Merge branch 'lm_clocales'

36 files changed, 338 insertions, 155 deletions

diff --git a/src/admesh/shared.cpp b/src/admesh/shared.cpp
index 902bbfc9b..a8fbc2a87 100644
--- a/src/admesh/shared.cpp
+++ b/src/admesh/shared.cpp
@@ -30,6 +30,8 @@
 
 #include "stl.h"
 
+#include "libslic3r/LocalesUtils.hpp"
+
 void stl_generate_shared_vertices(stl_file *stl, indexed_triangle_set &its)
 {
 	// 3 indices to vertex per face
@@ -127,6 +129,7 @@ void stl_generate_shared_vertices(stl_file *stl, indexed_triangle_set &its)
 
 bool its_write_off(const indexed_triangle_set &its, const char *file)
 {
+    Slic3r::CNumericLocalesSetter locales_setter;
 	/* Open the file */
 	FILE *fp = boost::nowide::fopen(file, "w");
 	if (fp == nullptr) {
@@ -146,6 +149,7 @@ bool its_write_off(const indexed_triangle_set &its, const char *file)
 
 bool its_write_vrml(const indexed_triangle_set &its, const char *file)
 {
+    Slic3r::CNumericLocalesSetter locales_setter;
 	/* Open the file */
   	FILE *fp = boost::nowide::fopen(file, "w");
 	if (fp == nullptr) {
@@ -188,7 +192,7 @@ bool its_write_vrml(const indexed_triangle_set &its, const char *file)
 
 bool its_write_obj(const indexed_triangle_set &its, const char *file)
 {
-
+    Slic3r::CNumericLocalesSetter locales_setter;
   	FILE *fp = boost::nowide::fopen(file, "w");
   	if (fp == nullptr) {
 		BOOST_LOG_TRIVIAL(error) << "stl_write_obj: Couldn't open " << file << " for writing";
diff --git a/src/admesh/stlinit.cpp b/src/admesh/stlinit.cpp
index 6aa2c4417..29131b1c7 100644
--- a/src/admesh/stlinit.cpp
+++ b/src/admesh/stlinit.cpp
@@ -32,6 +32,8 @@
 
 #include "stl.h"
 
+#include "libslic3r/LocalesUtils.hpp"
+
 #ifndef SEEK_SET
 #error "SEEK_SET not defined"
 #endif
@@ -232,6 +234,7 @@ static bool stl_read(stl_file *stl, FILE *fp, int first_facet, bool first)
 
 bool stl_open(stl_file *stl, const char *file)
 {
+    Slic3r::CNumericLocalesSetter locales_setter;
 	stl->clear();
 	FILE *fp = stl_open_count_facets(stl, file);
 	if (fp == nullptr)
diff --git a/src/libslic3r/AppConfig.cpp b/src/libslic3r/AppConfig.cpp
index d9301d1f3..cf532160d 100644
--- a/src/libslic3r/AppConfig.cpp
+++ b/src/libslic3r/AppConfig.cpp
@@ -2,8 +2,10 @@
 #include "libslic3r/Utils.hpp"
 #include "AppConfig.hpp"
 #include "Exception.hpp"
+#include "LocalesUtils.hpp"
 #include "Thread.hpp"
 
+
 #include <utility>
 #include <vector>
 #include <stdexcept>
@@ -376,7 +378,8 @@ void AppConfig::set_recent_projects(const std::vector<std::string>& recent_proje
     }
 }
 
-void AppConfig::set_mouse_device(const std::string& name, double translation_speed, double translation_deadzone, float rotation_speed, float rotation_deadzone, double zoom_speed, bool swap_yz)
+void AppConfig::set_mouse_device(const std::string& name, double translation_speed, double translation_deadzone,
+                                 float rotation_speed, float rotation_deadzone, double zoom_speed, bool swap_yz)
 {
     std::string key = std::string("mouse_device:") + name;
     auto it = m_storage.find(key);
@@ -384,11 +387,11 @@ void AppConfig::set_mouse_device(const std::string& name, double translation_spe
         it = m_storage.insert(std::map<std::string, std::map<std::string, std::string>>::value_type(key, std::map<std::string, std::string>())).first;
 
     it->second.clear();
-    it->second["translation_speed"] = std::to_string(translation_speed);
-    it->second["translation_deadzone"] = std::to_string(translation_deadzone);
-    it->second["rotation_speed"] = std::to_string(rotation_speed);
-    it->second["rotation_deadzone"] = std::to_string(rotation_deadzone);
-    it->second["zoom_speed"] = std::to_string(zoom_speed);
+    it->second["translation_speed"] = float_to_string_decimal_point(translation_speed);
+    it->second["translation_deadzone"] = float_to_string_decimal_point(translation_deadzone);
+    it->second["rotation_speed"] = float_to_string_decimal_point(rotation_speed);
+    it->second["rotation_deadzone"] = float_to_string_decimal_point(rotation_deadzone);
+    it->second["zoom_speed"] = float_to_string_decimal_point(zoom_speed);
     it->second["swap_yz"] = swap_yz ? "1" : "0";
 }
 
diff --git a/src/libslic3r/AppConfig.hpp b/src/libslic3r/AppConfig.hpp
index c8ccd18cd..03924175d 100644
--- a/src/libslic3r/AppConfig.hpp
+++ b/src/libslic3r/AppConfig.hpp
@@ -196,6 +196,6 @@ private:
 	bool                                                        m_legacy_datadir;
 };
 
-}; // namespace Slic3r
+} // namespace Slic3r
 
 #endif /* slic3r_AppConfig_hpp_ */
diff --git a/src/libslic3r/Arrange.cpp b/src/libslic3r/Arrange.cpp
index 61a32678b..9602ebdbd 100644
--- a/src/libslic3r/Arrange.cpp
+++ b/src/libslic3r/Arrange.cpp
@@ -1,5 +1,4 @@
 #include "Arrange.hpp"
-#include "SVG.hpp"
 
 #include "BoundingBox.hpp"
 
diff --git a/src/libslic3r/CMakeLists.txt b/src/libslic3r/CMakeLists.txt
index d98d0e10f..b7b90a8f5 100644
--- a/src/libslic3r/CMakeLists.txt
+++ b/src/libslic3r/CMakeLists.txt
@@ -126,6 +126,8 @@ add_library(libslic3r STATIC
     Line.hpp
     LibraryCheck.cpp
     LibraryCheck.hpp
+    LocalesUtils.cpp
+    LocalesUtils.hpp
     Model.cpp
     Model.hpp
     ModelArrange.hpp
diff --git a/src/libslic3r/Config.cpp b/src/libslic3r/Config.cpp
index 5db1d8179..bd396243c 100644
--- a/src/libslic3r/Config.cpp
+++ b/src/libslic3r/Config.cpp
@@ -1,6 +1,8 @@
 #include "Config.hpp"
 #include "format.hpp"
 #include "Utils.hpp"
+#include "LocalesUtils.hpp"
+
 #include <assert.h>
 #include <fstream>
 #include <iostream>
@@ -462,7 +464,7 @@ void ConfigBase::set(const std::string &opt_key, double value, bool create)
     switch (opt->type()) {
     	case coFloat:  			static_cast<ConfigOptionFloat*>(opt)->value = value; break;
     	case coFloatOrPercent:  static_cast<ConfigOptionFloatOrPercent*>(opt)->value = value; static_cast<ConfigOptionFloatOrPercent*>(opt)->percent = false; break;
-		case coString: 			static_cast<ConfigOptionString*>(opt)->value = std::to_string(value); break;
+        case coString: 			static_cast<ConfigOptionString*>(opt)->value = float_to_string_decimal_point(value); break;
     	default: throw BadOptionTypeException("Configbase::set() - conversion from float not possible");
     }
 }
diff --git a/src/libslic3r/Config.hpp b/src/libslic3r/Config.hpp
index adda2654e..e67b6b781 100644
--- a/src/libslic3r/Config.hpp
+++ b/src/libslic3r/Config.hpp
@@ -1819,10 +1819,10 @@ public:
     	SetDeserializeItem(const std::string &opt_key, const bool value, bool append = false) : opt_key(opt_key), opt_value(value ? "1" : "0"), append(append) {}
     	SetDeserializeItem(const char *opt_key, const int value, bool append = false) : opt_key(opt_key), opt_value(std::to_string(value)), append(append) {}
     	SetDeserializeItem(const std::string &opt_key, const int value, bool append = false) : opt_key(opt_key), opt_value(std::to_string(value)), append(append) {}
-    	SetDeserializeItem(const char *opt_key, const float value, bool append = false) : opt_key(opt_key), opt_value(std::to_string(value)), append(append) {}
-    	SetDeserializeItem(const std::string &opt_key, const float value, bool append = false) : opt_key(opt_key), opt_value(std::to_string(value)), append(append) {}
-    	SetDeserializeItem(const char *opt_key, const double value, bool append = false) : opt_key(opt_key), opt_value(std::to_string(value)), append(append) {}
-    	SetDeserializeItem(const std::string &opt_key, const double value, bool append = false) : opt_key(opt_key), opt_value(std::to_string(value)), append(append) {}
+        SetDeserializeItem(const char *opt_key, const float value, bool append = false) : opt_key(opt_key), opt_value(float_to_string_decimal_point(value)), append(append) {}
+        SetDeserializeItem(const std::string &opt_key, const float value, bool append = false) : opt_key(opt_key), opt_value(float_to_string_decimal_point(value)), append(append) {}
+        SetDeserializeItem(const char *opt_key, const double value, bool append = false) : opt_key(opt_key), opt_value(float_to_string_decimal_point(value)), append(append) {}
+        SetDeserializeItem(const std::string &opt_key, const double value, bool append = false) : opt_key(opt_key), opt_value(float_to_string_decimal_point(value)), append(append) {}
     	std::string opt_key; std::string opt_value; bool append = false;
     };
 	// May throw BadOptionTypeException() if the operation fails.
diff --git a/src/libslic3r/Format/3mf.cpp b/src/libslic3r/Format/3mf.cpp
index 152d72079..b98cc5f04 100644
--- a/src/libslic3r/Format/3mf.cpp
+++ b/src/libslic3r/Format/3mf.cpp
@@ -2,6 +2,7 @@
 #include "../Exception.hpp"
 #include "../Model.hpp"
 #include "../Utils.hpp"
+#include "../LocalesUtils.hpp"
 #include "../GCode.hpp"
 #include "../Geometry.hpp"
 #include "../GCode/ThumbnailData.hpp"
@@ -2408,6 +2409,7 @@ namespace Slic3r {
         };
 
