Keep a Decimal Point in the Wipe Tower's Travel Feedrate

merge_tcr formatted the feedrate of the travel that joins two wipe tower
blocks with std::to_string, which follows the numeric locale. The GUI slices
on a thread that keeps the user's locale, so a comma-decimal locale wrote
moves such as 'G1 Y249.463 F5400,000000', which Klipper rejects. Format it
with float_to_string_decimal_point like the X and Y beside it; the output in
the C locale is unchanged.

The comma-locale test helper moves to the shared test header so the wipe
tower test can use it.

src/libslic3r/GCode/WipeTower.cpp

@@ -3349,7 +3349,7 @@ WipeTower::ToolChangeResult WipeTower::merge_tcr(ToolChangeResult &first, ToolCh
     WipeTower::ToolChangeResult out = first;
     if ((first.end_pos - second.start_pos).norm() > (float)EPSILON) {
         std::string travel_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) + " F" + std::to_string(m_max_speed) + "\n";
+                                   Slic3r::float_to_string_decimal_point(second.start_pos.y(), 3) + " F" + Slic3r::float_to_string_decimal_point(m_max_speed, 6) + "\n";
         bool need_insert_travel = true;
         if (second.is_tool_change
             && is_approx(second.start_pos.x(), second.tool_change_start_pos.x())

tests/fff_print/test_wipe_tower.cpp

@@ -8,6 +8,7 @@
 #include <cstddef>
 #include "libslic3r/Model.hpp"
 #include "libslic3r/Print.hpp"
+#include <sstream>
 #include <string>
 #include <vector>
 
@@ -22,9 +23,11 @@
 #include "libslic3r/ClipperUtils.hpp"
 #include "libslic3r/GCode/GCodeProcessor.hpp"
 #include "libslic3r/GCode/WipeTower.hpp"
+#include "libslic3r/LocalesUtils.hpp"
 #include "libslic3r/PrintConfig.hpp"
 
 #include "test_helpers.hpp"
+#include "test_utils.hpp"
 #include "libslic3r/PrintBase.hpp"
 #include "libslic3r/TriangleMesh.hpp"
 
@@ -219,6 +222,24 @@ TEST_CASE("The wipe tower sets Klipper's acceleration and accel_to_decel on one
                       !Catch::Matchers::ContainsSubstring("M204"));
 }
 
+TEST_CASE("The wipe tower's G-code moves keep a decimal point in a comma-decimal locale", "[WipeTower]")
+{
+    // The GUI slices on a thread that keeps the user's numeric locale.
+    CommaNumericLocale comma;
+    CNumericLocalesSetter restore;
+    if (! comma.apply())
+        SKIP("no locale with a comma decimal separator is installed");
+    DynamicPrintConfig config = wipe_tower_toolchange_config("klipper");
+    // Type 1 towers join their toolchange blocks with a travel move of their own.
+    config.set_deserialize_strict({ { "wipe_tower_type", "type1" } });
+    const std::string gcode = slice_with_prime_tower(config);
+    REQUIRE_FALSE(wipe_tower_regions(gcode).empty());
+    std::istringstream lines(gcode);
+    for (std::string line; std::getline(lines, line);)
+        if (! line.empty() && line.front() == 'G' && line.find(',') != std::string::npos)
+            FAIL_CHECK(line);
+}
+
 // What Print feeds the shared estimate. The libslic3r WipeTowerEstimate cases cannot see this:
 // they call the estimator directly. The estimate counts the filaments the print really uses,
 // so the two-filament shape gives the outer wall the second one.
@@ -476,3 +497,4 @@ TEST_CASE("A tower printed without a tool change is still validated against the
     CHECK(print.wipe_tower_data(1).depth > 0.f);
     CHECK_THAT(print.validate().string, Catch::Matchers::ContainsSubstring("printable area"));
 }
+

tests/libslic3r/test_locales_utils.cpp

@@ -1,55 +1,17 @@
 #include <catch2/catch_all.hpp>
 
-#include <clocale>
-#include <locale.h>
-
 #include <catch2/catch_test_macros.hpp>
 #include <catch2/generators/catch_generators.hpp>
 #include <catch2/catch_message.hpp>
 #include <catch2/matchers/catch_matchers.hpp>
 #include <catch2/matchers/catch_matchers_floating_point.hpp>
 #include "libslic3r/LocalesUtils.hpp"
+#include "test_utils.hpp"
 
 #include <string>
 
 using namespace Slic3r;
 
-namespace {
-
-// Switches this thread's numeric locale to one whose decimal separator is a comma,
-// when the system has one installed.
-struct CommaNumericLocale
-{
-#ifdef _WIN32
-    bool apply()
-    {
-        for (const char* name : { "de-DE", "German_Germany.1252" })
-            if (std::setlocale(LC_NUMERIC, name) != nullptr)
-                return true;
-        return false;
-    }
-#else
-    locale_t locale { (locale_t) 0 };
-    bool apply()
-    {
-        for (const char* name : { "de_DE.UTF-8", "de_DE.utf8", "de_DE" })
-            if ((locale = newlocale(LC_NUMERIC_MASK, name, (locale_t) 0)) != (locale_t) 0) {
-                uselocale(locale);
-                return true;
-            }
-        return false;
-    }
-    // Freed once the setters around apply() have put the thread's own locale back.
-    ~CommaNumericLocale()
-    {
-        if (locale != (locale_t) 0)
-            freelocale(locale);
-    }
-#endif
-};
-
-} // namespace
-
 TEST_CASE("Floats print as printf prints them in the C locale", "[LocalesUtils]")
 {
     const auto [value, precision, text] = GENERATE(table<double, int, std::string>({

tests/test_utils.hpp

@@ -12,12 +12,16 @@
 #include <boost/filesystem.hpp>
 #include <boost/nowide/cstdlib.hpp>
 
+#include <clocale>
 #include <cstdio>
 #include <fstream>
+#include <initializer_list>
 #include <optional>
 #include <string>
 #include <utility>
 
+#include <locale.h>
+
 #if defined(WIN32) || defined(_WIN32)
 #define PATH_SEPARATOR R"(\)"
 #else
@@ -223,4 +227,36 @@ private:
     std::optional<std::string> m_previous;
 };
 
+// Switches this thread's numeric locale to one whose decimal separator is a comma,
+// when the system has one installed.
+struct CommaNumericLocale
+{
+#ifdef _WIN32
+    bool apply()
+    {
+        for (const char* name : { "de-DE", "German_Germany.1252" })
+            if (std::setlocale(LC_NUMERIC, name) != nullptr)
+                return true;
+        return false;
+    }
+#else
+    locale_t locale { (locale_t) 0 };
+    bool apply()
+    {
+        for (const char* name : { "de_DE.UTF-8", "de_DE.utf8", "de_DE" })
+            if ((locale = newlocale(LC_NUMERIC_MASK, name, (locale_t) 0)) != (locale_t) 0) {
+                uselocale(locale);
+                return true;
+            }
+        return false;
+    }
+    // Freed once the setters around apply() have put the thread's own locale back.
+    ~CommaNumericLocale()
+    {
+        if (locale != (locale_t) 0)
+            freelocale(locale);
+    }
+#endif
+};
+
 #endif // SLIC3R_TEST_UTILS