c
cordsacNov. 9, 2017, 7:04 a.m.

How can I implement this project for design Oval shape

qt, c++, oval

I am trying to implement an oval shape like this project .so I inherited Oval Graphics Item from QGraphicsEllipseItem and QObject, and implement logic,same as logic for Rectangle.here is my oval.cpp code,But my project is not working properly.can you explain how can I solve this and,what I need to do.what I did wrong.here with I attached I tested code.please help me sir..

#include "oval.h"
#include <QPainter>
#include <QDebug>
#include <QCursor>
#include <QGraphicsScene>
#include <QGraphicsSceneMouseEvent>
#include <QGraphicsEllipseItem>
#include <math.h>
#include <dotsignal.h>


static const double Pi = 3.14159265358979323846264338327950288419717;
static double TwoPi = 2.0 * Pi;

static qreal normalizeAngle(qreal angle)
{
    while (angle < 0)
        angle += TwoPi;
    while (angle > TwoPi)
        angle -= TwoPi;
    return angle;
}

oval::oval(QObject *parent) :
    QObject(parent),
    m_cornerFlags(0),
    m_actionFlags(ResizeState)
{
    setAcceptHoverEvents(true);
    setFlags(ItemIsSelectable|ItemSendsGeometryChanges);
    for(int i = 0; i < 8; i++){
        cornerGrabber[i] = new DotSignal(this);
    }
    setPositionGrabbers();
}

oval::~oval()
{
    for(int i = 0; i < 8; i++){
        delete cornerGrabber[i];
    }
}

QPointF oval::previousPosition() const
{
    return m_previousPosition;
}

void oval::setPreviousPosition(const QPointF previousPosition)
{
    if (m_previousPosition == previousPosition)
        return;

    m_previousPosition = previousPosition;
    emit previousPositionChanged();
}

void oval::setRect(qreal x, qreal y, qreal w, qreal h)
{
    setRect(QRectF(x,y,w,h));
}

void oval::setRect(const QRectF &rect)
{
    QGraphicsEllipseItem::setRect(rect);
    if(brush().gradient() != 0){
        const QGradient * grad = brush().gradient();
        if(grad->type() == QGradient::LinearGradient){
            auto tmpRect = this->rect();
            const QLinearGradient *lGradient = static_cast<const QLinearGradient *>(grad);
            QLinearGradient g = *const_cast<QLinearGradient*>(lGradient);
            g.setStart(tmpRect.left() + tmpRect.width()/2,tmpRect.top());
            g.setFinalStop(tmpRect.left() + tmpRect.width()/2,tmpRect.bottom());
            setBrush(g);
        }
    }
}

void oval::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    QPointF pt = event->pos();
    if(m_actionFlags == ResizeState){
        switch (m_cornerFlags) {
        case Top:
            resizeTop(pt);
            break;
        case Bottom:
            resizeBottom(pt);
            break;
        case Left:
            resizeLeft(pt);
            break;
        case Right:
            resizeRight(pt);
            break;
        case TopLeft:
            resizeTop(pt);
            resizeLeft(pt);
            break;
        case TopRight:
            resizeTop(pt);
            resizeRight(pt);
            break;
        case BottomLeft:
            resizeBottom(pt);
            resizeLeft(pt);
            break;
        case BottomRight:
            resizeBottom(pt);
            resizeRight(pt);
            break;
        default:
            if (m_leftMouseButtonPressed) {
                setCursor(Qt::ClosedHandCursor);
                auto dx = event->scenePos().x() - m_previousPosition.x();
                auto dy = event->scenePos().y() - m_previousPosition.y();
                moveBy(dx,dy);
                setPreviousPosition(event->scenePos());
                emit signalMove(this, dx, dy);
            }
            break;
        }
    } else {
        switch (m_cornerFlags) {
        case TopLeft:
        case TopRight:
        case BottomLeft:
        case BottomRight: {
            rotateItem(pt);
            break;
        }
        default:
            if (m_leftMouseButtonPressed) {
                setCursor(Qt::ClosedHandCursor);
                auto dx = event->scenePos().x() - m_previousPosition.x();
                auto dy = event->scenePos().y() - m_previousPosition.y();
                moveBy(dx,dy);
                setPreviousPosition(event->scenePos());
                emit signalMove(this, dx, dy);
            }
            break;
        }
    }
    QGraphicsItem::mouseMoveEvent(event);
}

void oval::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    if (event->button() & Qt::LeftButton) {
        m_leftMouseButtonPressed = true;
        setPreviousPosition(event->scenePos());
        emit clicked(this);
    }
    QGraphicsItem::mousePressEvent(event);
}

void oval::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
    if (event->button() & Qt::LeftButton) {
        m_leftMouseButtonPressed = false;
    }
    QGraphicsItem::mouseReleaseEvent(event);
}

void oval::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
{
    m_actionFlags = (m_actionFlags == ResizeState)?RotationState:ResizeState;
    setVisibilityGrabbers();
    QGraphicsItem::mouseDoubleClickEvent(event);
}

void oval::hoverEnterEvent(QGraphicsSceneHoverEvent *event)
{
    setPositionGrabbers();
    setVisibilityGrabbers();
    QGraphicsItem::hoverEnterEvent(event);
}

void oval::hoverLeaveEvent(QGraphicsSceneHoverEvent *event)
{
    m_cornerFlags = 0;
    hideGrabbers();
    setCursor(Qt::CrossCursor);
    QGraphicsItem::hoverLeaveEvent( event );
}

void oval::hoverMoveEvent(QGraphicsSceneHoverEvent *event)
{
    QPointF pt = event->pos();              // The current position of the mouse
    qreal drx = pt.x() - rect().right();    // Distance between the mouse and the right
    qreal dlx = pt.x() - rect().left();     // Distance between the mouse and the left

    qreal dby = pt.y() - rect().top();      // Distance between the mouse and the top
    qreal dty = pt.y() - rect().bottom();   // Distance between the mouse and the bottom

    // If the mouse position is within a radius of 7
    // to a certain side( top, left, bottom or right)
    // we set the Flag in the Corner Flags Register

    m_cornerFlags = 0;
    if( dby < 7 && dby > -7 ) m_cornerFlags |= Top;       // Top side
    if( dty < 7 && dty > -7 ) m_cornerFlags |= Bottom;    // Bottom side
    if( drx < 7 && drx > -7 ) m_cornerFlags |= Right;     // Right side
    if( dlx < 7 && dlx > -7 ) m_cornerFlags |= Left;      // Left side

    if(m_actionFlags == ResizeState){
        QPixmap p(":/icons/arrow-up-down.png");
        QPixmap pResult;
        QTransform trans = transform();
        switch (m_cornerFlags) {
        case Top:
        case Bottom:
            pResult = p.transformed(trans);
            setCursor(pResult.scaled(24,24,Qt::KeepAspectRatio));
            break;
        case Left:
        case Right:
            trans.rotate(90);
            pResult = p.transformed(trans);
            setCursor(pResult.scaled(24,24,Qt::KeepAspectRatio));
            break;
        case TopRight:
        case BottomLeft:
            trans.rotate(45);
            pResult = p.transformed(trans);
            setCursor(pResult.scaled(24,24,Qt::KeepAspectRatio));
            break;
        case TopLeft:
        case BottomRight:
            trans.rotate(135);
            pResult = p.transformed(trans);
            setCursor(pResult.scaled(24,24,Qt::KeepAspectRatio));
            break;
        default:
            setCursor(Qt::CrossCursor);
            break;
        }
    } else {
        switch (m_cornerFlags) {
        case TopLeft:
        case TopRight:
        case BottomLeft:
        case BottomRight: {
            QPixmap p(":/icons/rotate-right.png");
            setCursor(QCursor(p.scaled(24,24,Qt::KeepAspectRatio)));
            break;
        }
        default:
            setCursor(Qt::CrossCursor);
            break;
        }
    }
    QGraphicsItem::hoverMoveEvent( event );
}

QVariant oval::itemChange(QGraphicsItem::GraphicsItemChange change, const QVariant &value)
{
    switch (change) {
    case QGraphicsItem::ItemSelectedChange:
        m_actionFlags = ResizeState;
        break;
    default:
        break;
    }
    return QGraphicsItem::itemChange(change, value);
}


void oval::resizeLeft(const QPointF &pt)
{
    QRectF tmpRect = rect();
    // if the mouse is on the right side we return
    if( pt.x() > tmpRect.right() )
        return;
    qreal widthOffset =  ( pt.x() - tmpRect.right() );
    // limit the minimum width
    if( widthOffset > -10 )
        return;
    // if it's negative we set it to a positive width value
    if( widthOffset < 0 )
        tmpRect.setWidth( -widthOffset );
    else
        tmpRect.setWidth( widthOffset );
    // Since it's a left side , the rectange will increase in size
    // but keeps the topLeft as it was
    tmpRect.translate( rect().width() - tmpRect.width() , 0 );
    prepareGeometryChange();
    // Set the ne geometry
    setRect( tmpRect );
    // Update to see the result
    update();
    setPositionGrabbers();
}

void oval::resizeRight(const QPointF &pt)
{
    QRectF tmpRect = rect();
    if( pt.x() < tmpRect.left() )
        return;
    qreal widthOffset =  ( pt.x() - tmpRect.left() );
    if( widthOffset < 10 ) /// limit
        return;
    if( widthOffset < 10)
        tmpRect.setWidth( -widthOffset );
    else
        tmpRect.setWidth( widthOffset );
    prepareGeometryChange();
    setRect( tmpRect );
    update();
    setPositionGrabbers();
}

void oval::resizeBottom(const QPointF &pt)
{
    QRectF tmpRect = rect();
    if( pt.y() < tmpRect.top() )
        return;
    qreal heightOffset =  ( pt.y() - tmpRect.top() );
    if( heightOffset < 11 ) /// limit
        return;
    if( heightOffset < 0)
        tmpRect.setHeight( -heightOffset );
    else
        tmpRect.setHeight( heightOffset );
    prepareGeometryChange();
    setRect( tmpRect );
    update();
    setPositionGrabbers();
}

