From 2c009906e5cf36de1ab7eafa0e71009ab643596c Mon Sep 17 00:00:00 2001
From: Jeff Young <jeff@rokeby.ie>
Date: Thu, 25 Feb 2021 13:02:33 +0000
Subject: [PATCH] Set unprinted layer colors to background.

This allows our Black&White special cases to still work when the
hole annular rings aren't being printed.

Fixes https://gitlab.com/kicad/code/kicad/issues/7692
---
 common/board_printout.cpp  |  2 +-
 pcbnew/pcbnew_printout.cpp | 46 ++++++++++++++++++++++----------------
 2 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/common/board_printout.cpp b/common/board_printout.cpp
index 7839b18d34..b05c48f171 100644
--- a/common/board_printout.cpp
+++ b/common/board_printout.cpp
@@ -128,8 +128,8 @@ void BOARD_PRINTOUT::DrawPage( const wxString& aLayerName, int aPageNum, int aPa
 
     dstSettings->SetIsPrinting( true );
 
-    setupViewLayers( *view, m_settings.m_LayerSet );
     setupPainter( *painter );
+    setupViewLayers( *view, m_settings.m_LayerSet );
 
     auto sheetSizeMils = m_settings.m_pageInfo.GetSizeMils();
     VECTOR2I sheetSizeIU( milsToIU( sheetSizeMils.GetWidth() ), milsToIU( sheetSizeMils.GetHeight() ) );
diff --git a/pcbnew/pcbnew_printout.cpp b/pcbnew/pcbnew_printout.cpp
index aa33b9ca50..75af5daed1 100644
--- a/pcbnew/pcbnew_printout.cpp
+++ b/pcbnew/pcbnew_printout.cpp
@@ -132,22 +132,27 @@ void PCBNEW_PRINTOUT::setupViewLayers( KIGFX::VIEW& aView, const LSET& aLayerSet
 {
     BOARD_PRINTOUT::setupViewLayers( aView, aLayerSet );
 
-    for( LSEQ layerSeq = m_settings.m_LayerSet.Seq(); layerSeq; ++layerSeq )
+    for( PCB_LAYER_ID layer : m_settings.m_LayerSet.Seq() )
     {
-        aView.SetLayerVisible( PCBNEW_LAYER_ID_START + *layerSeq, true );
+        aView.SetLayerVisible( PCBNEW_LAYER_ID_START + layer, true );
 
         // Enable the corresponding zone layer
-        if( IsCopperLayer( *layerSeq ) )
-            aView.SetLayerVisible( LAYER_ZONE_START + *layerSeq, true );
+        if( IsCopperLayer( layer ) )
+            aView.SetLayerVisible( LAYER_ZONE_START + layer, true );
     }
 
+    RENDER_SETTINGS* renderSettings = aView.GetPainter()->GetSettings();
+    COLOR4D          backgroundColor = renderSettings->GetLayerColor( LAYER_PCB_BACKGROUND );
+
     if( m_pcbnewSettings.m_asItemCheckboxes )
     {
         auto setVisibility =
                 [&]( GAL_LAYER_ID aLayer )
                 {
                     if( m_board->IsElementVisible( aLayer ) )
-                        aView.SetLayerVisible( aLayer );
+                        aView.SetLayerVisible( aLayer, true );
+                    else
+                        renderSettings->SetLayerColor( aLayer, backgroundColor );
                 };
 
         setVisibility( LAYER_MOD_FR );
@@ -180,25 +185,29 @@ void PCBNEW_PRINTOUT::setupViewLayers( KIGFX::VIEW& aView, const LSET& aLayerSet
                     LAYER_VIA_THROUGH
                 };
 
-        for( int item : alwaysEnabled )
-            aView.SetLayerVisible( item, true );
+        for( int layer : alwaysEnabled )
+            aView.SetLayerVisible( layer, true );
     }
     else
     {
         // Enable pad layers corresponding to the selected copper layers
         if( aLayerSet.test( F_Cu ) )
             aView.SetLayerVisible( LAYER_PAD_FR, true );
+        else
+            renderSettings->SetLayerColor( LAYER_PAD_FR, backgroundColor );
 
         if( aLayerSet.test( B_Cu ) )
             aView.SetLayerVisible( LAYER_PAD_BK, true );
+        else
+            renderSettings->SetLayerColor( LAYER_PAD_BK, backgroundColor );
 
-        if( ( aLayerSet & LSET::AllCuMask() ).any() )   // Items visible on any copper layer
+        // Enable items on copper layers, but do not draw holes
+        for( GAL_LAYER_ID layer : { LAYER_PADS_TH, LAYER_VIA_THROUGH } )
         {
-            // Enable items on copper layers, but do not draw holes
-            for( GAL_LAYER_ID item : { LAYER_PADS_TH, LAYER_VIA_THROUGH } )
-            {
-                aView.SetLayerVisible( item, true );
-            }
+            if( ( aLayerSet & LSET::AllCuMask() ).any() )   // Items visible on any copper layer
+                aView.SetLayerVisible( layer, true );
+            else
+                renderSettings->SetLayerColor( layer, backgroundColor );
         }
 
         // Keep certain items always enabled/disabled and just rely on the layer visibility
@@ -209,18 +218,17 @@ void PCBNEW_PRINTOUT::setupViewLayers( KIGFX::VIEW& aView, const LSET& aLayerSet
                     LAYER_VIAS, LAYER_VIA_MICROVIA, LAYER_VIA_BBLIND
                 };
 
-        for( int item : alwaysEnabled )
-            aView.SetLayerVisible( item, true );
+        for( int layer : alwaysEnabled )
+            aView.SetLayerVisible( layer, true );
     }
 
     if( m_pcbnewSettings.m_drillMarks != PCBNEW_PRINTOUT_SETTINGS::NO_DRILL_SHAPE )
     {
         // Enable hole layers to draw drill marks
-        for( GAL_LAYER_ID holeLayer : { LAYER_PAD_PLATEDHOLES, LAYER_NON_PLATEDHOLES,
-                                        LAYER_VIA_HOLES } )
+        for( int layer : { LAYER_PAD_PLATEDHOLES, LAYER_NON_PLATEDHOLES, LAYER_VIA_HOLES } )
         {
-            aView.SetLayerVisible( holeLayer, true );
-            aView.SetTopLayer( holeLayer, true );
+            aView.SetLayerVisible( layer, true );
+            aView.SetTopLayer( layer, true );
         }
     }
 }