statistics: implement a bar series

Implement a bar series, which can plot stacked, grouped and single
bar charts in horizontal or vertical ways. On hovering over a
bar, an information is shown. The shown information depends on
whether the chart is count or value based, or is a multi-bin
chart.

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

1 files changed, 140 insertions, 0 deletions

diff --git a/stats/barseries.h b/stats/barseries.h
new file mode 100644
index 000000000..09d008094
--- /dev/null
+++ b/stats/barseries.h
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0
+// A small custom bar series, which displays information
+// when hovering over a bar. The QtCharts bar series were
+// too inflexible with respect to placement of the bars.
+#ifndef BAR_SERIES_H
+#define BAR_SERIES_H
+
+#include "statsseries.h"
+#include "statsvariables.h"
+
+#include <memory>
+#include <vector>
+#include <QGraphicsRectItem>
+
+namespace QtCharts {
+	class QAbstractAxis;
+}
+class InformationBox;
+class StatsVariable;
+
+class BarSeries : public StatsSeries {
+public:
+	// There are three versions of creating bar series: for value-based (mean, etc) charts, for counts
+	// based charts and for stacked bar charts with multiple items.
+	struct CountItem {
+		double lowerBound, upperBound;
+		int count;
+		std::vector<QString> label;
+		QString binName;
+		int total;
+	};
+	struct ValueItem {
+		double lowerBound, upperBound;
+		double value;
+		std::vector<QString> label;
+		QString binName;
+		StatsOperationResults res;
+	};
+	struct MultiItem {
+		double lowerBound, upperBound;
+		std::vector<std::pair<int, std::vector<QString>>> countLabels;
+		QString binName;
+	};
+
+	// If the horizontal flag is true, independent variable is plotted on the y-axis.
+	// A non-empty valueBinNames vector flags that this is a stacked bar chart.
+	// In that case, a valueVariable must also be provided.
+	// For count-based bar series in one variable, valueVariable is null.
+	// Note: this expects that all items are added with increasing pos
+	// and that no bar is inside another bar, i.e. lowerBound and upperBound
+	// are ordered identically.
+	BarSeries(QtCharts::QChart *chart, StatsAxis *xAxis, StatsAxis *yAxis,
+		  bool horizontal, const QString &categoryName,
+		  const std::vector<CountItem> &items);
+	BarSeries(QtCharts::QChart *chart, StatsAxis *xAxis, StatsAxis *yAxis,
+		  bool horizontal, const QString &categoryName, const StatsVariable *valueVariable,
+		  const std::vector<ValueItem> &items);
+	BarSeries(QtCharts::QChart *chart, StatsAxis *xAxis, StatsAxis *yAxis,
+		  bool horizontal, bool stacked, const QString &categoryName, const StatsVariable *valueVariable,
+		  std::vector<QString> valueBinNames,
+		  const std::vector<MultiItem> &items);
+	~BarSeries();
+
+	void updatePositions() override;
+	bool hover(QPointF pos) override;
+	void unhighlight() override;
+private:
+	BarSeries(QtCharts::QChart *chart, StatsAxis *xAxis, StatsAxis *yAxis,
+		  bool horizontal, bool stacked, const QString &categoryName, const StatsVariable *valueVariable,
+		  std::vector<QString> valueBinNames);
+
+	struct Index {
+		int bar;
+		int subitem;
+		Index();
+		Index(int bar, int subitem);
+		bool operator==(const Index &i2) const;
+	};
+
+	// Get item under mouse pointer, or -1 if none
+	Index getItemUnderMouse(const QPointF &f) const;
+
+	// A label that is composed of multiple lines
+	struct BarLabel {
+		std::vector<std::unique_ptr<QGraphicsSimpleTextItem>> items;
+		double totalWidth, totalHeight; // Size of the item
+		bool isOutside; // Is shown outside of bar
+		BarLabel(QtCharts::QChart *chart, const std::vector<QString> &labels, int bin_nr, int binCount);
+		void setVisible(bool visible);
+		void updatePosition(QtCharts::QChart *chart, QtCharts::QAbstractSeries *series,
+				    bool horizontal, bool center, const QRectF &rect, int bin_nr, int binCount);
+		void highlight(bool highlight, int bin_nr, int binCount);
+	};
+
+	struct SubItem {
+		std::unique_ptr<QGraphicsRectItem> item;
+		std::unique_ptr<BarLabel> label;
+		double value_from;
+		double value_to;
+		int bin_nr;
+		void updatePosition(QtCharts::QChart *chart, BarSeries *series, bool horizontal, bool stacked,
+				    double from, double to, int binCount);
+		void highlight(bool highlight, int binCount);
+	};
+
+	struct Item {
+		double lowerBound, upperBound;
+		std::vector<SubItem> subitems;
+		QRectF rect;
+		const QString binName;
+		StatsOperationResults res;
+		int total;
+		Item(QtCharts::QChart *chart, BarSeries *series, double lowerBound, double upperBound,
+		     std::vector<SubItem> subitems,
+		     const QString &binName, const StatsOperationResults &res, int total, bool horizontal,
+		     bool stacked, int binCount);
+		void updatePosition(QtCharts::QChart *chart, BarSeries *series, bool horizontal, bool stacked, int binCount);
+		void highlight(int subitem, bool highlight, int binCount);
+		int getSubItemUnderMouse(const QPointF &f, bool horizontal, bool stacked) const;
+	};
+
+	std::unique_ptr<InformationBox> information;
+	std::vector<Item> items;
+	std::vector<BarLabel> barLabels;
+	bool horizontal;
+	bool stacked;
+	QString categoryName;
+	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;
+	void add_item(double lowerBound, double upperBound, std::vector<SubItem> subitems,
+		      const QString &binName, const StatsOperationResults &res, int total, bool horizontal,
+		      bool stacked);
+	std::vector<QString> makeInfo(const Item &item, int subitem) const;
+	int binCount() const;
+};
+
+#endif