/*
 * Copyright © 2014 Canonical Ltd.
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 3,
 * as published by the Free Software Foundation.
 *
 * 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/>.
 *
 * Authored by: Robert Carr <robert.carr@canonical.com>
 */

#ifndef MIR_INPUT_TOUCH_VISUALIZER_H_
#define MIR_INPUT_TOUCH_VISUALIZER_H_

#include "mir/geometry/point.h"

#include <vector>

namespace mir
{
namespace input
{

/// An interface for listening to a low level stream of touches, in order to provide
// a "spot" style visualization.
class TouchVisualizer
{
public:
    virtual ~TouchVisualizer() = default;

    struct Spot
    {
        geometry::Point touch_location;
        
        // If pressure is zero, the touch-point can be interpreted as a hover.
        float pressure;
    };
    
    // Toggle visualization of touches
    virtual void enable() = 0;
    virtual void disable() = 0;
    
    // Visualize a given set of touches statelessly.
    virtual void visualize_touches(std::vector<Spot> const& touches) = 0;

protected:
    TouchVisualizer() = default;
    TouchVisualizer(const TouchVisualizer&) = delete;
    TouchVisualizer& operator=(const TouchVisualizer&) = delete;
};

inline bool operator==(TouchVisualizer::Spot const &lhs, TouchVisualizer::Spot const& rhs)
{
    return lhs.touch_location == rhs.touch_location &&
        lhs.pressure == rhs.pressure;
}

}
}

#endif // MIR_INPUT_TOUCH_VISUALIZER_H_
