statistics: use dive instead of count bins

If we want to make bar charts selectable (when clicking on a
bar select the dives the bar represents), then we must store
the dives behind bars. Therefore, use dive-based bins instead
of count based bins in bar charts and pie charts. This gave
some churn because every structure where a count is stored
has to be changed to store a vector of dives. Try to use
move semantics where possible to avoid duplication of dive
lists.

On a positive note, the count_dives() function of the
binners can now be removed, since it is unused.

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

7 files changed, 136 insertions, 153 deletions

diff --git a/stats/barseries.cpp b/stats/barseries.cpp
index 9e8d5d133..8767a04db 100644
--- a/stats/barseries.cpp
+++ b/stats/barseries.cpp
@@ -40,25 +40,24 @@ BarSeries::BarSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis,
 
 BarSeries::BarSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis,
 		     bool horizontal, const QString &categoryName,
-		     const std::vector<CountItem> &items) :
+		     std::vector<CountItem> items) :
 	BarSeries(view, xAxis, yAxis, horizontal, false, categoryName, nullptr, std::vector<QString>())
 {
-	for (const CountItem &item: items) {
+	for (CountItem &item: items) {
 		StatsOperationResults res;
-		res.count = item.count;
-		double value = item.count;
-		add_item(item.lowerBound, item.upperBound, makeSubItems(value, item.label),
+		double value = (double)item.dives.size();
+		add_item(item.lowerBound, item.upperBound, makeSubItems({ value, std::move(item.dives), std::move(item.label) }),
 			 item.binName, res, item.total, horizontal, stacked);
 	}
 }
 
 BarSeries::BarSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis,
 		     bool horizontal, const QString &categoryName, const StatsVariable *valueVariable,
-		     const std::vector<ValueItem> &items) :
+		     std::vector<ValueItem> items) :
 	BarSeries(view, xAxis, yAxis, horizontal, false, categoryName, valueVariable, std::vector<QString>())
 {
-	for (const ValueItem &item: items) {
-		add_item(item.lowerBound, item.upperBound, makeSubItems(item.value, item.label),
+	for (ValueItem &item: items) {
+		add_item(item.lowerBound, item.upperBound, makeSubItems({ item.value, std::move(item.res.dives), std::move(item.label) }),
 			 item.binName, item.res, -1, horizontal, stacked);
 	}
 }
@@ -66,19 +65,19 @@ BarSeries::BarSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis,
 BarSeries::BarSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis,
 		     bool horizontal, bool stacked, const QString &categoryName, const StatsVariable *valueVariable,
 		     std::vector<QString> valueBinNames,
-		     const std::vector<MultiItem> &items) :
+		     std::vector<MultiItem> items) :
 	BarSeries(view, xAxis, yAxis, horizontal, stacked, categoryName, valueVariable, std::move(valueBinNames))
 {
-	for (const MultiItem &item: items) {
+	for (MultiItem &item: items) {
 		StatsOperationResults res;
-		std::vector<std::pair<double, std::vector<QString>>> valuesLabels;
-		valuesLabels.reserve(item.countLabels.size());
+		std::vector<SubItemDesc> subitems;
+		subitems.reserve(item.items.size());
 		int total = 0;
-		for (auto &[count, label]: item.countLabels) {
-			valuesLabels.push_back({ static_cast<double>(count), std::move(label) });
-			total += count;
+		for (auto &[dives, label]: item.items) {
+			total += (int)dives.size();
+			subitems.push_back({ static_cast<double>(dives.size()), std::move(dives), std::move(label) });
 		}
-		add_item(item.lowerBound, item.upperBound, makeSubItems(valuesLabels),
+		add_item(item.lowerBound, item.upperBound, makeSubItems(std::move(subitems)),
 			 item.binName, res, total, horizontal, stacked);
 	}
 }
@@ -235,15 +234,16 @@ void BarSeries::SubItem::updatePosition(BarSeries *series, bool horizontal, bool
 		label->updatePosition(horizontal, stacked, rect, bin_nr, binCount, fill);
 }
 
-std::vector<BarSeries::SubItem> BarSeries::makeSubItems(const std::vector<std::pair<double, std::vector<QString>>> &values) const
+std::vector<BarSeries::SubItem> BarSeries::makeSubItems(std::vector<SubItemDesc> items) const
 {
 	std::vector<SubItem> res;
-	res.reserve(values.size());
+	res.reserve(items.size());
 	double from = 0.0;
 	int bin_nr = 0;
-	for (auto &[v, label]: values) {
+	for (auto &[v, dives, label]: items) {
 		if (v > 0.0) {
 			res.push_back({ view.createChartItem<ChartBarItem>(ChartZValue::Series, barBorderWidth, horizontal),
+					std::move(dives),
 					{}, from, from + v, bin_nr });
 			if (!label.empty())
 				res.back().label = std::make_unique<BarLabel>(view, label, bin_nr, binCount());
@@ -255,9 +255,9 @@ std::vector<BarSeries::SubItem> BarSeries::makeSubItems(const std::vector<std::p
 	return res;
 }
 
