QCameraImageCapture resource error on imageSave

SolaVitae · wrote on 15 Oct 2018, 04:36

I'm currently trying to capture a still image with a QCamera Widget, but whenever i try to run the capture() function of QCameraImageCapture, it errors and gives me a QCameraImageCapture::ResourceError "Could not save image to file."

Ive tried my hardest to copy directly from the QCamera example from QT, whilst cutting out the video recording part of it as i only need still images.

This is my widget's constructor

	connect(saveImageButton, SIGNAL(pressed()), this, SLOT(saveImagePressed()));
	

	if (!checkCameraAvailability()) close();

	QList<QCameraInfo> cameras = QCameraInfo::availableCameras();

	availableCameras->setFocusPolicy(Qt::NoFocus);

	QPalette p = palette();
	p.setBrush(QPalette::Highlight, QBrush(Qt::white));
	p.setBrush(QPalette::HighlightedText, QBrush(Qt::black));
	availableCameras->setPalette(p);

	foreach(const QCameraInfo &ci, cameras) {
		QCheckBox *cam = new QCheckBox(ci.description());
		QListWidgetItem *lwi = new QListWidgetItem();
		availableCameras->addItem(lwi);
		availableCameras->setItemWidget(lwi, cam);
	}

	m_camera.reset(new QCamera(QCameraInfo::availableCameras()[0]));
	
	connect(m_camera.data(), QOverload<QCamera::Error>::of(&QCamera::error), this, &WebCamDialog::displayCameraError);
	
	m_camera->setViewfinder(ui->viewFinder);
	m_camera->viewfinderSettings().setResolution(QSize(400, 400));
	qDebug() << m_camera->viewfinderSettings().resolution();

	m_camera->setCaptureMode(QCamera::CaptureStillImage);

	m_imageCapture.reset(new QCameraImageCapture(m_camera.data()));

	connect(m_imageCapture.data(), QOverload<int, QCameraImageCapture::Error, const QString &>::of(&QCameraImageCapture::error),
		this, &WebCamDialog::displayCaptureError);

	connect(m_imageCapture.data(), SIGNAL(imageCaptured(int, const QImage)), this, SLOT(imageCaptured(int, const QImage)));
	connect(m_imageCapture.data(), SIGNAL(imageSaved(int, const QString)), this, SLOT(imageSaved(int, const QString)));


	m_camera->start();

this is my capture function when a button is pressed

void WebCamDialog::saveImagePressed() {
	qDebug() << m_imageCapture->isReadyForCapture();
	qDebug() << m_camera->lockStatus() << m_imageCapture->isReadyForCapture();
	m_imageCapture->capture();
}

the above qDebug returns true, QCamera::Unlocked, true

these are my imageSaved, imageCaptured, and error functions

void WebCamDialog::imageCaptured(int id, const QImage &i) {
	QLabel *im = new QLabel();
	im->setPixmap(QPixmap::fromImage(i));
	im->show();

}

void WebCamDialog::imageSaved(int id, const QString &s) {
	qDebug() << s;
}

void WebCamDialog::displayCaptureError(int id, QCameraImageCapture::Error error, const QString &errorString) {
	Q_UNUSED(id);
	qDebug() << error;
	qDebug() << tr("Image Capture Error") << errorString;
}

imageCaptured displays the captured image correctly, imageSaved is never reached. I only have one camera available so i've ommited the actual selecting of a camera, and just made it default to the only camera i have

VRonin · wrote on 15 Oct 2018, 12:15

Try adding m_imageCapture.setCaptureDestination(QCameraImageCapture::CaptureToFile);.

P.S.

QCheckBox *cam = new QCheckBox(ci.description());
vailableCameras->setItemWidget(lwi, cam);

Hurts my feelings. See https://forum.qt.io/post/486329 it applies also to QListWidgetItem with the only difference that you don't, obviously, specify a column