From 53dd3594d5a87c15d15e57609eb0460c9cf7789a Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Sun, 22 Mar 2020 21:30:04 +0200 Subject: qcam: main_window: Document functions and reorganize member data The qcam application is our reference implementation of a libcamera GUI application. Document the code of the MainWindow class to make it easier to follow, and reorganize the member data in logical groups for clarity. No code change. Signed-off-by: Laurent Pinchart Reviewed-by: Kieran Bingham --- src/qcam/main_window.cpp | 69 +++++++++++++++++++++++++++++++++++++++++++++++- src/qcam/main_window.h | 24 ++++++++++------- 2 files changed, 82 insertions(+), 11 deletions(-) diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp index 7959c17c..20e84171 100644 --- a/src/qcam/main_window.cpp +++ b/src/qcam/main_window.cpp @@ -31,6 +31,9 @@ using namespace libcamera; +/** + * \brief Custom QEvent to signal capture completion + */ class CaptureEvent : public QEvent { public: @@ -51,6 +54,10 @@ MainWindow::MainWindow(CameraManager *cm, const OptionsParser::Options &options) { int ret; + /* + * Initialize the UI: Create the toolbar, set the window title and + * create the viewfinder widget. + */ createToolbars(); title_ = "QCam " + QString::fromStdString(CameraManager::version()); @@ -61,6 +68,7 @@ MainWindow::MainWindow(CameraManager *cm, const OptionsParser::Options &options) setCentralWidget(viewfinder_); adjustSize(); + /* Open the camera and start capture. */ ret = openCamera(); if (ret < 0) quit(); @@ -96,13 +104,14 @@ int MainWindow::createToolbars() /* Disable right click context menu. */ toolbar_->setContextMenuPolicy(Qt::PreventContextMenu); + /* Quit action. */ action = toolbar_->addAction(QIcon::fromTheme("application-exit", QIcon(":x-circle.svg")), "Quit"); action->setShortcut(Qt::CTRL | Qt::Key_Q); connect(action, &QAction::triggered, this, &MainWindow::quit); - /* Camera selection. */ + /* Camera selector. */ QComboBox *cameraCombo = new QComboBox(); connect(cameraCombo, QOverload::of(&QComboBox::activated), this, &MainWindow::switchCamera); @@ -114,6 +123,7 @@ int MainWindow::createToolbars() toolbar_->addSeparator(); + /* Start/Stop action. */ iconPlay_ = QIcon::fromTheme("media-playback-start", QIcon(":play-circle.svg")); iconStop_ = QIcon::fromTheme("media-playback-stop", @@ -125,6 +135,7 @@ int MainWindow::createToolbars() connect(action, &QAction::toggled, this, &MainWindow::toggleCapture); startStopAction_ = action; + /* Save As... action. */ action = toolbar_->addAction(QIcon::fromTheme("document-save-as", QIcon(":save.svg")), "Save As..."); @@ -142,6 +153,7 @@ void MainWindow::quit() void MainWindow::updateTitle() { + /* Calculate the average frame rate over the last period. */ unsigned int duration = frameRateInterval_.elapsed(); unsigned int frames = framesCaptured_ - previousFrames_; double fps = frames * 1000.0 / duration; @@ -153,8 +165,13 @@ void MainWindow::updateTitle() setWindowTitle(title_ + " : " + QString::number(fps, 'f', 2) + " fps"); } +/* ----------------------------------------------------------------------------- + * Camera Selection + */ + void MainWindow::switchCamera(int index) { + /* Get and acquire the new camera. */ const auto &cameras = cm_->cameras(); if (static_cast(index) >= cameras.size()) return; @@ -168,6 +185,10 @@ void MainWindow::switchCamera(int index) std::cout << "Switching to camera " << cam->name() << std::endl; + /* + * Stop the capture session, release the current camera, replace it with + * the new camera and start a new capture session. + */ startStopAction_->setChecked(false); camera_->release(); @@ -181,9 +202,11 @@ std::string MainWindow::chooseCamera() QStringList cameras; bool result; + /* If only one camera is available, use it automatically. */ if (cm_->cameras().size() == 1) return cm_->cameras()[0]->name(); + /* Present a dialog box to pick a camera. */ for (const std::shared_ptr &cam : cm_->cameras()) cameras.append(QString::fromStdString(cam->name())); @@ -200,6 +223,10 @@ int MainWindow::openCamera() { std::string cameraName; + /* + * Use the camera specified on the command line, if any, or display the + * camera selection dialog box otherwise. + */ if (options_.isSet(OptCamera)) cameraName = static_cast(options_[OptCamera]); else @@ -208,6 +235,7 @@ int MainWindow::openCamera() if (cameraName == "") return -EINVAL; + /* Get and acquire the camera. */ camera_ = cm_->get(cameraName); if (!camera_) { std::cout << "Camera " << cameraName << " not found" @@ -226,6 +254,10 @@ int MainWindow::openCamera() return 0; } +/* ----------------------------------------------------------------------------- + * Capture Start & Stop + */ + void MainWindow::toggleCapture(bool start) { if (start) { @@ -239,10 +271,16 @@ void MainWindow::toggleCapture(bool start) } } +/** + * \brief Start capture with the current camera + * + * This function shall not be called directly, use toggleCapture() instead. + */ int MainWindow::startCapture() { int ret; + /* Configure the camera. */ config_ = camera_->generateConfiguration({ StreamRole::Viewfinder }); StreamConfiguration &cfg = config_->at(0); @@ -279,6 +317,7 @@ int MainWindow::startCapture() return ret; } + /* Configure the viewfinder. */ Stream *stream = cfg.stream(); ret = viewfinder_->setFormat(cfg.pixelFormat, QSize(cfg.size.width, cfg.size.height)); @@ -289,6 +328,7 @@ int MainWindow::startCapture() adjustSize(); + /* Allocate buffers and requests. */ allocator_ = new FrameBufferAllocator(camera_); ret = allocator_->allocate(stream); if (ret < 0) { @@ -321,6 +361,7 @@ int MainWindow::startCapture() std::make_pair(memory, plane.length); } + /* Start the title timer and the camera. */ titleTimer_.start(2000); frameRateInterval_.start(); previousFrames_ = 0; @@ -335,6 +376,7 @@ int MainWindow::startCapture() camera_->requestCompleted.connect(this, &MainWindow::requestComplete); + /* Queue all requests. */ for (Request *request : requests) { ret = camera_->queueRequest(request); if (ret < 0) { @@ -368,6 +410,12 @@ error: return ret; } +/** + * \brief Stop ongoing capture + * + * This function may be called directly when tearing down the MainWindow. Use + * toggleCapture() instead in all other cases. + */ void MainWindow::stopCapture() { if (!isCapturing_) @@ -403,6 +451,10 @@ void MainWindow::stopCapture() setWindowTitle(title_); } +/* ----------------------------------------------------------------------------- + * Image Save + */ + void MainWindow::saveImageAs() { QImage image = viewfinder_->getCurrentImage(); @@ -418,11 +470,20 @@ void MainWindow::saveImageAs() writer.write(image); } +/* ----------------------------------------------------------------------------- + * Request Completion Handling + */ + void MainWindow::requestComplete(Request *request) { if (request->status() == Request::RequestCancelled) return; + /* + * We're running in the libcamera thread context, expensive operations + * are not allowed. Add the buffer to the done queue and post a + * CaptureEvent for the application thread to handle. + */ const std::map &buffers = request->buffers(); FrameBuffer *buffer = buffers.begin()->second; @@ -436,6 +497,11 @@ void MainWindow::requestComplete(Request *request) void MainWindow::processCapture() { + /* + * Retrieve the next buffer from the done queue. The queue may be empty + * if stopCapture() has been called while a CaptureEvent was posted but + * not processed yet. Return immediately in that case. + */ FrameBuffer *buffer; { @@ -460,6 +526,7 @@ void MainWindow::processCapture() << " fps: " << std::fixed << std::setprecision(2) << fps << std::endl; + /* Display the buffer and requeue it to the camera. */ display(buffer); queueRequest(buffer); diff --git a/src/qcam/main_window.h b/src/qcam/main_window.h index 34a090cc..c662a2ef 100644 --- a/src/qcam/main_window.h +++ b/src/qcam/main_window.h @@ -57,6 +57,7 @@ private Q_SLOTS: private: int createToolbars(); + std::string chooseCamera(); int openCamera(); @@ -68,34 +69,37 @@ private: int display(FrameBuffer *buffer); void queueRequest(FrameBuffer *buffer); + /* UI elements */ + QToolBar *toolbar_; + QAction *startStopAction_; + ViewFinder *viewfinder_; + QIcon iconPlay_; QIcon iconStop_; QString title_; QTimer titleTimer_; + /* Options */ const OptionsParser::Options &options_; + /* Camera manager, camera, configuration and buffers */ CameraManager *cm_; std::shared_ptr camera_; FrameBufferAllocator *allocator_; - bool isCapturing_; std::unique_ptr config_; + std::map> mappedBuffers_; - uint64_t lastBufferTime_; + /* Capture state, buffers queue and statistics */ + bool isCapturing_; + QQueue doneQueue_; + QMutex mutex_; /* Protects doneQueue_ */ + uint64_t lastBufferTime_; QElapsedTimer frameRateInterval_; uint32_t previousFrames_; uint32_t framesCaptured_; - - QMutex mutex_; - QQueue doneQueue_; - - QToolBar *toolbar_; - QAction *startStopAction_; - ViewFinder *viewfinder_; - std::map> mappedBuffers_; }; #endif /* __QCAM_MAIN_WINDOW__ */ -- cgit v1.2.1