fix: don't always fill perimeter gaps between inner wall and skin/inf…

…ill (CURA-4027, CURA-4251)

this solves a problem that too many gaps are filled when alternate extra wall is enabled or when the initial layer line width is larger
if the infill pattern is concentric

src/FffPolygonGenerator.cpp

@@ -432,12 +432,16 @@ void FffPolygonGenerator::processPerimeterGaps(SliceDataStorage& storage)
  {
  continue;
  }
- bool fill_gaps_between_inner_wall_and_skin_or_infill =
- mesh.getSettingInMicrons("infill_line_distance") > 0
- && !mesh.getSettingBoolean("infill_hollow")
- && mesh.getSettingInMicrons("infill_overlap_mm") >= 0;
  for (unsigned int layer_nr = 0; layer_nr < mesh.layers.size(); layer_nr++)
  {
+ const ExtruderTrain& train_wall_x = *storage.meshgroup->getExtruderTrain(mesh.getSettingAsExtruderNr("wall_x_extruder_nr"));
+ bool fill_gaps_between_inner_wall_and_skin_or_infill =
+ mesh.getSettingInMicrons("infill_line_distance") > 0
+ && !mesh.getSettingBoolean("infill_hollow")
+ && mesh.getSettingInMicrons("infill_overlap_mm") >= 0
+ && !(mesh.getSettingAsFillMethod("infill_pattern") == EFillMethod::CONCENTRIC
+ && (mesh.getSettingBoolean("alternate_extra_perimeter") || (layer_nr == 0 && train_wall_x.getSettingInPercentage("initial_layer_line_width_factor") > 100))
+ );
  SliceLayer& layer = mesh.layers[layer_nr];
  coord_t wall_line_width_0 = mesh.getSettingInMicrons("wall_line_width_0");
  coord_t wall_line_width_x = mesh.getSettingInMicrons("wall_line_width_x");