statistics: highlight selected bar

When all items of a bar in a bar chart are selected, highlight them
by overlaying with a checkerboard pattern. A gray checkerboard seems to
work reasonably well, regardless of base color.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

stats/barseries.cpp

@@ -6,6 +6,7 @@
 #include "statstranslations.h"
 #include "statsview.h"
 #include "zvalues.h"
+#include "core/dive.h"
 #include "core/selection.h"
 
 #include <math.h> // for lrint()
@@ -183,11 +184,14 @@ void BarSeries::Item::highlight(int subitem, bool highlight, int binCount)
 	subitems[subitem].highlight(highlight, binCount);
 }
 
+// For single-bin charts, selected items are marked with a special fill and border color.
+// For multi-bin charts, they are marked by a differend border color and border width.
 void BarSeries::SubItem::highlight(bool highlight, int binCount)
 {
 	fill = highlight ? highlightedColor : binColor(bin_nr, binCount);
 	QColor border = highlight ? highlightedBorderColor : ::borderColor;
 	item->setColor(fill, border);
+	item->setSelected(selected);
 	if (label)
 		label->highlight(highlight, bin_nr, binCount, fill);
 }
@@ -243,9 +247,10 @@ std::vector<BarSeries::SubItem> BarSeries::makeSubItems(std::vector<SubItemDesc>
 	int bin_nr = 0;
 	for (auto &[v, dives, label]: items) {
 		if (v > 0.0) {
+			bool selected = std::all_of(dives.begin(), dives.end(), [] (const dive *d) { return d->selected; });
 			res.push_back({ view.createChartItem<ChartBarItem>(ChartZValue::Series, barBorderWidth, horizontal),
 					std::move(dives),
-					{}, from, from + v, bin_nr });
+					{}, from, from + v, bin_nr, selected });
 			if (!label.empty())
 				res.back().label = std::make_unique<BarLabel>(view, label, bin_nr, binCount());
 		}
@@ -418,3 +423,19 @@ bool BarSeries::selectItemsUnderMouse(const QPointF &pos, bool)
 	setSelection(dives, dives.empty() ? nullptr : dives.front());
 	return true;
 }
+
+void BarSeries::divesSelected(const QVector<dive *> &)
+{
+	for (Item &item: items) {
+		for (SubItem &subitem: item.subitems) {
+			bool selected = std::all_of(subitem.dives.begin(), subitem.dives.end(), [] (const dive *d) { return d->selected; });
+			if (subitem.selected != selected) {
+				subitem.selected = selected;
+
+				Index idx(&item - &items[0], &subitem - &item.subitems[0]);
+				bool highlight = idx == highlighted;
+				item.highlight(idx.subitem, highlight, binCount());
+			}
+		}
+	}
+}

stats/barseries.h

@@ -104,6 +104,7 @@ private:
 		double value_from;
 		double value_to;
 		int bin_nr;
+		bool selected;
 		QColor fill;
 		void updatePosition(BarSeries *series, bool horizontal, bool stacked,
 				    double from, double to, int binCount);
@@ -146,6 +147,7 @@ private:
 		      bool stacked);
 	std::vector<QString> makeInfo(const Item &item, int subitem) const;
 	int binCount() const;
+	void divesSelected(const QVector<dive *> &) override;
 };
 
 #endif

stats/chartitem.cpp

@@ -9,6 +9,7 @@
 #include <QSGImageNode>
 #include <QSGRectangleNode>
 #include <QSGTexture>
+#include <QSGTextureMaterial>
 
 static int round_up(double f)
 {
@@ -140,6 +141,7 @@ static QSGTexture *createScatterTexture(StatsView &view, const QColor &color, co
 static QSGTexture *scatterItemTexture = nullptr;
 static QSGTexture *scatterItemSelectedTexture = nullptr;
 static QSGTexture *scatterItemHighlightedTexture = nullptr;
+static QSGTexture *selectedTexture = nullptr; // A checkerboard pattern.
 
 QSGTexture *ChartScatterItem::getTexture() const
 {
@@ -330,6 +332,12 @@ void setPoint(QSGGeometry::Point2D &v, const QPointF &p)
 	v.set(static_cast<float>(p.x()), static_cast<float>(p.y()));
 }
 
+void setPoint(QSGGeometry::TexturedPoint2D &v, const QPointF &p, const QPointF &t)
+{
+	v.set(static_cast<float>(p.x()), static_cast<float>(p.y()),
+	      static_cast<float>(t.x()), static_cast<float>(t.y()));
+}
+
 void ChartLineItem::render()
 {
 	if (!node) {
@@ -395,8 +403,8 @@ void ChartRectLineItem::render()
 }
 
 ChartBarItem::ChartBarItem(StatsView &v, ChartZValue z, double borderWidth, bool horizontal) : HideableChartItem(v, z),
-	borderWidth(borderWidth), horizontal(horizontal),
+	borderWidth(borderWidth), selected(false), horizontal(horizontal),
-	positionDirty(false), colorDirty(false)
+	positionDirty(false), colorDirty(false), selectedDirty(false)
 {
 }
 
