graph.cpp Example File
scenegraph/graph/graph.cpp
#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 nullptr;
}
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);
n->shadow->setGeometry(n->line->geometry());
}
m_geometryChanged = false;
m_samplesChanged = false;
return n;
}