         auto format_coordinate = [](float f, char *buf) -> char* {
+            assert(is_decimal_separator_point());
 #if EXPORT_3MF_USE_SPIRIT_KARMA_FP
             // Slightly faster than sprintf("%.9g"), but there is an issue with the karma floating point formatter,
             // https://github.com/boostorg/spirit/pull/586
@@ -2575,6 +2577,7 @@ namespace Slic3r {
 
     bool _3MF_Exporter::_add_layer_height_profile_file_to_archive(mz_zip_archive& archive, Model& model)
     {
+        assert(is_decimal_separator_point());
         std::string out = "";
         char buffer[1024];
 
@@ -2666,6 +2669,7 @@ namespace Slic3r {
 
     bool _3MF_Exporter::_add_sla_support_points_file_to_archive(mz_zip_archive& archive, Model& model)
     {
+        assert(is_decimal_separator_point());
         std::string out = "";
         char buffer[1024];
 
@@ -2700,6 +2704,7 @@ namespace Slic3r {
     
     bool _3MF_Exporter::_add_sla_drain_holes_file_to_archive(mz_zip_archive& archive, Model& model)
     {
+        assert(is_decimal_separator_point());
         const char *const fmt = "object_id=%d|";
         std::string out;
         
@@ -2750,6 +2755,7 @@ namespace Slic3r {
 
     bool _3MF_Exporter::_add_print_config_file_to_archive(mz_zip_archive& archive, const DynamicPrintConfig &config)
     {
+        assert(is_decimal_separator_point());
         char buffer[1024];
         sprintf(buffer, "; %s\n\n", header_slic3r_generated().c_str());
         std::string out = buffer;
@@ -2926,6 +2932,9 @@ bool load_3mf(const char* path, DynamicPrintConfig* config, Model* model, bool c
     if (path == nullptr || config == nullptr || model == nullptr)
         return false;
 
+    // All import should use "C" locales for number formatting.
+    CNumericLocalesSetter locales_setter;
+
     _3MF_Importer importer;
     bool res = importer.load_model_from_file(path, *model, *config, check_version);
     importer.log_errors();
@@ -2934,6 +2943,9 @@ bool load_3mf(const char* path, DynamicPrintConfig* config, Model* model, bool c
 
 bool store_3mf(const char* path, Model* model, const DynamicPrintConfig* config, bool fullpath_sources, const ThumbnailData* thumbnail_data, bool zip64)
 {
+    // All export should use "C" locales for number formatting.
+    CNumericLocalesSetter locales_setter;
+
     if (path == nullptr || model == nullptr)
         return false;
 
diff --git a/src/libslic3r/Format/AMF.cpp b/src/libslic3r/Format/AMF.cpp
index 1c9b6b27d..94318a930 100644
--- a/src/libslic3r/Format/AMF.cpp
+++ b/src/libslic3r/Format/AMF.cpp
@@ -15,6 +15,7 @@
 #include "../I18N.hpp"
 #include "../Geometry.hpp"
 #include "../CustomGCode.hpp"
+#include "../LocalesUtils.hpp"
 
 #include "AMF.hpp"
 
@@ -498,6 +499,7 @@ void AMFParserContext::characters(const XML_Char *s, int len)
 
 void AMFParserContext::endElement(const char * /* name */)
 {
+    assert(is_decimal_separator_point());
     switch (m_path.back()) {
 
     // Constellation transformation:
@@ -1052,6 +1054,8 @@ bool load_amf_archive(const char* path, DynamicPrintConfig* config, Model* model
 // If config is not a null pointer, updates it if the amf file/archive contains config data
 bool load_amf(const char* path, DynamicPrintConfig* config, Model* model, bool check_version)
 {
+    CNumericLocalesSetter locales_setter; // use "C" locales and point as a decimal separator
+
     if (boost::iends_with(path, ".amf.xml"))
         // backward compatibility with older slic3r output
         return load_amf_file(path, config, model);
@@ -1251,40 +1255,25 @@ bool store_amf(const char* path, Model* model, const DynamicPrintConfig* config,
         stream << "  </object>\n";
         if (!object->instances.empty()) {
             for (ModelInstance *instance : object->instances) {
-                char buf[512];
-                ::sprintf(buf,
-                    "    <instance objectid=\"%zu\">\n"
-                    "      <deltax>%lf</deltax>\n"
-                    "      <deltay>%lf</deltay>\n"
-                    "      <deltaz>%lf</deltaz>\n"
-                    "      <rx>%lf</rx>\n"
-                    "      <ry>%lf</ry>\n"
-                    "      <rz>%lf</rz>\n"
-                    "      <scalex>%lf</scalex>\n"
-                    "      <scaley>%lf</scaley>\n"
-                    "      <scalez>%lf</scalez>\n"
-                    "      <mirrorx>%lf</mirrorx>\n"
-                    "      <mirrory>%lf</mirrory>\n"
-                    "      <mirrorz>%lf</mirrorz>\n"
-                    "      <printable>%d</printable>\n"
-                    "    </instance>\n",
-                    object_id,
-                    instance->get_offset(X),
-                    instance->get_offset(Y),
-                    instance->get_offset(Z),
-                    instance->get_rotation(X),
-                    instance->get_rotation(Y),
-                    instance->get_rotation(Z),
-                    instance->get_scaling_factor(X),
-                    instance->get_scaling_factor(Y),
-                    instance->get_scaling_factor(Z),
-                    instance->get_mirror(X),
-                    instance->get_mirror(Y),
-                    instance->get_mirror(Z),
-                    instance->printable);
+                std::stringstream buf;
+                buf << "    <instance objectid=\"" << object_id << "\">\n"
+                    << "      <deltax>"  << instance->get_offset(X)         << "</deltax>\n"
+                    << "      <deltay>"  << instance->get_offset(Y)         << "</deltay>\n"
+                    << "      <deltaz>"  << instance->get_offset(Z)         << "</deltaz>\n"
+                    << "      <rx>"      << instance->get_rotation(X)       << "</rx>\n"
+                    << "      <ry>"      << instance->get_rotation(Y)       << "</ry>\n"
+                    << "      <rz>"      << instance->get_rotation(Z)       << "</rz>\n"
+                    << "      <scalex>"  << instance->get_scaling_factor(X) << "</scalex>\n"
+                    << "      <scaley>"  << instance->get_scaling_factor(Y) << "</scaley>\n"
+                    << "      <scalez>"  << instance->get_scaling_factor(Z) << "</scalez>\n"
+                    << "      <mirrorx>" << instance->get_mirror(X)         << "</mirrorx>\n"
+                    << "      <mirrory>" << instance->get_mirror(Y)         << "</mirrory>\n"
+                    << "      <mirrorz>" << instance->get_mirror(Z)         << "</mirrorz>\n"
+                    << "      <printable>" << instance->printable << "</printable>\n"
+                    << "    </instance>\n";
 
