Method Drag

src/TrackPanelResizeHandle.cpp:148–271

}

UIHandle::Result TrackPanelResizeHandle::Drag
(const TrackPanelMouseEvent &evt, AudacityProject *pProject)
{
   auto &tracks = TrackList::Get( *pProject );
   auto theChannel = FindChannel();
   if (!theChannel)
      return RefreshCode::Cancelled;

   auto &view = ChannelView::Get(*theChannel);

   if (view.GetMinimized() && mMode == IsResizingBetweenLinkedTracks)
      return RefreshCode::Cancelled;

   const wxMouseEvent &event = evt.event;

   int delta = (event.m_y - mMouseClickY);

   // On first drag, jump out of minimized mode.  Initial height
   // will be height of minimized track.
   //
   // This used to be in HandleResizeClick(), but simply clicking
   // on a resize border would switch the minimized state.
   if (view.GetMinimized()) {
      auto channels = GetTrack(*theChannel).Channels();
      for (auto pChannel : channels) {
         auto &channelView = ChannelView::Get(*pChannel);
         channelView.SetExpandedHeight(channelView.GetHeight());
         channelView.SetMinimized(false);
      }

      if (channels.size() > 1) {
         // Initial values must be reset since they weren't based on the
         // minimized heights.
         auto &channelView = ChannelView::Get(**channels.begin());
         mInitialUpperTrackHeight = channelView.GetHeight();
         mInitialTrackHeight = channelView.GetHeight();
      }
   }

   // Common pieces of code for MONO_WAVE_PAN and otherwise.
   auto doResizeBelow = [&] (Channel *prev) {
      // TODO: more-than-two-channels

      auto &prevView = ChannelView::Get(*prev);

      double proportion = static_cast < double >(mInitialTrackHeight)
      / (mInitialTrackHeight + mInitialUpperTrackHeight);

      int newTrackHeight = static_cast < int >
      (mInitialTrackHeight + delta * proportion);

      int newUpperTrackHeight = static_cast < int >
      (mInitialUpperTrackHeight + delta * (1.0 - proportion));

      //make sure neither track is smaller than its minimum height
      if (newTrackHeight < view.GetMinimizedHeight())
         newTrackHeight = view.GetMinimizedHeight();
      if (newUpperTrackHeight < prevView.GetMinimizedHeight())