-std::vector<BarSeries::SubItem> BarSeries::makeSubItems(double value, const std::vector<QString> &label) const
+std::vector<BarSeries::SubItem> BarSeries::makeSubItems(SubItemDesc item) const
 {
-	return makeSubItems(std::vector<std::pair<double, std::vector<QString>>>{ { value, label } });
+	return makeSubItems(std::vector<SubItemDesc>{ std::move(item) });
 }
 
 int BarSeries::binCount() const
@@ -329,7 +329,8 @@ static std::vector<QString> makeCountInfo(const QString &binName, const QString
 
 // Format information in a value bar chart: the name of the bin and the value with unit.
 static std::vector<QString> makeValueInfo(const QString &binName, const QString &axisName,
-					  const StatsVariable &valueVariable, const StatsOperationResults &values)
+					  const StatsVariable &valueVariable, const StatsOperationResults &values,
+					  int count)
 {
 	QLocale loc;
 	int decimals = valueVariable.decimals();
@@ -338,7 +339,7 @@ static std::vector<QString> makeValueInfo(const QString &binName, const QString
 	std::vector<QString> res;
 	res.reserve(operations.size() + 3);
 	res.push_back(QStringLiteral("%1: %2").arg(axisName, binName));
-	res.push_back(QStringLiteral("%1: %2").arg(StatsTranslations::tr("Count"), loc.toString(values.count)));
+	res.push_back(QStringLiteral("%1: %2").arg(StatsTranslations::tr("Count"), loc.toString(count)));
 	res.push_back(QStringLiteral("%1: ").arg(valueVariable.name()));
 	for (StatsOperation op: operations) {
 		QString valueFormatted = loc.toString(values.get(op), 'f', decimals);
@@ -349,19 +350,23 @@ static std::vector<QString> makeValueInfo(const QString &binName, const QString
 
 std::vector<QString> BarSeries::makeInfo(const Item &item, int subitem_idx) const
 {
+	if (item.subitems.empty())
+		return {};
 	if (!valueBinNames.empty() && valueVariable) {
 		if (subitem_idx < 0 || subitem_idx >= (int)item.subitems.size())
 			return {};
 		const SubItem &subitem = item.subitems[subitem_idx];
 		if (subitem.bin_nr < 0 || subitem.bin_nr >= (int)valueBinNames.size())
 			return {};
-		int count = (int)lrint(subitem.value_to - subitem.value_from);
+		int count = (int)subitem.dives.size();
 		return makeCountInfo(item.binName, categoryName, valueBinNames[subitem.bin_nr],
 				     valueVariable->name(), count, item.total);
 	} else if (valueVariable) {
-		return makeValueInfo(item.binName, categoryName, *valueVariable, item.res);
+		int count = (int)item.subitems[0].dives.size();
+		return makeValueInfo(item.binName, categoryName, *valueVariable, item.res, count);
 	} else {
-		return makeCountInfo(item.binName, categoryName, QString(), QString(), item.res.count, item.total);
+		int count = (int)item.subitems[0].dives.size();
+		return makeCountInfo(item.binName, categoryName, QString(), QString(), count, item.total);
 	}
 }
 
diff --git a/stats/barseries.h b/stats/barseries.h
index 9f9586fe8..8c83648ea 100644
--- a/stats/barseries.h
+++ b/stats/barseries.h
@@ -25,7 +25,7 @@ public:
 	// based charts and for stacked bar charts with multiple items.
 	struct CountItem {
 		double lowerBound, upperBound;
-		int count;
+		std::vector<dive *> dives;
 		std::vector<QString> label;
 		QString binName;
 		int total;
@@ -35,11 +35,15 @@ public:
 		double value;
 		std::vector<QString> label;
 		QString binName;
-		StatsOperationResults res;
+		StatsOperationResults res;	// Contains the dives
 	};
 	struct MultiItem {
+		struct Item {
+			std::vector<dive *> dives;
+			std::vector<QString> label;
+		};
 		double lowerBound, upperBound;
-		std::vector<std::pair<int, std::vector<QString>>> countLabels;
+		std::vector<Item> items;
 		QString binName;
 	};
 