                 //FIXME missing instance->scaling_factor
-                instances.append(buf);
+                instances.append(buf.str());
             }
         }
     }
diff --git a/src/libslic3r/Format/AMF.hpp b/src/libslic3r/Format/AMF.hpp
index 3e33d4aa3..b4e2c54ab 100644
--- a/src/libslic3r/Format/AMF.hpp
+++ b/src/libslic3r/Format/AMF.hpp
@@ -13,6 +13,6 @@ extern bool load_amf(const char* path, DynamicPrintConfig* config, Model* model,
 // The model could be modified during the export process if meshes are not repaired or have no shared vertices
 extern bool store_amf(const char* path, Model* model, const DynamicPrintConfig* config, bool fullpath_sources);
 
-}; // namespace Slic3r
+} // namespace Slic3r
 
 #endif /* slic3r_Format_AMF_hpp_ */
diff --git a/src/libslic3r/Format/SL1.cpp b/src/libslic3r/Format/SL1.cpp
index 4038cb046..1809c3e4f 100644
--- a/src/libslic3r/Format/SL1.cpp
+++ b/src/libslic3r/Format/SL1.cpp
@@ -345,6 +345,7 @@ std::string get_cfg_value(const DynamicPrintConfig &cfg, const std::string &key)
 
 void fill_iniconf(ConfMap &m, const SLAPrint &print)
 {
+    CNumericLocalesSetter locales_setter; // for to_string
     auto &cfg = print.full_print_config();
     m["layerHeight"]    = get_cfg_value(cfg, "layer_height");
     m["expTime"]        = get_cfg_value(cfg, "exposure_time");
diff --git a/src/libslic3r/Format/objparser.cpp b/src/libslic3r/Format/objparser.cpp
index 12cee350d..16a3f84dd 100644
--- a/src/libslic3r/Format/objparser.cpp
+++ b/src/libslic3r/Format/objparser.cpp
@@ -6,6 +6,8 @@
 
 #include "objparser.hpp"
 
+#include "libslic3r/LocalesUtils.hpp"
+
 namespace ObjParser {
 
 static bool obj_parseline(const char *line, ObjData &data)
@@ -15,6 +17,8 @@ static bool obj_parseline(const char *line, ObjData &data)
 	if (*line == 0)
 		return true;
 
+    assert(Slic3r::is_decimal_separator_point());
+
 	// Ignore whitespaces at the beginning of the line.
 	//FIXME is this a good idea?
 	EATWS();
@@ -322,6 +326,8 @@ static bool obj_parseline(const char *line, ObjData &data)
 
 bool objparse(const char *path, ObjData &data)
 {
+    Slic3r::CNumericLocalesSetter locales_setter;
+
 	FILE *pFile = boost::nowide::fopen(path, "rt");
 	if (pFile == 0)
 		return false;
@@ -365,6 +371,8 @@ bool objparse(const char *path, ObjData &data)
 
 bool objparse(std::istream &stream, ObjData &data)
 {
+    Slic3r::CNumericLocalesSetter locales_setter;
+    
     try {
         char buf[65536 * 2];
         size_t len = 0;
diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index d47d185a0..208363f35 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -12,6 +12,7 @@
 #include "Utils.hpp"
 #include "ClipperUtils.hpp"
 #include "libslic3r.h"
+#include "LocalesUtils.hpp"
 
 #include <algorithm>
 #include <cstdlib>
@@ -750,6 +751,7 @@ void GCode::do_export(Print* print, const char* path, GCodeProcessor::Result* re
     std::string path_tmp(path);
     path_tmp += ".tmp";
 
+    CNumericLocalesSetter c_locales_setter;
     FILE *file = boost::nowide::fopen(path_tmp.c_str(), "wb");
     if (file == nullptr)
         throw Slic3r::RuntimeError(std::string("G-code export to ") + path + " failed.\nCannot open the file for writing.\n");
@@ -981,6 +983,7 @@ namespace DoExport {
 	            double filament_weight = extruded_volume * extruder.filament_density() * 0.001;
 	            double filament_cost   = filament_weight * extruder.filament_cost()    * 0.001;
                 auto append = [&extruder](std::pair<std::string, unsigned int> &dst, const char *tmpl, double value) {
+                    assert(is_decimal_separator_point());
 	                while (dst.second < extruder.id()) {
 	                    // Fill in the non-printing extruders with zeros.
 	                    dst.first += (dst.second > 0) ? ", 0" : "0";
@@ -1620,7 +1623,7 @@ void GCode::print_machine_envelope(FILE *file, Print &print)
             int(print.config().machine_max_acceleration_retracting.values.front() + 0.5),
             travel_acc);
 
-
+        assert(is_decimal_separator_point());
         fprintf(file, "M205 X%.2lf Y%.2lf Z%.2lf E%.2lf ; sets the jerk limits, mm/sec\n",
             print.config().machine_max_jerk_x.values.front(),
             print.config().machine_max_jerk_y.values.front(),
@@ -1984,6 +1987,7 @@ void GCode::process_layer(
     }
 
     std::string gcode;
+    assert(is_decimal_separator_point()); // for the sprintfs
 
     // add tag for processor
 #if ENABLE_VALIDATE_CUSTOM_GCODE
@@ -2826,6 +2830,7 @@ std::string GCode::_extrude(const ExtrusionPath &path, std::string description,
     // so, if the last role was erWipeTower we force export of GCodeProcessor::Height_Tag lines
     bool last_was_wipe_tower = (m_last_processor_extrusion_role == erWipeTower);
     char buf[64];
+    assert(is_decimal_separator_point());
 
     if (path.role() != m_last_processor_extrusion_role) {
         m_last_processor_extrusion_role = path.role();
diff --git a/src/libslic3r/GCode/CoolingBuffer.cpp b/src/libslic3r/GCode/CoolingBuffer.cpp
index 07b9b07bb..6dd5e7e27 100644
--- a/src/libslic3r/GCode/CoolingBuffer.cpp
+++ b/src/libslic3r/GCode/CoolingBuffer.cpp
@@ -357,6 +357,8 @@ std::vector<PerExtruderAdjustments> CoolingBuffer::parse_layer_gcode(const std::
                 for (; *c == ' ' || *c == '\t'; ++ c);
                 if (*c == 0 || *c == ';')
                     break;
+
+                assert(is_decimal_separator_point()); // for atof
                 // Parse the axis.
                 size_t axis = (*c >= 'X' && *c <= 'Z') ? (*c - 'X') :
                               (*c == extrusion_axis) ? 3 : (*c == 'F') ? 4 : size_t(-1);
@@ -454,6 +456,7 @@ std::vector<PerExtruderAdjustments> CoolingBuffer::parse_layer_gcode(const std::
             line.type = CoolingLine::TYPE_G4;
             size_t pos_S = sline.find('S', 3);
             size_t pos_P = sline.find('P', 3);
+            assert(is_decimal_separator_point()); // for atof
             line.time = line.time_max = float(
                 (pos_S > 0) ? atof(sline.c_str() + pos_S + 1) :
                 (pos_P > 0) ? atof(sline.c_str() + pos_P + 1) * 0.001 : 0.);
diff --git a/src/libslic3r/GCode/GCodeProcessor.cpp b/src/libslic3r/GCode/GCodeProcessor.cpp
index 917f84f40..f4b38e2ec 100644
--- a/src/libslic3r/GCode/GCodeProcessor.cpp
+++ b/src/libslic3r/GCode/GCodeProcessor.cpp
@@ -1,6 +1,7 @@
 #include "libslic3r/libslic3r.h"
 #include "libslic3r/Utils.hpp"
 #include "libslic3r/Print.hpp"
+#include "libslic3r/LocalesUtils.hpp"
 #include "GCodeProcessor.hpp"
 
