graph.cpp Example File

scenegraph/graph/graph.cpp
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#include "graph.h" #include "noisynode.h" #include "gridnode.h" #include "linenode.h" Graph::Graph() : m_samplesChanged(false) , m_geometryChanged(false) { setFlag(ItemHasContents, true); } void Graph::appendSample(qreal value) { m_samples << value; m_samplesChanged = true; update(); } void Graph::removeFirstSample() { m_samples.removeFirst(); m_samplesChanged = true; update(); } void Graph::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry) { m_geometryChanged = true; update(); QQuickItem::geometryChanged(newGeometry, oldGeometry); } class GraphNode : public QSGNode { public: NoisyNode *background; GridNode *grid; LineNode *line; LineNode *shadow; }; QSGNode *Graph::updatePaintNode(QSGNode *oldNode, UpdatePaintNodeData *) { GraphNode *n= static_cast<GraphNode *>(oldNode); QRectF rect = boundingRect(); if (rect.isEmpty()) { delete n; return 0; } if (!n) { n = new GraphNode(); n->background = new NoisyNode(window()); n->grid = new GridNode(); n->line = new LineNode(10, 0.5, QColor("steelblue")); n->shadow = new LineNode(20, 0.2f, QColor::fromRgbF(0.2, 0.2, 0.2, 0.4)); n->appendChildNode(n->background); n->appendChildNode(n->grid); n->appendChildNode(n->shadow); n->appendChildNode(n->line); } if (m_geometryChanged) { n->background->setRect(rect); n->grid->setRect(rect); } if (m_geometryChanged || m_samplesChanged) { n->line->updateGeometry(rect, m_samples); // We don't need to calculate the geometry twice, so just steal it from the other one... n->shadow->setGeometry(n->line->geometry()); } m_geometryChanged = false; m_samplesChanged = false; return n; }