Fix small area flow comp regression and some other small tweaks (#5844)

* Fix regression, always create SmallAreaInfillFlowCompensator model
small_area_infill_flow_compensation is per-region parameter, it's not necessary to iterate though all regions to check whether to create a model.

* Make SmallAreaInfillFlowCompensator robus.
1. handle spaces/tabs/new lines etc
2. don't throw expection, fall back to no-op instead if parsing failed

* Fixing an issue that changing small_area_infill_flow_compensation per modifier didn't take effect

src/libslic3r/GCode.cpp

@@ -1977,7 +1977,7 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
     } else
 	    m_enable_extrusion_role_markers = false;
 
-    if (m_config.small_area_infill_flow_compensation.value && !print.config().small_area_infill_flow_compensation_model.empty())
+    if (!print.config().small_area_infill_flow_compensation_model.empty())
         m_small_area_infill_flow_compensator = make_unique<SmallAreaInfillFlowCompensator>(print.config());
 
     file.write_format("; HEADER_BLOCK_START\n");

src/libslic3r/GCode/SmallAreaInfillFlowCompensator.cpp

@@ -14,6 +14,7 @@
 #include "../PrintConfig.hpp"
 
 #include "SmallAreaInfillFlowCompensator.hpp"
+#include <boost/log/trivial.hpp>
 
 namespace Slic3r {
 
@@ -24,6 +25,7 @@ bool nearly_equal(double a, double b)
 
 SmallAreaInfillFlowCompensator::SmallAreaInfillFlowCompensator(const Slic3r::GCodeConfig& config)
 {
+    try {
         for (auto& line : config.small_area_infill_flow_compensation_model.values) {
             std::istringstream iss(line);
             std::string        value_str;
@@ -31,6 +33,11 @@ SmallAreaInfillFlowCompensator::SmallAreaInfillFlowCompensator(const Slic3r::GCo
 
             if (std::getline(iss, value_str, ',')) {
                 try {
+                    // Trim leading and trailing whitespace
+                    value_str = std::regex_replace(value_str, std::regex("^\\s+|\\s+$"), "");
+                    if (value_str.empty()) {
+                        continue;
+                    }
                     eLength = std::stod(value_str);
                     if (std::getline(iss, value_str, ',')) {
                         eLengths.push_back(eLength);
@@ -64,21 +71,29 @@ SmallAreaInfillFlowCompensator::SmallAreaInfillFlowCompensator(const Slic3r::GCo
             throw Slic3r::InvalidArgument("Final compensation factor for small area infill flow compensation model must be 1.0");
         }
 
-    flowModel.set_points(eLengths, flowComps);
-}
+        flowModel = std::make_unique<tk::spline>();
+        flowModel->set_points(eLengths, flowComps);
 
+    } catch (std::exception& e) {
+        BOOST_LOG_TRIVIAL(error) << "Error parsing small area infill compensation model: " << e.what();
+    }
+}
 double SmallAreaInfillFlowCompensator::flow_comp_model(const double line_length)
 {
+    if(flowModel == nullptr)
+        return 1.0;
+
     if (line_length == 0 || line_length > max_modified_length()) {
         return 1.0;
     }
 
-    return flowModel(line_length);
+    return (*flowModel)(line_length);
 }
 
 double SmallAreaInfillFlowCompensator::modify_flow(const double line_length, const double dE, const ExtrusionRole role)
 {
-    if (role == ExtrusionRole::erSolidInfill || role == ExtrusionRole::erTopSolidInfill || role == ExtrusionRole::erBottomSurface) {
+    if (flowModel &&
+        (role == ExtrusionRole::erSolidInfill || role == ExtrusionRole::erTopSolidInfill || role == ExtrusionRole::erBottomSurface)) {
         return dE * flow_comp_model(line_length);
     }
 

src/libslic3r/GCode/SmallAreaInfillFlowCompensator.hpp

@@ -5,6 +5,7 @@
 #include "../PrintConfig.hpp"
 #include "../ExtrusionEntity.hpp"
 #include "spline/spline.h"
+#include <memory>
 
 namespace Slic3r {
 
@@ -23,7 +24,7 @@ private:
     std::vector<double> flowComps;
 
     // TODO: Cubic Spline
-    tk::spline flowModel;
+    std::unique_ptr<tk::spline> flowModel;
 
     double flow_comp_model(const double line_length);
 

src/libslic3r/PrintObject.cpp

@@ -924,8 +924,7 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "wipe_speed") {
             steps.emplace_back(posPerimeters);
         } else if (
-               opt_key == "small_area_infill_flow_compensation"
-            || opt_key == "small_area_infill_flow_compensation_model") {
+            opt_key == "small_area_infill_flow_compensation_model") {
             steps.emplace_back(posSlice);
         } else if (opt_key == "gap_infill_speed"
             || opt_key == "filter_out_gap_fill" ) {
@@ -1080,7 +1079,8 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "infill_anchor"
             || opt_key == "infill_anchor_max"
             || opt_key == "top_surface_line_width"
-            || opt_key == "initial_layer_line_width") {
+            || opt_key == "initial_layer_line_width"
+            || opt_key == "small_area_infill_flow_compensation") {
             steps.emplace_back(posInfill);
         } else if (opt_key == "sparse_infill_pattern") {
             steps.emplace_back(posPrepareInfill);