 #include <boost/log/trivial.hpp>
@@ -465,9 +466,7 @@ void GCodeProcessor::TimeProcessor::post_process(const std::string& filename)
     };
 
     auto format_time_float = [](float time) {
-        char time_str[64];
-        sprintf(time_str, "%.2f", time);
-        return std::string(time_str);
+        return Slic3r::float_to_string_decimal_point(time, 2);
     };
 
     auto format_line_M73_stop_float = [format_time_float](const std::string& mask, float time) {
@@ -671,7 +670,7 @@ void GCodeProcessor::TimeProcessor::post_process(const std::string& filename)
 
                                         std::string time_float_str = format_time_float(time_in_last_minute(it_stop->elapsed_time - it->elapsed_time));
                                         std::string next_time_float_str = format_time_float(time_in_last_minute(it_stop->elapsed_time - next_it->elapsed_time));
-                                        is_last |= (std::stof(time_float_str) > 0.0f && std::stof(next_time_float_str) == 0.0f);
+                                        is_last |= (string_to_double_decimal_point(time_float_str) > 0. && string_to_double_decimal_point(next_time_float_str) == 0.);
                                     }
 
                                     if (is_last) {
@@ -1374,7 +1373,7 @@ void GCodeProcessor::apply_config_simplify3d(const std::string& filename)
             if (pos != cmt.npos) {
                 pos = cmt.find(',', pos);
                 if (pos != cmt.npos) {
-                    out = std::stod(cmt.substr(pos + 1));
+                    out = string_to_double_decimal_point(cmt.substr(pos+1));
                     return true;
                 }
             }
@@ -1524,9 +1523,9 @@ template<typename T>
             else if constexpr (std::is_same_v<T, long>)
                 out = std::stol(str, &read);
             else if constexpr (std::is_same_v<T, float>)
-                out = std::stof(str, &read);
+                out = string_to_double_decimal_point(str, &read);
             else if constexpr (std::is_same_v<T, double>)
-                out = std::stod(str, &read);
+                out = string_to_double_decimal_point(str, &read);
             return str.size() == read;
         } catch (...) {
             return false;
diff --git a/src/libslic3r/GCode/PressureEqualizer.cpp b/src/libslic3r/GCode/PressureEqualizer.cpp
index c3f084a24..48a16a8d5 100644
--- a/src/libslic3r/GCode/PressureEqualizer.cpp
+++ b/src/libslic3r/GCode/PressureEqualizer.cpp
@@ -4,6 +4,7 @@
 
 #include "../libslic3r.h"
 #include "../PrintConfig.hpp"
+#include "../LocalesUtils.hpp"
 
 #include "PressureEqualizer.hpp"
 
@@ -158,7 +159,7 @@ static inline int parse_int(const char *&line)
 static inline float parse_float(const char *&line)
 {
     char *endptr = NULL;
-    float result = strtof(line, &endptr);
+    float result = string_to_double_decimal_point(line, &endptr);
     if (endptr == NULL || !is_ws_or_eol(*endptr))
         throw Slic3r::RuntimeError("PressureEqualizer: Error parsing a float");
     line = endptr;
diff --git a/src/libslic3r/GCode/WipeTower.cpp b/src/libslic3r/GCode/WipeTower.cpp
index fc6a15b65..5e1937ad8 100644
--- a/src/libslic3r/GCode/WipeTower.cpp
+++ b/src/libslic3r/GCode/WipeTower.cpp
@@ -4,9 +4,12 @@
 #include <iostream>
 #include <vector>
 #include <numeric>
+#include <sstream>
+#include <iomanip>
 
 #include "GCodeProcessor.hpp"
 #include "BoundingBox.hpp"
+#include "LocalesUtils.hpp"
 
 
 namespace Slic3r
@@ -30,29 +33,27 @@ public:
         m_filpar(filament_parameters)
         {
             // adds tag for analyzer:
-            char buf[64];
+            std::ostringstream str;
 #if ENABLE_VALIDATE_CUSTOM_GCODE
-            sprintf(buf, ";%s%f\n", GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Height).c_str(), m_layer_height); // don't rely on GCodeAnalyzer knowing the layer height - it knows nothing at priming
-            m_gcode += buf;
-            sprintf(buf, ";%s%s\n", GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Role).c_str(), ExtrusionEntity::role_to_string(erWipeTower).c_str());
+            str << ";" << GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Height) << m_layer_height << "\n"; // don't rely on GCodeAnalyzer knowing the layer height - it knows nothing at priming
+            str << ";" << GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Role) << ExtrusionEntity::role_to_string(erWipeTower) << "\n";
 #else
-            sprintf(buf, ";%s%f\n", GCodeProcessor::Height_Tag.c_str(), m_layer_height); // don't rely on GCodeAnalyzer knowing the layer height - it knows nothing at priming
-            m_gcode += buf;
-            sprintf(buf, ";%s%s\n", GCodeProcessor::Extrusion_Role_Tag.c_str(), ExtrusionEntity::role_to_string(erWipeTower).c_str());
+            str << ";" << GCodeProcessor::Height_Tag << m_layer_height << "\n"; // don't rely on GCodeAnalyzer knowing the layer height - it knows nothing at priming
+            str << ";" << GCodeProcessor::Extrusion_Role_Tag << ExtrusionEntity::role_to_string(erWipeTower) << "\n";
 #endif // ENABLE_VALIDATE_CUSTOM_GCODE
-            m_gcode += buf;
+            m_gcode += str.str();
             change_analyzer_line_width(line_width);
     }
 
     WipeTowerWriter& change_analyzer_line_width(float line_width) {
         // adds tag for analyzer:
-        char buf[64];
+        std::stringstream str;
 #if ENABLE_VALIDATE_CUSTOM_GCODE
-        sprintf(buf, ";%s%f\n", GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Width).c_str(), line_width);
+        str << ";" << GCodeProcessor::reserved_tag(GCodeProcessor::ETags::Width) << line_width << "\n";
 #else
-        sprintf(buf, ";%s%f\n", GCodeProcessor::Width_Tag.c_str(), line_width);
+        str << ";" << GCodeProcessor::Width_Tag << line_width << "\n";
 #endif // ENABLE_VALIDATE_CUSTOM_GCODE
-        m_gcode += buf;
+        m_gcode += str.str();
         return *this;
     }
 
@@ -61,9 +62,9 @@ public:
         static const float area = float(M_PI) * 1.75f * 1.75f / 4.f;
         float mm3_per_mm = (len == 0.f ? 0.f : area * e / len);
         // adds tag for processor:
-        char buf[64];
-        sprintf(buf, ";%s%f\n", GCodeProcessor::Mm3_Per_Mm_Tag.c_str(), mm3_per_mm);
-        m_gcode += buf;
+        std::stringstream str;
+        str << ";" << GCodeProcessor::Mm3_Per_Mm_Tag << mm3_per_mm << "\n";
+        m_gcode += str.str();
         return *this;
     }
 #endif // ENABLE_GCODE_VIEWER_DATA_CHECKING
@@ -325,9 +326,7 @@ public:
 	{
         if (time==0.f)
             return *this;
-		char buf[128];
-		sprintf(buf, "G4 S%.3f\n", time);
-		m_gcode += buf;
+        m_gcode += "G4 S" + Slic3r::float_to_string_decimal_point(time, 3) + "\n";
 		return *this;
     }
 