void oval::resizeTop(const QPointF &pt)
{
    QRectF tmpRect = rect();
    if( pt.y() > tmpRect.bottom() )
        return;
    qreal heightOffset =  ( pt.y() - tmpRect.bottom() );
    if( heightOffset > -11 ) /// limit
        return;
    if( heightOffset < 0)
        tmpRect.setHeight( -heightOffset );
    else
        tmpRect.setHeight( heightOffset );
    tmpRect.translate( 0 , rect().height() - tmpRect.height() );
    prepareGeometryChange();
    setRect( tmpRect );
    update();
    setPositionGrabbers();
}

void oval::rotateItem(const QPointF &pt)
{
    QRectF tmpRect = rect();
    QPointF center = boundingRect().center();
    QPointF corner;
    switch (m_cornerFlags) {
    case TopLeft:
        corner = tmpRect.topLeft();
        break;
    case TopRight:
        corner = tmpRect.topRight();
        break;
    case BottomLeft:
        corner = tmpRect.bottomLeft();
        break;
    case BottomRight:
        corner = tmpRect.bottomRight();
        break;
    default:
        break;
    }

    QLineF lineToTarget(center,corner);
    QLineF lineToCursor(center, pt);
    // Angle to Cursor and Corner Target points
    qreal angleToTarget = ::acos(lineToTarget.dx() / lineToTarget.length());
    qreal angleToCursor = ::acos(lineToCursor.dx() / lineToCursor.length());

    if (lineToTarget.dy() < 0)
        angleToTarget = TwoPi - angleToTarget;
    angleToTarget = normalizeAngle((Pi - angleToTarget) + Pi / 2);

    if (lineToCursor.dy() < 0)
        angleToCursor = TwoPi - angleToCursor;
    angleToCursor = normalizeAngle((Pi - angleToCursor) + Pi / 2);

    // Result difference angle between Corner Target point and Cursor Point
    auto resultAngle = angleToTarget - angleToCursor;

    QTransform trans = transform();
    trans.translate( center.x(), center.y());
    trans.rotateRadians(rotation() + resultAngle, Qt::ZAxis);
    trans.translate( -center.x(),  -center.y());
    setTransform(trans);
}

void oval::setPositionGrabbers()
{
    QRectF tmpRect = rect();
    cornerGrabber[GrabberTop]->setPos(tmpRect.left() + tmpRect.width()/2, tmpRect.top());
    cornerGrabber[GrabberBottom]->setPos(tmpRect.left() + tmpRect.width()/2, tmpRect.bottom());
    cornerGrabber[GrabberLeft]->setPos(tmpRect.left(), tmpRect.top() + tmpRect.height()/2);
    cornerGrabber[GrabberRight]->setPos(tmpRect.right(), tmpRect.top() + tmpRect.height()/2);
    cornerGrabber[GrabberTopLeft]->setPos(tmpRect.topLeft().x(), tmpRect.topLeft().y());
    cornerGrabber[GrabberTopRight]->setPos(tmpRect.topRight().x(), tmpRect.topRight().y());
    cornerGrabber[GrabberBottomLeft]->setPos(tmpRect.bottomLeft().x(), tmpRect.bottomLeft().y());
    cornerGrabber[GrabberBottomRight]->setPos(tmpRect.bottomRight().x(), tmpRect.bottomRight().y());
}

void oval::setVisibilityGrabbers()
{
    cornerGrabber[GrabberTopLeft]->setVisible(true);
    cornerGrabber[GrabberTopRight]->setVisible(true);
    cornerGrabber[GrabberBottomLeft]->setVisible(true);
    cornerGrabber[GrabberBottomRight]->setVisible(true);

    if(m_actionFlags == ResizeState){
        cornerGrabber[GrabberTop]->setVisible(true);
        cornerGrabber[GrabberBottom]->setVisible(true);
        cornerGrabber[GrabberLeft]->setVisible(true);
        cornerGrabber[GrabberRight]->setVisible(true);
    } else {
        cornerGrabber[GrabberTop]->setVisible(false);
        cornerGrabber[GrabberBottom]->setVisible(false);
        cornerGrabber[GrabberLeft]->setVisible(false);
        cornerGrabber[GrabberRight]->setVisible(false);
    }
}

void oval::hideGrabbers()
{
    for(int i = 0; i < 8; i++){
        cornerGrabber[i]->setVisible(false);
    }
}
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2
Evgenii Legotckoi
  • Nov. 9, 2017, 1:15 p.m.

You forgot Q_OBJECT macros in oval.h. Therefore you could not build project.

class oval : public QObject, public QGraphicsEllipseItem
{
    Q_OBJECT

...
    c
    • Nov. 9, 2017, 2:17 p.m.

    Thank you very much sir,Now program is running without any errors.but problem is which can't draw a oval shape using mouse as your project.this image shows how my program is running.but problem is which cannot draw oval shape,can you tell me what is the reason.please check my sample project,thank you!!!



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