vbox6: add mouse pointer shape support

Implement 'MousePointerShapeChanged' event, retrieve parameters from
COM pointer, and update shape report.

fixes #4283

repos/ports/src/virtualbox6/main.cc

@@ -38,6 +38,7 @@
 #include <init.h>
 #include <fb.h>
 #include <input_adapter.h>
+#include <mouse_shape.h>
 
 using namespace Genode;
 
@@ -259,6 +260,8 @@ struct Main : Event_handler
 		}
 	} _capslock { _env, _config.xml(), _capslock_handler };
 
+	Mouse_shape _mouse_shape { _env };
+
 	Registry<Registered<Gui::Connection>> _gui_connections { };
 
 	Signal_handler<Main> _input_handler { _env.ep(), *this, &Main::_handle_input };
@@ -418,7 +421,25 @@ void Main::handle_vbox_event(VBoxEventType_T ev_type, IEvent &ev)
 			_input_adapter.mouse_absolute(!!absolute);
 		} break;
 
-	case VBoxEventType_OnMousePointerShapeChanged: break;
+	case VBoxEventType_OnMousePointerShapeChanged:
+		{
+			ComPtr<IMousePointerShapeChangedEvent> shape_ev = &ev;
+			BOOL  visible, alpha;
+			ULONG xHot, yHot, width, height;
+			com::SafeArray <BYTE> shape;
+
+			shape_ev->COMGETTER(Visible)(&visible);
+			shape_ev->COMGETTER(Alpha)(&alpha);
+			shape_ev->COMGETTER(Xhot)(&xHot);
+			shape_ev->COMGETTER(Yhot)(&yHot);
+			shape_ev->COMGETTER(Width)(&width);
+			shape_ev->COMGETTER(Height)(&height);
+			shape_ev->COMGETTER(Shape)(ComSafeArrayAsOutParam(shape));
+
+			_mouse_shape.update(visible, alpha, xHot, yHot, width, height,
+			                    ComSafeArrayAsInParam(shape));
+
+		} break;
 
 	case VBoxEventType_OnKeyboardLedsChanged:
 		{

repos/ports/src/virtualbox6/mouse_shape.h

@@ -0,0 +1,120 @@
+/*
+ * \brief  VM mouse shape support
+ * \author Christian Prochaska
+ * \author Sebastian Sumpf
+ * \date   2021-10-05
+ */
+
+/*
+ * Copyright (C) 2021 Genode Labs GmbH
+ *
+ * This file is distributed under the terms of the GNU General Public License
+ * version 2.
+ */
+
+#ifndef _MOUSE_SHAPE_H_
+#define _MOUSE_SHAPE_H_
+
+#include <report_session/connection.h>
+#include <pointer/shape_report.h>
+
+
+class Mouse_shape
+{
+	private:
+
+		Genode::Env &_env;
+
+		Report::Connection _report_connection { _env, "shape",
+			sizeof(Pointer::Shape_report) };
+
+		Genode::Attached_dataspace _report_ds { _env.rm(),
+			_report_connection.dataspace() };
+
+		Pointer::Shape_report *_shape_report {
+			_report_ds.local_addr<Pointer::Shape_report>() };
+
+	public:
+
+		Mouse_shape(Genode::Env &env)
+		  : _env(env)
+		{ }
+
+		void update(BOOL visible,
+		            BOOL alpha,
+		            ULONG xHot,
+		            ULONG yHot,
+		            ULONG width,
+		            ULONG height,
+		            ComSafeArrayIn(BYTE,inShape))
+		{
+			com::SafeArray <BYTE> aShape(ComSafeArrayInArg(inShape));
+
+			if (visible && ((width == 0) || (height == 0)))
+				return;
+
+			_shape_report->visible = visible;
+			_shape_report->x_hot   = xHot;
+			_shape_report->y_hot   = yHot;
+			_shape_report->width   = width;
+			_shape_report->height  = height;
+
+			unsigned int and_mask_size = (_shape_report->width + 7) / 8 *
+			                              _shape_report->height;
+
+			const unsigned char *and_mask = aShape.raw();
+
+			const unsigned char *shape = and_mask + ((and_mask_size + 3) & ~3);
+
+			size_t shape_size = aShape.size() - (shape - and_mask);
+
+			if (shape_size > Pointer::MAX_SHAPE_SIZE) {
+				Genode::error("mouse shape: data buffer too small for ",
+				              shape_size, " bytes");
+				return;
+			}
+
+			/* convert the shape data from BGRA encoding to RGBA encoding */
+
+			unsigned char const *bgra_shape = shape;
+			unsigned char       *rgba_shape = _shape_report->shape;
+
+			for (unsigned int y = 0; y < _shape_report->height; y++) {
+
+				unsigned char const *bgra_line = &bgra_shape[y * _shape_report->width * 4];
+				unsigned char *rgba_line       = &rgba_shape[y * _shape_report->width * 4];
+
+				for (unsigned int i = 0; i < _shape_report->width * 4; i += 4) {
+					rgba_line[i + 0] = bgra_line[i + 2];
+					rgba_line[i + 1] = bgra_line[i + 1];
+					rgba_line[i + 2] = bgra_line[i + 0];
+					rgba_line[i + 3] = bgra_line[i + 3];
+				}
+			}
+
+			if (visible && !alpha) {
+
+				for (unsigned int i = 0; i < width * height; i++) {
+
+					unsigned int *color =
+						&((unsigned int*)_shape_report->shape)[i];
+
+					/* heuristic from VBoxSDL.cpp */
+
+					if (and_mask[i / 8] & (1 << (7 - (i % 8)))) {
+
+						if (*color & 0x00ffffff)
+							*color = 0xff000000;
+						else
+							*color = 0x00000000;
+
+					} else
+						*color |= 0xff000000;
+				}
+			}
+
+			_report_connection.submit(sizeof(Pointer::Shape_report));
+		}
+};
+
+#endif /* _MOUSE_SHAPE_H_ */