CLI: Ensure that objects are on bed by default, new CLI config option:

'dont-ensure-on-bed' (which allows to override). This was the original
behaviour in Slic3r and Sli3rPE, probably broken long ago when CLI
was ported from  Perl.
Also, --scale-to-fit should now work again (#5772)

src/PrusaSlicer.cpp

@@ -258,6 +258,7 @@ int CLI::run(int argc, char **argv)
     Points bed = get_bed_shape(m_print_config);
     ArrangeParams arrange_cfg;
     arrange_cfg.min_obj_distance = scaled(min_object_distance(m_print_config));
+    bool user_ensure_on_bed = true;
     
     for (auto const &opt_key : m_transforms) {
         if (opt_key == "merge") {
@@ -330,6 +331,10 @@ int CLI::run(int argc, char **argv)
             }
         } else if (opt_key == "dont_arrange") {
             // do nothing - this option alters other transform options
+        } else if (opt_key == "dont_ensure_on_bed") {
+            // Remember that we saw this so we don't lift objects from the bed
+            // after the other transformations are processed.
+            user_ensure_on_bed = false;
         } else if (opt_key == "rotate") {
             for (auto &model : m_models)
                 for (auto &o : model.objects)
@@ -432,6 +437,13 @@ int CLI::run(int argc, char **argv)
         }
     }
 
+    // All transforms have been dealt with. Now ensure that the objects are on bed.
+    // (Unless the user said otherwise.)
+    if (user_ensure_on_bed)
+        for (auto &model : m_models)
+            for (auto &o : model.objects)
+                o->ensure_on_bed();
+
     // loop through action options
     for (auto const &opt_key : m_actions) {
         if (opt_key == "help") {

src/libslic3r/Model.cpp

@@ -1745,18 +1745,15 @@ void ModelVolume::scale(const Vec3d& scaling_factors)
 
 void ModelObject::scale_to_fit(const Vec3d &size)
 {
-/*
-    BoundingBoxf3 instance_bounding_box(size_t instance_idx, bool dont_translate = false) const;
     Vec3d orig_size = this->bounding_box().size();
-    float factor = fminf(
-        size.x / orig_size.x,
-        fminf(
-            size.y / orig_size.y,
-            size.z / orig_size.z
+    double factor = std::min(
+        size.x() / orig_size.x(),
+        std::min(
+            size.y() / orig_size.y(),
+            size.z() / orig_size.z()
         )
     );
     this->scale(factor);
-*/
 }
 
 void ModelVolume::assign_new_unique_ids_recursive()

src/libslic3r/PrintConfig.cpp

@@ -4154,6 +4154,10 @@ CLITransformConfigDef::CLITransformConfigDef()
     def->label = L("Don't arrange");
     def->tooltip = L("Do not rearrange the given models before merging and keep their original XY coordinates.");
 
+    def = this->add("dont_ensure_on_bed", coBool);
+    def->label = L("Don't ensure on bed");
+    def->tooltip = L("Do not lift the object above the bed when it is partially below.");
+
     def = this->add("duplicate", coInt);
     def->label = L("Duplicate");
     def->tooltip =L("Multiply copies by this factor.");