Fit In View a loaded image to QGraphicsView

[sincnarf]

anybody has ideas how to resize an image to fit the bounds of a qgraphicsview keeping aspect ratio... WITHOUT USING sceneRect() ? . ...

how about an example for
void QGraphicsScene::render ( QPainter * painter, const QRectF & target = QRectF(), const QRectF & source = QRectF(), Qt::AspectRatioMode aspectRatioMode = Qt::KeepAspectRatio ) . . . .

[wysota]

Why don't you want to use sceneRect()? You can resize the scene to the image and then fit the scene into the view, if that is an option for you.

[Bitto]

sincnarf, I don't understand... you can pass any rectangle to QGraphicsView::fitInView(). It's the first argument the function takes.

[sincnarf]

At last this code works.... Last question on this though... By default, pixmaps are added to the scene at the center. Am i correct? But In this code my x and y for the QRectF is always 0 and 0 respectively, so this means the added graphics item is not centered. How can I make the item centered on the view?

void MainWindow::loadGraphicsViewParameter(QGraphicsView *graphicsView) {
 
	QString fileName = QFileDialog::getOpenFileName(this, tr("Open Image"),
			QDir::currentPath());
	if (!fileName.isEmpty()) {
		QImage tempImage(fileName);
		if (tempImage.isNull()) {
			QMessageBox::information(this, tr("Load Warning"), tr("Cannot load %1.").arg(fileName));
			return;
		}
		QImage image = tempImage.convertToFormat(QImage::Format_RGB32);
		QPixmap pixmap = QPixmap::fromImage(image);
 
		int width = graphicsView->geometry().width();
		int height = graphicsView->geometry().height();
		//	        QMessageBox::information(this, tr("WIDTH HEIGHT"), tr("Width= %1 Height= %2").arg(QString::number(width, 10), QString::number(height, 10)));
		QGraphicsScene *viewScene = new QGraphicsScene(QRectF(0, 0, width, height), 0);
		QGraphicsPixmapItem *item = viewScene->addPixmap(pixmap.scaled(QSize(
				(int)viewScene->width(), (int)viewScene->height()),
				Qt::KeepAspectRatio, Qt::SmoothTransformation));
		graphicsView->fitInView(QRectF(0, 0, width, height),
				Qt::KeepAspectRatio);
		graphicsView->setScene(viewScene);
		graphicsView->show();
	}
}

void MainWindow::loadGraphicsViewParameter(QGraphicsView *graphicsView) {

	QString fileName = QFileDialog::getOpenFileName(this, tr("Open Image"),
			QDir::currentPath());
	if (!fileName.isEmpty()) {
		QImage tempImage(fileName);
		if (tempImage.isNull()) {
			QMessageBox::information(this, tr("Load Warning"), tr("Cannot load %1.").arg(fileName));
			return;
		}
		QImage image = tempImage.convertToFormat(QImage::Format_RGB32);
		QPixmap pixmap = QPixmap::fromImage(image);

		int width = graphicsView->geometry().width();
		int height = graphicsView->geometry().height();
		//	        QMessageBox::information(this, tr("WIDTH HEIGHT"), tr("Width= %1 Height= %2").arg(QString::number(width, 10), QString::number(height, 10)));
		QGraphicsScene *viewScene = new QGraphicsScene(QRectF(0, 0, width, height), 0);
		QGraphicsPixmapItem *item = viewScene->addPixmap(pixmap.scaled(QSize(
				(int)viewScene->width(), (int)viewScene->height()),
				Qt::KeepAspectRatio, Qt::SmoothTransformation));
		graphicsView->fitInView(QRectF(0, 0, width, height),
				Qt::KeepAspectRatio);
		graphicsView->setScene(viewScene);
		graphicsView->show();
	}
}

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[konikaka]

Thanks for your post, this is really helpful for me ^^