Make the generic filament the default fallback instead of using filaments sorted alphabetically by name. (#12124)

src/libslic3r/Preset.cpp

@@ -1388,7 +1388,7 @@ void PresetCollection::load_presets(
     }
     if (presets_loaded.size() > 0)
         m_presets.insert(m_presets.end(), std::make_move_iterator(presets_loaded.begin()), std::make_move_iterator(presets_loaded.end()));
-    std::sort(m_presets.begin() + m_num_default_presets, m_presets.end());
+    sort_presets();
     //BBS: add config related logs
     BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << boost::format(": loaded %1% presets from %2%, type %3%")%presets_loaded.size() %dir %Preset::get_type_string(m_type);
     //this->select_preset(first_visible_idx());
@@ -1583,7 +1583,7 @@ void PresetCollection::load_project_embedded_presets(std::vector<Preset*>& proje
     }
 
     m_presets.insert(m_presets.end(), std::make_move_iterator(presets_loaded.begin()), std::make_move_iterator(presets_loaded.end()));
-    std::sort(m_presets.begin() + m_num_default_presets, m_presets.end());
+    sort_presets();
     //don't select it here
     //this->select_preset(first_visible_idx());
     unlock();
@@ -1976,7 +1976,7 @@ void PresetCollection::update_after_user_presets_loaded()
     lock();
     std::string     selected_name = get_selected_preset_name();
     BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << boost::format(", before sort, type %1%, selected_idx %2%, selected_name %3%") %m_type %m_idx_selected %selected_name;
-    std::sort(m_presets.begin() + m_num_default_presets, m_presets.end());
+    sort_presets();
     this->select_preset_by_name(selected_name, false);
     unlock();
     BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << boost::format(", after sort, type %1%, selected_idx %2%") %m_type %m_idx_selected;
@@ -3129,7 +3129,9 @@ std::vector<std::string> PresetCollection::merge_presets(PresetCollection &&othe
         if (preset.is_default || preset.is_external)
             continue;
         Preset key(m_type, preset.name);
-        auto it = std::lower_bound(m_presets.begin() + m_num_default_presets, m_presets.end(), key);
+        auto it = (m_type == Preset::TYPE_FILAMENT)
+            ? std::lower_bound(m_presets.begin() + m_num_default_presets, m_presets.end(), key, filament_preset_less)
+            : std::lower_bound(m_presets.begin() + m_num_default_presets, m_presets.end(), key);
         if (it == m_presets.end() || it->name != preset.name) {
             if (preset.vendor != nullptr) {
                 // Re-assign a pointer to the vendor structure in the new PresetBundle.

src/libslic3r/Preset.hpp

@@ -8,6 +8,7 @@
 #include <unordered_set>
 #include <functional>
 #include <mutex>
+#include <boost/algorithm/string/predicate.hpp>
 #include <boost/filesystem/path.hpp>
 #include <boost/property_tree/ptree_fwd.hpp>
 
@@ -75,6 +76,8 @@
 #define ORCA_JSON_KEY_RENAMED_FROM              "renamed_from"
 
 
+static constexpr const char* GENERIC_PREFIX = "Generic ";
+
 namespace Slic3r {
 
 class AppConfig;
@@ -764,13 +767,39 @@ protected:
     void            set_custom_preset_alias(Preset &preset);
 
 private:
+    // Comparator that sorts "Generic " prefixed presets before others, then alphabetically within each group.
+    static bool filament_preset_less(const Preset &a, const Preset &b) {
+        bool a_generic = boost::starts_with(a.name, GENERIC_PREFIX);
+        bool b_generic = boost::starts_with(b.name, GENERIC_PREFIX);
+        if (a_generic != b_generic)
+            return a_generic; // generics first
+        return a.name < b.name;
+    }
+
+    // Sort presets: filament presets use generic-first ordering, others sort alphabetically.
+    void sort_presets() {
+        if (m_type == Preset::TYPE_FILAMENT)
+            std::sort(m_presets.begin() + m_num_default_presets, m_presets.end(), filament_preset_less);
+        else
+            std::sort(m_presets.begin() + m_num_default_presets, m_presets.end());
+    }
+
     // Find a preset position in the sorted list of presets.
     // The "-- default -- " preset is always the first, so it needs
     // to be handled differently.
     // If a preset does not exist, an iterator is returned indicating where to insert a preset with the same name.
     std::deque<Preset>::iterator find_preset_internal(const std::string &name, bool from_orca_lib_only = false)
     {
-        auto it = Slic3r::lower_bound_by_predicate(m_presets.begin() + m_num_default_presets, m_presets.end(), [&name](const auto& l) { return l.name < name;  });
+        auto it = Slic3r::lower_bound_by_predicate(m_presets.begin() + m_num_default_presets, m_presets.end(),
+            [&name, this](const auto& l) {
+                if (m_type == Preset::TYPE_FILAMENT) {
+                    bool l_generic = boost::starts_with(l.name, GENERIC_PREFIX);
+                    bool name_generic = boost::starts_with(name, GENERIC_PREFIX);
+                    if (l_generic && !name_generic) return true;
+                    if (!l_generic && name_generic) return false;
+                }
+                return l.name < name;
+            });
         if (it == m_presets.end() || it->name != name) {
             // Preset has not been not found in the sorted list of non-default presets. Try the defaults.
             for (size_t i = 0; i < m_num_default_presets; ++ i)