Move drawing code for track names

src/tracks/ui/CommonTrackView.cpp

@@ -15,11 +15,18 @@ Paul Licameli split from class TrackView
 #include "TrackControls.h"
 #include "ZoomHandle.h"
 #include "../ui/SelectHandle.h"
+#include "../../AColor.h"
+#include "../../AllThemeResources.h"
 #include "../../ProjectSettings.h"
 #include "../../Track.h"
+#include "../../TrackArtist.h"
 #include "../../TrackInfo.h"
+#include "../../TrackPanelDrawingContext.h"
 #include "../../TrackPanelMouseEvent.h"
 
+#include <wx/dc.h>
+#include <wx/graphics.h>
+
 std::vector<UIHandlePtr> CommonTrackView::HitTest
 (const TrackPanelMouseState &st,
  const AudacityProject *pProject)
@@ -74,6 +81,76 @@ std::vector<UIHandlePtr> CommonTrackView::HitTest
    return results;
 }
 
+// Draws the track name on the track, if it is needed.
+static void DrawTrackName(
+   TrackPanelDrawingContext &context, const Track * t, const wxRect & rect )
+{
+   auto name = t->GetName();
+   if( name.IsEmpty())
+      return;
+   if( !t->IsLeader())
+      return;
+   auto &dc = context.dc;
+   wxBrush Brush;
+   wxCoord x,y;
+   wxFont labelFont(12, wxFONTFAMILY_SWISS, wxFONTSTYLE_NORMAL, wxFONTWEIGHT_NORMAL);
+   dc.SetFont(labelFont);
+   dc.GetTextExtent( t->GetName(), &x, &y );
+
+   // Logic for name background translucency (aka 'shields')
+   // Tracks less than kOpaqueHeight high will have opaque shields.
+   // Tracks more than kTranslucentHeight will have maximum translucency for shields.
+   const int kOpaqueHeight = 44;
+   const int kTranslucentHeight = 124;
+   int h = rect.GetHeight();
+   // f codes the opacity as a number between 0.0 and 1.0
+   float f= wxClip((h -kOpaqueHeight)/(float)(kTranslucentHeight-kOpaqueHeight),0.0,1.0);
+   // kOpaque is the shield's alpha for tracks that are not tall
+   // kTranslucent is the shield's alpha for tracks that are tall.
+   const int kOpaque = 255;
+   const int kTranslucent = 140;
+   // 0.0 maps to full opacity, 1.0 maps to full translucency.
+   int opacity = 255 - (255-140)*f;
+
+#ifdef __WXMAC__
+   // Mac dc is a graphics dc already.
+   AColor::UseThemeColour( &dc, clrTrackInfoSelected, clrTrackPanelText, opacity );
+   dc.DrawRoundedRectangle( rect.x+7, rect.y+1,  x+16, y+4, 8.0 );
+#else
+   // This little dance with wxImage in order to draw to a graphic dc
+   // which we can then paste as a translucent bitmap onto the real dc.
+   wxImage image( x+18, y+6 );
+   image.InitAlpha();
+   unsigned char *alpha=image.GetAlpha();
+   memset(alpha, wxIMAGE_ALPHA_TRANSPARENT, image.GetWidth()*image.GetHeight());
+   
+   {
+      std::unique_ptr< wxGraphicsContext >
+         pGc{ wxGraphicsContext::Create(image) };
+      auto &gc = *pGc;
+      // This is to a gc, not a dc.
+      AColor::UseThemeColour( &gc, clrTrackInfoSelected, clrTrackPanelText, opacity );
+      // Draw at 1,1, not at 0,0 to avoid clipping of the antialiasing.
+      gc.DrawRoundedRectangle( 1, 1,  x+16, y+4, 8.0 );
+      // destructor of gc updates the wxImage.
+   }
+   wxBitmap bitmap( image );
+   dc.DrawBitmap( bitmap, rect.x+6, rect.y);
+#endif
+   dc.SetTextForeground(theTheme.Colour( clrTrackPanelText ));
+   dc.DrawText (t->GetName(), rect.x+15, rect.y+3);  // move right 15 pixels to avoid overwriting <- symbol
+}
+
+void CommonTrackView::Draw(
+   TrackPanelDrawingContext &context, const wxRect &rect, unsigned iPass )
+{
+   // This overpaints only the track area, so any pass after tracks is late
+   // enough.
+   if ( iPass == TrackArtist::PassMargins )
+      DrawTrackName(
+         context, FindTrack()->SubstitutePendingChangedTrack().get(), rect );
+}
+
 std::shared_ptr<TrackPanelCell> CommonTrackView::ContextMenuDelegate()
 {
    return TrackControls::Get( *FindTrack() ).shared_from_this();

src/tracks/ui/CommonTrackView.h

@@ -31,6 +31,11 @@ public:
       (const TrackPanelMouseState &, const AudacityProject *pProject)
       final override;
 
+   // TrackPanelDrawable implementation
+   void Draw(
+      TrackPanelDrawingContext &context,
+      const wxRect &rect, unsigned iPass ) override;
+
    virtual int GetMinimizedHeight() const override;
 
 protected: