[Qt-interest] problem with QGraphicsView

[Fred Duarte]

You should set the Position of the Pixmap after adding it to the scene.

By default, QGraphicsView positions all items at the (0, 0) point.

You can use the *setPos*( QPointF ) method or the *moveBy*( qreal , qreal )
method. The first
sets the Position of the Item on the scene and the second moves the item
from the current
position by a given offset. Both are methods from *QGraphicsItem* class.

Just pass the center point of the QGraphicsView object to one of these
methods. In the case
of the *moveBy* method, you need to separate the *X* and *Y* coordinates in
2 parameters.

*Example:*
...
currItm = scene->addPixmap(myPix);

QPointF center(400.0, 300.0);

currItem->setPos(center);
...

On Thu, Jun 25, 2009 at 6:07 AM, Sajauddin Shariff Mohammad <
shariff at mic.co.in> wrote:

> Dear Friends,
> Iam new to graphics programming in QT. I want to show the image selected by
> the user in graphics view widget. Ican show the image but a small problem
> with it.
>  My .h and .CPP files are as follows
>
> .H file
>
> class myWidget : public QWidget, Ui_Form
> {
>    Q_OBJECT
>
>    public:
>
>    QPixmap *pix;
>    QGraphicsScene *scene;
>    QString imgFilename;
>    QGraphicsItem *prvItm, *currItm;
>
>    myWidget(QWidget *parent = 0);
>    ~myWidget();
>    public slots:
>    void on_browseButton_clicked();
>    void on_showButton_clicked();
> };
>
> .cpp file
> myWidget::myWidget(QWidget *parent):QWidget(parent)
> {
>    pix = new QPixmap();
>    scene = new QGraphicsScene();
>    currItm = NULL;
>    setupUi(this);
>    graphicsView->setScene(scene);
>    graphicsView->setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
>    graphicsView->setAlignment(Qt::AlignCenter);
> }
>
> myWidget::~myWidget()
> {
> }
>
> void myWidget::on_browseButton_clicked()
> {
>    QString filename;
>    filename = QFileDialog::getOpenFileName(this, tr("Select Image File"),
> "/data", tr("Images (*.bmp *.png *.jpg)"));
>    browseLE->setText(filename);
> }
>
> void myWidget::on_showButton_clicked()
> {
>    QPixmap myPix;
>    imgFilename = browseLE->text();
>    myPix.fill();
>    myPix.load(imgFilename);
>    if(currItm!=NULL)  scene->removeItem(currItm);
>    currItm = scene->addPixmap(myPix);
> }
>
> The image that is being displayed in graphics view is not alligned at the
> center.
>
> Pleas eguide me what should I do so that the image is shown at thecenter of
> the graphics view.
>
>
> Regards,
> Sajauddin Shariff
> shariff at mic.co.in
> +91-998-904-5546
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>


-- 
Frederico Simas Duarte
MLS - Mobile Linux Software
INDT - Nokia Institute

http://fredyduarte.net/blog/
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