关于QGraphicsObject类的一个诡异问题

2015-07-02 08:33:30 287 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

图数据挖掘 ECC K-core core number truss number clique K-core:什么叫k-core，给定一个正整数k（k>=0），k-core是一个G的最大子图（也就是说k-core是一个图的限制），将这个子图定义为Hk，对于Hk中的每个顶点v，他的度数都是大于等于k的。 k-core是内嵌的，如下图所示，集合{ABCD}是H3，也就是3-core的子图。而集合{ABCDE}是H2，也就是2-core的子图，集合{ABCDEGF}是H1，也就是1-core的子图，而从集合的角度来讲H3<H2<H1。 core number:什么叫kcor 阅读详情

我自写了一个类ClockHand,父类是QGraphicsObject。
paint（）函数里画了两个矩形，但是它们的形状却出乎意料，请大神指教！
clockhand.h

#ifndef CLOCKHAND_H

#define CLOCKHAND_H



#include <QGraphicsObject>



class ClockHand : public QGraphicsObject

{

public:

    explicit ClockHand();

public:

    QRectF boundingRect() const;

    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);

protected:

    void dragEnterEvent(QGraphicsSceneDragDropEvent *event);

    void dragLeaveEvent(QGraphicsSceneDragDropEvent *event);

    void dropEvent(QGraphicsSceneDragDropEvent *event);

private:

    QColor color;

    bool dropOver;

    //QPoint *shape;

};



#endif // CLOCKHAND_H

clockhand.cpp

#include "clockhand.h"

#include <QtGui>





ClockHand::ClockHand() : color(Qt::white),dropOver(false)

{

    setAcceptDrops(true);

}



QRectF ClockHand::boundingRect() const

{

    return QRectF(-21,-66,21,6);

}



void ClockHand::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)

{

    Q_UNUSED(option);

    Q_UNUSED(widget);

    painter->setRenderHint(QPainter::Antialiasing);

    painter->setBrush(dropOver ? color.light(140) : color);

    painter->drawRect(-9,-9,25,25);

    painter->drawRect(-20,-65,20,5);

}



void ClockHand::dragEnterEvent(QGraphicsSceneDragDropEvent *event)

{

    if(event->mimeData()->hasColor())

    {

        event->setAccepted(true);

        dropOver = true;

        update();

    }

    else

    {

        event->setAccepted(false);

    }

}



void ClockHand::dragLeaveEvent(QGraphicsSceneDragDropEvent *event)

{

    Q_UNUSED(event);

    dropOver = false;

    update();

}



void ClockHand::dropEvent(QGraphicsSceneDragDropEvent *event)

{

    dropOver = false;

    if(event->mimeData()->hasColor())

        color = qvariant_cast<QColor>(event->mimeData()->colorData());



    update();

}

main.cpp

#include "coloritem.h"

#include <QApplication>

#include "coloritem.h"

#include "clock.h"

#include <QtGui>

#include "clockhand.h"



int main(int argc, char *argv[])

{

    QApplication a(argc, argv);

    qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));



    QGraphicsScene *scene  = new QGraphicsScene(-500,-500,1000,1000);

//    ColorItem *c1=new ColorItem;

//    ColorItem *c2=new ColorItem;

//    c1->setPos(60,40);

//    c2->setPos(80,40);

//    Clock *clock = new Clock;

//    clock->setPos(200,200);

//    QPoint secPolygon[4] = {QPoint(0,5),QPoint(-20,-15),QPoint(0,-65),QPoint(20,-15)};

    ClockHand *secHand = new ClockHand();

    secHand->setPos(-100,0);

//    scene->addItem(c1);

//    scene->addItem(c2);

//    scene->addItem(clock);

    scene->addItem(secHand);



    QGraphicsView view(scene);

    view.setViewportUpdateMode(QGraphicsView::BoundingRectViewportUpdate);

    view.show();



    return a.exec();

}