void MyQGraphicsView::deleteItem(QGraphicsItem *item)
{
....
removeItem(item);
delete item;
....
}
class Point : public QGraphicsItem
{
public:
Point(const QPointF & p = QPointF(0,0), int pos = 0);
void setIn(Line *e) { in = e; }
void setOut(Line *e) { out = e; }
QVariant itemChange(GraphicsItemChange change, const QVariant &value);
QRectF boundingRect() const;
void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
QWidget *widget);
private:
Line * in, * out;
int Position;
};
Point::Point(const QPointF & p, int pos) :
in(nullptr),out(nullptr)
{
setFlags(ItemIsMovable | ItemIsSelectable | ItemIgnoresTransformations | ItemSendsGeometryChanges);
setCursor(Qt::PointingHandCursor);
setZValue(pos);
setPos(p);
Position = pos;
}
QVariant Point::itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant &value)
{
if(change == ItemPositionHasChanged && scene()) {
if(in)
in->adjust();
if(out)
out->adjust();
}
return QGraphicsItem::itemChange(change, value);
}
QRectF WayPoint::boundingRect() const
{
return QRectF( -5, -5 ,10 ,10);
}
void WayPoint::paint(QPainter *painter, const QStyleOptionGraphicsItem */*option*/, QWidget */*widget*/)
{
painter->drawEllipse(QRectF(-5, -5, 10,10));
}class Line : public QGraphicsItem
{
public:
Line(Point *, Point *);
void setStart(Point *);
void setFinish(Point *);
void adjust();
QRectF boundingRect() const;
void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
QWidget *widget);
private:
Point *start, *finish;
};
Line::Line(Point *s, Point *f) :
start(s), finish(f)
{
s->setOut(this);
f->setIn(this);
setZValue(-2);
adjust();
}
void Line::setStart(Point * start_)
{
start = start_;
start->setOut(this);
adjust();
}
void Line::setFinish(Point * finish_)
{
finish = finish_;
finish->setIn(this);
adjust();
}
QRectF Line::boundingRect() const
{
return QRectF(start->pos(), finish->pos()).normalized().adjusted(-2,-2,2,2);
}
void Line::adjust()
{
prepareGeometryChange();
}
void Line::paint(QPainter *painter, const QStyleOptionGraphicsItem */*option*/, QWidget */*widget*/)
{
qreal q = scene()->views().at(0)->transform().m11();
QPen pen(QColor(0, 145, 255), 5 * (1. / q));
painter->setRenderHint(QPainter::Antialiasing);
painter->setPen(pen);
painter->drawLine(start->pos(), finish->pos());
}class MyGraphicsView : public QGraphicsView
{
Q_OBJECT
public:
MyGraphicsView(QWidget * parent = 0);
~MyGraphicsView();
public slots:
void addPoint();
void removePoint();
private:
typedef QVector<Point *> p_vector;
typedef QVector<Line *> line_vector;
p_vector ps;
line_vector lines;
};
void MyGraphicsView::addPoint(const QPointF & local)
{
Point * p = new Point(local, ps.size() + 1);
if(!ps.empty())
{
line * e = new Line(ps.back(), p);
lines.push_back(e);
scene()->addItem(e);
}
ps.push_back(p);
scene()->addItem(p);
}
void MyGraphicsView::removePoint(int i)
{
if(i <= 1)
{
auto it_p = ps.begin();
scene()->removeItem(*it_p);
delete *it_p;
ps.erase(it_p);
if(!lines.empty())
{
auto it_l = lines.begin();
scene()->removeItem(*it_l);
delete *it_l;
lines.erase(it_l);
(*(ps.begin()))->setIn(nullptr);
}
} else {
if(i > 1 && i < wps.size())
{
auto it_p = ps.begin() + i - 1;
auto it_l = lines.begin() + i - 2;
scene()->removeItem(*it_p);
scene()->removeItem(*it_l);
scene()->removeItem(*(it_l + 1));
delete *it_p;
delete *it_l;
delete *(it_l + 1);
Line * e = new Line(*(it_p - 1),*(it_p + 1));
(*it_l) = e;
scene()->addItem(e);
ps.erase(it_p);
lines.erase(it_l + 1);
} else {
if(i >= ps.size())
{
auto it_p = ps.begin() + ps.size() - 1;
scene()->removeItem(*it_p);
delete *it_p;
ps.erase(it_p);
if(!lines.empty())
{
auto it_l = lines.begin() + lines.size() - 1;
scene()->removeItem(*it_l);
delete *it_l;
lines.erase(it_l);
(*(ps.end() - 1))->setOut(nullptr);
}
}
}
}
}delete *it_p;
ps.erase(it_p);delete *it_p;
ps.erase(it_p);void QGraphicsView::removePoint(int i)
{
if(i <= 1)
{
auto it_p = ps.begin();
if(!lines.empty())
{
auto it_l = lines.begin();
(*it_p)->setOut(nullptr);
(*(it_p + 1))->setIn(nullptr);
scene()->removeItem(*it_l);
delete *it_l;
lines.erase(it_l);
}
scene()->removeItem(*it_p);
delete *it_p;
ps.erase(it_p);
} else {
if(i > 1 && i < ps.size())
{
auto it_p = ps.begin() + i - 1;
auto it_l = lines.begin() + i - 2;
(*it_p)->setOut(nullptr);
(*(it_p+1))->setIn(nullptr);
scene()->removeItem(*(it_l + 1));
delete *(it_l + 1);
(*it_p)->setIn(nullptr);
(*it_l)->setFinish(*(it_p + 1));
scene()->removeItem(*it_p);
delete *it_p;
ps.erase(it_p);
lines.erase(it_l + 1);
} else {
if(i >= ps.size())
{
auto it_p = ps.begin() + ps.size() - 1;
if(!lines.empty())
{
auto it_l = lines.begin() + lines.size() - 1;
(*(it_p-1))->setOut(nullptr);
(*it_p)->setIn(nullptr);
scene()->removeItem(*it_l);
delete *it_l;
lines.erase(it_l);
}
scene()->removeItem(*it_p);
delete *it_p;
ps.erase(it_p);
}
}
}
}class Line : public QGraphicsItem
{
public:
Line(Point *, Point *);
void setStart(Point *);
void setFinish(Point *);
void adjust();
QRectF boundingRect() const;
void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
QWidget *widget);
private:
Point *start, *finish;
QPointF startPoint, finishPoint; // именно по ним будет идти отрисовка
};
.....
QRectF Line::boundingRect() const
{
return QRectF(startPoint, finishPoint).normalized().adjusted(-2,-2,2,2);
}
void Line::adjust() // корень зла
{
prepareGeometryChange(); //эта функция должна вызываться строго до изменения геометрии ограничивающей области
startPoint = start->pos();
finishPoint = finish->pos();
}
void Line::paint(QPainter *painter, const QStyleOptionGraphicsItem */*option*/, QWidget */*widget*/)
{
qreal q = scene()->views().at(0)->transform().m11();
QPen pen(QColor(0, 145, 255), 5 * (1. / q));
painter->setRenderHint(QPainter::Antialiasing);
painter->setPen(pen);
painter->drawLine(startPoint, finishPoint);
}