zoom_controller.cpp

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2012 Torsten Hueter, torstenhtr <at> gmx.de
 * Copyright (C) 2013-2015 CERN
 * Copyright The KiCad Developers, see AUTHORS.txt for contributors.
 *
 * @author Tomasz Wlostowski <[email protected]>
 * @author Maciej Suminski <[email protected]>
 *
 * 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, see <https://www.gnu.org/licenses/>.
 */
 
#include <view/zoom_controller.h>
 
#include <trace_helpers.h>
 
#include <wx/log.h>
 
#include <algorithm>
#include <cmath>
 
using namespace KIGFX;
 
 
// Bounds the zoom of a single event however many notches it reports
static constexpr double MAX_MERGED_NOTCHES = 10.0;
 
 
// Notches carried by one wheel event, where aWheelDelta is the rotation of a single notch
// A zero aWheelDelta means the rotation is a scroll distance, so the event counts as one notch
static double notchCount( int aRotation, int aWheelDelta )
{
    if( aWheelDelta <= 0 )
        return 1.0;
 
    return std::clamp( std::abs( double( aRotation ) ) / aWheelDelta, 1.0, MAX_MERGED_NOTCHES );
}
 

class SIMPLE_TIMESTAMPER : public ACCELERATING_ZOOM_CONTROLLER::TIMESTAMP_PROVIDER
{
public:
    ACCELERATING_ZOOM_CONTROLLER::TIME_PT GetTimestamp() override
    {
        return ACCELERATING_ZOOM_CONTROLLER::CLOCK::now();
    }
};
 
 
ACCELERATING_ZOOM_CONTROLLER::ACCELERATING_ZOOM_CONTROLLER(
        double aScale, const TIMEOUT& aAccTimeout, TIMESTAMP_PROVIDER* aTimestampProv ) :
        m_accTimeout( aAccTimeout ),
        m_scale( aScale )
{
    if( aTimestampProv )
    {
        m_timestampProv = aTimestampProv;
    }
    else
    {
        m_ownTimestampProv = std::make_unique<SIMPLE_TIMESTAMPER>();
        m_timestampProv = m_ownTimestampProv.get();
    }
 
    m_prevTimestamp = m_timestampProv->GetTimestamp();
}
 
 
double ACCELERATING_ZOOM_CONTROLLER::GetScaleForRotation( int aRotation, int aWheelDelta )
{
    // The minimal step value when changing the current zoom level
    const double minStep = 1.05;
 
    const auto timestamp = m_timestampProv->GetTimestamp();
    auto       timeDiff = std::chrono::duration_cast<TIMEOUT>( timestamp - m_prevTimestamp );
 
    m_prevTimestamp = timestamp;
 
    wxLogTrace( traceZoomScroll,
            wxString::Format( "Rot %d, time diff: %ldms", aRotation, (long)timeDiff.count() ) );
 
    double zoomScale;
 
    // Set scaling speed depending on scroll wheel event interval
    if( timeDiff < m_accTimeout
        && ( (aRotation > 0) == m_prevRotationPositive ) )
    {
        zoomScale = ( 2.05 * m_scale / 5.0 ) - timeDiff / m_accTimeout;
 
        // be sure zoomScale value is significant
        zoomScale = std::max( zoomScale, minStep );
 
        if( aRotation < 0 )
            zoomScale = 1.0 / zoomScale;
    }
    else
    {
        zoomScale = ( aRotation > 0 ) ? minStep : 1 / minStep;
    }
    m_prevRotationPositive = aRotation > 0;
 
    if( notchCount( aRotation, aWheelDelta ) > 1.0 )
        zoomScale = std::pow( zoomScale, notchCount( aRotation, aWheelDelta ) );
 
    wxLogTrace( traceZoomScroll, wxString::Format( "  Zoom factor: %f", zoomScale ) );
 
    return zoomScale;
}
 
#ifdef __MINGW32__
// For some reason, this is needed to avoid a link issue
// (undefined reference to ACCELERATING_ZOOM_CONTROLLER::DEFAULT_TIMEOUT
// and GAL_API CONSTANT_ZOOM_CONTROLLER::MSW_SCALE)
constexpr ACCELERATING_ZOOM_CONTROLLER::TIMEOUT ACCELERATING_ZOOM_CONTROLLER::DEFAULT_TIMEOUT;
constexpr double GAL_API CONSTANT_ZOOM_CONTROLLER::MSW_SCALE;
#endif
 
 
CONSTANT_ZOOM_CONTROLLER::CONSTANT_ZOOM_CONTROLLER( double aScale ) : m_scale( aScale )
{
}
 
 
double CONSTANT_ZOOM_CONTROLLER::GetScaleForRotation( int aRotation, int aWheelDelta )
{
    wxLogTrace( traceZoomScroll, wxString::Format( "Rot %d", aRotation ) );
 
    // One notch is worth at most 100 units, and each further notch of a merged event zooms by it again
    const double stepCap = aWheelDelta > 0 ? std::min( aWheelDelta, 100 ) : 100;
    const double oneStep = std::min( std::abs( double( aRotation ) ), stepCap );
    const double factor = std::pow( 1.0 + oneStep * m_scale, notchCount( aRotation, aWheelDelta ) );
    const double zoom_scale = aRotation > 0 ? factor : 1.0 / factor;
 
    wxLogTrace( traceZoomScroll, wxString::Format( "  Zoom factor: %f", zoom_scale ) );
 
    return zoom_scale;
}