statistics: convert box-and-whiskers plot to QSG

This is lazy: Derive from the bar chart item and add whiskers
in the subclassed render() function. The code is ugly, because
the base class function clears the dirty flags and therefore
the derived class has to remember them. Oh well.

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

1 files changed, 74 insertions, 0 deletions

diff --git a/stats/chartitem.cpp b/stats/chartitem.cpp
index ce5e6860c..67cfb4937 100644
--- a/stats/chartitem.cpp
+++ b/stats/chartitem.cpp
@@ -279,3 +279,77 @@ QRectF ChartBarItem::getRect() const
 {
 	return rect;
 }
+
+ChartBoxItem::ChartBoxItem(StatsView &v, ChartZValue z, double borderWidth) :
+	ChartBarItem(v, z, borderWidth, false) // Only support for vertical boxes
+{
+}
+
+ChartBoxItem::~ChartBoxItem()
+{
+}
+
+void ChartBoxItem::render()
+{
+	// Remember old dirty values, since ChartBarItem::render() will clear them
+	bool oldPositionDirty = positionDirty;
+	bool oldColorDirty = colorDirty;
+	ChartBarItem::render();		// This will create the base node, so no need to check for that.
+	if (!whiskersNode) {
+		whiskersGeometry.reset(new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), 10));
+		whiskersGeometry->setDrawingMode(QSGGeometry::DrawLines);
+		whiskersGeometry->setLineWidth(static_cast<float>(borderWidth));
+		whiskersMaterial.reset(new QSGFlatColorMaterial);
+		whiskersNode.reset(new QSGGeometryNode);
+		whiskersNode->setGeometry(whiskersGeometry.get());
+		whiskersNode->setMaterial(whiskersMaterial.get());
+
+		node->node->appendChildNode(whiskersNode.get());
+		// If this is the first time, make sure to update the geometry.
+		oldPositionDirty = oldColorDirty = true;
+	}
+
+	if (oldColorDirty) {
+		whiskersMaterial->setColor(borderColor);
+		whiskersNode->markDirty(QSGNode::DirtyMaterial);
+	}
+
+	if (oldPositionDirty) {
+		auto vertices = whiskersGeometry->vertexDataAsPoint2D();
+		double left = rect.left();
+		double right = rect.right();
+		double mid = (left + right) / 2.0;
+		// top bar
+		setPoint(vertices[0], QPointF(left, max));
+		setPoint(vertices[1], QPointF(right, max));
+		// top whisker
+		setPoint(vertices[2], QPointF(mid, max));
+		setPoint(vertices[3], QPointF(mid, rect.top()));
+		// bottom bar
+		setPoint(vertices[4], QPointF(left, min));
+		setPoint(vertices[5], QPointF(right, min));
+		// bottom whisker
+		setPoint(vertices[6], QPointF(mid, min));
+		setPoint(vertices[7], QPointF(mid, rect.bottom()));
+		// median indicator
+		setPoint(vertices[8], QPointF(left, median));
+		setPoint(vertices[9], QPointF(right, median));
+		whiskersNode->markDirty(QSGNode::DirtyGeometry);
+	}
+}
+
+void ChartBoxItem::setBox(const QRectF &rect, double minIn, double maxIn, double medianIn)
+{
+	min = minIn;
+	max = maxIn;
+	median = medianIn;
+	setRect(rect);
+}
+
+QRectF ChartBoxItem::getRect() const
+{
+	QRectF res = rect;
+	res.setTop(min);
+	res.setBottom(max);
+	return rect;
+}