QtCollider/widgets/QcKnob.cpp

   1 /************************************************************************
   2 *
   3 * Copyright 2011-2012 Jakob Leben (jakob.leben@gmail.com)
   4 *
   5 * This file is part of SuperCollider Qt GUI.
   6 *
   7 * This program is free software: you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License as published by
   9 * the Free Software Foundation, either version 3 of the License, or
  10 * (at your option) any later version.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 *
  17 * You should have received a copy of the GNU General Public License
  18 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 *
  20 ************************************************************************/
  21
  22 #include "QcKnob.hpp"
  23 #include "../QcWidgetFactory.h"
  24 #include "../style/routines.hpp"
  25
  26 #include <QMouseEvent>
  27 #include <QPainter>
  28
  29 using namespace QtCollider;
  30
  31 QC_DECLARE_QWIDGET_FACTORY(QcKnob);
  32
  33 QcKnob::QcKnob() :
  34   Style::Client(this),
  35   _value(0.f),
  36   _mode(0),
  37   _step(0.01),
  38   _centered(false)
  39 {
  40   setFocusPolicy( Qt::StrongFocus );
  41   setSizePolicy( QSizePolicy::Minimum, QSizePolicy::Minimum );
  42 }
  43
  44 void QcKnob::setValue( double val )
  45 {
  46   _value = qBound( 0.0, val, 1.0 );
  47   update();
  48 }
  49
  50 void QcKnob::mousePressEvent( QMouseEvent *e )
  51 {
  52   if( _mode == 0 ) {
  53     setValue( value( e->pos() ) );
  54     Q_EMIT( action() );
  55   }
  56   _prevPos = e->pos();
  57 }
  58
  59 void QcKnob::mouseMoveEvent( QMouseEvent *e )
  60 {
  61   if( _mode == 0 ) {
  62       double val = value( e->pos() );
  63       if( !(val < 0.0 && _value > 0.5) && !(val > 1.0 && _value < 0.5) )
  64         setValue( value( e->pos() ) );
  65       Q_EMIT( action() );
  66   }
  67   else {
  68     int dif;
  69     dif = _mode == 1 ?
  70           e->pos().x() - _prevPos.x() :
  71           _prevPos.y() - e->pos().y();
  72     if( dif != 0 ) {
  73       float step = _step;
  74       modifyStep( &step );
  75       setValue( _value + dif * step );
  76       Q_EMIT( action() );
  77     }
  78   }
  79   _prevPos = e->pos();
  80 }
  81
  82 void QcKnob::paintEvent( QPaintEvent * )
  83 {
  84   using namespace QtCollider::Style;
  85   using QtCollider::Style::Ellipse;
  86
  87   QPainter p(this);
  88   p.setRenderHint( QPainter::Antialiasing, true );
  89
  90   const QPalette &plt( palette() );
  91   QColor cGroove = plt.color( QPalette::Window ).lighter( 115 );
  92   QColor cVal = plt.color( QPalette::ButtonText );
  93
  94   QRect bounds( rect() );
  95   int sz = qMin( bounds.width(), bounds.height() );
  96   float sz_2 = sz * 0.5f;
  97   QPointF center = QRectF(bounds).center();
  98
  99   p.translate( center );
 100
 101   double rad = sz_2 * 0.75;
 102   Ellipse shKnob(QRectF(-rad, -rad, rad*2, rad*2));
 103   drawRaised( &p, plt, shKnob,
 104               plt.color( QPalette::Button ).lighter(105),
 105               hasFocus() ? focusColor() : QColor() );
 106
 107   p.scale( sz_2, sz_2 );
 108
 109   QPen pen;
 110   pen.setWidthF( 0.1 );
 111   p.setBrush( Qt::NoBrush );
 112
 113   QRectF r( -0.95, -0.95, 1.9, 1.9 );
 114
 115   p.save(); // groove & value indicator rotation
 116
 117   double range = 300.0;
 118
 119   p.rotate( - 90 - range * 0.5 );
 120
 121   double valAng = - _value * range;
 122
 123   if( _centered ) {
 124     double min = qMin( valAng, -range * 0.5 );
 125     double max = qMax( valAng, -range * 0.5 );
 126
 127     pen.setColor( cGroove );
 128     p.setPen( pen );
 129     p.drawArc( r, -range * 16.f, (min + range) * 16.f );
 130     p.drawArc( r, max * 16.f, -max * 16.f );
 131
 132     pen.setColor( plt.color(QPalette::WindowText) );
 133     p.setPen( pen );
 134     p.drawArc( r, min * 16.f, (max - min) * 16.f );
 135   }
 136   else {
 137     pen.setColor( cGroove );
 138     p.setPen( pen );
 139     p.drawArc( r, -range * 16.f, (valAng + range) * 16.f );
 140
 141     pen.setColor( plt.color(QPalette::WindowText) );
 142     p.setPen( pen );
 143     p.drawArc( r, valAng * 16.f, -valAng * 16.f );
 144   }
 145
 146   p.restore(); // groove & value indicator rotation
 147
 148   p.rotate( (360.0 - range) * 0.5 - valAng );
 149
 150   QLineF line( 0, 0.05, 0, 0.55 );
 151   pen.setColor(cVal);
 152   pen.setWidthF( 0.15 );
 153   pen.setCapStyle( Qt::RoundCap );
 154   p.setPen( pen );
 155   p.drawLine( line );
 156 }
 157
 158 double QcKnob::value( const QPoint &pt )
 159 {
 160   double angle = QLineF( rect().center(), pt ).angle();
 161
 162   if( angle > 270.0 ) angle -= 270.0;
 163   else angle += 90;
 164   return (330 - angle) / 300.0;
 165 }