obs-studio/UI/qt-display.cpp

#include "qt-display.hpp"
#include "qt-wrappers.hpp"
#include "display-helpers.hpp"
#include <QWindow>
#include <QScreen>
#include <QResizeEvent>
#include <QShowEvent>

#include <obs-config.h>

#ifdef ENABLE_WAYLAND
#include <obs-nix-platform.h>

class SurfaceEventFilter : public QObject {
	OBSQTDisplay *display;
	int mTimerId;

public:
	SurfaceEventFilter(OBSQTDisplay *src) : display(src), mTimerId(0) {}

protected:
	bool eventFilter(QObject *obj, QEvent *event) override
	{
		bool result = QObject::eventFilter(obj, event);
		QPlatformSurfaceEvent *surfaceEvent;

		switch (event->type()) {
		case QEvent::PlatformSurface:
			surfaceEvent =
				static_cast<QPlatformSurfaceEvent *>(event);
			if (surfaceEvent->surfaceEventType() !=
			    QPlatformSurfaceEvent::SurfaceCreated)
				return result;

			if (display->windowHandle()->isExposed())
				createOBSDisplay();
			else
				mTimerId = startTimer(67); // Arbitrary
			break;
		case QEvent::Expose:
			createOBSDisplay();
			break;
		default:
			break;
		}

		return result;
	}

	void timerEvent(QTimerEvent *) { createOBSDisplay(true); }

private:
	void createOBSDisplay(bool force = false)
	{
		display->CreateDisplay(force);
		if (mTimerId > 0) {
			killTimer(mTimerId);
			mTimerId = 0;
		}
	}
};

#endif

static inline long long color_to_int(const QColor &color)
{
	auto shift = [&](unsigned val, int shift) {
		return ((val & 0xff) << shift);
	};

	return shift(color.red(), 0) | shift(color.green(), 8) |
	       shift(color.blue(), 16) | shift(color.alpha(), 24);
}

static inline QColor rgba_to_color(uint32_t rgba)
{
	return QColor::fromRgb(rgba & 0xFF, (rgba >> 8) & 0xFF,
			       (rgba >> 16) & 0xFF, (rgba >> 24) & 0xFF);
}

OBSQTDisplay::OBSQTDisplay(QWidget *parent, Qt::WindowFlags flags)
	: QWidget(parent, flags)
{
	setAttribute(Qt::WA_PaintOnScreen);
	setAttribute(Qt::WA_StaticContents);
	setAttribute(Qt::WA_NoSystemBackground);
	setAttribute(Qt::WA_OpaquePaintEvent);
	setAttribute(Qt::WA_DontCreateNativeAncestors);
	setAttribute(Qt::WA_NativeWindow);

	auto windowVisible = [this](bool visible) {
		if (!visible) {
#ifdef ENABLE_WAYLAND
			if (obs_get_nix_platform() == OBS_NIX_PLATFORM_WAYLAND)
				display = nullptr;
#endif
			return;
		}

		if (!display) {
			CreateDisplay();
		} else {
			QSize size = GetPixelSize(this);
			obs_display_resize(display, size.width(),
					   size.height());
		}
	};

	auto screenChanged = [this](QScreen *) {
		CreateDisplay();

		QSize size = GetPixelSize(this);
		obs_display_resize(display, size.width(), size.height());
	};

	connect(windowHandle(), &QWindow::visibleChanged, windowVisible);
	connect(windowHandle(), &QWindow::screenChanged, screenChanged);

#ifdef ENABLE_WAYLAND
	if (obs_get_nix_platform() == OBS_NIX_PLATFORM_WAYLAND)
		windowHandle()->installEventFilter(
			new SurfaceEventFilter(this));
#endif
}

QColor OBSQTDisplay::GetDisplayBackgroundColor() const
{
	return rgba_to_color(backgroundColor);
}

void OBSQTDisplay::SetDisplayBackgroundColor(const QColor &color)
{
	uint32_t newBackgroundColor = (uint32_t)color_to_int(color);

	if (newBackgroundColor != backgroundColor) {
		backgroundColor = newBackgroundColor;
		UpdateDisplayBackgroundColor();
	}
}

void OBSQTDisplay::UpdateDisplayBackgroundColor()
{
	obs_display_set_background_color(display, backgroundColor);
}

void OBSQTDisplay::CreateDisplay(bool force)
{
	if (display)
		return;

	if (!windowHandle()->isExposed() && !force)
		return;

	QSize size = GetPixelSize(this);

	gs_init_data info = {};
	info.cx = size.width();
	info.cy = size.height();
	info.format = GS_BGRA;
	info.zsformat = GS_ZS_NONE;

	if (!QTToGSWindow(windowHandle(), info.window))
		return;

	display = obs_display_create(&info, backgroundColor);

	emit DisplayCreated(this);
}

void OBSQTDisplay::resizeEvent(QResizeEvent *event)
{
	QWidget::resizeEvent(event);

	CreateDisplay();

	if (isVisible() && display) {
		QSize size = GetPixelSize(this);
		obs_display_resize(display, size.width(), size.height());
	}

	emit DisplayResized();
}

void OBSQTDisplay::paintEvent(QPaintEvent *event)
{
	CreateDisplay();

	QWidget::paintEvent(event);
}

QPaintEngine *OBSQTDisplay::paintEngine() const
{
	return nullptr;
}