Keep netnames on tracks within the viewport when possible.

Fixes https://gitlab.com/kicad/code/kicad/issues/2032

include/eda_rect.h

@@ -50,6 +50,14 @@ public:
             m_init( true )
     { }
 
+    template<class T>
+    EDA_RECT( const BOX2<T> aBox )
+    {
+        m_pos = (wxPoint) aBox.GetPosition();
+        m_size.x = aBox.GetWidth();
+        m_size.y = aBox.GetHeight();
+    }
+
     virtual ~EDA_RECT() { };
 
     wxPoint Centre() const

include/view/view.h

@@ -451,6 +451,9 @@ public:
         }
     }
 
+    /**
+     * Set a layer display-only (ie: to be rendered but not returned by hit test queries).
+     */
     inline void SetLayerDisplayOnly( int aLayer, bool aDisplayOnly = true )
     {
         wxCHECK( aLayer < (int) m_layers.size(), /*void*/ );

pcbnew/pcb_draw_panel_gal.cpp

@@ -389,15 +389,13 @@ void PCB_DRAW_PANEL_GAL::SetTopLayer( PCB_LAYER_ID aLayer )
                                    m_view->GetLayerOrder( LAYER_MARKER_SHADOWS ) + 4 );
         }
     }
-    else if( IsCopperLayer( aLayer ) )
+
+    if( IsCopperLayer( aLayer ) )
     {
+        m_view->SetTopLayer( ZONE_LAYER_FOR( aLayer ) );
+
         // Display labels for copper layers on the top
         m_view->SetTopLayer( GetNetnameLayer( aLayer ) );
-        m_view->SetTopLayer( ZONE_LAYER_FOR( aLayer ) );
-    }
-    else
-    {
-        m_view->SetTopLayer( ZONE_LAYER_FOR( aLayer ) );
     }
 
     m_view->EnableTopLayer( true );

pcbnew/pcb_edit_frame.cpp

@@ -177,7 +177,8 @@ END_EVENT_TABLE()
 PCB_EDIT_FRAME::PCB_EDIT_FRAME( KIWAY* aKiway, wxWindow* aParent ) :
     PCB_BASE_EDIT_FRAME( aKiway, aParent, FRAME_PCB_EDITOR, _( "PCB Editor" ), wxDefaultPosition,
                          wxDefaultSize, KICAD_DEFAULT_DRAWFRAME_STYLE, PCB_EDIT_FRAME_NAME ),
-    m_exportNetlistAction( nullptr ), m_findDialog( nullptr )
+    m_exportNetlistAction( nullptr ),
+    m_findDialog( nullptr )
 {
     m_maximizeByDefault = true;
     m_showBorderAndTitleBlock = true;   // true to display sheet references
@@ -309,6 +310,22 @@ PCB_EDIT_FRAME::PCB_EDIT_FRAME( KIWAY* aKiway, wxWindow* aParent ) :
     // to calculate the wrong zoom size.  See PCB_EDIT_FRAME::onSize().
     Bind( wxEVT_SIZE, &PCB_EDIT_FRAME::onSize, this );
 
+    // Redraw netnames (so that they fall within the current viewport) after the viewport
+    // has stopped changing.  Redrawing them without the timer moves them smoothly with scrolling,
+    // making it look like the tracks are being dragged -- which we don't want.
+    m_redrawNetnamesTimer.SetOwner( this );
+    Connect( wxEVT_TIMER, wxTimerEventHandler( PCB_EDIT_FRAME::redrawNetnames ), nullptr, this );
+
+    Bind( wxEVT_IDLE,
+            [this]( wxIdleEvent& aEvent )
+            {
+                if( GetCanvas()->GetView()->GetViewport() != m_lastViewport )
+                {
+                    m_lastViewport = GetCanvas()->GetView()->GetViewport();
+                    m_redrawNetnamesTimer.StartOnce( 100 );
+                }
+            } );
+
     resolveCanvasType();
 
     setupUnits( config() );
@@ -438,6 +455,20 @@ BOARD_ITEM_CONTAINER* PCB_EDIT_FRAME::GetModel() const
 }
 
 
+void PCB_EDIT_FRAME::redrawNetnames( wxTimerEvent& aEvent )
+{
+    KIGFX::VIEW* view = GetCanvas()->GetView();
+
+    for( PCB_TRACK* track : GetBoard()->Tracks() )
+    {
+        if( track->ViewGetLOD( GetNetnameLayer( track->GetLayer() ), view ) < view->GetScale() )
+            view->Update( track, KIGFX::REPAINT );
+    }
+
+    GetCanvas()->Refresh();
+}
+
+
 void PCB_EDIT_FRAME::SetPageSettings( const PAGE_INFO& aPageSettings )
 {
     PCB_BASE_FRAME::SetPageSettings( aPageSettings );

pcbnew/pcb_edit_frame.h

@@ -760,6 +760,8 @@ protected:
 
     int inferLegacyEdgeClearance( BOARD* aBoard );
 