@@ -443,37 +442,29 @@ private:
     const std::vector<WipeTower::FilamentParameters>& m_filpar;
 
 	std::string   set_format_X(float x)
-	{
-		char buf[64];
-		sprintf(buf, " X%.3f", x);
-		m_current_pos.x() = x;
-		return buf;
+    {
+        m_current_pos.x() = x;
+        return " X" + Slic3r::float_to_string_decimal_point(x, 3);
 	}
 
 	std::string   set_format_Y(float y) {
-		char buf[64];
-		sprintf(buf, " Y%.3f", y);
-		m_current_pos.y() = y;
-		return buf;
+        m_current_pos.y() = y;
+        return " Y" + Slic3r::float_to_string_decimal_point(y, 3);
 	}
 
 	std::string   set_format_Z(float z) {
-		char buf[64];
-		sprintf(buf, " Z%.3f", z);
-		return buf;
+        return " Z" + Slic3r::float_to_string_decimal_point(z, 3);
 	}
 
 	std::string   set_format_E(float e) {
-		char buf[64];
-		sprintf(buf, " E%.4f", e);
-		return buf;
+        return " E" + Slic3r::float_to_string_decimal_point(e, 4);
 	}
 
 	std::string   set_format_F(float f) {
-		char buf[64];
-		sprintf(buf, " F%d", int(floor(f + 0.5f)));
-		m_current_feedrate = f;
-		return buf;
+        char buf[64];
+        sprintf(buf, " F%d", int(floor(f + 0.5f)));
+        m_current_feedrate = f;
+        return buf;
 	}
 
 	WipeTowerWriter& operator=(const WipeTowerWriter &rhs);
@@ -959,8 +950,8 @@ void WipeTower::toolchange_Change(
     // postprocessor that we absolutely want to have this in the gcode, even if it thought it is the same as before.
     Vec2f current_pos = writer.pos_rotated();
     writer.feedrate(m_travel_speed * 60.f) // see https://github.com/prusa3d/PrusaSlicer/issues/5483
-          .append(std::string("G1 X") + std::to_string(current_pos.x())
-                             +  " Y"  + std::to_string(current_pos.y())
+          .append(std::string("G1 X") + Slic3r::float_to_string_decimal_point(current_pos.x())
+                             +  " Y"  + Slic3r::float_to_string_decimal_point(current_pos.y())
                              + never_skip_tag() + "\n");
 
     // The toolchange Tn command will be inserted later, only in case that the user does
@@ -1310,11 +1301,10 @@ static WipeTower::ToolChangeResult merge_tcr(WipeTower::ToolChangeResult& first,
 {
     assert(first.new_tool == second.initial_tool);
     WipeTower::ToolChangeResult out = first;
-    if (first.end_pos != second.start_pos) {
-        char buf[2048];     // Add a travel move from tc1.end_pos to tc2.start_pos.
-        sprintf(buf, "G1 X%.3f Y%.3f F7200\n", second.start_pos.x(), second.start_pos.y());
-        out.gcode += buf;
-    }
+    if (first.end_pos != second.start_pos)
+        out.gcode += "G1 X" + Slic3r::float_to_string_decimal_point(second.start_pos.x(), 3)
+                     + " Y" + Slic3r::float_to_string_decimal_point(second.start_pos.y(), 3)
+                     + " F7200\n";
     out.gcode += second.gcode;
     out.extrusions.insert(out.extrusions.end(), second.extrusions.begin(), second.extrusions.end());
     out.end_pos = second.end_pos;
diff --git a/src/libslic3r/GCodeReader.cpp b/src/libslic3r/GCodeReader.cpp
index 9753e4820..5ab1ae50c 100644
--- a/src/libslic3r/GCodeReader.cpp
+++ b/src/libslic3r/GCodeReader.cpp
@@ -6,6 +6,8 @@
 #include <iostream>
 #include <iomanip>
 
+#include "LocalesUtils.hpp"
+
 #include <Shiny/Shiny.h>
 
 namespace Slic3r {
@@ -25,6 +27,7 @@ void GCodeReader::apply_config(const DynamicPrintConfig &config)
 const char* GCodeReader::parse_line_internal(const char *ptr, GCodeLine &gline, std::pair<const char*, const char*> &command)
 {
     PROFILE_FUNC();
+    CNumericLocalesSetter locales_setter; // for strtod
     
     // command and args
     const char *c = ptr;
@@ -150,6 +153,7 @@ bool GCodeReader::GCodeLine::has(char axis) const
 
 bool GCodeReader::GCodeLine::has_value(char axis, float &value) const
 {
+    CNumericLocalesSetter locales_setter; // for strtod
     const char *c = m_raw.c_str();
     // Skip the whitespaces.
     c = skip_whitespaces(c);
diff --git a/src/libslic3r/LocalesUtils.cpp b/src/libslic3r/LocalesUtils.cpp
new file mode 100644
index 000000000..cb118f99c
--- /dev/null
+++ b/src/libslic3r/LocalesUtils.cpp
@@ -0,0 +1,76 @@
+#include "LocalesUtils.hpp"
+
+#include <stdexcept>
+
+namespace Slic3r {
+
+
+CNumericLocalesSetter::CNumericLocalesSetter()
+{
+#ifdef _WIN32
+    _configthreadlocale(_ENABLE_PER_THREAD_LOCALE);
+    m_orig_numeric_locale = std::setlocale(LC_NUMERIC, nullptr);
+    std::setlocale(LC_NUMERIC, "C");
+#else
+    m_original_locale = uselocale((locale_t)0);
+    m_new_locale = duplocale(m_original_locale);
+    m_new_locale = newlocale(LC_NUMERIC_MASK, "C", m_new_locale);
+    uselocale(m_new_locale);
+#endif
+}
+
+
+
+CNumericLocalesSetter::~CNumericLocalesSetter()
+{
+#ifdef _WIN32
+    std::setlocale(LC_NUMERIC, m_orig_numeric_locale.data());
+#else
+    uselocale(m_original_locale);
+    freelocale(m_new_locale);
+#endif
+}
+
+
+
+bool is_decimal_separator_point()
+{
+    char str[5] = "";
+    sprintf(str, "%.1f", 0.5f);
+    return str[1] == '.';
+}
+
+
+double string_to_double_decimal_point(const std::string& str, size_t* pos /* = nullptr*/)
+{
+    double out;
+    std::istringstream stream(str);
+    if (! (stream >> out))
+        throw std::invalid_argument("string_to_double_decimal_point conversion failed.");
+    if (pos) {
+        if (stream.eof())
+            *pos = str.size();
+        else
+            *pos = stream.tellg();
+    }
+    return out;
+}
+
+std::string float_to_string_decimal_point(double value, int precision/* = -1*/)
+{
+    assert(is_decimal_separator_point());
+    std::stringstream buf;
+    if (precision >= 0)
+        buf << std::fixed << std::setprecision(precision);
+    buf << value;
+    return buf.str();
+}
+
+//std::string float_to_string_decimal_point(float value, int precision/* = -1*/)
+//{
+//    return float_to_string_decimal_point(double(value), precision);
+//}
+
+
+} // namespace Slic3r
+
diff --git a/src/libslic3r/LocalesUtils.hpp b/src/libslic3r/LocalesUtils.hpp
new file mode 100644
index 000000000..113cfa04b
--- /dev/null
+++ b/src/libslic3r/LocalesUtils.hpp
@@ -0,0 +1,47 @@
+#ifndef slic3r_LocalesUtils_hpp_
+#define slic3r_LocalesUtils_hpp_
+
+#include <string>
+#include <clocale>
+#include <iomanip>
+#include <cassert>
+
+#ifdef __APPLE__
+#include <xlocale.h>
+#endif
+
+namespace Slic3r {
+
+// RAII wrapper that sets LC_NUMERIC to "C" on construction
+// and restores the old value on destruction.
+class CNumericLocalesSetter {
+public:
+    CNumericLocalesSetter();
+    ~CNumericLocalesSetter();
+
+private:
+#ifdef _WIN32
+    std::string m_orig_numeric_locale;
+#else
+    locale_t m_original_locale;
+    locale_t m_new_locale;
+#endif
+
+};
+
+// A function to check that current C locale uses decimal point as a separator.
+// Intended mostly for asserts.
+bool is_decimal_separator_point();
+
+
+// A substitute for std::to_string that works according to
+// C++ locales, not C locale. Meant to be used when we need
+// to be sure that decimal point is used as a separator.
+// (We use user C locales and "C" C++ locales in most of the code.)
+std::string float_to_string_decimal_point(double value, int precision = -1);
+//std::string float_to_string_decimal_point(float value,  int precision = -1);
+double string_to_double_decimal_point(const std::string& str, size_t* pos = nullptr);
+
+} // namespace Slic3r
+
+#endif // slic3r_LocalesUtils_hpp_
diff --git a/src/libslic3r/Point.hpp b/src/libslic3r/Point.hpp
index 12870b713..e5ce68420 100644
--- a/src/libslic3r/Point.hpp
+++ b/src/libslic3r/Point.hpp
@@ -11,6 +11,8 @@
 
