camera.cpp Example File

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 #include "camera.h"
 #include "ui_camera.h"
 #include "videosettings.h"
 #include "imagesettings.h"

 #include <qmediaservice.h>
 #include <qmediarecorder.h>
 #include <qcamera.h>
 #include <qcameraviewfinder.h>

 #include <qmessagebox.h>
 #include <qpalette.h>

 #include <QtWidgets>

 #if (defined(Q_WS_MAEMO_6)) && QT_VERSION >= 0x040700
 #define HAVE_CAMERA_BUTTONS
 #endif

 Camera::Camera(QWidget *parent) :
     QMainWindow(parent),
     ui(new Ui::Camera),
     camera(0),
     imageCapture(0),
     mediaRecorder(0),
     isCapturingImage(false),
     applicationExiting(false)
 {
     ui->setupUi(this);

     //Camera devices:
     QByteArray cameraDevice;

     QActionGroup *videoDevicesGroup = new QActionGroup(this);
     videoDevicesGroup->setExclusive(true);
     foreach(const QByteArray &deviceName, QCamera::availableDevices()) {
         QString description = camera->deviceDescription(deviceName);
         QAction *videoDeviceAction = new QAction(description, videoDevicesGroup);
         videoDeviceAction->setCheckable(true);
         videoDeviceAction->setData(QVariant(deviceName));
         if (cameraDevice.isEmpty()) {
             cameraDevice = deviceName;
             videoDeviceAction->setChecked(true);
         }
         ui->menuDevices->addAction(videoDeviceAction);
     }

     connect(videoDevicesGroup, SIGNAL(triggered(QAction*)), this, SLOT(updateCameraDevice(QAction*)));
     connect(ui->captureWidget, SIGNAL(currentChanged(int)), SLOT(updateCaptureMode()));

 #ifdef HAVE_CAMERA_BUTTONS
     ui->lockButton->hide();
 #endif

     setCamera(cameraDevice);
 }

 Camera::~Camera()
 {
     delete mediaRecorder;
     delete imageCapture;
     delete camera;
 }

 void Camera::setCamera(const QByteArray &cameraDevice)
 {
     delete imageCapture;
     delete mediaRecorder;
     delete camera;

     if (cameraDevice.isEmpty())
         camera = new QCamera;
     else
         camera = new QCamera(cameraDevice);

     connect(camera, SIGNAL(stateChanged(QCamera::State)), this, SLOT(updateCameraState(QCamera::State)));
     connect(camera, SIGNAL(error(QCamera::Error)), this, SLOT(displayCameraError()));

     mediaRecorder = new QMediaRecorder(camera);
     connect(mediaRecorder, SIGNAL(stateChanged(QMediaRecorder::State)), this, SLOT(updateRecorderState(QMediaRecorder::State)));

     imageCapture = new QCameraImageCapture(camera);

     connect(mediaRecorder, SIGNAL(durationChanged(qint64)), this, SLOT(updateRecordTime()));
     connect(mediaRecorder, SIGNAL(error(QMediaRecorder::Error)), this, SLOT(displayRecorderError()));

     mediaRecorder->setMetaData(QtMultimedia::MetaData::Title, QVariant(QLatin1String("Test Title")));

     connect(ui->exposureCompensation, SIGNAL(valueChanged(int)), SLOT(setExposureCompensation(int)));

     camera->setViewfinder(ui->viewfinder);

     updateCameraState(camera->state());
     updateLockStatus(camera->lockStatus(), QCamera::UserRequest);
     updateRecorderState(mediaRecorder->state());

     connect(imageCapture, SIGNAL(readyForCaptureChanged(bool)), this, SLOT(readyForCapture(bool)));
     connect(imageCapture, SIGNAL(imageCaptured(int,QImage)), this, SLOT(processCapturedImage(int,QImage)));
     connect(imageCapture, SIGNAL(imageSaved(int,QString)), this, SLOT(imageSaved(int,QString)));

     connect(camera, SIGNAL(lockStatusChanged(QCamera::LockStatus, QCamera::LockChangeReason)),
             this, SLOT(updateLockStatus(QCamera::LockStatus, QCamera::LockChangeReason)));