@@ -52,14 +56,14 @@ public:
 	// are ordered identically.
 	BarSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis,
 		  bool horizontal, const QString &categoryName,
-		  const std::vector<CountItem> &items);
+		  std::vector<CountItem> items);
 	BarSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis,
 		  bool horizontal, const QString &categoryName, const StatsVariable *valueVariable,
-		  const std::vector<ValueItem> &items);
+		  std::vector<ValueItem> items);
 	BarSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis,
 		  bool horizontal, bool stacked, const QString &categoryName, const StatsVariable *valueVariable,
 		  std::vector<QString> valueBinNames,
-		  const std::vector<MultiItem> &items);
+		  std::vector<MultiItem> items);
 	~BarSeries();
 
 	void updatePositions() override;
@@ -93,6 +97,7 @@ private:
 
 	struct SubItem {
 		ChartItemPtr<ChartBarItem> item;
+		std::vector<dive *> dives;
 		std::unique_ptr<BarLabel> label;
 		double value_from;
 		double value_to;
@@ -127,8 +132,13 @@ private:
 	const StatsVariable *valueVariable; // null: this is count based
 	std::vector<QString> valueBinNames;
 	Index highlighted;
-	std::vector<SubItem> makeSubItems(double value, const std::vector<QString> &label) const;
-	std::vector<SubItem> makeSubItems(const std::vector<std::pair<double, std::vector<QString>>> &values) const;
+	struct SubItemDesc {
+		double v;
+		std::vector<dive *> dives;
+		std::vector<QString> label;
+	};
+	std::vector<SubItem> makeSubItems(SubItemDesc item) const;
+	std::vector<SubItem> makeSubItems(std::vector<SubItemDesc> items) const;
 	void add_item(double lowerBound, double upperBound, std::vector<SubItem> subitems,
 		      const QString &binName, const StatsOperationResults &res, int total, bool horizontal,
 		      bool stacked);
diff --git a/stats/pieseries.cpp b/stats/pieseries.cpp
index d837abe5a..f8c5aa980 100644
--- a/stats/pieseries.cpp
+++ b/stats/pieseries.cpp
@@ -16,14 +16,15 @@ static const double pieBorderWidth = 1.0;
 static const double innerLabelRadius = 0.75; // 1.0 = at outer border of pie
 static const double outerLabelRadius = 1.01; // 1.0 = at outer border of pie
 
-PieSeries::Item::Item(StatsView &view, const QString &name, int from, int count, int totalCount,
+PieSeries::Item::Item(StatsView &view, const QString &name, int from, std::vector<dive *> divesIn, int totalCount,
 		      int bin_nr, int numBins) :
 	name(name),
-	count(count)
+	dives(std::move(divesIn))
 {
 	QFont f; // make configurable
 	QLocale loc;
 
+	int count = (int)dives.size();
 	angleFrom = static_cast<double>(from) / totalCount;
 	angleTo = static_cast<double>(from + count) / totalCount;
 	double meanAngle = M_PI / 2.0 - (from + count / 2.0) / totalCount * M_PI * 2.0; // Note: "-" because we go CW.
@@ -74,7 +75,7 @@ void PieSeries::Item::highlight(ChartPieItem &item, int bin_nr, bool highlight,
 }
 
 PieSeries::PieSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis, const QString &categoryName,
-		     const std::vector<std::pair<QString, int>> &data, bool keepOrder) :
+		     std::vector<std::pair<QString, std::vector<dive *>>> data, bool keepOrder) :
 	StatsSeries(view, xAxis, yAxis),
 	item(view.createChartItem<ChartPieItem>(ChartZValue::Series, pieBorderWidth)),
 	categoryName(categoryName),
@@ -89,8 +90,8 @@ PieSeries::PieSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis, const
 
 	// Easier to read than std::accumulate
 	totalCount = 0;
-	for (const auto &[name, count]: data)
-		totalCount += count;
+	for (const auto &[name, dives]: data)
+		totalCount += (int)dives.size();
 
 	// First of all, sort from largest to smalles slice. Instead
 	// of sorting the initial array, sort a list of indices, so that
@@ -102,19 +103,19 @@ PieSeries::PieSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis, const
 	//  - do a lexicographic sort by (count, idx) so that for equal counts the order is preserved.
 	std::sort(sorted.begin(), sorted.end(),
 		  [&data](int idx1, int idx2)
-		  { return std::make_tuple(-data[idx1].second, idx1) <
-			   std::make_tuple(-data[idx2].second, idx2); });
+		  { return std::make_tuple(-data[idx1].second.size(), idx1) <
+			   std::make_tuple(-data[idx2].second.size(), idx2); });
 	auto it = std::find_if(sorted.begin(), sorted.end(),
 			       [count=totalCount, &data](int idx)
-			       { return data[idx].second * 100 / count < smallest_slice_percentage; });
+			       { return (int)data[idx].second.size() * 100 / count < smallest_slice_percentage; });
 	if (it - sorted.begin() < min_slices) {
 		// Take minimum amount of slices below 50%...
 		int sum = 0;
 		for (auto it2 = sorted.begin(); it2 != it; ++it2)
-			sum += data[*it2].second;
+			sum += (int)data[*it2].second.size();
 
 		while(it != sorted.end() && sum * 2 < totalCount && it - sorted.begin() < min_slices) {
-			sum += data[*it].second;
+			sum += (int)data[*it].second.size();
 			++it;
 		}
 	}
@@ -135,18 +136,24 @@ PieSeries::PieSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis, const
 	items.reserve(numBins);
 	int act = 0;
 	for (auto it2 = sorted.begin(); it2 != it; ++it2) {
-		int count = data[*it2].second;
-		items.emplace_back(view, data[*it2].first, act, count, totalCount, (int)items.size(), numBins);
+		int count = (int)data[*it2].second.size();
+		items.emplace_back(view, data[*it2].first, act, std::move(data[*it2].second),
+				   totalCount, (int)items.size(), numBins);
 		act += count;
 	}
 
