Refresh QGraphicsView

jk_mk

Hello,

I am using a QGraphicsView and a button, in order to load and display images as seems from the following code. But when I have already loaded an image in my QGraphicsView, and I am trying to load an other image, then my new image is displayed on my previous image. What should I change to refresh my QGraphicsView correctly? graphicsView_inputImage is the name of my QGraphicsView and scene is a global pointer to my QGraphicsScene.

@ void MainWindow::push_button_File(void)
{

 QString fileName = QFileDialog::getOpenFileName(this,
                                 tr("Open File"&#41;, QDir::currentPath());
 if (!fileName.isEmpty()) {
scene->addPixmap(QPixmap(fileName, 0, Qt::AutoColor));
     ui->graphicsView_inputImage->setScene(scene);

 }

return ;
}@

Satmosc

Addpixmap is actually a part of QGraphicsPixmapItem , so try to use set pixmap http://doc.qt.nokia.com/latest/qgraphicspixmapitem.html

As it is clear in your code , you are adding new PixMAP Item to the item and not setting new or removing old one.

jk_mk

Thanks for your response. But the scene is member of QGraphicsScene and scene doesn't include the method setPixmap(). How could I set a new pixmap? Could you be more specific?

baysmith

Perhaps something like this.
@
void MainWindow::push_button_File(void)
{
static QGraphicsPixmapItem* pixmapItem;
QString fileName = QFileDialog::getOpenFileName(this,
tr("Open File"), QDir::currentPath());
if (!fileName.isEmpty()) {
if (!pixmapItem) {
pixmapItem = scene->addPixmap(QPixmap(fileName, 0, Qt::AutoColor));
ui->graphicsView_inputImage->setScene(scene);
} else {
pixmapItem->setPixmap(QPixmap(fileName, 0, Qt::AutoColor));
}
}

return;

}
@

jk_mk

I have tried this and I couldn't display my image in the QGraphicsView at all:

@void MainWindow::push_button_File(void)
{
QGraphicsPixmapItem* pixmapItem = new QGraphicsPixmapItem();
QString fileName = QFileDialog::getOpenFileName(this,
tr("Open File"), QDir::currentPath());
if (!fileName.isEmpty()) {
if (!pixmapItem) {
pixmapItem = scene->addPixmap(QPixmap(fileName, 0, Qt::AutoColor));
ui->graphicsView_inputImage->setScene(scene);
} else {
pixmapItem->setPixmap(QPixmap(fileName, 0, Qt::AutoColor));
}
}

return;

}@

and also I have tried this, but I took the same results (the new image on the previous image)

@void MainWindow::push_button_File(void)
{

 QString fileName = QFileDialog::getOpenFileName(this,
                                 tr("Open File"), QDir::currentPath());
 if (!fileName.isEmpty()) {

QGraphicsPixmapItem *pix= new QGraphicsPixmapItem();
pix->setPixmap(QPixmap(fileName, 0, Qt::AutoColor));
scene->addItem(pix);
ui->graphicsView_inputImage->setScene(scene);
}

return ;

}@

baysmith

The first thing you tried is not what I suggested. Remove the "new QGraphicsPixmapItem()"

jk_mk

Ok that was my mistake. Now I am taking the correct results. Thanks a lot for your help!!

Aniket

following Error Coming in my system..!
QPixmap::operator=: Cannot assign to pixmap during painting.

When i was trying to do this code with menubar actions.

Please help me out.