Update sublayer option check. Add validation warning for gradient mixed filament without sublayer mixing

src/libslic3r/Print.cpp

@@ -1328,6 +1328,19 @@ StringObjectException Print::validate(std::vector<StringObjectException> *warnin
     if (extruders.empty())
         return { L("No extrusions under current settings.") };
 
+    // Orca: a gradient mixed filament only renders its gradient with "Mixed color sublayer" on;
+    // without it ToolOrdering::resolve_mixed_filaments prints one whole component per layer and
+    // the gradient is dropped silently. extruders() already covers painting, height ranges,
+    // per-feature filament ids and supports, and still lists mixed slots under their own id here.
+    if (!m_config.enable_mixed_color_sublayer.value) {
+        const auto &is_mixed = m_config.filament_is_mixed.values;
+        const auto &gradient = m_config.filament_mixed_gradient.values;
+        if (std::any_of(extruders.begin(), extruders.end(), [&](unsigned int e) {
+                return e < is_mixed.size() && is_mixed[e] && e < gradient.size() && gradient[e]; }))
+            warn(L("A gradient mixed filament is used, but 'Mixed color sublayer' is disabled. The gradient will not be printed."),
+                 "enable_mixed_color_sublayer");
+    }
+
     if (nozzles < 2 && extruders.size() > 1) {
         auto ret = check_multi_filament_valid(*this);
         if (!ret.string.empty())

src/slic3r/GUI/MixedFilamentDialog.cpp

@@ -23,8 +23,6 @@
 #include "GradientCurveEditor.hpp"
 #include "FilamentBitmapUtils.hpp"
 #include "wxExtensions.hpp"
-#include "Tab.hpp"
-#include "libslic3r/Preset.hpp"
 #include "Widgets/Button.hpp"
 #include "Widgets/CheckBox.hpp"
 #include "Widgets/ComboBox.hpp"
@@ -1492,28 +1490,6 @@ void MixedFilamentDialog::on_ratio_changed(int new_ratio_a)
 
 void MixedFilamentDialog::on_gradient_toggled()
 {
-    // Orca: a gradient is only sliced when the print profile's "enable_mixed_color_sublayer"
-    // option is on; without it ToolOrdering picks a single component per whole layer. Offer to
-    // turn the option on instead of silently ignoring the gradient the user just enabled.
-    bool checked = m_chk_gradient->GetValue();
-
-    if (checked) {
-        auto& print_config = wxGetApp().preset_bundle->prints.get_edited_preset().config;
-        if (!print_config.opt_bool("enable_mixed_color_sublayer")) {
-            wxMessageDialog dlg(this,
-                _L("Gradient effect requires 'Mixed color sublayer' to be enabled. Enable it now?"),
-                _L("Mixed Color Sublayer"),
-                wxYES_NO | wxICON_QUESTION);
-            if (dlg.ShowModal() == wxID_YES) {
-                DynamicPrintConfig new_conf;
-                new_conf.set_key_value("enable_mixed_color_sublayer", new ConfigOptionBool(true));
-                wxGetApp().get_tab(Preset::TYPE_PRINT)->load_config(new_conf);
-            } else {
-                m_chk_gradient->SetValue(false);
-                return;
-            }
-        }
-    }
 
     m_result.gradient_enabled = m_chk_gradient->GetValue();
 

tests/fff_print/test_mixed_filament.cpp

@@ -253,3 +253,72 @@ TEST_CASE("Print::validate rejects a mixed filament as the wipe tower filament",
         CHECK(err.opt_key == "wipe_tower_filament");
     }
 }
+
+TEST_CASE("Print::validate warns when a gradient mixed filament is used without sublayer mixing", "[MixedFilament]")
+{
+    // A gradient mixed filament only renders its gradient with the process option enabled; without
+    // it ToolOrdering prints one whole component per layer and the gradient is dropped silently,
+    // so validate() warns whenever the slot actually takes part in the print. The layer-change
+    // reset avoids an unrelated relative-extrusion warning, as in the wipe tower test above.
+    DynamicPrintConfig config = mixed_config(false);
+    config.set_deserialize_strict({
+        {"filament_mixed_gradient", "0,0,1"},
+        {"layer_change_gcode",       "G92 E0\n"},
+    });
+
+    auto count_opt = [](Print &print, const char *opt_key) {
+        std::vector<StringObjectException> warnings;
+        print.validate(&warnings);
+        return std::count_if(warnings.begin(), warnings.end(),
+                             [&](const StringObjectException &w) { return w.opt_key == opt_key; });
+    };
+
+    SECTION("gradient slot used, sublayer mixing off") {
+        Print print;
+        Model model;
+        init_print({cube(20)}, print, model, config);
+        std::vector<StringObjectException> warnings;
+        const StringObjectException err = print.validate(&warnings);
+        CHECK(err.string.empty());
+        const auto it = std::find_if(warnings.begin(), warnings.end(), [](const StringObjectException &w) {
+            return w.opt_key == "enable_mixed_color_sublayer";
+        });
+        REQUIRE(it != warnings.end());
+        CHECK(it->is_warning);
+        CHECK(std::count_if(warnings.begin(), warnings.end(), [](const StringObjectException &w) {
+                  return w.opt_key == "enable_mixed_color_sublayer";
+              }) == 1);
+    }
+
+    SECTION("sublayer mixing on") {
+        config.set_deserialize_strict({{"enable_mixed_color_sublayer", "1"}});
+        Print print;
+        Model model;
+        init_print({cube(20)}, print, model, config);
+        CHECK(count_opt(print, "enable_mixed_color_sublayer") == 0);
+    }
+
+    SECTION("gradient flag off") {
+        config.set_deserialize_strict({{"filament_mixed_gradient", "0,0,0"}});
+        Print print;
+        Model model;
+        init_print({cube(20)}, print, model, config);
+        CHECK(count_opt(print, "enable_mixed_color_sublayer") == 0);
+    }
+
+    SECTION("mixed slot not used") {
+        config.set_deserialize_strict({
+            {"outer_wall_filament_id",     "0"},
+            {"inner_wall_filament_id",     "0"},
+            {"sparse_infill_filament_id",  "0"},
+            {"internal_solid_filament_id", "0"},
+            {"top_surface_filament_id",    "0"},
+            {"bottom_surface_filament_id", "0"},
+        });
+        Print print;
+        Model model;
+        const std::vector<std::vector<ConfigBase::SetDeserializeItem>> overrides{{{ "extruder", "1" }}};
+        init_print(std::vector<TriangleMesh>{cube(20)}, print, model, config, &overrides);
+        CHECK(count_opt(print, "enable_mixed_color_sublayer") == 0);
+    }
+}