 	// Register the items of the "other" group.
 	if (it != sorted.end()) {
+		std::vector<dive *> otherDives;
+		otherDives.reserve(totalCount - act);
 		other.reserve(sorted.end() - it);
-		for (auto it2 = it; it2 != sorted.end(); ++it2)
-			other.push_back({ data[*it2].first, data[*it2].second });
+		for (auto it2 = it; it2 != sorted.end(); ++it2) {
+			other.push_back({ data[*it2].first, (int)data[*it2].second.size() });
+			for (dive *d: data[*it2].second)
+				otherDives.push_back(d);
+		}
 		QString name = StatsTranslations::tr("other (%1 items)").arg(other.size());
-		items.emplace_back(view, name, act, totalCount - act, totalCount, (int)items.size(), numBins);
+		items.emplace_back(view, name, act, std::move(otherDives), totalCount, (int)items.size(), numBins);
 	}
 }
 
@@ -212,15 +219,15 @@ std::vector<QString> PieSeries::makeInfo(int idx) const
 		// This is the "other" bin. Format all these items and an overview item.
 		res.reserve(other.size() + 1);
 		res.push_back(QString("%1: %2").arg(StatsTranslations::tr("other"),
-						    makePercentageLine(items[idx].count, totalCount)));
+						    makePercentageLine((int)items[idx].dives.size(), totalCount)));
 		for (const OtherItem &item: other)
 			res.push_back(QString("%1: %2").arg(item.name,
-							    makePercentageLine(item.count, totalCount)));
+							    makePercentageLine((int)item.count, totalCount)));
 	} else {
 		// A "normal" item.
 		res.reserve(2);
 		res.push_back(QStringLiteral("%1: %2").arg(categoryName, items[idx].name));
-		res.push_back(makePercentageLine(items[idx].count, totalCount));
+		res.push_back(makePercentageLine((int)items[idx].dives.size(), totalCount));
 	}
 	return res;
 }
diff --git a/stats/pieseries.h b/stats/pieseries.h
index 0cb5e12cb..4fbf689bd 100644
--- a/stats/pieseries.h
+++ b/stats/pieseries.h
@@ -10,6 +10,7 @@
 #include <vector>
 #include <QString>
 
+struct dive;
 struct InformationBox;
 struct ChartPieItem;
 struct ChartTextItem;
@@ -21,7 +22,7 @@ public:
 	// If keepOrder is false, bins will be sorted by size, otherwise the sorting
 	// of the shown bins will be retained. Small bins are omitted for clarity.
 	PieSeries(StatsView &view, StatsAxis *xAxis, StatsAxis *yAxis, const QString &categoryName,
-		  const std::vector<std::pair<QString, int>> &data, bool keepOrder);
+		  std::vector<std::pair<QString, std::vector<dive *>>> data, bool keepOrder);
 	~PieSeries();
 
 	void updatePositions() override;
@@ -42,9 +43,9 @@ private:
 		ChartItemPtr<ChartTextItem> innerLabel, outerLabel;
 		QString name;
 		double angleFrom, angleTo; // In fraction of total
-		int count;
+		std::vector<dive *> dives;
 		QPointF innerLabelPos, outerLabelPos; // With respect to a (-1, -1)-(1, 1) rectangle.
-		Item(StatsView &view, const QString &name, int from, int count, int totalCount,
+		Item(StatsView &view, const QString &name, int from, std::vector<dive *> dives, int totalCount,
 		     int bin_nr, int numBins);
 		void updatePositions(const QPointF &center, double radius);
 		void highlight(ChartPieItem &item, int bin_nr, bool highlight, int numBins);
diff --git a/stats/statsvariables.cpp b/stats/statsvariables.cpp
index 8b2dc9bc3..498314ae7 100644
--- a/stats/statsvariables.cpp
+++ b/stats/statsvariables.cpp
@@ -434,15 +434,16 @@ StatsOperationResults StatsVariable::applyOperations(const std::vector<dive *> &
 	std::vector<StatsValue> val = values(dives);
 
 	double sumTime = 0.0;
-	res.count = (int)val.size();
+	res.dives.reserve(val.size());
 	res.median = quartiles(val).q2;
 
