Fix various rendering issues with non-through vias

Correctly hide netnames in high contrast mode
Correct highlighting for blind/buried/micro via drills
Repaint vias when needed to support stacked microvias

Fixes https://gitlab.com/kicad/code/kicad/-/issues/2593

pcbnew/pcb_base_frame.cpp

@@ -755,6 +755,7 @@ void PCB_BASE_FRAME::ActivateGalCanvas()
 
 void PCB_BASE_FRAME::SetDisplayOptions( const PCB_DISPLAY_OPTIONS& aOptions )
 {
+    bool hcChanged   = m_displayOptions.m_ContrastModeDisplay != aOptions.m_ContrastModeDisplay;
     m_displayOptions = aOptions;
 
     EDA_DRAW_PANEL_GAL* canvas = GetCanvas();
@@ -764,5 +765,19 @@ void PCB_BASE_FRAME::SetDisplayOptions( const PCB_DISPLAY_OPTIONS& aOptions )
     canvas->SetHighContrastLayer( GetActiveLayer() );
     OnDisplayOptionsChanged();
 
+    // Vias on a restricted layer set must be redrawn when high contrast mode is changed
+    if( hcChanged )
+    {
+        GetCanvas()->GetView()->UpdateAllItemsConditionally( KIGFX::REPAINT,
+                []( KIGFX::VIEW_ITEM* aItem ) -> bool
+                {
+                    if( VIA* via = dynamic_cast<VIA*>( aItem ) )
+                        return ( via->GetViaType() == VIATYPE::BLIND_BURIED ||
+                                 via->GetViaType() == VIATYPE::MICROVIA );
+
+                    return false;
+                } );
+    }
+
     canvas->Refresh();
 }

pcbnew/pcb_edit_frame.cpp

@@ -982,6 +982,17 @@ void PCB_EDIT_FRAME::SetActiveLayer( PCB_LAYER_ID aLayer )
     GetCanvas()->SetFocus();                                // allow capture of hotkeys
     GetCanvas()->SetHighContrastLayer( aLayer );
 
+    // Vias on a restricted layer set must be redrawn when the active layer is changed
+    GetCanvas()->GetView()->UpdateAllItemsConditionally( KIGFX::REPAINT,
+            []( KIGFX::VIEW_ITEM* aItem ) -> bool
+            {
+                if( VIA* via = dynamic_cast<VIA*>( aItem ) )
+                    return ( via->GetViaType() == VIATYPE::BLIND_BURIED ||
+                             via->GetViaType() == VIATYPE::MICROVIA );
+
+                return false;
+            } );
+
     // Clearances could be layer-dependent so redraw them when the active layer is changed
     if( GetDisplayOptions().m_DisplayPadIsol )
     {

pcbnew/pcb_painter.cpp

@@ -320,7 +320,8 @@ COLOR4D PCB_RENDER_SETTINGS::GetColor( const VIEW_ITEM* aItem, int aLayer ) cons
         ( aLayer == LAYER_VIAS_HOLES   ||
           aLayer == LAYER_VIA_THROUGH  ||
           aLayer == LAYER_VIA_MICROVIA ||
-          aLayer == LAYER_VIA_BBLIND ) )
+          aLayer == LAYER_VIA_BBLIND ||
+          aLayer == LAYER_VIAS_NETNAMES ) )
     {
         const VIA*   via = static_cast<const VIA*>( item );
         const BOARD* pcb = static_cast<const BOARD*>( item->GetParent() );
@@ -332,6 +333,9 @@ COLOR4D PCB_RENDER_SETTINGS::GetColor( const VIEW_ITEM* aItem, int aLayer ) cons
             viaActiveLayer |= via->IsOnLayer( lay_id ) && pcb->IsLayerVisible( lay_id );
         }
 
+        if( !viaActiveLayer && m_contrastModeDisplay == HIGH_CONTRAST_MODE::HIDDEN )
+            return COLOR4D::CLEAR;
+
         if( !viaActiveLayer )
             color.Darken( 1.0 - m_highlightFactor );
     }
@@ -592,9 +596,29 @@ void PCB_PAINTER::draw( const VIA* aVia, int aLayer )
         VECTOR2D position( center );
 
         // Is anything that we can display enabled?
-        if( m_pcbSettings.m_netNamesOnVias )
+        if( !m_pcbSettings.m_netNamesOnVias || aVia->GetNetname().empty() )
+            return;
+
+        // We won't get CLEAR from GetColor below for a non-through via on an inactive layer in
+        // high contrast mode because LAYER_VIAS_NETNAMES will always be part of the high-contrast
+        // set.  So we do another check here to prevent drawing netnames for these vias.
+        if( m_pcbSettings.GetHighContrast() )
         {
-            bool displayNetname = ( !aVia->GetNetname().empty() );
+            bool draw = false;
+
+            for( unsigned int layer : m_pcbSettings.GetHighContrastLayers() )
+            {
+                if( aVia->IsOnLayer( static_cast<PCB_LAYER_ID>( layer ) ) )
+                {
+                    draw = true;
+                    break;
+                }
+            }
+
+            if( !draw )
+                return;
+        }
+
         double maxSize = PCB_RENDER_SETTINGS::MAX_FONT_SIZE;
         double size = aVia->GetWidth();
 
@@ -612,8 +636,6 @@ void PCB_PAINTER::draw( const VIA* aVia, int aLayer )
         // Set the text position to the pad shape position (the pad position is not the best place)
         VECTOR2D textpos( 0.0, 0.0 );
 
-            if( displayNetname )
-            {
         wxString netname = UnescapeString( aVia->GetShortNetname() );
         // calculate the size of net name text:
         double tsize = 1.5 * size / netname.Length();
@@ -625,13 +647,9 @@ void PCB_PAINTER::draw( const VIA* aVia, int aLayer )
         m_gal->SetGlyphSize( namesize );
         m_gal->SetLineWidth( namesize.x / 12.0 );
         m_gal->BitmapText( netname, textpos, 0.0 );
-            }
-
 
         m_gal->Restore();
     }
-        return;
-    }
 
     // Choose drawing settings depending on if we are drawing via's pad or hole
     if( aLayer == LAYER_VIAS_HOLES )
@@ -647,6 +665,9 @@ void PCB_PAINTER::draw( const VIA* aVia, int aLayer )
     bool sketchMode = false;
     COLOR4D color = m_pcbSettings.GetColor( aVia, aLayer );
 
+    if( color == COLOR4D::CLEAR )
+        return;
+
     switch( aVia->GetViaType() )
     {
     case VIATYPE::THROUGH:

pcbnew/widgets/appearance_controls.cpp

@@ -447,8 +447,6 @@ APPEARANCE_CONTROLS::APPEARANCE_CONTROLS( PCB_BASE_FRAME* aParent, wxWindow* aFo
                 opts.m_ContrastModeDisplay = aMode;
 
                 m_frame->SetDisplayOptions( opts );
-                m_frame->GetCanvas()->SetHighContrastLayer( m_frame->GetActiveLayer() );
-                m_frame->GetCanvas()->Refresh();
                 passOnFocus();
             };