From cb66867768f72d04570654b6999fc0f1c94a8d2b Mon Sep 17 00:00:00 2001
From: Clifford Garwood <cliff@cigii.com>
Date: Thu, 14 May 2026 13:25:37 -0400
Subject: [PATCH] feat(imex): topology-aware Tool 0 Position dropdown
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For single-gantry IMEX setups, front/rear is meaningless — only left/right
matters. Collapse the imex_tool_layout dropdown to two items ("Left" / "Right",
mapped to front-left/front-right internally) when imex_gantry_count == 1, and
show all four corner items otherwise. Normalize stored rear-* selections to
their front-* equivalents on the transition so the displayed selection always
matches the persisted value.

Also rename the field label "Tool 0 Corner" → "Tool 0 Position" so it reads
correctly in both single- and dual-gantry contexts, with a tooltip that
explains the IDEX/IQEX distinction.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
---
 src/libslic3r/PrintConfig.cpp |  8 ++++---
 src/slic3r/GUI/Tab.cpp        | 43 +++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index 3ee62be297..9107ee6c7c 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -5821,10 +5821,12 @@ void PrintConfigDef::init_fff_params()
     def->set_default_value(new ConfigOptionInt(2));
 
     def = this->add("imex_tool_layout", coEnum);
-    def->label = L("Tool 0 Corner");
-    def->tooltip = L("Physical corner of the bed where tool T0 (index 0) is located. "
+    def->label = L("Tool 0 Position");
+    def->tooltip = L("Physical position on the bed where tool T0 (index 0) is located. "
                      "Determines how tool indices map to bed zones. "
-                     "front = lower Y (near the operator), rear = higher Y (back of machine).");
+                     "For single-gantry setups (IDEX) only left/right matters; "
+                     "for dual-gantry setups (IQEX) all four corners are selectable "
+                     "(front = lower Y / near the operator, rear = higher Y / back of machine).");
     def->mode = comAdvanced;
     def->enum_keys_map = &ConfigOptionEnum<ImexToolLayout>::get_enum_values();
     def->enum_values.push_back("front-left");
diff --git a/src/slic3r/GUI/Tab.cpp b/src/slic3r/GUI/Tab.cpp
index 2f77290117..779690270e 100644
--- a/src/slic3r/GUI/Tab.cpp
+++ b/src/slic3r/GUI/Tab.cpp
@@ -6141,6 +6141,49 @@ void TabPrinter::toggle_options()
         toggle_option("imex_viz_theme",   is_imex);
         toggle_option("imex_firmware_managed_zones", is_imex);
         if (m_imex_modes_ctrl) m_imex_modes_ctrl->Show(is_imex);
+
+        // IDEX/IQEX: the tool_layout dropdown carries 4 corner values
+        // (front-left / front-right / rear-left / rear-right) in storage, but front/rear
+        // is meaningless on single-gantry setups. Collapse the dropdown to just two
+        // items ("Left" / "Right") when imex_gantry_count == 1 — mapped to front-left
+        // and front-right internally — and normalize any stored rear-* selection to its
+        // front-* equivalent so the displayed selection always matches the stored value.
+        if (is_imex) {
+            if (Field* layout_field = get_field("imex_tool_layout"); layout_field) {
+                if (auto* choice = dynamic_cast<Choice*>(layout_field); choice) {
+                    const int gantry_count = m_config->opt_int("imex_gantry_count");
+                    int current_val = 0;
+                    if (auto* o = m_config->option<ConfigOptionEnum<ImexToolLayout>>("imex_tool_layout"))
+                        current_val = static_cast<int>(o->value);
+
+                    // Normalize rear-* → front-* when collapsing to 1 gantry.
+                    if (gantry_count == 1 && (current_val == static_cast<int>(ImexToolLayout::RearLeft)
+                                           || current_val == static_cast<int>(ImexToolLayout::RearRight))) {
+                        ImexToolLayout normalized = (current_val == static_cast<int>(ImexToolLayout::RearLeft))
+                                                  ? ImexToolLayout::FrontLeft
+                                                  : ImexToolLayout::FrontRight;
+                        DynamicPrintConfig new_conf = *m_config;
+                        new_conf.set_key_value("imex_tool_layout",
+                                               new ConfigOptionEnum<ImexToolLayout>(normalized));
+                        load_config(new_conf);
+                        current_val = static_cast<int>(normalized);
+                    }
+
+                    wxArrayString items;
+                    if (gantry_count >= 2) {
+                        items.Add(_L("Front-left"));
+                        items.Add(_L("Front-right"));
+                        items.Add(_L("Rear-left"));
+                        items.Add(_L("Rear-right"));
+                    } else {
+                        items.Add(_L("Left"));
+                        items.Add(_L("Right"));
+                    }
+                    choice->set_values(items);
+                    choice->set_value(boost::any(current_val), false);
+                }
+            }
+        }
     }
     wxString extruder_number;
     long val = 1;