statistics: convert HistogramMarkers to QSGNodes

This is in analogy to the quartile markers.

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

Subsurface-mobile.pro

@@ -133,6 +133,7 @@ SOURCES += subsurface-mobile-main.cpp \
 	stats/boxseries.cpp \
 	stats/chartitem.cpp \
 	stats/chartlistmodel.cpp \
+	stats/histogrammarker.cpp \
 	stats/informationbox.cpp \
 	stats/legend.cpp \
 	stats/pieseries.cpp \
@@ -283,6 +284,7 @@ HEADERS += \
 	stats/boxseries.h \
 	stats/chartitem.h \
 	stats/chartlistmodel.h \
+	stats/histogrammarker.h \
 	stats/informationbox.h \
 	stats/legend.h \
 	stats/pieseries.h \

stats/CMakeLists.txt

@@ -13,6 +13,9 @@ set(SUBSURFACE_STATS_SRCS
 	chartitem.cpp
 	chartlistmodel.h
 	chartlistmodel.cpp
+	histogrammarker.h
+	histogrammarker.cpp
+	chartlistmodel.cpp
 	informationbox.h
 	informationbox.cpp
 	legend.h

stats/histogrammarker.cpp

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "histogrammarker.h"
+#include "statsaxis.h"
+#include "zvalues.h"
+
+static const double histogramMarkerWidth = 2.0;
+
+HistogramMarker::HistogramMarker(StatsView &view, double val, bool horizontal,
+				 QColor color, StatsAxis *xAxis, StatsAxis *yAxis) :
+	ChartLineItem(view, ChartZValue::ChartFeatures, color, histogramMarkerWidth),
+	xAxis(xAxis), yAxis(yAxis),
+	val(val), horizontal(horizontal)
+{
+}
+
+void HistogramMarker::updatePosition()
+{
+	if (!xAxis || !yAxis)
+		return;
+	if (horizontal) {
+		double y = yAxis->toScreen(val);
+		auto [x1, x2] = xAxis->minMaxScreen();
+		setLine(QPointF(x1, y), QPointF(x2, y));
+	} else {
+		double x = xAxis->toScreen(val);
+		auto [y1, y2] = yAxis->minMaxScreen();
+		setLine(QPointF(x, y1), QPointF(x, y2));
+	}
+}

stats/histogrammarker.h

@@ -0,0 +1,21 @@
+// A line to show median an mean in histograms
+#ifndef HISTOGRAM_MARKER_H
+#define HISTOGRAM_MARKER_H
+
+#include "chartitem.h"
+
+class StatsAxis;
+class StatsView;
+
+// A line marking median or mean in histograms
+class HistogramMarker : public ChartLineItem {
+public:
+	HistogramMarker(StatsView &view, double val, bool horizontal, QColor color, StatsAxis *xAxis, StatsAxis *yAxis);
+	void updatePosition();
+private:
+	StatsAxis *xAxis, *yAxis;
+	double val;
+	bool horizontal;
+};
+
+#endif

stats/statsview.cpp

@@ -2,6 +2,7 @@
 #include "statsview.h"
 #include "barseries.h"
 #include "boxseries.h"
+#include "histogrammarker.h"
 #include "legend.h"
 #include "pieseries.h"
 #include "quartilemarker.h"
@@ -214,8 +215,8 @@ void StatsView::plotAreaChanged(const QSizeF &s)
 		marker->updatePosition();
 	for (RegressionLine &line: regressionLines)
 		line.updatePosition();
-	for (HistogramMarker &marker: histogramMarkers)
+	for (auto &marker: histogramMarkers)
-		marker.updatePosition();
+		marker->updatePosition();
 	if (legend)
 		legend->resize();
 	updateTitlePos();
@@ -849,33 +850,9 @@ void StatsView::RegressionLine::updatePosition()
 	central->setPolygon(line.intersected(box));
 }
 
