How to save images from QGraphicsView?

Question

I'm creating a very simple image editor on Qt. The user can open an image(the image is displayed on a QGraphicsView) and he has the ability to rotate either clockwise or counterclockwise.Then he can save the rotated image.Here lies my problem.How can i get the rotated image displayed in the QGraphicsView and then save it?

Here is my code of opening the image file.The variable image is QPixmap type and the imageObject is a QImage pointer.

Answer 1

Take a look at this method:

void QGraphicsView::render(QPainter * painter, const QRectF & target = QRectF(), const QRect & source = QRect(), Qt::AspectRatioMode aspectRatioMode = Qt::KeepAspectRatio)

Renders the source rect, which is in view coordinates, from the scene into target, which is in paint device coordinates, using painter. This function is useful for capturing the contents of the view onto a paint device, such as a QImage (e.g., to take a screenshot)

As for the rotation, the method you need is void QGraphicsItem::setRotation(qreal angle) or alternatively void QGraphicsView::rotate(qreal angle) - depending on whether you want to rotate the item or the entire view.

Answer 2

One way to do it is to create a QPixmap and then use a QPainter to paint the QGraphicsScene onto the pixmap.

# Get the size of your graphicsview
rect = graphicsview.viewport().rect()

# Create a pixmap the same size as your graphicsview
# You can make this larger or smaller if you want.
pixmap = QPixmap(rect.size())
painter = QPainter(pixmap)

# Render the graphicsview onto the pixmap and save it out.
graphicsview.render(painter, pixmap.rect(), rect)
pixmap.save('/path/to/file.png')