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#include <QtGui/QApplication>
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#include <QtGui>
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#include <QDebug>
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class Slice : public QGraphicsItem
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{
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public:
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Slice(const QColor& color, qreal startAngle, qreal span)
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:m_color(color),
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m_startAngle(startAngle),
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m_span(span)
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{
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setAcceptHoverEvents(true);
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}
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~Slice()
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{
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}
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virtual QRectF boundingRect() const
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{
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return parentItem()->boundingRect();
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}
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QPainterPath shape() const
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{
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qreal angle = (-m_startAngle) + (90);
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qreal span = -m_span;
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QPainterPath path;
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path.moveTo(boundingRect().center());
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path.arcTo(boundingRect(), angle, span);
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// TODO: draw the shape so that it might have a hole in the center
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// - Sin & Cos will be needed to find inner/outer arc endpoints
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// dx, dy are offsets from the center
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//qreal l = boundingRect().height();
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//qreal dx = qSin(angle*(M_PI/180)) * l;
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//qreal dy = qCos(angle*(M_PI/180)) * l;
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// TODO: exploded slice?
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return path;
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}
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virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
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{
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// Setup painter
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painter->setBrush(m_color);
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QPen pen;
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//pen.setColor(m_color.darker());
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pen.setColor(Qt::gray);
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pen.setWidth(1);
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painter->setPen(pen);
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// From Qt docs:
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// The startAngle and spanAngle must be specified in 1/16th of a degree, i.e. a full circle equals 5760 (16 * 360).
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// Positive values for the angles mean counter-clockwise while negative values mean the clockwise direction.
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// Zero degrees is at the 3 o'clock position.
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//
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// For sake of simplicity convert this so that zero degrees is at 12 o'clock and full circle is 360.
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//qreal angle = (-m_startAngle*16) + (90*16);
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//qreal span = -m_span*16;
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//painter->drawPie(boundingRect(), angle, span);
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painter->drawPath(shape());
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}
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virtual void hoverEnterEvent( QGraphicsSceneHoverEvent * event)
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{
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QGraphicsItem::hoverEnterEvent(event);
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qDebug() << "hover" << m_color << m_startAngle << m_span;
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}
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private:
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QColor m_color;
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qreal m_startAngle;
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qreal m_span;
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};
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class PieChart : public QGraphicsItem
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{
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public:
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PieChart()
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{
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qsrand(QTime::currentTime().msec());
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}
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~PieChart()
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{
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}
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QColor randomColor()
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{
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QColor c;
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c.setRed(qrand() % 255);
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c.setGreen(qrand() % 255);
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c.setBlue(qrand() % 255);
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return c;
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}
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void setData(QList<int> data)
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{
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qreal fullPie = 360;
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qreal total = 0;
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foreach (qreal value, data)
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total += value;
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qreal angle = 0;
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foreach (qreal value, data) {
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qreal span = value / total * fullPie;
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Slice *slice = new Slice(randomColor(), angle, span);
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slice->setParentItem(this);
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m_slices.append(slice);
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angle += span;
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}
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}
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virtual QRectF boundingRect() const
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{
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return QRectF(-200, -200, 200, 200);
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}
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virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
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{
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//painter->setBrush(Qt::red);
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//painter->drawRect(boundingRect());
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}
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private:
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QList<Slice*> m_slices;
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QSizeF m_size;
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};
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int main(int argc, char *argv[])
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{
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QApplication a(argc, argv);
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QGraphicsScene scene;
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PieChart *pieChart = new PieChart();
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scene.addItem(pieChart);
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QGraphicsView view(&scene);
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view.setRenderHint(QPainter::Antialiasing);
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view.resize(400, 300);
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view.show();
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QList<int> data;
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data << 1;
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data << 2;
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data << 3;
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data << 20;
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data << 2;
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data << 3;
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data << 10;
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data << 2;
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data << 1;
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data << 5;
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pieChart->setData(data);
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return a.exec();
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}
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