qcam: Add Qt-based GUI application

qcam is a sample camera GUI application based on Qt. It demonstrates
integration of the Qt event loop with libcamera.

The application lets the user select a camera through the GUI, and then
captures a single stream from the camera and displays it in a window.
Only streams in YUYV formats are supported for now.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Tested-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 145 insertions, 0 deletions

diff --git a/src/qcam/qt_event_dispatcher.cpp b/src/qcam/qt_event_dispatcher.cpp
new file mode 100644
index 00000000..5ba451bf
--- /dev/null
+++ b/src/qcam/qt_event_dispatcher.cpp
@@ -0,0 +1,145 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * qt_event_dispatcher.cpp - qcam - Qt-based event dispatcher
+ */
+
+#include <iostream>
+
+#include <QAbstractEventDispatcher>
+#include <QCoreApplication>
+#include <QSocketNotifier>
+#include <QTimerEvent>
+
+#include <libcamera/event_notifier.h>
+#include <libcamera/timer.h>
+
+#include "qt_event_dispatcher.h"
+
+using namespace libcamera;
+
+QtEventDispatcher::QtEventDispatcher()
+{
+}
+
+QtEventDispatcher::~QtEventDispatcher()
+{
+	for (auto &it : notifiers_) {
+		NotifierSet &set = it.second;
+		delete set.read.qnotifier;
+		delete set.write.qnotifier;
+		delete set.exception.qnotifier;
+	}
+}
+
+void QtEventDispatcher::registerEventNotifier(EventNotifier *notifier)
+{
+	NotifierSet &set = notifiers_[notifier->fd()];
+	QSocketNotifier::Type qtype;
+	void (QtEventDispatcher::*method)(int);
+	NotifierPair *pair;
+
+	switch (notifier->type()) {
+	case EventNotifier::Read:
+	default:
+		qtype = QSocketNotifier::Read;
+		method = &QtEventDispatcher::readNotifierActivated;
+		pair = &set.read;
+		break;
+
+	case EventNotifier::Write:
+		qtype = QSocketNotifier::Write;
+		method = &QtEventDispatcher::writeNotifierActivated;
+		pair = &set.write;
+		break;
+
+	case EventNotifier::Exception:
+		qtype = QSocketNotifier::Exception;
+		method = &QtEventDispatcher::exceptionNotifierActivated;
+		pair = &set.exception;
+		break;
+	}
+
+	QSocketNotifier *qnotifier = new QSocketNotifier(notifier->fd(), qtype);
+	connect(qnotifier, &QSocketNotifier::activated, this, method);
+	pair->notifier = notifier;
+	pair->qnotifier = qnotifier;
+}
+
+void QtEventDispatcher::unregisterEventNotifier(EventNotifier *notifier)
+{
+	NotifierSet &set = notifiers_[notifier->fd()];
+	NotifierPair *pair;
+
+	switch (notifier->type()) {
+	case EventNotifier::Read:
+	default:
+		pair = &set.read;
+		break;
+
+	case EventNotifier::Write:
+		pair = &set.write;
+		break;
+
+	case EventNotifier::Exception:
+		pair = &set.exception;
+		break;
+	}
+
+	delete pair->qnotifier;
+	pair->qnotifier = nullptr;
+	pair->notifier = nullptr;
+}
+
+void QtEventDispatcher::readNotifierActivated(int socket)
+{
+	EventNotifier *notifier = notifiers_[socket].read.notifier;
+	notifier->activated.emit(notifier);
+}
+
+void QtEventDispatcher::writeNotifierActivated(int socket)
+{
+	EventNotifier *notifier = notifiers_[socket].write.notifier;
+	notifier->activated.emit(notifier);
+}
+
+void QtEventDispatcher::exceptionNotifierActivated(int socket)
+{
+	EventNotifier *notifier = notifiers_[socket].exception.notifier;
+	notifier->activated.emit(notifier);
+}
+
+void QtEventDispatcher::registerTimer(Timer *timer)
+{
+	int timerId = startTimer(timer->interval());
+	timers_[timerId] = timer;
+	timerIds_[timer] = timerId;
+}
+
+void QtEventDispatcher::unregisterTimer(Timer *timer)
+{
+	auto it = timerIds_.find(timer);
+	timers_.erase(it->second);
+	killTimer(it->second);
+	timerIds_.erase(it);
+}
+
+void QtEventDispatcher::timerEvent(QTimerEvent *event)
+{
+	auto it = timers_.find(event->timerId());
+	timerIds_.erase(it->second);
+	killTimer(it->first);
+	timers_.erase(it);
+}
+
+void QtEventDispatcher::processEvents()
+{
+	std::cout << "QtEventDispatcher::processEvents() should not be called"
+		  << std::endl;
+}
+
+void QtEventDispatcher::interrupt()
+{
+	QCoreApplication::eventDispatcher()->interrupt();
+}