Support Klipper exclude_objects feature (PR #10618):

comment by @lukasmatena: The functions are not called anywhere because of how I resolved conflicts. I will integrate the functions into current PrusaSlicer in the next commit.

src/libslic3r/GCode.cpp

@@ -130,6 +130,43 @@ namespace Slic3r {
         return ok;
     }
 
+    inline std::string make_klipper_exclude_object_name(const std::string &name, int object_id, int instance_id)
+    {
+        constexpr char banned_chars[] = "-. \r\n\v\t\f";
+        std::string cleaned_name = name;
+        const char *next = cleaned_name.c_str();
+        while (next = std::strpbrk(next, banned_chars))
+            cleaned_name[next - cleaned_name.c_str()] = '_';
+        return cleaned_name + "_id_" + std::to_string(object_id) + "_copy_" + std::to_string(instance_id);
+    }
+
+    // Label excluded objects for Klipper
+    std::string make_klipper_exclude_object_header(const Print &print) {
+        std::string output;
+        int object_id = 0;
+        for (auto object : print.objects()) {
+            int instance_id = 0;
+            for (auto instance : object->instances()) {
+                char buffer[64];
+                output += "EXCLUDE_OBJECT_DEFINE NAME=";
+                output += make_klipper_exclude_object_name(object->model_object()->name, object_id, instance_id++);
+                Polygon outline = object->model_object()->convex_hull_2d(instance.model_instance->get_matrix());
+                outline.douglas_peucker(50000.f);
+                auto center = outline.centroid();
+                std::snprintf(buffer, sizeof(buffer) - 1, " CENTER=%.3f,%.3f", unscale<float>(center[0]), unscale<float>(center[1]));
+                output += buffer + std::string(" POLYGON=[");
+                for (auto point : outline) {
+                    std::snprintf(buffer, sizeof(buffer) - 1, "[%.3f,%.3f],", unscale<float>(point[0]), unscale<float>(point[1]));
+                    output += buffer;
+                }
+                output.pop_back();
+                output += "]\n";
+            }
+            ++object_id;
+        }
+        return output;
+    }
+
     std::string OozePrevention::pre_toolchange(GCodeGenerator &gcodegen)
     {
         std::string gcode;