Add "Source interact" action

plugins/base/utils/source-preview-widget.hpp

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <obs.h>
+#include <graphics/graphics.h>
+
+#include <QWidget>
+
+class QResizeEvent;
+
+namespace advss {
+
+// A native window widget that renders an OBS source via obs_display.
+// Stores letterbox geometry for coordinate mapping.
+class SourcePreviewWidget : public QWidget {
+	Q_OBJECT
+public:
+	SourcePreviewWidget(QWidget *parent, obs_weak_source_t *source);
+	~SourcePreviewWidget();
+
+	// Maps a widget-local point to source-space coordinates.
+	bool GetSourceRelativeXY(int widgetX, int widgetY, int &srcX,
+				 int &srcY) const;
+
+protected:
+	void resizeEvent(QResizeEvent *) override;
+	QPaintEngine *paintEngine() const override { return nullptr; }
+
+private:
+	static void DrawCallback(void *param, uint32_t cx, uint32_t cy);
+
+	obs_weak_source_t *_source;
+	obs_display_t *_display = nullptr;
+	bool _showing = false;
+
+	int _offsetX = 0;
+	int _offsetY = 0;
+	float _scale = 1.0f;
+};
+
+} // namespace advss