-	if (res.count <= 0)
+	if (val.empty())
 		return res;
 
 	res.min = std::numeric_limits<double>::max();
 	res.max = std::numeric_limits<double>::lowest();
 	for (auto [v, d]: val) {
+		res.dives.push_back(d);
 		res.sum += v;
 		res.mean += v;
 		sumTime += d->duration.seconds;
@@ -453,19 +454,19 @@ StatsOperationResults StatsVariable::applyOperations(const std::vector<dive *> &
 			res.max = v;
 	}
 
-	res.mean /= res.count;
+	res.mean /= val.size();
 	res.timeWeightedMean /= sumTime;
 	return res;
 }
 
 StatsOperationResults::StatsOperationResults() :
-	count(0), median(0.0), mean(0.0), timeWeightedMean(0.0), sum(0.0), min(0.0), max(0.0)
+	median(0.0), mean(0.0), timeWeightedMean(0.0), sum(0.0), min(0.0), max(0.0)
 {
 }
 
 bool StatsOperationResults::isValid() const
 {
-	return count > 0;
+	return !dives.empty();
 }
 
 double StatsOperationResults::get(StatsOperation op) const
@@ -584,7 +585,6 @@ struct SimpleBinner : public StatsBinner {
 public:
 	using Type = decltype(Bin::value);
 	std::vector<StatsBinDives> bin_dives(const std::vector<dive *> &dives, bool fill_empty) const override;
-	std::vector<StatsBinCount> count_dives(const std::vector<dive *> &dives, bool fill_empty) const override;
 	const Binner &derived() const {
 		return static_cast<const Binner &>(*this);
 	}
@@ -664,24 +664,6 @@ std::vector<StatsBinDives> SimpleBinner<Binner, Bin>::bin_dives(const std::vecto
 	return value_vector_to_bin_vector<Bin>(*this, value_bins, fill_empty);
 }
 
-template<typename Binner, typename Bin>
-std::vector<StatsBinCount> SimpleBinner<Binner, Bin>::count_dives(const std::vector<dive *> &dives, bool fill_empty) const
-{
-	// First, collect a value / counts vector and then produce the final vector
-	// out of that. I wonder if that is premature optimization?
-	using Pair = std::pair<Type, int>;
-	std::vector<Pair> value_bins;
-	for (const dive *d: dives) {
-		Type value = derived().to_bin_value(d);
-		if (is_invalid_value(value))
-			continue;
-		register_bin_value(value_bins, value, [](int &i){ ++i; });
-	}
-
-	// Now, turn that into our result array with allocated bin objects.
-	return value_vector_to_bin_vector<Bin>(*this, value_bins, fill_empty);
-}
-
 // A simple binner (see above) that works on continuous (or numeric) variables
 // and can return bin-ranges. The binner must implement an inc() function
 // that turns a bin into the next-higher bin.
@@ -778,7 +760,6 @@ struct MultiBinner : public StatsBinner {
 public:
 	using Type = decltype(Bin::value);
 	std::vector<StatsBinDives> bin_dives(const std::vector<dive *> &dives, bool fill_empty) const override;
-	std::vector<StatsBinCount> count_dives(const std::vector<dive *> &dives, bool fill_empty) const override;
 	const Binner &derived() const {
 		return static_cast<const Binner &>(*this);
 	}
@@ -807,25 +788,6 @@ std::vector<StatsBinDives> MultiBinner<Binner, Bin>::bin_dives(const std::vector
 	return value_vector_to_bin_vector<Bin>(*this, value_bins, false);
 }
 
-template<typename Binner, typename Bin>
-std::vector<StatsBinCount> MultiBinner<Binner, Bin>::count_dives(const std::vector<dive *> &dives, bool) const
-{
-	// First, collect a value / counts vector and then produce the final vector
-	// out of that. I wonder if that is premature optimization?
-	using Pair = std::pair<Type, int>;
-	std::vector<Pair> value_bins;
-	for (const dive *d: dives) {
-		for (const Type &s: derived().to_bin_values(d)) {
-			if (is_invalid_value(s))
-				continue;
-			register_bin_value(value_bins, s, [](int &i){ ++i; });
-		}
-	}
-
-	// Now, turn that into our result array with allocated bin objects.
-	return value_vector_to_bin_vector<Bin>(*this, value_bins, false);
-}
-
 // A binner that works on string-based bins whereby each dive can
 // produce multiple strings (e.g. dive buddies). The binner must
 // feature a to_bin_values() function that produces a vector of
diff --git a/stats/statsvariables.h b/stats/statsvariables.h
index 3469033e2..845ee1a67 100644
--- a/stats/statsvariables.h
+++ b/stats/statsvariables.h
@@ -33,7 +33,7 @@ enum class StatsOperation : int {
 
