fix ironing for support interface pattern

#153

src/libslic3r/Fill/FillSmooth.cpp

@@ -38,7 +38,7 @@ namespace Slic3r {
         else params_modifided.flow_mult *= (float)percentFlow[idx];
 
         //choose if we are going to extrude with or without overlap
-        if ((params.flow->bridge && idx == 0) || has_overlap[idx]){
+        if ((params.flow->bridge && idx == 0) || has_overlap[idx] || this->no_overlap_expolygons.empty()){
             this->fill_expolygon(idx, *eec, srf_source, params_modifided, volume);
         }
         else{
@@ -90,12 +90,12 @@ namespace Slic3r {
                 good_role = params.flow->bridge && idx == 0 ? erBridgeInfill : rolePass[idx];
             }
             // print
-            float mult_flow = (params.fill_exactly /*&& idx == 0*/ ? std::min(2., volume / extrudedVolume) : 1);
+            float mult_flow = float(params.fill_exactly /*&& idx == 0*/ ? std::min(2., volume / extrudedVolume) : 1);
             extrusion_entities_append_paths(
                 eec.entities, std::move(polylines_layer),
                 good_role,
                 params.flow->mm3_per_mm() * params.flow_mult * mult_flow,
-                //min-reduced flow width for a better view (it's only a gui thing)
+                //min-reduced flow width for a better view (it's mostly a gui thing, but some support code can want to mess with it)
                 (float)(params.flow->width * (params.flow_mult* mult_flow < 0.1 ? 0.1 : params.flow_mult * mult_flow)), (float)params.flow->height);
         }
     }
@@ -121,6 +121,9 @@ namespace Slic3r {
             //extruded volume: see http://manual.slic3r.org/advanced/flow-math, and we need to remove a circle at an end (as the flow continue)
             volumeToOccupy += poylineVolume;
         }
+        if (this->no_overlap_expolygons.empty()) {
+            volumeToOccupy = unscaled(unscaled(surface->area())) * params.flow->height;
+        }
 
         //create root node
         ExtrusionEntityCollection *eecroot = new ExtrusionEntityCollection();

src/libslic3r/SupportMaterial.cpp

@@ -2811,8 +2811,10 @@ void modulate_extrusion_by_overlapping_layers(
         path_fragments.back().polylines = diff_pl(path_fragments.back().polylines, polygons_trimming, false);
         // Adjust the extrusion parameters for a reduced layer height and a non-bridging flow (nozzle_dmr = -1, does not matter).
         assert(this_layer.print_z > overlapping_layer.print_z);
+        float old_height = frag.height;
         frag.height = float(this_layer.print_z - overlapping_layer.print_z);
-        frag.mm3_per_mm = Flow(frag.width, frag.height, -1.f, false).mm3_per_mm();
+        // don't recompute the flow, just use a simple % reduction/increase
+        frag.mm3_per_mm = frag.mm3_per_mm * frag.height / old_height;
 #ifdef SLIC3R_DEBUG
         svg.draw(frag.polylines, dbg_index_to_color(i_overlapping_layer), scale_(0.1));
 #endif /* SLIC3R_DEBUG */

src/slic3r/GUI/Field.cpp

@@ -935,7 +935,7 @@ void Choice::set_value(const boost::any& value, bool change_event)
     case coEnum: {
         int val = boost::any_cast<int>(value);
         if (m_opt_id == "top_fill_pattern" || m_opt_id == "bottom_fill_pattern" || m_opt_id == "solid_fill_pattern"
-            || m_opt_id == "fill_pattern" || m_opt_id == "support_fill_pattern")
+            || m_opt_id == "fill_pattern" || m_opt_id == "support_material_interface_pattern")
         {
             val = idx_from_enum_value<InfillPattern>(val);
         } else if (m_opt_id.compare("perimeter_loop_seam") == 0) {