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backends/keymapper/virtual-mouse.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef BACKENDS_KEYMAPPER_VIRTUAL_MOUSE_H
+#define BACKENDS_KEYMAPPER_VIRTUAL_MOUSE_H
+
+#include "common/scummsys.h"
+
+#include "common/events.h"
+
+namespace Common {
+
+class EventDispatcher;
+class Keymap;
+
+/**
+ * The Virtual Mouse can produce mouse move events on systems without a physical mouse.
+ *
+ * It is useful for moving the mouse cursor using a gamepad or a keyboard.
+ *
+ * This class defines a keymap with actions for moving the cursor in all four directions.
+ * The keymapper produces custom backend events whenever keys bound to these actions are
+ * pressed. This class handles the events through its EventObserver interface and produces
+ * mouse move events when necesssary through its EventSource interface.
+ */
+class VirtualMouse : public EventSource, public EventObserver {
+public:
+	VirtualMouse(EventDispatcher *eventDispatcher);
+	~VirtualMouse() override;
+
+	// EventSource API
+	bool pollEvent(Event &event) override;
+
+	// EventObserver API
+	bool notifyEvent(const Event &event) override;
+
+	/** Add the virtual mouse keymapper actions to a keymap */
+	void addActionsToKeymap(Keymap *keymap);
+
+private:
+	static const int32 kUpdateDelay = 12;
+	static const int32 kDefaultScreenWidth = 640;
+
+	enum {
+		kCustomActionVirtualAxisUp    = 10000,
+		kCustomActionVirtualAxisDown  = 10001,
+		kCustomActionVirtualAxisLeft  = 10002,
+		kCustomActionVirtualAxisRight = 10003,
+		kCustomActionVirtualMouseSlow = 10004
+	};
+
+	void handleAxisMotion(int16 axisPositionX, int16 axisPositionY);
+	float computeJoystickMouseSpeedFactor() const;
+
+	EventDispatcher *_eventDispatcher;
+
+	int16 _inputAxisPositionX;
+	int16 _inputAxisPositionY;
+
+	float _mouseVelocityX;
+	float _mouseVelocityY;
+	float _slowModifier;
+
+	float _subPixelRemainderX;
+	float _subPixelRemainderY;
+
+	uint32 _lastUpdateMillis;
+};
+
+} // End of namespace Common
+
+#endif // #ifndef BACKENDS_KEYMAPPER_VIRTUAL_MOUSE_H