Rotary.cpp

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/*
 * Hydrogen
 * Copyright(c) 2002-2008 by Alex >Comix< Cominu [comix@users.sourceforge.net]
 * Copyright(c) 2008-2025 The hydrogen development team [hydrogen-devel@lists.sourceforge.net]
 *
 * http://www.hydrogen-music.org
 *
 * 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 "Rotary.h"
#include "../Skin.h"
#include "../HydrogenApp.h"
#include "../MainForm.h"
 
#include <cmath>
 
#include <QFile>
#include <QSvgRenderer>
 
#include <core/Globals.h>
 
Rotary::Rotary( QWidget* parent, Type type, QString sBaseTooltip, bool bUseIntSteps, float fMin, float fMax, bool bModifyOnChange )
        : WidgetWithInput( parent,
                                           bUseIntSteps,
                                           sBaseTooltip,
                                           1, //nScrollSpeed,
                                           5, // nScrollSpeedFast,
                                           fMin,
                                           fMax,
                                           bModifyOnChange )
        , m_type( type ) {
 
        connect( HydrogenApp::get_instance(), &HydrogenApp::preferencesChanged,
                         this, &Rotary::onPreferencesChanged );
 
        installEventFilter( HydrogenApp::get_instance()->getMainForm() );
 
        if ( type == Type::Small ) {
                m_nWidgetWidth = 18;
                m_nWidgetHeight = 18;
        } else {
                m_nWidgetWidth = 44;
                m_nWidgetHeight = 26;
        }
 
        if ( bUseIntSteps ) {
                m_fDefaultValue = static_cast<int>( type == Type::Center ? ( m_fMin + ( m_fMax - m_fMin ) / 2.0 ) : m_fMin );
        }
        else {
                m_fDefaultValue = ( type == Type::Center ? ( m_fMin + ( m_fMax - m_fMin ) / 2.0 ) : m_fMin );
        }
 
        m_fValue = m_fDefaultValue;
        updateTooltip();
 
        // Since the load function does not report success, we will check
        // for the existence of the knob image separately.
        QString sKnobPath( Skin::getSvgImagePath() + "/rotary.svg" ); 
        QFile knobFile( sKnobPath );
        if ( knobFile.exists() ) {
                m_knob = new QSvgRenderer( sKnobPath, this );
        } else {
                m_knob = nullptr;
                ERRORLOG( QString( "Unable to load knob image [%1]" ).arg( sKnobPath ) );
        }
 
        QString sBackgroundPath( Skin::getSvgImagePath() + "/rotary_background.svg" ); 
        QFile backgroundFile( sBackgroundPath );
        if ( backgroundFile.exists() ) {
                m_background = new QSvgRenderer( sBackgroundPath, this );
        } else {
                m_background = nullptr;
                ERRORLOG( QString( "Unable to load background image [%1]" ).arg( sBackgroundPath ) );
        }
        
        resize( m_nWidgetWidth, m_nWidgetHeight );
}
 
Rotary::~ Rotary() {
}
 
void Rotary::paintEvent( QPaintEvent* ev )
{
 
        auto pPref = H2Core::Preferences::get_instance();
 
        ev->accept();
        QPainter painter( this );
 
        painter.setRenderHint( QPainter::Antialiasing, true );
 
        QColor colorHighlightActive;
        QColor colorArc;
        QColor colorArcCenterSet;
        QColor colorArcCenterUnset;
        if ( m_bIsActive ) {
                colorHighlightActive = pPref->getColorTheme()->m_highlightColor;
                colorArc = Qt::red;
                colorArcCenterSet = Qt::green;
                colorArcCenterUnset = Qt::gray;
        } else {
                colorHighlightActive = pPref->getColorTheme()->m_lightColor;
                colorArc = Qt::darkGray;
                colorArcCenterSet = Qt::darkGray;
                colorArcCenterUnset = Qt::lightGray;
        }
        QColor colorHandle = Qt::black;
        QColor colorFont = Qt::white;
 
        // If the mouse is placed on the widget but the user hasn't
        // clicked it yet, the highlight will be done more transparent to
        // indicate that keyboard inputs are not accepted yet.
        if ( ! hasFocus() ) {
                colorHighlightActive.setAlpha( 150 );
        }
        