 // Results of the above operations
 struct StatsOperationResults {
-	int count;
+	std::vector<dive *> dives;
 	double median;
 	double mean;
 	double timeWeightedMean;
@@ -77,7 +77,6 @@ struct StatsBinValue {
 };
 using StatsBinDives = StatsBinValue<std::vector<dive *>>;
 using StatsBinValues = StatsBinValue<std::vector<StatsValue>>;
-using StatsBinCount = StatsBinValue<int>;
 using StatsBinQuartiles = StatsBinValue<StatsQuartiles>;
 using StatsBinOp = StatsBinValue<StatsOperationResults>;
 
@@ -89,7 +88,6 @@ struct StatsBinner {
 	// The binning functions have a parameter "fill_empty". If true, missing
 	// bins in the range will be filled with empty bins. This only works for continuous variables.
 	virtual std::vector<StatsBinDives> bin_dives(const std::vector<dive *> &dives, bool fill_empty) const = 0;
-	virtual std::vector<StatsBinCount> count_dives(const std::vector<dive *> &dives, bool fill_empty) const = 0;
 
 	// Note: these functions will crash with an exception if passed incompatible bins!
 	virtual QString format(const StatsBin &bin) const = 0;
diff --git a/stats/statsview.cpp b/stats/statsview.cpp
index eec7b4ba5..133f39219 100644
--- a/stats/statsview.cpp
+++ b/stats/statsview.cpp
@@ -534,10 +534,10 @@ CountAxis *StatsView::createCountAxis(int maxVal, bool isHorizontal)
 }
 
 // For "two-dimensionally" binned plots (eg. stacked bar or grouped bar):
-// Counts for each bin on the independent variable, including the total counts for that bin.
-struct BinCounts {
+// Dives for each bin on the independent variable, including the total counts for that bin.
+struct BinDives {
 	StatsBinPtr bin;
-	std::vector<int> counts;
+	std::vector<std::vector<dive *>> dives;
 	int total;
 };
 
@@ -547,7 +547,7 @@ struct BinCounts {
 // Perhaps we should determine the bins of all dives first and then
 // query the counts for precisely those bins?
 struct BarPlotData {
-	std::vector<BinCounts> hbin_counts; // For each category bin the counts for all value bins
+	std::vector<BinDives> hbins;		// For each category bin the counts for all value bins
 	std::vector<StatsBinPtr> vbins;
 	std::vector<QString> vbinNames;
 	int maxCount;				// Highest count of any bin-combination
@@ -561,8 +561,8 @@ BarPlotData::BarPlotData(std::vector<StatsBinDives> &categoryBins, const StatsBi
 {
 	for (auto &[bin, dives]: categoryBins) {
 		// This moves the bin - the original pointer is invalidated
-		hbin_counts.push_back({ std::move(bin), std::vector<int>(vbins.size(), 0), 0 });
-		for (auto &[vbin, count]: valueBinner.count_dives(dives, false)) {
+		hbins.push_back({ std::move(bin), std::vector<std::vector<dive *>>(vbins.size()), 0 });
+		for (auto &[vbin, dives]: valueBinner.bin_dives(dives, false)) {
 			// Note: we assume that the bins are sorted!
 			auto it = std::lower_bound(vbins.begin(), vbins.end(), vbin,
 						   [] (const StatsBinPtr &p, const StatsBinPtr &bin)
@@ -573,15 +573,16 @@ BarPlotData::BarPlotData(std::vector<StatsBinDives> &categoryBins, const StatsBi
 				// Attn: this invalidates "vbin", which must not be used henceforth!
 				vbins.insert(it, std::move(vbin));
 				// Fix the old arrays
-				for (auto &[bin, v, total]: hbin_counts)
-					v.insert(v.begin() + pos, 0);
+				for (auto &[bin, v, total]: hbins)
+					v.insert(v.begin() + pos, std::vector<dive *>());
 			}
-			hbin_counts.back().counts[pos] = count;
-			hbin_counts.back().total += count;
+			int count = (int)dives.size();
+			hbins.back().dives[pos] = std::move(dives);
+			hbins.back().total += count;
 			if (count > maxCount)
 				maxCount = count;
 		}
-		maxCategoryCount = std::max(maxCategoryCount, hbin_counts.back().total);
+		maxCategoryCount = std::max(maxCategoryCount, hbins.back().total);
 	}
 
 	vbinNames.reserve(vbins.size());
@@ -601,17 +602,17 @@ static std::vector<QString> makePercentageLabels(int count, int total, bool isHo
 		return { countString, percentageString };
 }
 
