editor/connection.cpp

#include "connection.h"

#include <QPen>
#include <QPainter>

Connection::Connection(Item* from, Item::AnchorType fromType,
                       Item* to, Item::AnchorType toType, QGraphicsItem* parent)
    : QGraphicsLineItem(parent),
      from_(from), to_(to), fromType_(fromType), toType_(toType)
{
    setZValue(-1); // 在图元之下
    setPen(QPen(Qt::black, 2));
    setFlags(QGraphicsItem::ItemIsSelectable);
    from_->addConnection(this);
    to_->addConnection(this);
    updatePosition();
}

void Connection::updatePosition()
{
    setLine(QLineF(from_->anchorPos(fromType_), to_->anchorPos(toType_)));
}

void Connection::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
{
    QPen pen = this->pen();
    if (isSelected()) {
        pen.setColor(Qt::red); // 选中变红
        pen.setWidth(3);
    }
    painter->setPen(pen);
    painter->drawLine(line());
}