Zooming with mouse wheel center

include/SongEditor.h

@@ -135,6 +135,7 @@ private slots:
 
  bool m_scrollBack;
  bool m_smoothScroll;
+ int m_widgetWidthTotal;
 
  EditMode m_mode;
  EditMode m_ctrlMode; // mode they were in before they hit ctrl

src/gui/editors/AutomationEditor.cpp

@@ -1634,6 +1634,17 @@ void AutomationEditor::wheelEvent(QWheelEvent * we )
  x--;
  }
  x = qBound( 0, x, m_zoomingXModel.size() - 1 );
+
+ int mouseX = (we->x() - VALUES_WIDTH)* MidiTime::ticksPerTact();
+ // ticks based on the mouse x-position where the scroll wheel was used
+ int ticks = mouseX / m_ppt;
+ // what would be the ticks in the new zoom level on the very same mouse x
+ int newTicks = mouseX / (DEFAULT_PPT * m_zoomXLevels[x]);
+
+ // scroll so the tick "selected" by the mouse x doesn't move on the screen
+ m_leftRightScroll->setValue(m_leftRightScroll->value() + ticks - newTicks);
+
+
  m_zoomingXModel.setValue( x );
  }
  else if( we->modifiers() & Qt::ShiftModifier

src/gui/editors/PianoRoll.cpp

@@ -3289,6 +3289,14 @@ void PianoRoll::wheelEvent(QWheelEvent * we )
  z--;
  }
  z = qBound( 0, z, m_zoomingModel.size() - 1 );
+
+ int x = (we->x() - WHITE_KEY_WIDTH)* MidiTime::ticksPerTact();
+ // ticks based on the mouse x-position where the scroll wheel was used
+ int ticks = x / m_ppt;
+ // what would be the ticks in the new zoom level on the very same mouse x
+ int newTicks = x / (DEFAULT_PR_PPT * m_zoomLevels[z]);
+ // scroll so the tick "selected" by the mouse x doesn't move on the screen
+ m_leftRightScroll->setValue(m_leftRightScroll->value() + ticks - newTicks);
  // update combobox with zooming-factor
  m_zoomingModel.setValue( z );
  }

src/gui/editors/SongEditor.cpp

@@ -82,11 +82,11 @@ SongEditor::SongEditor( Song * song ) :
 {
  m_zoomingModel->setParent(this);
  // create time-line
- int widgetTotal = ConfigManager::inst()->value( "ui",
+ m_widgetWidthTotal = ConfigManager::inst()->value( "ui",
  "compacttrackbuttons" ).toInt()==1 ?
  DEFAULT_SETTINGS_WIDGET_WIDTH_COMPACT + TRACK_OP_WIDTH_COMPACT :
  DEFAULT_SETTINGS_WIDGET_WIDTH + TRACK_OP_WIDTH;
- m_timeLine = new TimeLineWidget( widgetTotal, 32,
+ m_timeLine = new TimeLineWidget( m_widgetWidthTotal, 32,
  pixelsPerTact(),
  m_song->m_playPos[Song::Mode_PlaySong],
  m_currentPosition, this );
@@ -384,6 +384,16 @@ void SongEditor::wheelEvent( QWheelEvent * we )
  z--;
  }
  z = qBound( 0, z, m_zoomingModel->size() - 1 );
+
+
+ int x = (we->x() - m_widgetWidthTotal);
+ // tact based on the mouse x-position where the scroll wheel was used
+ int tact= x / pixelsPerTact();
+ // what would be the tact in the new zoom level on the very same mouse x
+ int newTact = x / DEFAULT_PIXELS_PER_TACT / m_zoomLevels[z];
+ // scroll so the tact "selected" by the mouse x doesn't move on the screen
+ m_leftRightScroll->setValue(m_leftRightScroll->value() + tact - newTact);
+
  // update combobox with zooming-factor
  m_zoomingModel->setValue( z );