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#include "diagramitem.h"
#include "arrow.h"

#include <QGraphicsScene>
#include <QGraphicsSceneContextMenuEvent>
#include <QMenu>
#include <QPainter>

//! [0]
DiagramItem::DiagramItem(DiagramType diagramType, QMenu *contextMenu,
                         QGraphicsItem *parent)
    : QGraphicsPolygonItem(parent), myDiagramType(diagramType)
    , myContextMenu(contextMenu) //设置右键Item的上下文菜单
{
    /*
     * 根据Type 为当前Item设置不同的形状,并且设置基本Flags
     * 但是没有绘制，只是保存在了类中： setPolygon
     */
    QPainterPath path;
    switch (myDiagramType) {
    case StartEnd:
        //绘制圆角矩形
        path.moveTo(200, 50);
        path.arcTo(150, 0, 50, 50, 0, 90);
        path.arcTo(50, 0, 50, 50, 90, 90);
        path.arcTo(50, 50, 50, 50, 180, 90);
        path.arcTo(150, 50, 50, 50, 270, 90);
        path.lineTo(200, 25);
        myPolygon = path.toFillPolygon();
        break;
    case Conditional:
        //绘制倾斜的正方形
        myPolygon << QPointF(-100, 0) << QPointF(0, 100)
                  << QPointF(100, 0) << QPointF(0, -100)
                  << QPointF(-100, 0);
        break;
    case Step:
        //绘制正方形
        myPolygon << QPointF(-100, -100) << QPointF(100, -100)
                  << QPointF(100, 100) << QPointF(-100, 100)
                  << QPointF(-100, -100);
        break;
    case Io:
        //绘制平行四边形
        myPolygon << QPointF(-120, -80) << QPointF(-70, 80)
                  << QPointF(120, 80) << QPointF(70, -80)
                  << QPointF(-120, -80);
        break;
    default: break;
    }
    //设置当前DiagramItem为此形状
    setPolygon(myPolygon);
    //QGraphcisItem::Itemxxx设置可以移动，选中,发送形状改变信号
    setFlag(QGraphicsItem::ItemIsMovable, true);
    setFlag(QGraphicsItem::ItemIsSelectable, true);
    setFlag(QGraphicsItem::ItemSendsGeometryChanges, true);
}
//! [0]

//! [1]
void DiagramItem::removeArrow(Arrow *arrow)
{
    arrows.removeAll(arrow);
}
//! [1]

//! [2]
void DiagramItem::removeArrows()
{
    // need a copy here since removeArrow() will
    // modify the arrows container
    // 删除此Item所有的箭头
    const auto arrowsCopy = arrows;
    for (Arrow *arrow : arrowsCopy) {
        arrow->startItem()->removeArrow(arrow);
        arrow->endItem()->removeArrow(arrow);
        scene()->removeItem(arrow);
        delete arrow;
    }
}
//! [2]

//! [3]
void DiagramItem::addArrow(Arrow *arrow)
{
    arrows.append(arrow);
}
//! [3]

//! [4]
QPixmap DiagramItem::image() const
{
    QPixmap pixmap(250, 250);
    pixmap.fill(Qt::transparent); //透明
    QPainter painter(&pixmap);    //画家
    painter.setPen(QPen(Qt::black, 8));
    painter.translate(125, 125);
    //！！！！！！绘制填充图形！！！！！！！！！！
    painter.drawPolyline(myPolygon);

    return pixmap;
}
//! [4]

//! [5]
void DiagramItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
{
    scene()->clearSelection();
    setSelected(true);
    //对Item右键弹出上下文菜单
    myContextMenu->exec(event->screenPos());
}
//! [5]

//! [6]
QVariant DiagramItem::itemChange(GraphicsItemChange change, const QVariant &value)
{
    //Item的位置改变，当设置 ItemSendsGeometryChanges 时才有效
    if (change == QGraphicsItem::ItemPositionChange) {
        //对于此Item拥有的所有箭头更新位置
        for (Arrow *arrow : qAsConst(arrows))
            arrow->updatePosition();
    }

    return value;
}
//! [6]