     ui->captureWidget->setTabEnabled(0, (camera->isCaptureModeSupported(QCamera::CaptureStillImage)));
     ui->captureWidget->setTabEnabled(1, (camera->isCaptureModeSupported(QCamera::CaptureVideo)));

     updateCaptureMode();
     camera->start();
 }

 void Camera::keyPressEvent(QKeyEvent * event)
 {
     if (event->isAutoRepeat())
         return;

     switch (event->key()) {
 #if QT_VERSION >= 0x040700
     case Qt::Key_CameraFocus:
         displayViewfinder();
         camera->searchAndLock();
         event->accept();
         break;
     case Qt::Key_Camera:
         if (camera->captureMode() == QCamera::CaptureStillImage) {
             takeImage();
         } else {
             if (mediaRecorder->state() == QMediaRecorder::RecordingState)
                 stop();
             else
                 record();
         }
         event->accept();
         break;
 #endif
     default:
         QMainWindow::keyPressEvent(event);
     }
 }

 void Camera::keyReleaseEvent(QKeyEvent * event)
 {
     if (event->isAutoRepeat())
         return;

     switch (event->key()) {
 #if QT_VERSION >= 0x040700
     case Qt::Key_CameraFocus:
         camera->unlock();
         break;
 #endif
     default:
         QMainWindow::keyReleaseEvent(event);
     }
 }

 void Camera::updateRecordTime()
 {
     QString str = QString("Recorded %1 sec").arg(mediaRecorder->duration()/1000);
     ui->statusbar->showMessage(str);
 }

 void Camera::processCapturedImage(int requestId, const QImage& img)
 {
     Q_UNUSED(requestId);
     QImage scaledImage = img.scaled(ui->viewfinder->size(),
                                     Qt::KeepAspectRatio,
                                     Qt::SmoothTransformation);

     ui->lastImagePreviewLabel->setPixmap(QPixmap::fromImage(scaledImage));
     //display captured image for 4 seconds
     displayCapturedImage();
     QTimer::singleShot(4000, this, SLOT(displayViewfinder()));
 }

 void Camera::configureCaptureSettings()
 {
     switch (camera->captureMode()) {
     case QCamera::CaptureStillImage:
         configureImageSettings();
         break;
     case QCamera::CaptureVideo:
         configureVideoSettings();
         break;
     default:
         break;
     }
 }

 void Camera::configureVideoSettings()
 {
     VideoSettings settingsDialog(mediaRecorder);

     settingsDialog.setAudioSettings(audioSettings);
     settingsDialog.setVideoSettings(videoSettings);
     settingsDialog.setFormat(videoContainerFormat);

     if (settingsDialog.exec()) {
         audioSettings = settingsDialog.audioSettings();
         videoSettings = settingsDialog.videoSettings();
         videoContainerFormat = settingsDialog.format();

         mediaRecorder->setEncodingSettings(
                     audioSettings,
                     videoSettings,
                     videoContainerFormat);
     }
 }

 void Camera::configureImageSettings()
 {
     ImageSettings settingsDialog(imageCapture);

     settingsDialog.setImageSettings(imageSettings);

     if (settingsDialog.exec()) {
         imageSettings = settingsDialog.imageSettings();
         imageCapture->setEncodingSettings(imageSettings);
     }
 }

 void Camera::record()
 {
     mediaRecorder->record();
     updateRecordTime();
 }

 void Camera::pause()
 {
     mediaRecorder->pause();
 }

 void Camera::stop()
 {
     mediaRecorder->stop();
 }

 void Camera::setMuted(bool muted)
 {
     mediaRecorder->setMuted(muted);
 }

 void Camera::toggleLock()
 {
     switch (camera->lockStatus()) {
     case QCamera::Searching:
     case QCamera::Locked:
         camera->unlock();
         break;
     case QCamera::Unlocked:
         camera->searchAndLock();
     }
 }

 void Camera::updateLockStatus(QCamera::LockStatus status, QCamera::LockChangeReason reason)
 {
     QColor indicationColor = Qt::black;

