[libcamera-devel] [PATCH v2 4/7] qcam: Introduce a toolbar and camera switching

[Kieran Bingham]

Implement a quit button, and a list of cameras.

Selecting a different camera from the Toolbar will stop the current
stream, and start streaming the chosen camera device if it can be
acquired.

Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

---
v2:

 - Add name to toolbar
 - Rename setCamera to switchCamera
 - Disable right click context menu on toolbar.
 - Utilise a combo box for camera selections
 - Squash in "qcam: Expose quit method for MainWindow"

 src/qcam/main_window.cpp | 64 ++++++++++++++++++++++++++++++++++++++--
 src/qcam/main_window.h   |  5 ++++
 2 files changed, 67 insertions(+), 2 deletions(-)

diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp
index 2ed84cacf655..0e9e717b7e1a 100644
--- a/src/qcam/main_window.cpp
+++ b/src/qcam/main_window.cpp
@@ -10,9 +10,12 @@
 #include <string>
 #include <sys/mman.h>
 
+#include <QComboBox>
 #include <QCoreApplication>
 #include <QInputDialog>
 #include <QTimer>
+#include <QToolBar>
+#include <QToolButton>
 
 #include <libcamera/camera_manager.h>
 #include <libcamera/version.h>
@@ -27,6 +30,8 @@ MainWindow::MainWindow(CameraManager *cm, const OptionsParser::Options &options)
 {
 	int ret;
 
+	createToolbars();
+
 	title_ = "QCam " + QString::fromStdString(CameraManager::version());
 	setWindowTitle(title_);
 	connect(&titleTimer_, SIGNAL(timeout()), this, SLOT(updateTitle()));
@@ -40,8 +45,7 @@ MainWindow::MainWindow(CameraManager *cm, const OptionsParser::Options &options)
 		ret = startCapture();
 
 	if (ret < 0)
-		QTimer::singleShot(0, QCoreApplication::instance(),
-				   &QCoreApplication::quit);
+		quit();
 }
 
 MainWindow::~MainWindow()
@@ -53,6 +57,39 @@ MainWindow::~MainWindow()
 	}
 }
 
+int MainWindow::createToolbars()
+{
+	QAction *action;
+
+	toolbar_ = addToolBar("Main");
+
+	/* Disable right click context menu */
+	toolbar_->setContextMenuPolicy(Qt::PreventContextMenu);
+
+	action = toolbar_->addAction("Quit");
+	connect(action, &QAction::triggered, this, &MainWindow::quit);
+
+	/* Camera selection */
+	QComboBox *cameraCombo = new QComboBox();
+	connect(cameraCombo, QOverload<int>::of(&QComboBox::activated),
+		this, &MainWindow::switchCamera);
+
+	for (const std::shared_ptr<Camera> &cam : cm_->cameras())
+		cameraCombo->addItem(QString::fromStdString(cam->name()));
+
+	toolbar_->addWidget(cameraCombo);
+
+	toolbar_->addSeparator();
+
+	return 0;
+}
+
+void MainWindow::quit()
+{
+	QTimer::singleShot(0, QCoreApplication::instance(),
+			   &QCoreApplication::quit);
+}
+
 void MainWindow::updateTitle()
 {
 	unsigned int duration = frameRateInterval_.elapsed();
@@ -66,6 +103,29 @@ void MainWindow::updateTitle()
 	setWindowTitle(title_ + " : " + QString::number(fps, 'f', 2) + " fps");
 }
 
+void MainWindow::switchCamera(int index)
+{
+	const auto &cameras = cm_->cameras();
+	if (static_cast<unsigned int>(index) >= cameras.size())
+		return;
+
+	const std::shared_ptr<Camera> &cam = cameras[index];
+
+	if (cam->acquire()) {
+		std::cout << "Failed to acquire camera " << cam->name() << std::endl;
+		return;
+	}
+
+	std::cout << "Switching to camera " << cam->name() << std::endl;
+
+	stopCapture();
+
+	camera_->release();
+	camera_ = cam;
+
+	startCapture();
+}
+
 std::string MainWindow::chooseCamera()
 {
 	QStringList cameras;
diff --git a/src/qcam/main_window.h b/src/qcam/main_window.h
index d19cda16e36b..12af103f87d0 100644
--- a/src/qcam/main_window.h
+++ b/src/qcam/main_window.h
@@ -41,9 +41,13 @@ public:
 	~MainWindow();
 
 private Q_SLOTS:
+	void quit();
 	void updateTitle();
 
+	void switchCamera(int index);
+
 private:
+	int createToolbars();
 	std::string chooseCamera();
 	int openCamera();
 
@@ -71,6 +75,7 @@ private:
 	uint32_t previousFrames_;
 	uint32_t framesCaptured_;
 
+	QToolBar *toolbar_;
 	ViewFinder *viewfinder_;
 	std::map<int, std::pair<void *, unsigned int>> mappedBuffers_;
 };
-- 
2.20.1