UI: Make window-projector its own top level QWidget

Previously OBSProjector was a subclass of OBSQTDisplay, which is
intended to own the entire surface it draws on. On wayland some
compositors expect the client to draw decorations (window titlebar), but
because OBSQTDisplay draws on the entire surface directly the client
decorations from QT are overwritten.

Instead promote OBSProjector to a simple QWidget with a single layout
containing the OBSQTDisplay. This allows the OBSQTDisplay to own the
entire contents while OBSProjector draws the decorations.

fixes obsproject#6283

UI/qt-display.hpp

@@ -5,12 +5,16 @@
 
 #define GREY_COLOR_BACKGROUND 0xFF4C4C4C
 
+class OBSProjector;
+
 class OBSQTDisplay : public QWidget {
 	Q_OBJECT
 	Q_PROPERTY(QColor displayBackgroundColor MEMBER backgroundColor READ
 			   GetDisplayBackgroundColor WRITE
 				   SetDisplayBackgroundColor)
 
+	friend class OBSProjector;
+
 	OBSDisplay display;
 
 	virtual void paintEvent(QPaintEvent *event) override;

UI/window-projector.cpp

@@ -19,11 +19,16 @@ static size_t maxSrcs, numSrcs;
 
 OBSProjector::OBSProjector(QWidget *widget, obs_source_t *source_, int monitor,
 			   ProjectorType type_)
-	: OBSQTDisplay(widget, Qt::Window),
+	: display(this),
 	  source(source_),
 	  removedSignal(obs_source_get_signal_handler(source), "remove",
 			OBSSourceRemoved, this)
 {
+	QVBoxLayout *layout = new QVBoxLayout;
+	layout->addWidget(&display);
+	layout->setContentsMargins(0, 0, 0, 0);
+	this->setLayout(layout);
+
 	isAlwaysOnTop = config_get_bool(GetGlobalConfig(), "BasicWindow",
 					"ProjectorAlwaysOnTop");
 
@@ -32,7 +37,7 @@ OBSProjector::OBSProjector(QWidget *widget, obs_source_t *source_, int monitor,
 
 	// Mark the window as a projector so SetDisplayAffinity
 	// can skip it
-	windowHandle()->setProperty("isOBSProjectorWindow", true);
+	display.windowHandle()->setProperty("isOBSProjectorWindow", true);
 
 #if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__)
 	// Prevents resizing of projector windows
@@ -69,12 +74,14 @@ OBSProjector::OBSProjector(QWidget *widget, obs_source_t *source_, int monitor,
 	auto addDrawCallback = [this]() {
 		bool isMultiview = type == ProjectorType::Multiview;
 		obs_display_add_draw_callback(
-			GetDisplay(),
+			display.GetDisplay(),
 			isMultiview ? OBSRenderMultiview : OBSRender, this);
-		obs_display_set_background_color(GetDisplay(), 0x000000);
+		obs_display_set_background_color(display.GetDisplay(),
+						 0x000000);
 	};
 
-	connect(this, &OBSQTDisplay::DisplayCreated, addDrawCallback);
+	display.connect(&display, &OBSQTDisplay::DisplayCreated,
+			addDrawCallback);
 	connect(App(), &QGuiApplication::screenRemoved, this,
 		&OBSProjector::ScreenRemoved);
 
@@ -106,8 +113,8 @@ OBSProjector::~OBSProjector()
 {
 	bool isMultiview = type == ProjectorType::Multiview;
 	obs_display_remove_draw_callback(
-		GetDisplay(), isMultiview ? OBSRenderMultiview : OBSRender,
-		this);
+		display.GetDisplay(),
+		isMultiview ? OBSRenderMultiview : OBSRender, this);
 
 	if (source)
 		obs_source_dec_showing(source);
@@ -874,7 +881,7 @@ static int getSourceByPosition(int x, int y, float ratio)
 
 void OBSProjector::mouseDoubleClickEvent(QMouseEvent *event)
 {
-	OBSQTDisplay::mouseDoubleClickEvent(event);
+	display.mouseDoubleClickEvent(event);
 
 	if (!mouseSwitching)
 		return;
@@ -901,7 +908,7 @@ void OBSProjector::mouseDoubleClickEvent(QMouseEvent *event)
 
 void OBSProjector::mousePressEvent(QMouseEvent *event)
 {
-	OBSQTDisplay::mousePressEvent(event);
+	display.mousePressEvent(event);
 
 	if (event->button() == Qt::RightButton) {
 		OBSBasic *main =

UI/window-projector.hpp

@@ -26,12 +26,13 @@ enum class MultiviewLayout : uint8_t {
 	SCENES_ONLY_25_SCENES = 9,
 };
 
-class OBSProjector : public OBSQTDisplay {
+class OBSProjector : public QWidget {
 	Q_OBJECT
 
 private:
 	OBSSource source;
 	OBSSignal removedSignal;
+	OBSQTDisplay display;
 
 	static void OBSRenderMultiview(void *data, uint32_t cx, uint32_t cy);
 	static void OBSRender(void *data, uint32_t cx, uint32_t cy);