statistics: implement rectangle selection in scatter plot

Allow the user to select regions of the scatter plot using
a rectangular selection. When shift is pressed, do an
incremental selection.

Unfortunately, the list-selection code is so slow that this
becomes unusable for a large number of selected dives.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

1 files changed, 6 insertions, 3 deletions

diff --git a/stats/pieseries.cpp b/stats/pieseries.cpp
index 9f55d41d2..61579df74 100644
--- a/stats/pieseries.cpp
+++ b/stats/pieseries.cpp
@@ -265,12 +265,15 @@ void PieSeries::unhighlight()
 	highlighted = -1;
 }
 
-void PieSeries::selectItemsUnderMouse(const QPointF &pos, bool)
+bool PieSeries::selectItemsUnderMouse(const QPointF &pos, bool)
 {
 	int index = getItemUnderMouse(pos);
-	if (index < 0)
-		return setSelection({}, nullptr);
+	if (index < 0) {
+		setSelection({}, nullptr);
+		return false;
+	}
 
 	const std::vector<dive *> &dives = items[index].dives;
 	setSelection(dives, dives.empty() ? nullptr : dives.front());
+	return true;
 }