Fix pad clearance bounding box and initial display

Fixes https://gitlab.com/kicad/code/kicad/-/issues/7673

pcbnew/pad.cpp

@@ -1310,9 +1310,15 @@ const BOX2I PAD::ViewBBox() const
     VECTOR2I solderPasteMargin = VECTOR2D( GetSolderPasteMargin() );
     EDA_RECT bbox              = GetBoundingBox();
 
+    // get the biggest possible clearance
+    int clearance = 0;
+
+    for( PCB_LAYER_ID layer : GetLayerSet().Seq() )
+        clearance = std::max( clearance, GetOwnClearance( layer ) );
+
     // Look for the biggest possible bounding box
-    int xMargin = std::max( solderMaskMargin, solderPasteMargin.x );
-    int yMargin = std::max( solderMaskMargin, solderPasteMargin.y );
+    int xMargin = std::max( solderMaskMargin, solderPasteMargin.x ) + clearance;
+    int yMargin = std::max( solderMaskMargin, solderPasteMargin.y ) + clearance;
 
     return BOX2I( VECTOR2I( bbox.GetOrigin() ) - VECTOR2I( xMargin, yMargin ),
                   VECTOR2I( bbox.GetSize() ) + VECTOR2I( 2 * xMargin, 2 * yMargin ) );

pcbnew/pcb_edit_frame.cpp

@@ -1081,6 +1081,9 @@ void PCB_EDIT_FRAME::onBoardLoaded()
     // Display the loaded board:
     Zoom_Automatique( false );
 
+    // Invalidate painting as loading the DRC engine will cause clearances to become valid
+    GetCanvas()->GetView()->UpdateAllItems( KIGFX::ALL );
+
     Refresh();
 
     SetMsgPanel( GetBoard() );