 #include <Eigen/Geometry> 
 
+#include "LocalesUtils.hpp"
+
 namespace Slic3r {
 
 class BoundingBox;
@@ -88,10 +90,10 @@ inline Vec3d   unscale(coord_t x, coord_t y, coord_t z) { return Vec3d(unscale<d
 inline Vec3d   unscale(const Vec3crd &pt) { return Vec3d(unscale<double>(pt(0)), unscale<double>(pt(1)), unscale<double>(pt(2))); }
 inline Vec3d   unscale(const Vec3d   &pt) { return Vec3d(unscale<double>(pt(0)), unscale<double>(pt(1)), unscale<double>(pt(2))); }
 
-inline std::string to_string(const Vec2crd &pt) { return std::string("[") + std::to_string(pt(0)) + ", " + std::to_string(pt(1)) + "]"; }
-inline std::string to_string(const Vec2d   &pt) { return std::string("[") + std::to_string(pt(0)) + ", " + std::to_string(pt(1)) + "]"; }
-inline std::string to_string(const Vec3crd &pt) { return std::string("[") + std::to_string(pt(0)) + ", " + std::to_string(pt(1)) + ", " + std::to_string(pt(2)) + "]"; }
-inline std::string to_string(const Vec3d   &pt) { return std::string("[") + std::to_string(pt(0)) + ", " + std::to_string(pt(1)) + ", " + std::to_string(pt(2)) + "]"; }
+inline std::string to_string(const Vec2crd &pt) { return std::string("[") + float_to_string_decimal_point(pt(0)) + ", " + float_to_string_decimal_point(pt(1)) + "]"; }
+inline std::string to_string(const Vec2d   &pt) { return std::string("[") + float_to_string_decimal_point(pt(0)) + ", " + float_to_string_decimal_point(pt(1)) + "]"; }
+inline std::string to_string(const Vec3crd &pt) { return std::string("[") + float_to_string_decimal_point(pt(0)) + ", " + float_to_string_decimal_point(pt(1)) + ", " + float_to_string_decimal_point(pt(2)) + "]"; }
+inline std::string to_string(const Vec3d   &pt) { return std::string("[") + float_to_string_decimal_point(pt(0)) + ", " + float_to_string_decimal_point(pt(1)) + ", " + float_to_string_decimal_point(pt(2)) + "]"; }
 
 std::vector<Vec3f> transform(const std::vector<Vec3f>& points, const Transform3f& t);
 Pointf3s transform(const Pointf3s& points, const Transform3d& t);
diff --git a/src/libslic3r/SLAPrintSteps.cpp b/src/libslic3r/SLAPrintSteps.cpp
index 46064c55b..51e2430aa 100644
--- a/src/libslic3r/SLAPrintSteps.cpp
+++ b/src/libslic3r/SLAPrintSteps.cpp
@@ -166,8 +166,8 @@ struct FaceHash {
         Vec<3, int64_t> c = a.cross(b) + (pts[0] + pts[1] + pts[2]) / 3;
 
         // Return a concatenated string representation of the coordinates
-        return std::to_string(c(0)) + std::to_string(c(1)) + std::to_string(c(2));
-    };
+        return float_to_string_decimal_point(c(0)) + float_to_string_decimal_point(c(1)) + float_to_string_decimal_point(c(2));
+    }
 
     FaceHash(const indexed_triangle_set &its)
     {
diff --git a/src/slic3r/GUI/BitmapCache.cpp b/src/slic3r/GUI/BitmapCache.cpp
index 0a6f3e4f9..2c756c3b9 100644
--- a/src/slic3r/GUI/BitmapCache.cpp
+++ b/src/slic3r/GUI/BitmapCache.cpp
@@ -266,7 +266,7 @@ wxBitmap* BitmapCache::load_svg(const std::string &bitmap_name, unsigned target_
     std::string bitmap_key = bitmap_name + ( target_height !=0 ? 
                                            "-h" + std::to_string(target_height) : 
                                            "-w" + std::to_string(target_width))
-                                         + (m_scale != 1.0f ? "-s" + std::to_string(m_scale) : "")
+                                         + (m_scale != 1.0f ? "-s" + float_to_string_decimal_point(m_scale) : "")
                                          + (grayscale ? "-gs" : "");
 
     /* For the Dark mode of any platform, we should draw icons in respect to OS background
diff --git a/src/slic3r/GUI/ConfigWizard.cpp b/src/slic3r/GUI/ConfigWizard.cpp
index 52df39fd5..f7d16d843 100644
--- a/src/slic3r/GUI/ConfigWizard.cpp
+++ b/src/slic3r/GUI/ConfigWizard.cpp
@@ -1388,17 +1388,21 @@ static void focus_event(wxFocusEvent& e, wxTextCtrl* ctrl, double def_value)
 {
     e.Skip();
     wxString str = ctrl->GetValue();
-    // Replace the first occurence of comma in decimal number.
-    bool was_replace = str.Replace(",", ".", false) > 0;
+
+    const char dec_sep = is_decimal_separator_point() ? '.' : ',';
+    const char dec_sep_alt = dec_sep == '.' ? ',' : '.';
+    // Replace the first incorrect separator in decimal number.
+    bool was_replaced = str.Replace(dec_sep_alt, dec_sep, false) != 0;
+
     double val = 0.0;
-    if (!str.ToCDouble(&val)) {
+    if (!str.ToDouble(&val)) {
         if (val == 0.0)
             val = def_value;
         ctrl->SetValue(double_to_string(val));
         show_error(nullptr, _L("Invalid numeric input."));
         ctrl->SetFocus();
     }
-    else if (was_replace)
+    else if (was_replaced)
         ctrl->SetValue(double_to_string(val));
 }
 
@@ -1447,17 +1451,17 @@ PageDiameters::PageDiameters(ConfigWizard *parent)
 void PageDiameters::apply_custom_config(DynamicPrintConfig &config)
 {
     double val = 0.0;
-    diam_nozzle->GetValue().ToCDouble(&val);
+    diam_nozzle->GetValue().ToDouble(&val);
     auto *opt_nozzle = new ConfigOptionFloats(1, val);
     config.set_key_value("nozzle_diameter", opt_nozzle);
 
     val = 0.0;
-    diam_filam->GetValue().ToCDouble(&val);
+    diam_filam->GetValue().ToDouble(&val);
     auto * opt_filam = new ConfigOptionFloats(1, val);
     config.set_key_value("filament_diameter", opt_filam);
 
     auto set_extrusion_width = [&config, opt_nozzle](const char *key, double dmr) {
-        char buf[64];
+        char buf[64]; // locales don't matter here (sprintf/atof)
         sprintf(buf, "%.2lf", dmr * opt_nozzle->values.front() / 0.4);
         config.set_key_value(key, new ConfigOptionFloatOrPercent(atof(buf), false));
     };
diff --git a/src/slic3r/GUI/DoubleSlider.cpp b/src/slic3r/GUI/DoubleSlider.cpp
index 6d41e3c82..9c280dee6 100644
--- a/src/slic3r/GUI/DoubleSlider.cpp
+++ b/src/slic3r/GUI/DoubleSlider.cpp
@@ -2162,7 +2162,7 @@ static void upgrade_text_entry_dialog(wxTextEntryDialog* dlg, double min = -1.0,
         bool disable = textctrl->IsEmpty();
         if (!disable && min >= 0.0 && max >= 0.0) {
             double value = -1.0;
-            if (!textctrl->GetValue().ToCDouble(&value))    // input value couldn't be converted to double
+            if (!textctrl->GetValue().ToDouble(&value))    // input value couldn't be converted to double
                 disable = true;
             else
                 disable = value < min - epsilon() || value > max + epsilon();       // is input value is out of valid range ?
@@ -2231,7 +2231,7 @@ static double get_value_to_jump(double active_value, double min_z, double max_z,
         return -1.0;
 
     double value = -1.0;
-    return dlg.GetValue().ToCDouble(&value) ? value : -1.0;
+    return dlg.GetValue().ToDouble(&value) ? value : -1.0;
 }
 
 void Control::add_code_as_tick(Type type, int selected_extruder/* = -1*/)
diff --git a/src/slic3r/GUI/ExtruderSequenceDialog.cpp b/src/slic3r/GUI/ExtruderSequenceDialog.cpp
index e505f1470..8ae5e9f32 100644
--- a/src/slic3r/GUI/ExtruderSequenceDialog.cpp
+++ b/src/slic3r/GUI/ExtruderSequenceDialog.cpp
@@ -98,9 +98,14 @@ ExtruderSequenceDialog::ExtruderSequenceDialog(const DoubleSlider::ExtrudersSequ
             return;
         }
 