-// From a list of counts, make (count, label) pairs, where the label
+// From a list of dive bins, make (dives, label) pairs, where the label
 // formats the total number and the percentage of dives.
-static std::vector<std::pair<int, std::vector<QString>>> makeCountLabels(const std::vector<int> &counts, int total, bool isHorizontal)
+static std::vector<BarSeries::MultiItem::Item> makeMultiItems(std::vector<std::vector<dive *>> bins, int total, bool isHorizontal)
 {
-	std::vector<std::pair<int, std::vector<QString>>> count_labels;
-	count_labels.reserve(counts.size());
-	for (int count: counts) {
-		std::vector<QString> label = makePercentageLabels(count, total, isHorizontal);
-		count_labels.push_back(std::make_pair(count, label));
+	std::vector<BarSeries::MultiItem::Item> res;
+	res.reserve(bins.size());
+	for (std::vector<dive*> &bin: bins) {
+		std::vector<QString> label = makePercentageLabels((int)bin.size(), total, isHorizontal);
+		res.push_back({ std::move(bin), std::move(label) });
 	}
-	return count_labels;
+	return res;
 }
 
 void StatsView::plotBarChart(const std::vector<dive *> &dives,
@@ -648,15 +649,15 @@ void StatsView::plotBarChart(const std::vector<dive *> &dives,
 	legend = createChartItem<Legend>(data.vbinNames);
 
 	std::vector<BarSeries::MultiItem> items;
-	items.reserve(data.hbin_counts.size());
+	items.reserve(data.hbins.size());
 	double pos = 0.0;
-	for (auto &[hbin, counts, total]: data.hbin_counts) {
-		items.push_back({ pos - 0.5, pos + 0.5, makeCountLabels(counts, total, isHorizontal),
+	for (auto &[hbin, dives, total]: data.hbins) {
+		items.push_back({ pos - 0.5, pos + 0.5, makeMultiItems(std::move(dives), total, isHorizontal),
 				  categoryBinner->formatWithUnit(*hbin) });
 		pos += 1.0;
 	}
 
-	createSeries<BarSeries>(isHorizontal, isStacked, categoryVariable->name(), valueVariable, std::move(data.vbinNames), items);
+	createSeries<BarSeries>(isHorizontal, isStacked, categoryVariable->name(), valueVariable, std::move(data.vbinNames), std::move(items));
 }
 
 const double NaN = std::numeric_limits<double>::quiet_NaN();
@@ -770,14 +771,14 @@ void StatsView::plotValueChart(const std::vector<dive *> &dives,
 		pos += 1.0;
 	}
 
-	createSeries<BarSeries>(isHorizontal, categoryVariable->name(), valueVariable, items);
+	createSeries<BarSeries>(isHorizontal, categoryVariable->name(), valueVariable, std::move(items));
 }
 
-static int getTotalCount(const std::vector<StatsBinCount> &bins)
+static int getTotalCount(const std::vector<StatsBinDives> &bins)
 {
 	int total = 0;
-	for (const auto &[bin, count]: bins)
-		total += count;
+	for (const auto &[bin, dives]: bins)
+		total += (int)dives.size();
 	return total;
 }
 
@@ -785,10 +786,8 @@ template<typename T>
 static int getMaxCount(const std::vector<T> &bins)
 {
 	int res = 0;
-	for (auto const &[dummy, val]: bins) {
-		if (val > res)
-			res = val;
-	}
+	for (auto const &[dummy, dives]: bins)
+		res = std::max(res, (int)(dives.size()));
 	return res;
 }
 
@@ -801,7 +800,7 @@ void StatsView::plotDiscreteCountChart(const std::vector<dive *> &dives,
 
 	setTitle(categoryVariable->nameWithBinnerUnit(*categoryBinner));
 
-	std::vector<StatsBinCount> categoryBins = categoryBinner->count_dives(dives, false);
+	std::vector<StatsBinDives> categoryBins = categoryBinner->bin_dives(dives, false);
 
 	// If there is nothing to display, quit
 	if (categoryBins.empty())
@@ -824,14 +823,14 @@ void StatsView::plotDiscreteCountChart(const std::vector<dive *> &dives,
 	std::vector<BarSeries::CountItem> items;
 	items.reserve(categoryBins.size());
 	double pos = 0.0;
-	for (auto const &[bin, count]: categoryBins) {
-		std::vector<QString> label = makePercentageLabels(count, total, isHorizontal);
-		items.push_back({ pos - 0.5, pos + 0.5, count, label,
+	for (auto const &[bin, dives]: categoryBins) {
+		std::vector<QString> label = makePercentageLabels((int)dives.size(), total, isHorizontal);
+		items.push_back({ pos - 0.5, pos + 0.5, std::move(dives), label,
 				  categoryBinner->formatWithUnit(*bin), total });
 		pos += 1.0;
 	}
 
-	createSeries<BarSeries>(isHorizontal, categoryVariable->name(), items);
+	createSeries<BarSeries>(isHorizontal, categoryVariable->name(), std::move(items));
 }
 
 void StatsView::plotPieChart(const std::vector<dive *> &dives,
@@ -842,19 +841,19 @@ void StatsView::plotPieChart(const std::vector<dive *> &dives,
 
 	setTitle(categoryVariable->nameWithBinnerUnit(*categoryBinner));
 
