Fix SPE-2304. Rear seam not respecting paiting.

If a rear seam was projected it was not respecting seam paiting,
because it continued to search the points even if they had
'worse' point_type (e.g. common/blocker). Now the search
is aborted if there is an enforcer and it is not picked.

src/libslic3r/GCode/SeamAligned.cpp

@@ -236,26 +236,14 @@ double VisibilityCalculator::get_angle_visibility_modifier(
     return -angle_smooth_weight;
 }
 
-std::vector<Vec2d> extract_points(
-    const Perimeters::Perimeter &perimeter, const Perimeters::PointType point_type
-) {
-    std::vector<Vec2d> result;
-    for (std::size_t i{0}; i < perimeter.positions.size(); ++i) {
-        if (perimeter.point_types[i] == point_type) {
-            result.push_back(perimeter.positions[i]);
-        }
-    }
-    return result;
-}
-
 std::vector<Vec2d> get_starting_positions(const Shells::Shell<> &shell) {
     const Perimeters::Perimeter &perimeter{shell.front().boundary};
 
-    std::vector<Vec2d> enforcers{extract_points(perimeter, Perimeters::PointType::enforcer)};
+    std::vector<Vec2d> enforcers{Perimeters::extract_points(perimeter, Perimeters::PointType::enforcer)};
     if (!enforcers.empty()) {
         return enforcers;
     }
-    std::vector<Vec2d> common{extract_points(perimeter, Perimeters::PointType::common)};
+    std::vector<Vec2d> common{Perimeters::extract_points(perimeter, Perimeters::PointType::common)};
     if (!common.empty()) {
         return common;
     }

src/libslic3r/GCode/SeamChoice.cpp

@@ -18,6 +18,9 @@ std::optional<SeamChoice> maybe_choose_seam_point(
                 return seam_choice;
             }
         }
+        if (!Perimeters::extract_points(perimeter, point_type).empty()) {
+            return std::nullopt;
+        }
     }
 
     return std::nullopt;

src/libslic3r/GCode/SeamPerimeters.hpp

@@ -185,6 +185,19 @@ inline std::size_t get_layer_count(
     }
     return layer_count;
 }
+
+inline std::vector<Vec2d> extract_points(
+    const Perimeters::Perimeter &perimeter, const Perimeters::PointType point_type
+) {
+    std::vector<Vec2d> result;
+    for (std::size_t i{0}; i < perimeter.positions.size(); ++i) {
+        if (perimeter.point_types[i] == point_type) {
+            result.push_back(perimeter.positions[i]);
+        }
+    }
+    return result;
+}
+
 } // namespace Slic3r::Seams::Perimeters
 
 #endif // libslic3r_SeamPerimeters_hpp_

src/libslic3r/Slicing.hpp

@@ -13,6 +13,7 @@
 #include <type_traits>
 #include <vector>
 
+#include "Point.hpp"
 #include "libslic3r.h"
 #include "Utils.hpp"