-        str.Replace(",", ".", false);
+        char dec_sep = '.';
+        if (! is_decimal_separator_point()) {
+            str.Replace(".", ",", false);
+            dec_sep = ',';
+        }
+
         double val;
-        if (str == "." || !str.ToCDouble(&val) || val <= 0.0)
+        if (str == dec_sep || !str.ToDouble(&val) || val <= 0.0)
             val = 3.0; // default value
 
         if (fabs(m_sequence.interval_by_layers - val) < 0.001)
diff --git a/src/slic3r/GUI/Field.cpp b/src/slic3r/GUI/Field.cpp
index 1fe28eb34..de8d3c104 100644
--- a/src/slic3r/GUI/Field.cpp
+++ b/src/slic3r/GUI/Field.cpp
@@ -37,12 +37,13 @@ wxString double_to_string(double const value, const int max_precision /*= 4*/)
 	// with the exception that here one sets the decimal separator explicitely to dot.
     // If number is in scientific format, trailing zeroes belong to the exponent and cannot be removed.
     if (s.find_first_of("eE") == wxString::npos) {
-	    const size_t posDecSep = s.find(".");
+        char dec_sep = is_decimal_separator_point() ? '.' : ',';
+        const size_t posDecSep = s.find(dec_sep);
 	    // No decimal point => removing trailing zeroes irrelevant for integer number.
 	    if (posDecSep != wxString::npos) {
 		    // Find the last character to keep.
 		    size_t posLastNonZero = s.find_last_not_of("0");
-		    // If it's the decimal separator itself, don't keep it neither.
+            // If it's the decimal separator itself, don't keep it either.
 		    if (posLastNonZero == posDecSep)
 		        -- posLastNonZero;
 		    s.erase(posLastNonZero + 1);
@@ -236,16 +237,22 @@ void Field::get_value_by_opt_type(wxString& str, const bool check_value/* = true
 			m_value = double(m_opt.min);
 			break;
 		}
-		double val;
-		// Replace the first occurence of comma in decimal number.
-		str.Replace(",", ".", false);
-        if (str == ".")
+        double val;
+
+        const char dec_sep = is_decimal_separator_point() ? '.' : ',';
+        const char dec_sep_alt = dec_sep == '.' ? ',' : '.';
+        // Replace the first incorrect separator in decimal number.
+        if (str.Replace(dec_sep_alt, dec_sep, false) != 0)
+            set_value(str, false);
+
+
+        if (str == dec_sep)
             val = 0.0;
         else
         {
             if (m_opt.nullable && str == na_value())
                 val = ConfigOptionFloatsNullable::nil_value();
-            else if (!str.ToCDouble(&val))
+            else if (!str.ToDouble(&val))
             {
                 if (!check_value) {
                     m_value.clear();
@@ -293,14 +300,18 @@ void Field::get_value_by_opt_type(wxString& str, const bool check_value/* = true
         if (m_opt.type == coFloatOrPercent && !str.IsEmpty() &&  str.Last() != '%')
         {
             double val = 0.;
-			// Replace the first occurence of comma in decimal number.
-			str.Replace(",", ".", false);
+            const char dec_sep = is_decimal_separator_point() ? '.' : ',';
+            const char dec_sep_alt = dec_sep == '.' ? ',' : '.';
+            // Replace the first incorrect separator in decimal number.
+            if (str.Replace(dec_sep_alt, dec_sep, false) != 0)
+                set_value(str, false);
+
 
             // remove space and "mm" substring, if any exists
             str.Replace(" ", "", true);
             str.Replace("m", "", true);
 
-            if (!str.ToCDouble(&val))
+            if (!str.ToDouble(&val))
             {
                 if (!check_value) {
                     m_value.clear();
@@ -1215,8 +1226,8 @@ boost::any& Choice::get_value()
 	return m_value;
 }
 
-void Choice::enable()  { dynamic_cast<choice_ctrl*>(window)->Enable(); };
-void Choice::disable() { dynamic_cast<choice_ctrl*>(window)->Disable(); };
+void Choice::enable()  { dynamic_cast<choice_ctrl*>(window)->Enable(); }
+void Choice::disable() { dynamic_cast<choice_ctrl*>(window)->Disable(); }
 
 void Choice::msw_rescale()
 {
@@ -1478,7 +1489,7 @@ boost::any& PointCtrl::get_value()
 		!y_textctrl->GetValue().ToDouble(&y))
 	{
 		set_value(m_value.empty() ? Vec2d(0.0, 0.0) : m_value, true);
-		show_error(m_parent, _L("Invalid numeric input."));
+        show_error(m_parent, _L("Invalid numeric input."));
 	}
 	else
 	if (m_opt.min > x || x > m_opt.max ||
diff --git a/src/slic3r/GUI/GCodeViewer.cpp b/src/slic3r/GUI/GCodeViewer.cpp
index 209679c0f..285f07051 100644
--- a/src/slic3r/GUI/GCodeViewer.cpp
+++ b/src/slic3r/GUI/GCodeViewer.cpp
@@ -5,6 +5,7 @@
 #include "libslic3r/Geometry.hpp"
 #include "libslic3r/Model.hpp"
 #include "libslic3r/Utils.hpp"
+#include "libslic3r/LocalesUtils.hpp"
 #include "GUI_App.hpp"
 #include "MainFrame.hpp"
 #include "Plater.hpp"
@@ -78,6 +79,7 @@ static float round_to_nearest(float value, unsigned int decimals)
         res = std::round(value);
     else {
         char buf[64];
+        // locales should not matter, both sprintf and stof are sensitive, so...
         sprintf(buf, "%.*g", decimals, value);
         res = std::stof(buf);
     }
@@ -990,6 +992,9 @@ void GCodeViewer::export_toolpaths_to_obj(const char* filename) const
     // save materials file
     boost::filesystem::path mat_filename(filename);
     mat_filename.replace_extension("mtl");
+
+    CNumericLocalesSetter locales_setter;
+
     FILE* fp = boost::nowide::fopen(mat_filename.string().c_str(), "w");
     if (fp == nullptr) {
         BOOST_LOG_TRIVIAL(error) << "GCodeViewer::export_toolpaths_to_obj: Couldn't open " << mat_filename.string().c_str() << " for writing";
@@ -3465,18 +3470,16 @@ void GCodeViewer::render_statistics() const
     ImGuiWrapper& imgui = *wxGetApp().imgui();
 
     auto add_time = [this, &imgui](const std::string& label, int64_t time) {
-        char buf[1024];
-        sprintf(buf, "%lld ms (%s)", time, get_time_dhms(static_cast<float>(time) * 0.001f).c_str());
         imgui.text_colored(ImGuiWrapper::COL_ORANGE_LIGHT, label);
         ImGui::SameLine(offset);
-        imgui.text(buf);
+        imgui.text(std::to_string(time) + " ms (" + get_time_dhms(static_cast<float>(time) * 0.001f) + ")");
     };
 
     auto add_memory = [this, &imgui](const std::string& label, int64_t memory) {
-        auto format_string = [memory](const std::string& units, float value) {
-            char buf[1024];
-            sprintf(buf, "%lld bytes (%.3f %s)", memory, static_cast<float>(memory) * value, units.c_str());
-            return std::string(buf);
+        auto format_string = [memory](const std::string& units, float value) {            
+            return std::to_string(memory) + " bytes (" +
+                   Slic3r::float_to_string_decimal_point(float(memory) * value, 3)
+                    + " " + units + ")";
         };
 
         static const float kb = 1024.0f;
@@ -3496,11 +3499,9 @@ void GCodeViewer::render_statistics() const
     };
 
     auto add_counter = [this, &imgui](const std::string& label, int64_t counter) {
-        char buf[1024];
-        sprintf(buf, "%lld", counter);
         imgui.text_colored(ImGuiWrapper::COL_ORANGE_LIGHT, label);
         ImGui::SameLine(offset);
-        imgui.text(buf);
+        imgui.text(std::to_string(counter));
     };
 
     imgui.set_next_window_pos(0.5f * wxGetApp().plater()->get_current_canvas3D()->get_canvas_size().get_width(), 0.0f, ImGuiCond_Once, 0.5f, 0.0f);
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 734bc24aa..455eb8a78 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -3800,7 +3800,7 @@ bool GLCanvas3D::_render_arrange_menu(float pos_x)
     if (imgui->slider_float(_L("Spacing"), &settings.distance, dist_min, 100.0f, "%5.2f") || dist_min > settings.distance) {
         settings.distance = std::max(dist_min, settings.distance);
         settings_out.distance = settings.distance;
-        appcfg->set("arrange", dist_key.c_str(), std::to_string(settings_out.distance));
+        appcfg->set("arrange", dist_key.c_str(), float_to_string_decimal_point(settings_out.distance));
         settings_changed = true;
     }
 