-	std::vector<StatsBinCount> categoryBins = categoryBinner->count_dives(dives, false);
+	std::vector<StatsBinDives> categoryBins = categoryBinner->bin_dives(dives, false);
 
 	// If there is nothing to display, quit
 	if (categoryBins.empty())
 		return;
 
-	std::vector<std::pair<QString, int>> data;
+	std::vector<std::pair<QString, std::vector<dive *>>> data;
 	data.reserve(categoryBins.size());
-	for (auto const &[bin, count]: categoryBins)
-		data.emplace_back(categoryBinner->formatWithUnit(*bin), count);
+	for (auto &[bin, dives]: categoryBins)
+		data.emplace_back(categoryBinner->formatWithUnit(*bin), std::move(dives));
 
 	bool keepOrder = categoryVariable->type() != StatsVariable::Type::Discrete;
-	PieSeries *series = createSeries<PieSeries>(categoryVariable->name(), data, keepOrder);
+	PieSeries *series = createSeries<PieSeries>(categoryVariable->name(), std::move(data), keepOrder);
 
 	legend = createChartItem<Legend>(series->binNames());
 }
@@ -967,7 +966,7 @@ void StatsView::plotHistogramCountChart(const std::vector<dive *> &dives,
 
 	setTitle(categoryVariable->name());
 
-	std::vector<StatsBinCount> categoryBins = categoryBinner->count_dives(dives, true);
+	std::vector<StatsBinDives> categoryBins = categoryBinner->bin_dives(dives, true);
 
 	// If there is nothing to display, quit
 	if (categoryBins.empty())
@@ -990,16 +989,17 @@ void StatsView::plotHistogramCountChart(const std::vector<dive *> &dives,
 	std::vector<BarSeries::CountItem> items;
 	items.reserve(categoryBins.size());
 
-	for (auto const &[bin, count]: categoryBins) {
+	// Attention: this moves away the dives
+	for (auto &[bin, dives]: categoryBins) {
 		double lowerBound = categoryBinner->lowerBoundToFloat(*bin);
 		double upperBound = categoryBinner->upperBoundToFloat(*bin);
-		std::vector<QString> label = makePercentageLabels(count, total, isHorizontal);
+		std::vector<QString> label = makePercentageLabels((int)dives.size(), total, isHorizontal);
 
-		items.push_back({ lowerBound, upperBound, count, label,
+		items.push_back({ lowerBound, upperBound, std::move(dives), label,
 				  categoryBinner->formatWithUnit(*bin), total });
 	}
 
-	createSeries<BarSeries>(isHorizontal, categoryVariable->name(), items);
+	createSeries<BarSeries>(isHorizontal, categoryVariable->name(), std::move(items));
 
 	if (categoryVariable->type() == StatsVariable::Type::Numeric) {
 		double mean = categoryVariable->mean(dives);
@@ -1058,7 +1058,7 @@ void StatsView::plotHistogramValueChart(const std::vector<dive *> &dives,
 				  categoryBinner->formatWithUnit(*bin), res });
 	}
 
-	createSeries<BarSeries>(isHorizontal, categoryVariable->name(), valueVariable, items);
+	createSeries<BarSeries>(isHorizontal, categoryVariable->name(), valueVariable, std::move(items));
 }
 
 void StatsView::plotHistogramStackedChart(const std::vector<dive *> &dives,
@@ -1090,16 +1090,16 @@ void StatsView::plotHistogramStackedChart(const std::vector<dive *> &dives,
 		setAxes(catAxis, valAxis);
 
 	std::vector<BarSeries::MultiItem> items;
-	items.reserve(data.hbin_counts.size());
+	items.reserve(data.hbins.size());
 
-	for (auto &[hbin, counts, total]: data.hbin_counts) {
+	for (auto &[hbin, dives, total]: data.hbins) {
 		double lowerBound = categoryBinner->lowerBoundToFloat(*hbin);
 		double upperBound = categoryBinner->upperBoundToFloat(*hbin);
-		items.push_back({ lowerBound, upperBound, makeCountLabels(counts, total, isHorizontal),
+		items.push_back({ lowerBound, upperBound, makeMultiItems(std::move(dives), total, isHorizontal),
 				  categoryBinner->formatWithUnit(*hbin) });
 	}
 
-	createSeries<BarSeries>(isHorizontal, true, categoryVariable->name(), valueVariable, std::move(data.vbinNames), items);
+	createSeries<BarSeries>(isHorizontal, true, categoryVariable->name(), valueVariable, std::move(data.vbinNames), std::move(items));
 }
 
 void StatsView::plotHistogramBoxChart(const std::vector<dive *> &dives,