qtmultimedia/examples/multimediawidgets/camera/camera.cpp

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

#include <QMediaService>
#include <QMediaRecorder>
#include <QCameraViewfinder>
#include <QCameraInfo>
#include <QMediaMetaData>

#include <QMessageBox>
#include <QPalette>

#include <QtWidgets>

Q_DECLARE_METATYPE(QCameraInfo)

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:

    QActionGroup *videoDevicesGroup = new QActionGroup(this);
    videoDevicesGroup->setExclusive(true);
    foreach (const QCameraInfo &cameraInfo, QCameraInfo::availableCameras()) {
        QAction *videoDeviceAction = new QAction(cameraInfo.description(), videoDevicesGroup);
        videoDeviceAction->setCheckable(true);
        videoDeviceAction->setData(QVariant::fromValue(cameraInfo));
        if (cameraInfo == QCameraInfo::defaultCamera())
            videoDeviceAction->setChecked(true);

        ui->menuDevices->addAction(videoDeviceAction);
    }

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

    setCamera(QCameraInfo::defaultCamera());
}

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

void Camera::setCamera(const QCameraInfo &cameraInfo)
{
    delete imageCapture;
    delete mediaRecorder;
    delete camera;

    camera = new QCamera(cameraInfo);

    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(QMediaMetaData::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(imageCapture, SIGNAL(error(int,QCameraImageCapture::Error,QString)), this,
            SLOT(displayCaptureError(int,QCameraImageCapture::Error,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()) {
    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;
    default:
        QMainWindow::keyPressEvent(event);
    }
}

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

    switch (event->key()) {
    case Qt::Key_CameraFocus:
        camera->unlock();
        break;
    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::displayCaptureError(int id, const QCameraImageCapture::Error error, const QString &errorString)
{
    Q_UNUSED(id);
    Q_UNUSED(error);
    QMessageBox::warning(this, tr("Image Capture Error"), errorString);
    isCapturingImage = false;
}

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(qvariant_cast<QCameraInfo>(action->data()));
}

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();
    }
}