Prepare arrange for variable bed distance

src/libslic3r/Arrange.cpp

@@ -489,7 +489,7 @@ void _arrange(
 {
     // Integer ceiling the min distance from the bed perimeters
     coord_t md = params.min_obj_distance;
-    md = md / 2;
+    md = md / 2 - params.min_bed_distance;
     
     auto corrected_bin = bin;
     sl::offset(corrected_bin, md);

src/libslic3r/Arrange.hpp

@@ -81,6 +81,9 @@ struct ArrangeParams {
     /// pair of items on the print bed in any direction.
     coord_t min_obj_distance = 0;
 
+    /// The minimum distance of any object from bed edges
+    coord_t min_bed_distance = 0;
+
     /// The accuracy of optimization.
     /// Goes from 0.0 to 1.0 and scales performance as well
     float accuracy = 1.f;

src/slic3r/GUI/GLCanvas3D.hpp

@@ -476,7 +476,8 @@ public:
 
     struct ArrangeSettings
     {
-        float distance           = 6.;
+        float distance           = 6.f;
+        float distance_from_bed  = 0.f;
 //        float distance_seq_print = 6.;    // Used when sequential print is ON
 //        float distance_sla       = 6.;
         float accuracy           = 0.65f; // Unused currently

src/slic3r/GUI/Jobs/ArrangeJob.cpp

@@ -286,6 +286,7 @@ arrangement::ArrangeParams get_arrange_params(Plater *p)
     arrangement::ArrangeParams params;
     params.allow_rotations  = settings.enable_rotation;
     params.min_obj_distance = scaled(settings.distance);
+    params.min_bed_distance = scaled(settings.distance_from_bed);
 
     return params;
 }