kicad/include/view/zoom_controller.h

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/*
* This program source code file is part of KiCad, a free EDA CAD application.
*
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* 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
*
*/
/**
* @file zoom_control.h
* @brief ZOOM_CONTROLLER class definition.
*/
#ifndef __ZOOM_CONTROLLER_H
#define __ZOOM_CONTROLLER_H
#include <chrono>
#include <memory>
namespace KIGFX
{
/**
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* Handle the response of the zoom scale to external inputs.
*/
class ZOOM_CONTROLLER
{
public:
virtual ~ZOOM_CONTROLLER() = default;
/**
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* Get the scale factor produced by a given mousewheel rotation.
*
* @param aRotation rotation of the mouse wheel (this comes from
* wxMouseEvent::GetWheelRotation()).
* @return the scale factor to scroll by.
*/
virtual double GetScaleForRotation( int aRotation ) = 0;
};
/**
* Class that zooms faster if scroll events happen very close together.
*/
class ACCELERATING_ZOOM_CONTROLLER : public ZOOM_CONTROLLER
{
public:
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///< The type of the acceleration timeout.
using TIMEOUT = std::chrono::milliseconds;
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///< The clock used for the timestamp (guaranteed to be monotonic).
using CLOCK = std::chrono::steady_clock;
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///< The type of the time stamps.
using TIME_PT = std::chrono::time_point<CLOCK>;
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///< The default timeout, after which a another scroll will not be accelerated.
static constexpr TIMEOUT DEFAULT_TIMEOUT = std::chrono::milliseconds( 500 );
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///< The default minimum step factor for accelerating controller.
static constexpr double DEFAULT_ACCELERATION_SCALE = 5.0;
/*
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* A class interface that provides timestamps for events.
*/
class TIMESTAMP_PROVIDER
{
public:
virtual ~TIMESTAMP_PROVIDER() = default;
/*
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* @return the timestamp at the current time.
*/
virtual TIME_PT GetTimestamp() = 0;
};
/**
* @param aAccTimeout the timeout - if a scroll happens within this timeframe,
* the zoom will be faster
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* @param aTimestampProv a provider for timestamps. If null, a default will be provided,
* which is the main steady_clock (this is probably what you want
* for real usage)
*/
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:
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///< The timestamp provider to use (might be provided externally).
TIMESTAMP_PROVIDER* m_timestampProv;
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///< Any provider owned by this class (the default one, if used).
std::unique_ptr<TIMESTAMP_PROVIDER> m_ownTimestampProv;
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///< The timestamp of the last event.
TIME_PT m_lastTimestamp;
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///< The timeout value.
TIMEOUT m_accTimeout;
/// A multiplier for the minimum zoom step size
double m_scale;
};
/**
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* A #ZOOM_CONTROLLER that zooms by a fixed factor based only on the magnitude of the scroll
* wheel rotation.
*/
class CONSTANT_ZOOM_CONTROLLER : public ZOOM_CONTROLLER
{
public:
/**
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* @param aScale a scaling parameter that adjusts the magnitude of the scroll. This factor
* might be dependent on the platform for comfort.
*/
CONSTANT_ZOOM_CONTROLLER( double aScale );
double GetScaleForRotation( int aRotation ) override;
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///< A suitable (magic) scale factor for GTK3 systems.
static constexpr double GTK3_SCALE = 0.002;
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///< A suitable (magic) scale factor for Mac systems.
static constexpr double MAC_SCALE = 0.01;
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///< Multiplier for manual scale ssetting.
static constexpr double MANUAL_SCALE_FACTOR = 0.001;
private:
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///< The scale factor set by the constructor.
double m_scale;
};
} // namespace KIGFX
#endif