Need to help to select the QGraphicsPixmapItem when click on it.

[Himanshu Rohilla]

Hello everyone,

I want to draw image on QGraphicsView. For this, I created a sub class of QGraphicsPixmapItem. When i click on QGraphicsView, it shows a QFileDialog to select image from the system and displaying successfully on view.
Now, I want to select this image when i click on this. For this, I write the code but it does not work. The following is the my code.

@/* This is my HEADER File which is subclass of QGraphicsPixmapItem */

#include <QGraphicsPixmapItem>
#include <QDebug>

class WhiteBoardItems : public QGraphicsPixmapItem
{
public:
WhiteBoardItems(QWidget *parent = 0);

virtual ~WhiteBoardItems();

virtual void mousePressEvent(QGraphicsSceneMouseEvent *event);
virtual void mouseMoveEvent(QGraphicsSceneMouseEvent *event);
virtual void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);

};
@

This is Header File of subclass of QGraphicsView.

@#include "WhiteBoardItems.h"

class WhiteBoardItems;

class WhiteBoardView : public QGraphicsView
{
Q_OBJECT

public:
WhiteBoardView(QWidget* pParent = 0);
virtual ~WhiteBoardView();

protected:

void mousePressEvent(QMouseEvent *event);
void mouseMoveEvent(QMouseEvent *event);
void mouseReleaseEvent(QMouseEvent *event);

private:

void AddImgToview(QString fileName);

bool vbMousePressed, vbImageSelected;

QString vstrImgFileName;

WhiteBoardItems* mImageItem;

};@

@/* This is CPP File of the subclass */

#include "WhiteBoardItems.h"

WhiteBoardItems::WhiteBoardItems(QWidget *parent) :
QGraphicsPixmapItem()
{

}

WhiteBoardItems::~WhiteBoardItems()
{

}

void WhiteBoardItems::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
qDebug() << "Mouse is clicked in QGraphicsItem";

}

void WhiteBoardItems::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{

}

void WhiteBoardItems::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{

}
@

This is CPP File of subclass of QGraphicsView .

@void WhiteBoardView::mousePressEvent (QMouseEvent *event)
{
if(event->button() == Qt::LeftButton)
{
vbMousePressed = true;

    if(vbImageSelected)
    {
        previousPt = event->pos();
    }
}

}

void WhiteBoardView::mouseReleaseEvent (QMouseEvent event)
{
if(vbImageSelected)
{
vstrImgFileName = QFileDialog::getOpenFileName(this,"OPEN FILE", QDir::currentPath(),tr("Image Files (.png *.jpg *.bmp *.jpeg *.gif)"));

        if (QImage(vstrImgFileName).isNull() && !vstrImgFileName.isEmpty())
        {
               QMessageBox::information(this,"White Board","There is some problem with image file. This file can't be loaded.");

               return;
        }

        AddImgToview(vstrImgFileName);

    }
    
    vbMousePressed = false;

}

void WhiteBoardView::AddImgToview(QString fileName)
{
mImageItem = new WhiteBoardItems();

mImageItem = (WhiteBoardItems*)(this->scene()->addPixmap(QPixmap(fileName)));
mImageItem->setFlag(QGraphicsItem::ItemIsMovable);
mImageItem->setFlag(QGraphicsItem::ItemIsSelectable);

mImageItem->setX(previousPt.x());
mImageItem->setY(previousPt.y());

mImageItem->setScale(0.5);

}@

[Himanshu Rohilla]

Thanks in advance ...... :)

[raven-worx]

it should be enough to call this on your QGraphicsPixmapItem:
@item->setFlag(QGraphicsItem::ItemIsSelectable);@

[Himanshu Rohilla]

But, I also want to draw rectangle around the image when i click on or select it ...

[Himanshu Rohilla]

I am attaching the URL of images of my desire result.

The following link is just my normal image on view.

http://www.image-upload.net/di/28SA/33.png

The following link will show my desirable result.

http://www.image-upload.net/di/QQVM/44.png

[raven-worx]

then also implement the paint method:
@
void MyGraphicsPixmapItem::paint(QPainter painter, const QStyleOptionGraphicsItem option, QWidget *widget)
{
Q_UNUSED(widget);

painter->setRenderHint(QPainter::SmoothPixmapTransform, (d->transformationMode == Qt::SmoothTransformation));

painter->drawPixmap(this->offset(), this->pixmap());

if (option->state & QStyle::State_Selected)
{
    //draw your selection frame
}

}
@

But since it seems that you also want interaction with the graphicsitem it would be better to introduce a subclassed QGraphicsItemGroup and do your painting and interaction there. Because you would also have to update the bounding rect of the pixmap item once it is selected, etc. ...

[Himanshu Rohilla]

Ok....

Can i do same task for QGraphicsPathItem or whatever i draw on View using this method ?

[raven-worx]

as long as you stay generic to QGraphicsItem ... why not.

[Himanshu Rohilla]

paint method is not calling ..... :(

[Himanshu Rohilla]

sry.... i forgot to addItem in the scene. :P

[Himanshu Rohilla]

But when i click on or select the image, it does not show its Selected State(i.e. QStyle::State_Selected) .