zoom_controller.h

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2013-2020 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * 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 2
 * 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, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 *
 */

#ifndef __ZOOM_CONTROLLER_H
#define __ZOOM_CONTROLLER_H

#include <chrono>
#include <memory>

namespace KIGFX
{

class ZOOM_CONTROLLER
{
public:
    virtual ~ZOOM_CONTROLLER() = default;

    virtual double GetScaleForRotation( int aRotation ) = 0;
};


class ACCELERATING_ZOOM_CONTROLLER : public ZOOM_CONTROLLER
{
public:
    using TIMEOUT = std::chrono::milliseconds;

    using CLOCK = std::chrono::steady_clock;

    using TIME_PT = std::chrono::time_point<CLOCK>;

    static constexpr TIMEOUT DEFAULT_TIMEOUT = std::chrono::milliseconds( 500 );

    static constexpr double DEFAULT_ACCELERATION_SCALE = 5.0;

    /*
     * A class interface that provides timestamps for events.
     */
    class TIMESTAMP_PROVIDER
    {
    public:
        virtual ~TIMESTAMP_PROVIDER() = default;

        /*
         * @return the timestamp at the current time.
         */
        virtual TIME_PT GetTimestamp() = 0;
    };

    ACCELERATING_ZOOM_CONTROLLER( double aScale = DEFAULT_ACCELERATION_SCALE,
                                  const TIMEOUT& aAccTimeout = DEFAULT_TIMEOUT,
                                  TIMESTAMP_PROVIDER* aTimestampProv = nullptr );

    double GetScaleForRotation( int aRotation ) override;

    TIMEOUT GetTimeout() const
    {
        return m_accTimeout;
    }

    void SetTimeout( const TIMEOUT& aNewTimeout )
    {
        m_accTimeout = aNewTimeout;
    }

private:
    TIMESTAMP_PROVIDER* m_timestampProv;

    std::unique_ptr<TIMESTAMP_PROVIDER> m_ownTimestampProv;

    TIME_PT m_lastTimestamp;

    TIMEOUT m_accTimeout;

    double m_scale;
};


class CONSTANT_ZOOM_CONTROLLER : public ZOOM_CONTROLLER
{
public:
    CONSTANT_ZOOM_CONTROLLER( double aScale );

    double GetScaleForRotation( int aRotation ) override;

    static constexpr double GTK3_SCALE = 0.002;

    static constexpr double MAC_SCALE = 0.01;

    static constexpr double MSW_SCALE = 0.005;

    static constexpr double MANUAL_SCALE_FACTOR = 0.001;

private:
    double m_scale;
};

} // namespace KIGFX

#endif