Move the Cube with the Wipe Tower in the Profile Validator

The slice check centres its cube on the bed, puts the prime tower beside
it, then pulls the tower alone inside the printable outline. On a bed too
narrow for the estimated footprint that pull drags the tower back over
the cube: Volumic EXO42 IDRE MIRROR MODE (189 mm wide, 87.6 mm estimate)
logged "gcode path conflicts found between WipeTower and cube" in every
run, and three ~105 mm beds were left with 0.15 to 3.3 mm of clearance.

The cube and the tower's footprint are now pulled inside as one rigid
pair, so the clearance between them is fixed by construction. A bed too
small for the pair keeps the old placement, and presets that were never
clamped keep their exact layout.

src/dev-utils/OrcaSlicer_profile_validator.cpp

@@ -122,17 +122,19 @@ Vec2d printable_area_center(const DynamicPrintConfig &cfg)
 
 // Put the prime tower where the GUI and CLI would before slicing. The config default (x 15, y 220)
 // lies off any bed shallower than the tower, and generation rejects an off-plate tower instead of
-// exporting it. Beside the centred cube, clear of the edge exclusion strips some beds carry, then
-// pulled inside the printable outline by the tower's own estimated footprint, with a few mm of
-// clearance so the conflict checker never sees the two touch.
-void place_wipe_tower(DynamicPrintConfig &cfg, const Vec2d &center)
+// exporting it. Beside the cube at the bed centre, clear of the edge exclusion strips some beds
+// carry, with a few mm of clearance so the conflict checker never sees the two touch. The cube and
+// the tower's estimated footprint are then pulled inside the printable outline as one rigid pair:
+// moving the tower alone would push it back onto the cube on a narrow bed. Returns that move for
+// the cube.
+Vec2d place_wipe_tower(DynamicPrintConfig &cfg, const Vec2d &center)
 {
     const auto *area = cfg.option<ConfigOptionPoints>("printable_area");
     if (area == nullptr || area->values.size() < 3)
-        return;
+        return Vec2d::Zero();
     const WipeTowerFootprint footprint = estimate_wipe_tower_footprint(cfg, resolve_wipe_tower_type(cfg), {0, 1}, cfg.opt_float("layer_height"), 10.);
     if (footprint.depth < EPSILON)
-        return;
+        return Vec2d::Zero();
     const double margin = WIPE_TOWER_MARGIN + footprint.brim_width;
     // The position is the tower's own origin; a rotated tower extends from it in another
     // direction, so place the rotated box's extents rather than the origin.
@@ -143,13 +145,22 @@ void place_wipe_tower(DynamicPrintConfig &cfg, const Vec2d &center)
     const Vec2d       size  = unscale(local.max) - lo;
     Vec2d             pos(center.x() + 5. + margin + 5. - lo.x(), center.y() - size.y() / 2. - lo.y());
     box.translate(Point::new_scale(pos.x(), pos.y()));
-    const Vec2f move = WipeTower::move_box_inside_polygon(get_extents(box), Polygons{Polygon::new_scale(area->values)}, scaled<coord_t>(margin));
-    pos += move.cast<double>();
+    // A bed too small for the pair keeps the cube at its centre and places the tower alone.
+    const Polygons    bed{Polygon::new_scale(area->values)};
+    const BoundingBox tower = get_extents(box);
+    BoundingBox       pair  = tower;
+    pair.merge(Point::new_scale(center.x() - 5., center.y() - 5.));
+    pair.merge(Point::new_scale(center.x() + 5., center.y() + 5.));
+    const Point       room  = get_extents(bed).size() - Point::new_scale(2. * margin, 2. * margin);
+    const bool        rigid = pair.size().x() < room.x() && pair.size().y() < room.y();
+    const Vec2d       move  = WipeTower::move_box_inside_polygon(rigid ? pair : tower, bed, scaled<coord_t>(margin)).cast<double>();
+    pos += move;
     cfg.option<ConfigOptionFloats>("wipe_tower_x", true)->values = {pos.x()};
     cfg.option<ConfigOptionFloats>("wipe_tower_y", true)->values = {pos.y()};
+    return rigid ? move : Vec2d::Zero();
 }
 
-// Slice one centered cube that switches from filament 1 to filament 2 partway up, so exactly one
+// Slice one cube that switches from filament 1 to filament 2 partway up, so exactly one
 // filament change fires, then export. The change drives the printer's own change_filament_gcode: on a
 // single-nozzle machine it rides the AMS prime tower (append_tcr), on a multi-nozzle machine it routes
 // through the nozzle swap (set_extruder / append_tcr2) - the engine picks the path from the printer's
@@ -157,10 +168,10 @@ void place_wipe_tower(DynamicPrintConfig &cfg, const Vec2d &center)
 // Slic3r::PlaceholderParserError from export.
 std::string slice_two_color_cube_and_export(DynamicPrintConfig cfg, bool is_bbl)
 {
-    const Vec2d center = printable_area_center(cfg);
-    place_wipe_tower(cfg, center);
+    const Vec2d center   = printable_area_center(cfg);
+    const Vec2d cube_min = center - Vec2d(5., 5.) + place_wipe_tower(cfg, center);
     TriangleMesh m = make_cube(10, 10, 10);
-    m.translate(float(center.x() - 5.), float(center.y() - 5.), 0.f);
+    m.translate(static_cast<float>(cube_min.x()), static_cast<float>(cube_min.y()), 0.f);
 
     Model  model;
     Print  print;