        QRect rectBackground( 0, 0, m_nWidgetWidth, m_nWidgetHeight );
        // Contains both the painted arc and the actual SVG image of the
        // knob.
        QRect rectRotary, rectArc;
        float fArcLineWidth, fBlackMargin;
        if ( m_type != Type::Small ) {
                // Center the rotary while using the full height of the widget.
                fArcLineWidth = 2.0;
                rectArc = QRect( ( m_nWidgetWidth - m_nWidgetHeight + fArcLineWidth ) * 0.5,
                                                 fArcLineWidth / 2,
                                                 m_nWidgetHeight - fArcLineWidth,
                                                 m_nWidgetHeight - fArcLineWidth );
                rectRotary = QRect( rectArc.x() + fArcLineWidth / 2,
                                                        rectArc.y() + fArcLineWidth / 2,
                                                        rectArc.width() - fArcLineWidth,
                                                        rectArc.height() - fArcLineWidth );
        }
        
        if ( m_background != nullptr && m_type != Type::Small ) {
                m_background->render( &painter, rectBackground );
        }
                        
        if ( m_bEntered || hasFocus()  ) {
                painter.fillRect( 0, m_nWidgetHeight - 2, m_nWidgetWidth, 2, colorHighlightActive );
        }
 
        if ( m_knob != nullptr ) {
                if ( m_type == Type::Small ) {
                        m_knob->render( &painter, rectBackground );
                } else {
                        m_knob->render( &painter, "layer2", rectRotary );
                }
        }
 
        if ( m_bIsActive ) {
                if ( m_type != Type::Small ) {
                        if ( m_type == Type::Normal ) {
                                int nStartAngle = 210 * 16; // given in 1/16 of a degree
                                int nSpanAngle  = static_cast<int>( -239 * 16 * ( m_fValue - m_fMin ) / ( m_fMax - m_fMin ) );
 
                                painter.setPen( QPen( colorArc, fArcLineWidth ) );
                                painter.drawArc( rectArc, nStartAngle, nSpanAngle );
                        } else {
                                // Type::Center
 
                                // There will be a special indication of the
                                // center. Either as a gray dot or a bigger green one if
                                // the value is smaller than +/-1% of the range around 0.
                                if ( ( m_fValue - 0.5 * ( m_fMax + m_fMin ) ) == 0 ) {
                                
                                        painter.setPen( QPen( colorArcCenterSet, fArcLineWidth * 1.25 ) );
                                        painter.drawArc( rectArc, 91 * 16, -3 * 16 );
                                
                                } else {
                                
                                        painter.setPen( QPen( colorArcCenterUnset, fArcLineWidth * 1.25 ) );
                                        painter.drawArc( rectArc, 91 * 16, -3 * 16 );
 
                                        int nStartAngle = -18 * 16;
                                        int nSpanAngle  = static_cast<int>( -200* 16 * ( m_fValue - 0.5 * ( m_fMax + m_fMin ) ) / ( m_fMax - m_fMin ) );
                                        if ( m_fValue - 0.5 * ( m_fMax + m_fMin ) < 0 ) {
                                                nStartAngle *= -1;
                                                nStartAngle -= 2 * 16;
                                        }
                                        nStartAngle += 90 * 16;
                                
                                        painter.setPen( QPen( colorArc, fArcLineWidth ) );
                                        painter.drawArc( rectArc, nStartAngle, nSpanAngle ); 
                                }
                        }
                }
        }
        
        float fCurrentAngle;
        float fStartAngle;
        if ( m_type == Type::Center ) {
                fStartAngle = -90 * M_PI / 180;
                fCurrentAngle = fStartAngle + 255 * M_PI / 180 * ( m_fValue - 0.5 * ( m_fMax + m_fMin ) ) / (  m_fMax - m_fMin );
        } else {
                fStartAngle = -90 * M_PI / 180;
                fCurrentAngle = fStartAngle + 255 * M_PI / 180 * ( m_fValue - m_fMin - 0.5 * ( m_fMax - m_fMin ) ) / ( m_fMax - m_fMin );
        }
        