-StatsView::HistogramMarker::HistogramMarker(double val, bool horizontal, QPen pen, QGraphicsScene *scene, StatsAxis *xAxis, StatsAxis *yAxis) :
+void StatsView::addHistogramMarker(double pos, QColor color, bool isHorizontal, StatsAxis *xAxis, StatsAxis *yAxis)
-	item(createItemPtr<QGraphicsLineItem>(scene)),
-	xAxis(xAxis), yAxis(yAxis),
-	val(val), horizontal(horizontal)
 {
-	item->setZValue(ZValues::chartFeatures);
+	histogramMarkers.push_back(createChartItem<HistogramMarker>(pos, isHorizontal, color, xAxis, yAxis));
-	item->setPen(pen);
-}
-
-void StatsView::HistogramMarker::updatePosition()
-{
-	if (!xAxis || !yAxis)
-		return;
-	if (horizontal) {
-		double y = yAxis->toScreen(val);
-		auto [x1, x2] = xAxis->minMaxScreen();
-		item->setLine(x1, y, x2, y);
-	} else {
-		double x = xAxis->toScreen(val);
-		auto [y1, y2] = yAxis->minMaxScreen();
-		item->setLine(x, y1, x, y2);
-	}
-}
-
-void StatsView::addHistogramMarker(double pos, const QPen &pen, bool isHorizontal, StatsAxis *xAxis, StatsAxis *yAxis)
-{
-	histogramMarkers.emplace_back(pos, isHorizontal, pen, &scene, xAxis, yAxis);
 }
 
 void StatsView::addLinearRegression(const struct regression_data reg, StatsAxis *xAxis, StatsAxis *yAxis)
@@ -959,17 +936,13 @@ void StatsView::plotHistogramCountChart(const std::vector<dive *> &dives,
 	if (categoryVariable->type() == StatsVariable::Type::Numeric) {
 		if (showMean) {
 			double mean = categoryVariable->mean(dives);
-			QPen meanPen(Qt::green);
-			meanPen.setWidth(2);
 			if (!std::isnan(mean))
-				addHistogramMarker(mean, meanPen, isHorizontal, xAxis, yAxis);
+				addHistogramMarker(mean, Qt::green, isHorizontal, xAxis, yAxis);
 		}
 		if (showMedian) {
 			double median = categoryVariable->quartiles(dives).q2;
-			QPen medianPen(Qt::red);
-			medianPen.setWidth(2);
 			if (!std::isnan(median))
-				addHistogramMarker(median, medianPen, isHorizontal, xAxis, yAxis);
+				addHistogramMarker(median, Qt::red, isHorizontal, xAxis, yAxis);
 		}
 	}
 }

stats/statsview.h

@@ -24,6 +24,7 @@ class CategoryAxis;
 class ChartItem;
 class CountAxis;
 class HistogramAxis;
+class HistogramMarker;
 class QuartileMarker;
 class StatsAxis;
 class StatsGrid;
@@ -136,18 +137,8 @@ private:
 		RegressionLine(const struct regression_data reg, QBrush brush, QGraphicsScene *scene, StatsAxis *xAxis, StatsAxis *yAxis);
 	};
 
-	// A line marking median or mean in histograms
-	struct HistogramMarker {
-		std::unique_ptr<QGraphicsLineItem> item;
-		StatsAxis *xAxis, *yAxis;
-		double val;
-		bool horizontal;
-		void updatePosition();
-		HistogramMarker(double val, bool horizontal, QPen pen, QGraphicsScene *scene, StatsAxis *xAxis, StatsAxis *yAxis);
-	};
-
 	void addLinearRegression(const struct regression_data reg, StatsAxis *xAxis, StatsAxis *yAxis);
-	void addHistogramMarker(double pos, const QPen &pen, bool isHorizontal, StatsAxis *xAxis, StatsAxis *yAxis);
+	void addHistogramMarker(double pos, QColor color, bool isHorizontal, StatsAxis *xAxis, StatsAxis *yAxis);
 
 	StatsState state;
 	QFont titleFont;
@@ -157,7 +148,7 @@ private:
 	std::unique_ptr<Legend> legend;
 	std::vector<std::unique_ptr<QuartileMarker>> quartileMarkers;
 	std::vector<RegressionLine> regressionLines;
-	std::vector<HistogramMarker> histogramMarkers;
+	std::vector<std::unique_ptr<HistogramMarker>> histogramMarkers;
 	std::unique_ptr<QGraphicsSimpleTextItem> title;
 	StatsSeries *highlightedSeries;
 	StatsAxis *xAxis, *yAxis;