@@ -3815,7 +3815,7 @@ bool GLCanvas3D::_render_arrange_menu(float pos_x)
     if (imgui->button(_L("Reset"))) {
         settings_out = ArrangeSettings{};
         settings_out.distance = std::max(dist_min, settings_out.distance);
-        appcfg->set("arrange", dist_key.c_str(), std::to_string(settings_out.distance));
+        appcfg->set("arrange", dist_key.c_str(), float_to_string_decimal_point(settings_out.distance));
         appcfg->set("arrange", rot_key.c_str(), settings_out.enable_rotation? "1" : "0");
         settings_changed = true;
     }
diff --git a/src/slic3r/GUI/GUI.cpp b/src/slic3r/GUI/GUI.cpp
index f3a8f6ba1..c6cb05fac 100644
--- a/src/slic3r/GUI/GUI.cpp
+++ b/src/slic3r/GUI/GUI.cpp
@@ -2,6 +2,8 @@
 #include "GUI_App.hpp"
 #include "I18N.hpp"
 
+#include "libslic3r/LocalesUtils.hpp"
+
 #include <string>
 
 #include <boost/algorithm/string.hpp>
@@ -113,7 +115,7 @@ void change_opt_value(DynamicPrintConfig& config, const t_config_option_key& opt
 				str.pop_back();
 				percent = true;
 			}
-			double val = stod(str);
+            double val = std::stod(str); // locale-dependent (on purpose - the input is the actual content of the field)
 			config.set_key_value(opt_key, new ConfigOptionFloatOrPercent(val, percent));
 			break;}
 		case coPercent:
diff --git a/src/slic3r/GUI/GUI_App.cpp b/src/slic3r/GUI/GUI_App.cpp
index 803ab5a14..d6520335b 100644
--- a/src/slic3r/GUI/GUI_App.cpp
+++ b/src/slic3r/GUI/GUI_App.cpp
@@ -1586,7 +1586,7 @@ bool GUI_App::load_language(wxString language, bool initial)
     m_wxLocale->AddCatalog(SLIC3R_APP_KEY);
     m_imgui->set_language(into_u8(language_info->CanonicalName));
     //FIXME This is a temporary workaround, the correct solution is to switch to "C" locale during file import / export only.
-    wxSetlocale(LC_NUMERIC, "C");
+    //wxSetlocale(LC_NUMERIC, "C");
     Preset::update_suffix_modified((" (" + _L("modified") + ")").ToUTF8().data());
 	return true;
 }
diff --git a/src/slic3r/GUI/GUI_ObjectLayers.cpp b/src/slic3r/GUI/GUI_ObjectLayers.cpp
index d079a6ebd..7c13c20d6 100644
--- a/src/slic3r/GUI/GUI_ObjectLayers.cpp
+++ b/src/slic3r/GUI/GUI_ObjectLayers.cpp
@@ -397,12 +397,16 @@ coordf_t LayerRangeEditor::get_value()
     wxString str = GetValue();
 
     coordf_t layer_height;
-    // Replace the first occurence of comma in decimal number.
-    str.Replace(",", ".", false);
+    const char dec_sep = is_decimal_separator_point() ? '.' : ',';
+    const char dec_sep_alt = dec_sep == '.' ? ',' : '.';
+    // Replace the first incorrect separator in decimal number.
+    if (str.Replace(dec_sep_alt, dec_sep, false) != 0)
+        SetValue(str);
+
     if (str == ".")
         layer_height = 0.0;
     else {
-        if (!str.ToCDouble(&layer_height) || layer_height < 0.0f) {
+        if (!str.ToDouble(&layer_height) || layer_height < 0.0f) {
             show_error(m_parent, _L("Invalid numeric input."));
             SetValue(double_to_string(layer_height));
         }
diff --git a/src/slic3r/GUI/GUI_ObjectManipulation.cpp b/src/slic3r/GUI/GUI_ObjectManipulation.cpp
index 095a926ad..cdffbc88d 100644
--- a/src/slic3r/GUI/GUI_ObjectManipulation.cpp
+++ b/src/slic3r/GUI/GUI_ObjectManipulation.cpp
@@ -1095,15 +1095,19 @@ double ManipulationEditor::get_value()
     wxString str = GetValue();
 
     double value;
-    // Replace the first occurence of comma in decimal number.
-    str.Replace(",", ".", false);
+    const char dec_sep = is_decimal_separator_point() ? '.' : ',';
+    const char dec_sep_alt = dec_sep == '.' ? ',' : '.';
+    // Replace the first incorrect separator in decimal number.
+    if (str.Replace(dec_sep_alt, dec_sep, false) != 0)
+        SetValue(str);
+
     if (str == ".")
         value = 0.0;
 
-    if ((str.IsEmpty() || !str.ToCDouble(&value)) && !m_valid_value.IsEmpty()) {
+    if ((str.IsEmpty() || !str.ToDouble(&value)) && !m_valid_value.IsEmpty()) {
         str = m_valid_value;
         SetValue(str);
-        str.ToCDouble(&value);
+        str.ToDouble(&value);
     }
 
     return value;
diff --git a/src/slic3r/GUI/Selection.cpp b/src/slic3r/GUI/Selection.cpp
index 4cf71363d..5c34d7de0 100644
--- a/src/slic3r/GUI/Selection.cpp
+++ b/src/slic3r/GUI/Selection.cpp
@@ -11,6 +11,7 @@
 #include "Camera.hpp"
 #include "Plater.hpp"
 
+#include "libslic3r/LocalesUtils.hpp"
 #include "libslic3r/Model.hpp"
 #if DISABLE_ALLOW_NEGATIVE_Z_FOR_SLA
 #include "libslic3r/PresetBundle.hpp"
@@ -1927,7 +1928,7 @@ void Selection::render_sidebar_layers_hints(const std::string& sidebar_field) co
     if (pos == std::string::npos)
         return;
 
-    double max_z = std::stod(field.substr(pos + 1));
+    double max_z = string_to_double_decimal_point(field.substr(pos + 1));
 
     // extract min_z
     field = field.substr(0, pos);
@@ -1935,7 +1936,7 @@ void Selection::render_sidebar_layers_hints(const std::string& sidebar_field) co
     if (pos == std::string::npos)
         return;
 
-    const double min_z = std::stod(field.substr(pos + 1));
+    const double min_z = string_to_double_decimal_point(field.substr(pos + 1));
 
     // extract type
     field = field.substr(0, pos);
diff --git a/tests/libslic3r/test_config.cpp b/tests/libslic3r/test_config.cpp
index c3f17def2..417a29dca 100644
--- a/tests/libslic3r/test_config.cpp
+++ b/tests/libslic3r/test_config.cpp
@@ -1,6 +1,7 @@
 #include <catch2/catch.hpp>
 
 #include "libslic3r/PrintConfig.hpp"
+#include "libslic3r/LocalesUtils.hpp"
 
 using namespace Slic3r;
 
@@ -112,7 +113,7 @@ SCENARIO("Config accessor functions perform as expected.", "[Config]") {
         WHEN("A string option is set through the double interface") {
             config.set("end_gcode", 100.5);
             THEN("The underlying value is set correctly.") {
-                REQUIRE(config.opt<ConfigOptionString>("end_gcode")->value == std::to_string(100.5));
+                REQUIRE(config.opt<ConfigOptionString>("end_gcode")->value == float_to_string_decimal_point(100.5));
             }
         }
         WHEN("A float or percent is set as a percent through the string interface.") {