@@ -404,6 +412,18 @@ ChartBarItem::~ChartBarItem()
 {
 }
 
+QSGTexture *ChartBarItem::getSelectedTexture() const
+{
+	if (!selectedTexture) {
+		QImage img(2, 2, QImage::Format_ARGB32);
+		img.fill(Qt::transparent);
+		img.setPixelColor(0, 0, selectionOverlayColor);
+		img.setPixelColor(1, 1, selectionOverlayColor);
+		selectedTexture = view.w()->createTextureFromImage(img, QQuickWindow::TextureHasAlphaChannel);
+	}
+	return selectedTexture;
+}
+
 void ChartBarItem::render()
 {
 	if (!node) {
@@ -419,7 +439,7 @@ void ChartBarItem::render()
 
 		node->node->appendChildNode(borderNode.get());
 		view.addQSGNode(node.get(), zValue);
-		positionDirty = colorDirty = true;
+		positionDirty = colorDirty = selectedDirty = true;
 	}
 	updateVisible();
 
@@ -448,11 +468,48 @@ void ChartBarItem::render()
 		borderNode->markDirty(QSGNode::DirtyGeometry);
 	}
 
-	positionDirty = colorDirty = false;
+	if (selectedDirty) {
+		if (selected) {
+			if (!selectionNode) {
+				// Create the selection overlay if it didn't exist up to now.
+				selectionGeometry.reset(new QSGGeometry(QSGGeometry::defaultAttributes_TexturedPoint2D(), 4));
+				selectionGeometry->setDrawingMode(QSGGeometry::DrawTriangleFan);
+				selectionMaterial.reset(new QSGTextureMaterial);
+				selectionMaterial->setTexture(getSelectedTexture());
+				selectionMaterial->setHorizontalWrapMode(QSGTexture::Repeat);
+				selectionMaterial->setVerticalWrapMode(QSGTexture::Repeat);
+				selectionNode.reset(new QSGGeometryNode);
+				selectionNode->setGeometry(selectionGeometry.get());
+				selectionNode->setMaterial(selectionMaterial.get());
+			}
+
+			node->node->appendChildNode(selectionNode.get());
+
+			// Update the position of the selection overlay, even if the position didn't change.
+			positionDirty = true;
+		} else {
+			if (selectionNode)
+				node->node->removeChildNode(selectionNode.get());
+		}
+	}
+
+	if (selected && positionDirty) {
+		// The checkerboard texture is 2x2. By dividing the coordinates by 4, every square is 2x2 pixels on the screen.
+		auto selectionVertices = selectionGeometry->vertexDataAsTexturedPoint2D();
+		selectionNode->markDirty(QSGNode::DirtyGeometry);
+		setPoint(selectionVertices[0], rect.topLeft(), QPointF());
+		setPoint(selectionVertices[1], rect.topRight(), QPointF(rect.width() / 4.0, 0.0));
+		setPoint(selectionVertices[2], rect.bottomRight(), QPointF(rect.width() / 4.0, rect.height() / 4.0));
+		setPoint(selectionVertices[3], rect.bottomLeft(), QPointF(0.0, rect.height() / 4.0));
+	}
+
+	positionDirty = colorDirty = selectedDirty = false;
 }
 
 void ChartBarItem::setColor(QColor colorIn, QColor borderColorIn)
 {
+	if (color == colorIn)
+		return;
 	color = colorIn;
 	borderColor = borderColorIn;
 	colorDirty = true;
@@ -461,11 +518,22 @@ void ChartBarItem::setColor(QColor colorIn, QColor borderColorIn)
 
 void ChartBarItem::setRect(const QRectF &rectIn)
 {
+	if (rect == rectIn)
+		return;
 	rect = rectIn;
 	positionDirty = true;
 	markDirty();
 }
 
+void ChartBarItem::setSelected(bool selectedIn)
+{
+	if (selected == selectedIn)
+		return;
+	selected = selectedIn;
+	selectedDirty = true;
+	markDirty();
+}
+
 QRectF ChartBarItem::getRect() const
 {
 	return rect;

stats/chartitem.h

@@ -15,6 +15,7 @@ class QSGFlatColorMaterial;
 class QSGImageNode;
 class QSGRectangleNode;
 class QSGTexture;
+class QSGTextureMaterial;
 class StatsView;
 enum class ChartZValue : int;
 
@@ -148,18 +149,27 @@ public:
 	~ChartBarItem();
 	void setColor(QColor color, QColor borderColor);
 	void setRect(const QRectF &rect);
+	void setSelected(bool selected);
 	QRectF getRect() const;
 	void render() override;		// Only call on render thread!
 protected:
 	QColor color, borderColor;
 	double borderWidth;
 	QRectF rect;
+	bool selected;
 	bool horizontal;
 	bool positionDirty;
 	bool colorDirty;
+	bool selectedDirty;
 	std::unique_ptr<QSGGeometryNode> borderNode;
 	std::unique_ptr<QSGFlatColorMaterial> borderMaterial;
 	std::unique_ptr<QSGGeometry> borderGeometry;
+private:
+	// Overlay for selected items. Created on demand.
+	std::unique_ptr<QSGGeometryNode> selectionNode;
+	std::unique_ptr<QSGTextureMaterial> selectionMaterial;
+	std::unique_ptr<QSGGeometry> selectionGeometry;
+	QSGTexture *getSelectedTexture() const;
 };
 
 // A box-and-whiskers item. This is a bit lazy: derive from the bar item and add whiskers.

stats/statscolors.h

@@ -25,6 +25,7 @@ inline const QColor regressionItemColor(Qt::red);
 inline const QColor meanMarkerColor(Qt::green);
 inline const QColor medianMarkerColor(Qt::red);
 inline const QColor selectionLassoColor(Qt::black);
+inline const QColor selectionOverlayColor(Qt::lightGray);
 
 QColor binColor(int bin, int numBins);
 QColor labelColor(int bin, size_t numBins);