Move V4L2 grabber code to separate library

Former-commit-id: f3003eb0142af3d085ccf93fff1b297ebc2321fc

libsrc/grabber/dispmanx/DispmanxFrameGrabber.h

@@ -0,0 +1,71 @@
+#pragma once
+
+// BCM includes
+#pragma GCC system_header
+#include <bcm_host.h>
+
+// STL includes
+#include <cstdint>
+
+// Utils includes
+#include <utils/Image.h>
+#include <utils/ColorRgba.h>
+#include <utils/VideoMode.h>
+
+///
+/// The DispmanxFrameGrabber is used for creating snapshots of the display (screenshots) with a
+/// downsized and scaled resolution.
+///
+class DispmanxFrameGrabber
+{
+public:
+	///
+	/// Construct a DispmanxFrameGrabber that will capture snapshots with specified dimensions.
+	///
+	/// @param[in] width  The width of the captured screenshot
+	/// @param[in] height The heigth of the captured screenshot
+	///
+	DispmanxFrameGrabber(const unsigned width, const unsigned height);
+	~DispmanxFrameGrabber();
+
+	///
+	/// Updates the frame-grab flags as used by the VC library for frame grabbing
+	///
+	/// @param vc_flags  The snapshot grabbing mask
+	///
+	void setFlags(const int vc_flags);
+
+	///
+	/// Set the video mode (2D/3D)
+	/// @param[in] mode The new video mode
+	///
+	void setVideoMode(const VideoMode videoMode);
+
+	///
+	/// Captures a single snapshot of the display and writes the data to the given image. The
+	/// provided image should have the same dimensions as the configured values (_width and
+	/// _height)
+	///
+	/// @param[out] image  The snapped screenshot (should be initialized with correct width and
+	/// height)
+	///
+	void grabFrame(Image<ColorRgba> & image);
+
+private:
+	/// Handle to the display that is being captured
+	DISPMANX_DISPLAY_HANDLE_T _vc_display;
+
+	/// Handle to the resource for storing the captured snapshot
+	DISPMANX_RESOURCE_HANDLE_T _vc_resource;
+
+	/// Rectangle of the captured resource that is transfered to user space
+	VC_RECT_T _rectangle;
+
+	/// Flags (transforms) for creating snapshots
+	int _vc_flags;
+
+	/// With of the captured snapshot [pixels]
+	const unsigned _width;
+	/// Height of the captured snapshot [pixels]
+	const unsigned _height;
+};