+               else
+                       // Remove the top margin to make as many traces fit on screen as possible
+                       set_v_offset(extents.first);
+       }
+}
+
 void View::update_scroll()
 {
        assert(viewport_);
@@ -816,11 +839,6 @@ void View::set_scroll_default()
        else
                // Put the first trace at the top, letting the bottom ones overflow
                set_v_offset(extents.first);
-
-       // If we're not sure whether setting the defaults worked as
-       // the window wasn't set up entirely yet, we want to be called
-       // again later to make sure
-       scroll_needs_defaults_ = !size_finalized_;
 }
 
 void View::update_layout()
@@ -936,35 +954,38 @@ bool View::eventFilter(QObject *object, QEvent *event)
        } else if (type == QEvent::Leave) {
                hover_point_ = QPoint(-1, -1);
                hover_point_changed();
+       } else if (type == QEvent::Show) {
+
+               // 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 shown, which happens after all widgets were
+               // resized to their final sizes.
+               update_layout();
+
+               if (scroll_needs_defaults_) {
+                       set_scroll_default();
+                       scroll_needs_defaults_ = false;
+               }
+
+               if (saved_v_offset_) {
+                       set_v_offset(saved_v_offset_);
+                       saved_v_offset_ = 0;
+               }
        }
 
        return QObject::eventFilter(object, event);
 }
 
-void View::resizeEvent(QResizeEvent*)
+void View::resizeEvent(QResizeEvent* event)
 {
-       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.
+       // Only adjust the top margin if we shrunk vertically
+       if (event->size().height() < event->oldSize().height())
+               adjust_top_margin();
 
-       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();
+       update_layout();
 }
 
 void View::row_item_appearance_changed(bool label, bool content)