citra_qt: camera integration (#3566)

* Implement camera feature

* Make OpenCVCamera optional

* Fix styling problems

* CI configuration

* Fix CI

* Hopefully final fix

* Hopefully final fix

* Fix all the problems

* Oops..

* Add Qt Multimedia Camera

* Another oops

* Try to fix broken linux CI

* Try to fix broken linux CI

* Fix problems

* Improve UI

* Fix problems

* camera: Add support for Qt <5.10 and fix preview error

* CI: try to fix linux-frozen travis build

* camera: fix problems and add multiple handlers support

* fix CI

* remove most ServiceFramework changes

* Fix format

* Remove last ServiceFramework change

* camera: remove unused interfaces; revert submodule change

* camera: fix CI error

* ci: use ccache for opencv build

* citra_qt: fix configuration error; CI: add mediaservice plugin

* citra_qt: fix clang-format

* citra_qt: fix documentation error

* citra_qt: fix configuration page; camera: fix pausing crash

* citra_qt: fix preview not stopping

* camera: extend handlers length

* camera: fix camera resume error

* camera: fix clang-format

* camera: remove all OpenCV; citra_qt: rewrite configuration

* camera: remove all OpenCV; citra_qt: rewrite configuration

* camera: remove all OpenCV; citra_qt: rewrite configuration

* CI: fix linux ci

* camera: check settings update; citra_qt: fix configuration error

* service_cam: use a better way to apply configuration

* Service_CAM: rewrite camera reload

* cam: fix clang format

* citra_qt: fix argument load issue; camera: base of system camera selection

* citra_qt: Add system camera selection

* camera: fix image upside down, Implement SetFrameRate in Qt Multimedia Camera

* camera: Add missing <array> include, update SetFrameRate and add settings in Qt Multimedia Camera header

* camera: move started in Qt Multimedia Camera header

* QtMultimediaCamera: Move frame rates to SetFrameRate; Set minimum and maximum frame rate

* Update appveyor.yml

src/citra_qt/camera/qt_camera_factory.cpp

@@ -0,0 +1,24 @@
+// Copyright 2018 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <QMessageBox>
+#include "citra_qt/camera/qt_camera_factory.h"
+
+namespace Camera {
+
+std::unique_ptr<CameraInterface> QtCameraFactory::CreatePreview(const std::string& config,
+                                                                int width, int height) const {
+    std::unique_ptr<CameraInterface> camera = Create(config);
+
+    if (camera->IsPreviewAvailable()) {
+        return camera;
+    }
+    QMessageBox::critical(nullptr, QObject::tr("Error"),
+                          QObject::tr("Couldn't load ") +
+                              (config.empty() ? QObject::tr("the camera") : "") +
+                              QString::fromStdString(config));
+    return nullptr;
+}
+
+} // namespace Camera