Addressing problem with items slightly out of bed due to simplification

solves SPE-1824

src/libslic3r/Arrange/Arrange.hpp

@@ -90,6 +90,10 @@ public:
 
     virtual ArrItem convert(const Arrangeable &arrbl, coord_t offs = 0) const = 0;
 
+    // Returns the extent of simplification that the converter utilizes when
+    // creating arrange items. Zero shall mean no simplification at all.
+    virtual coord_t simplification_tolerance() const { return 0; }
+
     static std::unique_ptr<ArrangeableToItemConverter> create(
         ArrangeSettingsView::GeometryHandling geometry_handling,
         coord_t                               safety_d);
@@ -120,11 +124,19 @@ template<class ArrItem>
 class BasicItemConverter : public ArrangeableToItemConverter<ArrItem>
 {
     coord_t m_safety_d;
+    coord_t m_simplify_tol;
 
 public:
-    BasicItemConverter(coord_t safety_d = 0) : m_safety_d{safety_d} {}
+    BasicItemConverter(coord_t safety_d = 0, coord_t simpl_tol = 0)
+        : m_safety_d{safety_d}, m_simplify_tol{simpl_tol}
+    {}
 
     coord_t safety_dist() const noexcept { return m_safety_d; }
+
+    coord_t simplification_tolerance() const override
+    {
+        return m_simplify_tol;
+    }
 };
 
 template<class ArrItem>
@@ -231,6 +243,18 @@ double get_fit_into_bed_rotation(const ArrItem &itm, const RectangleBed &bed)
     return ret;
 }
 
+template<class ArrItem>
+auto get_corrected_bed(const ExtendedBed &bed,
+                       const ArrangeableToItemConverter<ArrItem> &converter)
+{
+    auto bedcpy = bed;
+    visit_bed([tol = -converter.simplification_tolerance()](auto &rawbed) {
+        rawbed = offset(rawbed, tol);
+    }, bedcpy);
+
+    return bedcpy;
+}
+
 }} // namespace Slic3r::arr2
 
 #endif // ARRANGE2_HPP

src/libslic3r/Arrange/ArrangeImpl.hpp

@@ -416,12 +416,22 @@ ArrItem AdvancedItemConverter<ArrItem>::get_arritem(const Arrangeable &arrbl,
 
     auto outline = arrbl.full_outline();
     auto envelope = arrbl.full_envelope();
+
     if (infl != 0) {
         outline = offset_ex(outline, infl);
         if (! envelope.empty())
             envelope = offset_ex(envelope, infl);
     }
 
+    auto simpl_tol = static_cast<double>(this->simplification_tolerance());
+
+    if (simpl_tol > 0)
+    {
+        outline = expolygons_simplify(outline, simpl_tol);
+        if (!envelope.empty())
+            envelope = expolygons_simplify(envelope, simpl_tol);
+    }
+
     ArrItem ret;
     set_shape(ret, outline);
     if (! envelope.empty())
@@ -448,15 +458,17 @@ ArrangeableToItemConverter<ArrItem>::create(
 {
     std::unique_ptr<ArrangeableToItemConverter<ArrItem>> ret;
 
+    constexpr coord_t SimplifyTol = scaled(.2);
+
     switch(gh) {
     case arr2::ArrangeSettingsView::ghConvex:
         ret = std::make_unique<ConvexItemConverter<ArrItem>>(safety_d);
         break;
     case arr2::ArrangeSettingsView::ghBalanced:
-        ret = std::make_unique<BalancedItemConverter<ArrItem>>(safety_d);
+        ret = std::make_unique<BalancedItemConverter<ArrItem>>(safety_d, SimplifyTol);
         break;
     case arr2::ArrangeSettingsView::ghAdvanced:
-        ret = std::make_unique<AdvancedItemConverter<ArrItem>>(safety_d);
+        ret = std::make_unique<AdvancedItemConverter<ArrItem>>(safety_d, SimplifyTol);
         break;
     default:
         ;

src/libslic3r/Arrange/Items/ArrangeItem.cpp

@@ -114,8 +114,7 @@ Vec2crd DecomposedShape::centroid() const
 
 DecomposedShape decompose(const ExPolygons &shape)
 {
-    ExPolygons shape_s = expolygons_simplify(shape, scaled(.2));
-    return DecomposedShape{convex_decomposition_tess(shape_s)};
+    return DecomposedShape{convex_decomposition_tess(shape)};
 }
 
 DecomposedShape decompose(const Polygon &shape)
@@ -126,9 +125,7 @@ DecomposedShape decompose(const Polygon &shape)
     if (is_convex) {
         convex_shapes.emplace_back(shape);
     } else {
-        Polygon shape_s = shape;
-        shape_s.simplify(scaled(.2));
-        convex_shapes = convex_decomposition_tess(shape_s);
+        convex_shapes = convex_decomposition_tess(shape);
     }
 
     return DecomposedShape{std::move(convex_shapes)};

src/libslic3r/Arrange/Tasks/ArrangeTaskImpl.hpp

@@ -47,7 +47,7 @@ std::unique_ptr<ArrangeTask<ArrItem>> ArrangeTask<ArrItem>::create(
 
     task->settings.set_from(sc.settings());
 
-    task->bed = sc.bed();
+    task->bed = get_corrected_bed(sc.bed(), converter);
 
     extract_selected(*task, sc.model(), converter);
 

src/libslic3r/Arrange/Tasks/FillBedTaskImpl.hpp

@@ -124,7 +124,7 @@ std::unique_ptr<FillBedTask<ArrItem>> FillBedTask<ArrItem>::create(
 
     task->settings.set_from(sc.settings());
 
-    task->bed = sc.bed();
+    task->bed = get_corrected_bed(sc.bed(), converter);
 
     extract(*task, sc, converter);
 

src/libslic3r/Arrange/Tasks/MultiplySelectionTaskImpl.hpp

@@ -15,7 +15,7 @@ std::unique_ptr<MultiplySelectionTask<ArrItem>> MultiplySelectionTask<ArrItem>::
 
     task.settings.set_from(scene.settings());
 
-    task.bed = scene.bed();
+    task.bed = get_corrected_bed(scene.bed(), itm_conv);
 
     task.prototype_item = {};