     switch (status) {
     case QCamera::Searching:
         indicationColor = Qt::yellow;
         ui->statusbar->showMessage(tr("Focusing..."));
         ui->lockButton->setText(tr("Focusing..."));
         break;
     case QCamera::Locked:
         indicationColor = Qt::darkGreen;
         ui->lockButton->setText(tr("Unlock"));
         ui->statusbar->showMessage(tr("Focused"), 2000);
         break;
     case QCamera::Unlocked:
         indicationColor = reason == QCamera::LockFailed ? Qt::red : Qt::black;
         ui->lockButton->setText(tr("Focus"));
         if (reason == QCamera::LockFailed)
             ui->statusbar->showMessage(tr("Focus Failed"), 2000);
     }

     QPalette palette = ui->lockButton->palette();
     palette.setColor(QPalette::ButtonText, indicationColor);
     ui->lockButton->setPalette(palette);
 }

 void Camera::takeImage()

 {
     isCapturingImage = true;
     imageCapture->capture();
 }

 void Camera::startCamera()
 {
     camera->start();
 }

 void Camera::stopCamera()
 {
     camera->stop();
 }

 void Camera::updateCaptureMode()
 {
     int tabIndex = ui->captureWidget->currentIndex();
     QCamera::CaptureModes captureMode = tabIndex == 0 ? QCamera::CaptureStillImage : QCamera::CaptureVideo;

     if (camera->isCaptureModeSupported(captureMode))
         camera->setCaptureMode(captureMode);
 }

 void Camera::updateCameraState(QCamera::State state)
 {
     switch (state) {
     case QCamera::ActiveState:
         ui->actionStartCamera->setEnabled(false);
         ui->actionStopCamera->setEnabled(true);
         ui->captureWidget->setEnabled(true);
         ui->actionSettings->setEnabled(true);
         break;
     case QCamera::UnloadedState:
     case QCamera::LoadedState:
         ui->actionStartCamera->setEnabled(true);
         ui->actionStopCamera->setEnabled(false);
         ui->captureWidget->setEnabled(false);
         ui->actionSettings->setEnabled(false);
     }
 }

 void Camera::updateRecorderState(QMediaRecorder::State state)
 {
     switch (state) {
     case QMediaRecorder::StoppedState:
         ui->recordButton->setEnabled(true);
         ui->pauseButton->setEnabled(true);
         ui->stopButton->setEnabled(false);
         break;
     case QMediaRecorder::PausedState:
         ui->recordButton->setEnabled(true);
         ui->pauseButton->setEnabled(false);
         ui->stopButton->setEnabled(true);
         break;
     case QMediaRecorder::RecordingState:
         ui->recordButton->setEnabled(false);
         ui->pauseButton->setEnabled(true);
         ui->stopButton->setEnabled(true);
         break;
     }
 }

 void Camera::setExposureCompensation(int index)
 {
     camera->exposure()->setExposureCompensation(index*0.5);
 }

 void Camera::displayRecorderError()
 {
     QMessageBox::warning(this, tr("Capture error"), mediaRecorder->errorString());
 }

 void Camera::displayCameraError()
 {
     QMessageBox::warning(this, tr("Camera error"), camera->errorString());
 }

 void Camera::updateCameraDevice(QAction *action)
 {
     setCamera(action->data().toByteArray());
 }

 void Camera::displayViewfinder()
 {
     ui->stackedWidget->setCurrentIndex(0);
 }

 void Camera::displayCapturedImage()
 {
     ui->stackedWidget->setCurrentIndex(1);
 }

 void Camera::readyForCapture(bool ready)
 {
     ui->takeImageButton->setEnabled(ready);
 }

 void Camera::imageSaved(int id, const QString &fileName)
 {
     Q_UNUSED(id);
     Q_UNUSED(fileName);

     isCapturingImage = false;
     if (applicationExiting)
         close();
 }

 void Camera::closeEvent(QCloseEvent *event)
 {
     if (isCapturingImage) {
         setEnabled(false);
         applicationExiting = true;
         event->ignore();
     } else {
         event->accept();
     }
 }