+    void redrawNetnames( wxTimerEvent& aEvent );
+
 public:
     PCB_LAYER_BOX_SELECTOR* m_SelLayerBox;  // a combo box to display and select active layer
 
@@ -785,7 +787,13 @@ private:
 
     DIALOG_FIND* m_findDialog;
 
-    wxTimer* m_eventCounterTimer;
+    /**
+     * Keep track of viewport so that track net labels can be adjusted when it changes.
+     */
+    BOX2D        m_lastViewport;
+    wxTimer      m_redrawNetnamesTimer;
+
+    wxTimer*     m_eventCounterTimer;
 };
 
 #endif  // __PCB_EDIT_FRAME_H__

pcbnew/pcb_painter.cpp

@@ -117,7 +117,7 @@ void PCB_RENDER_SETTINGS::LoadColors( const COLOR_SETTINGS* aSettings )
     // Netnames for copper layers
     for( LSEQ cu = LSET::AllCuMask().CuStack();  cu;  ++cu )
     {
-        const COLOR4D lightLabel( 0.8, 0.8, 0.8, 0.7 );
+        const COLOR4D lightLabel( 1.0, 1.0, 1.0, 0.7 );
         const COLOR4D darkLabel = lightLabel.Inverted();
         PCB_LAYER_ID  layer = *cu;
 
@@ -538,8 +538,8 @@ bool PCB_PAINTER::Draw( const VIEW_ITEM* aItem, int aLayer )
 
 void PCB_PAINTER::draw( const PCB_TRACK* aTrack, int aLayer )
 {
-    VECTOR2D start( aTrack->GetStart() );
-    VECTOR2D end( aTrack->GetEnd() );
+    VECTOR2I start( aTrack->GetStart() );
+    VECTOR2I end( aTrack->GetEnd() );
     int      width = aTrack->GetWidth();
     COLOR4D  color = m_pcbSettings.GetColor( aTrack, aLayer );
 
@@ -551,11 +551,23 @@ void PCB_PAINTER::draw( const PCB_TRACK* aTrack, int aLayer )
         if( aTrack->GetNetCode() <= NETINFO_LIST::UNCONNECTED )
             return;
 
-        VECTOR2D line = ( end - start );
+        // When drawing netnames, clip the track to the viewport
+        BOX2D    viewport;
+        VECTOR2D screenSize = m_gal->GetScreenPixelSize();
+        const MATRIX3x3D& matrix = m_gal->GetScreenWorldMatrix();
+
+        viewport.SetOrigin( VECTOR2D( matrix * VECTOR2D( 0, 0 ) ) );
+        viewport.SetEnd( VECTOR2D( matrix * screenSize ) );
+
+        EDA_RECT clipBox( viewport.Normalize() );
+
+        ClipLine( &clipBox, start.x, start.y, end.x, end.y );
+
+        VECTOR2I line = ( end - start );
         double length = line.EuclideanNorm();
 
         // Check if the track is long enough to have a netname displayed
-        if( length < 10 * width )
+        if( length < 6 * width )
             return;
 
         const wxString& netName = UnescapeString( aTrack->GetShortNetname() );
@@ -581,7 +593,6 @@ void PCB_PAINTER::draw( const PCB_TRACK* aTrack, int aLayer )
             textPosition.y += penWidth / 1.4;
         }
 
-
         m_gal->SetIsStroke( true );
         m_gal->SetIsFill( false );
         m_gal->SetStrokeColor( color );

pcbnew/pcb_track.cpp

@@ -556,6 +556,9 @@ double PCB_TRACK::ViewGetLOD( int aLayer, KIGFX::VIEW* aView ) const
 
     if( IsNetnameLayer( aLayer ) )
     {
+        if( GetNetCode() <= NETINFO_LIST::UNCONNECTED )
+            return HIDE;
+
         // Hide netnames on dimmed tracks
         if( renderSettings->GetHighContrast() )
         {
@@ -563,6 +566,20 @@ double PCB_TRACK::ViewGetLOD( int aLayer, KIGFX::VIEW* aView ) const
                 return HIDE;
         }
 
+        // When drawing netnames, clip the track to the viewport
+        VECTOR2I start( GetStart() );
+        VECTOR2I end( GetEnd() );
+        EDA_RECT clipBox( aView->GetViewport() );
+
+        ClipLine( &clipBox, start.x, start.y, end.x, end.y );
+
+        VECTOR2I line = ( end - start );
+        double length = line.EuclideanNorm();
+
+        // Check if the track is long enough to have a netname displayed
+        if( length < 6 * GetWidth() )
+            return HIDE;
+
         // Netnames will be shown only if zoom is appropriate
         return ( double ) Millimeter2iu( 4 ) / ( m_Width + 1 );
     }