Fix draw order issues in eeschema and libedit.

Eeschema (where only the parent component is in the view) uses
draw order.

LibEdit (where the individual items are in the view) uses the
viewPriority setting.

eeschema/libedit/lib_edit_frame.cpp

@@ -287,6 +287,7 @@ LIB_EDIT_FRAME::LIB_EDIT_FRAME( KIWAY* aKiway, wxWindow* aParent ) :
 
     SyncView();
     GetGalCanvas()->GetViewControls()->SetSnapping( true );
+    GetGalCanvas()->GetView()->UseDrawPriority( true );
 }
 
 

eeschema/sch_painter.cpp

@@ -164,7 +164,6 @@ bool SCH_PAINTER::Draw( const VIEW_ITEM *aItem, int aLayer )
     //printf("bkgd2 %.02f %.02f %.02f %.02f\n", c2.r, c2.g, c2.b, c2.a);
 
     m_gal->EnableDepthTest( false );
-    m_gal->AdvanceDepth();
 
 /*    m_gal->SetLineWidth( 10 );
     m_gal->SetIsFill( false );
@@ -215,16 +214,19 @@ void SCH_PAINTER::draw( LIB_PART *aComp, int aLayer, bool aDrawFields, int aUnit
 {
     size_t pinIndex = 0;
 
-    for( auto& item : aComp->GetDrawItems() )
+    auto visitItem = [&]( LIB_ITEM& item, bool aBackground )
     {
-		if( !aDrawFields && item.Type() == LIB_FIELD_T )
+        if( aBackground != ( item.GetFillMode() == FILLED_WITH_BG_BODYCOLOR ) )
-            continue;
+            return;
+
+        if( !aDrawFields && item.Type() == LIB_FIELD_T )
+            return;
 
         if( aUnit && item.GetUnit() && aUnit != item.GetUnit() )
-            continue;
+            return;
 
         if( aConvert && item.GetConvert() && aConvert != item.GetConvert() )
-            continue;
+            return;
 
         if( item.Type() == LIB_PIN_T )
         {
@@ -239,7 +241,16 @@ void SCH_PAINTER::draw( LIB_PART *aComp, int aLayer, bool aDrawFields, int aUnit
         }
         else
             Draw( &item, aLayer );
-    }
+    };
+
+    // Apply a z-order heuristic (because we don't yet let the user edit it):
+    // draw body-filled objects first.
+
+    for( auto& item : aComp->GetDrawItems() )
+        visitItem( item, true );
+
+    for( auto& item : aComp->GetDrawItems() )
+        visitItem( item, false );
 }
 
 
@@ -1040,7 +1051,6 @@ void SCH_PAINTER::draw ( SCH_GLOBALLABEL *aLabel, int aLayer )
     m_gal->SetIsStroke( true );
     m_gal->SetStrokeColor( m_schSettings.GetLayerColor( LAYER_GLOBLABEL ) );
     m_gal->DrawPolyline( pts2 );
-    m_gal->AdvanceDepth(); // fixme
 
     draw( static_cast<SCH_TEXT*>( aLabel ), aLayer );
 }
@@ -1060,7 +1070,6 @@ void SCH_PAINTER::draw ( SCH_HIERLABEL *aLabel, int aLayer )
     m_gal->SetIsStroke( true );
     m_gal->SetStrokeColor( m_schSettings.GetLayerColor( LAYER_SHEETLABEL ) );
     m_gal->DrawPolyline( pts2 );
-    m_gal->AdvanceDepth(); // fixme
 
     draw( static_cast<SCH_TEXT*>( aLabel ), aLayer );
 }
@@ -1108,11 +1117,7 @@ void SCH_PAINTER::draw ( SCH_SHEET *aSheet, int aLayer )
 
 
     for( auto& sheetPin : aSheet->GetPins() )
-    {
-        m_gal->AdvanceDepth();
         draw( static_cast<SCH_HIERLABEL*>( &sheetPin ), aLayer );
-    }
-
 }
 
 void SCH_PAINTER::draw ( SCH_NO_CONNECT *aNC, int aLayer )

eeschema/sch_view.cpp

@@ -116,10 +116,19 @@ void SCH_VIEW::DisplayComponent( LIB_PART *aPart )
 {
     Clear();
 
+    int fgPriority = INT_MAX / 2;
+    int bgPriority = 0;
+
     for ( auto &item : aPart->GetDrawItems() )
     {
         //printf("-- ADD %p\n", &item );
-        Add( &item );
+
+        // Apply a z-order heuristic (because we don't yet let the user edit it):
+        // push body-filled objects to the back.
+        if( item.GetFillMode() == FILLED_WITH_BG_BODYCOLOR )
+            Add( &item, bgPriority++ );
+        else
+            Add( &item, fgPriority++ );
     }
 
     m_selectionArea.reset( new KIGFX::PREVIEW::SELECTION_AREA( ) );