        // Indicating the current position using a rotated line instead of
        // a dot
        //
        // float fLength, fWidth, fBaseX, fBaseY;
        // if ( m_type == Type::Small ) {
        //      fBaseX = 9.0;
        //      fBaseY = 9.0;
        //      fLength = 4;
        //      fWidth = 2;
        // } else {
        //      fBaseX = 22.0;
        //      fBaseY = 14.0;
        //      fLength = 6;
        //      fWidth = 3;
        // }
        //
        // QPointF p1( fBaseX + std::cos( fCurrentAngle + M_PI / 2 ) * fWidth / 2,
        //                      fBaseY + std::sin( fCurrentAngle + M_PI / 2 ) * fWidth / 2 );
        // QPointF p2( p1.x() + std::cos( fCurrentAngle ) * fLength,
        //                      p1.y() + std::sin( fCurrentAngle ) * fLength );
        // QPointF p3( p2.x() - std::cos( fCurrentAngle + M_PI / 2 ) * fWidth / 2,
        //                      p2.y() - std::sin( fCurrentAngle + M_PI / 2 ) * fWidth / 2 );
        // QPointF p4( p3.x() - std::cos( fCurrentAngle ) * fLength,
        //                      p3.y() - std::sin( fCurrentAngle ) * fLength );
        // QPainterPath path;
        // path.moveTo( p1 );
        // path.lineTo( p2 );
        // path.lineTo( p3 );
        // path.lineTo( p4 );
        //
        // path.setFillRule( Qt::WindingFill );
        // QPen pen( colorHandle );
        // pen.setJoinStyle( Qt::RoundJoin );
        // pen.setWidth( 1.7 );
        // painter.setPen( pen );
        // painter.setBrush( QBrush( colorHandle ) );
        // painter.drawPath( path );
 
        if ( m_bIsActive ) {
                float fDistance, fRadius, fBaseX, fBaseY;
                if ( m_type == Type::Small ) {
                        fBaseX = static_cast<float>( m_nWidgetWidth ) / 2.0;
                        fBaseY = static_cast<float>( m_nWidgetHeight ) / 2.0;
                        fDistance = 3;
                        fRadius = 1;
                } else {
                        fBaseX = rectRotary.x() + rectRotary.width()/2;
                        fBaseY = rectRotary.y() + rectRotary.height()/2;
                        fDistance = 4;
                        fRadius = 1.5;
                }
 
                QPointF p1( fBaseX + std::cos( fCurrentAngle ) * fDistance,
                                        fBaseY + std::sin( fCurrentAngle ) * fDistance );
                painter.setPen( QPen( colorHandle, 1 ) );
                painter.setBrush( QBrush( colorHandle ) );
                painter.drawEllipse( p1, fRadius, fRadius );
        }
 
        if ( m_type != Type::Small ) {
                QRectF leftTextRec( 2, 16, 7, 7 );
                QRectF rightTextRec( 34, 16, 9, 7 );
 
                QFont font( H2Core::Preferences::get_instance()->getApplicationFontFamily() );
                painter.setPen( QPen( colorFont, 3 ) );
                if ( std::fmod( m_fMin, 1 ) == 0 && std::fabs( m_fMin ) < 10 ) {
                        font.setPixelSize( 7 );
                        painter.setFont( font );
                        painter.drawText( leftTextRec, Qt::AlignCenter, QString::number( m_fMin ) );
                } else {
                        font.setPixelSize( 9 );
                        painter.setFont( font );
                        painter.drawText( leftTextRec, Qt::AlignCenter, "-" );
                }
                if ( std::fmod( m_fMax, 1 ) == 0 && std::fabs( m_fMax ) < 10 ) {
                        font.setPixelSize( 7 );
                        painter.setFont( font );
                        painter.drawText( rightTextRec, Qt::AlignCenter, QString::number( m_fMax ) );
                } else {
                        font.setPixelSize( 9 );
                        painter.setFont( font );
                        painter.drawText( rightTextRec, Qt::AlignCenter, "+" );
                }
        }
}
 
void Rotary::onPreferencesChanged( H2Core::Preferences::Changes changes ) {     
        if ( changes & H2Core::Preferences::Changes::Colors ) {
                update();
        }
}