Add segmentize::unique().

Given an input of linestrings where each has just two points, remove
repeats.  This works a little better than std::unique because it knows
about directional segments.

eulerian_paths.cpp

@@ -13,16 +13,14 @@ using std::pair;
 
 // This calls segmentize and then get_eulerian_paths.  If unique is
 // true, remove repeated segments.
-  multi_linestring_type_fp make_eulerian_paths(const vector<linestring_type_fp>& paths, bool reversible, bool unique) {
+multi_linestring_type_fp make_eulerian_paths(const vector<linestring_type_fp>& paths, bool reversible, bool unique) {
   vector<pair<linestring_type_fp, bool>> path_to_simplify;
   for (const auto& ls : paths) {
     path_to_simplify.push_back(std::make_pair(ls, reversible));
   }
   path_to_simplify = segmentize::segmentize_paths(path_to_simplify);
   if (unique) {
-    sort(path_to_simplify.begin(), path_to_simplify.end());
-    auto last = std::unique(path_to_simplify.begin(), path_to_simplify.end());
-    path_to_simplify.erase(last, path_to_simplify.end());
+    path_to_simplify = segmentize::unique(path_to_simplify);
   }
   auto eulerian_paths = get_eulerian_paths<
       point_type_fp,

segmentize.cpp

@@ -3,6 +3,7 @@
 
 #include "geometry_int.hpp"
 #include "geometry.hpp"
+#include "bg_helpers.hpp"
 #include "merge_near_points.hpp"
 #include <boost/polygon/isotropy.hpp>
 #include <boost/polygon/segment_concept.hpp>
@@ -25,6 +26,34 @@ int sgn(T val) {
   return (T(0) < val) - (val < T(0));
 }
 
+vector<pair<linestring_type_fp, bool>> unique(const vector<pair<linestring_type_fp, bool>>& lss) {
+  std::set<pair<linestring_type_fp, bool>> ret;
+  for (const auto& ls : lss) {
+    // Should we add this to the output?  Is it unique?
+    if (ls.second) {
+      // This is reversible, check if it exists in any form in ret.
+      if (ret.count({{ls.first.front(), ls.first.back()}, true}) > 0 ||
+          ret.count({{ls.first.back(), ls.first.front()}, true}) > 0) {
+        // Found it so don't add it.
+        continue;
+      }
+      // Erase any directional ones if they exist.
+      ret.erase({{ls.first.front(), ls.first.back()}, false});
+      ret.erase({{ls.first.back(), ls.first.front()}, false});
+    } else {
+      // Not reversible.
+      if (ret.count({{ls.first.front(), ls.first.back()}, true}) ||
+          ret.count({{ls.first.back(), ls.first.front()}, true}) ||
+          ret.count({{ls.first.front(), ls.first.back()}, false})) {
+        // Found it so don't add it.
+        continue;
+      }
+    }
+    ret.insert(ls);
+  }
+  return {ret.cbegin(), ret.cend()};
+}
+
 /* Given a multi_linestring, return a new multiline_string where there
  * are no segments that cross any other segments.  Nor are there any T
  * shapes where the end of a linestring butts up against the center of

segmentize.hpp

@@ -11,6 +11,10 @@
 
 namespace segmentize {
 
+// Return a vector of unique linestrings.  Each input linestring must have just 2 points.
+std::vector<std::pair<linestring_type_fp, bool>> unique(
+    const std::vector<std::pair<linestring_type_fp, bool>>& lss);
+
 /* Convert each linestring, which might have multiple points in it,
  * into a linestrings that have just two points, the start and the
  * end.  Directionality is maintained on each one along with whether

surface_vectorial.cpp

@@ -239,9 +239,7 @@ multi_linestring_type_fp Surface_vectorial::post_process_toolpath(
   auto toolpath1 = toolpath;
   if (mill->eulerian_paths) {
     toolpath1 = segmentize::segmentize_paths(toolpath1);
-    sort(toolpath1.begin(), toolpath1.end());
-    auto last = unique(toolpath1.begin(), toolpath1.end());
-    toolpath1.erase(last, toolpath1.end());
+    toolpath1 = segmentize::unique(toolpath1);
 
     vector<pair<linestring_type_fp, bool>> paths_to_add;
     paths_to_add = backtrack::backtrack(

testing/gerbv_example/mill_masking/expected/front.ngc

@@ -490,14 +490,57 @@ G01 X4.50000 Y-3.79848
 G01 X4.50170 Y-3.79950
 G01 X4.50000 Y-3.79848
 G01 X4.49875 Y-3.79900
+G01 X4.50052 Y-3.79826
+G01 X4.50272 Y-3.79759
+G01 X4.50502 Y-3.79736
+G01 X4.55198 Y-3.79727
+G01 X4.55583 Y-3.79772
+G01 X4.55925 Y-3.79900
+G01 X4.56064 Y-3.79968
+G01 X4.56192 Y-3.80054
+G01 X4.56444 Y-3.80291
+G01 X4.56591 Y-3.80470
+G01 X4.56700 Y-3.80675
+G01 X4.56774 Y-3.80852
+G01 X4.56841 Y-3.81074
+G01 X4.56864 Y-3.81304
+G01 X4.56864 Y-3.81496
+G01 X4.56841 Y-3.81726
+G01 X4.56774 Y-3.81948
+G01 X4.56700 Y-3.82125
+G01 X4.56591 Y-3.82329
+G01 X4.56444 Y-3.82509
+G01 X4.56192 Y-3.82746
+G01 X4.56064 Y-3.82832
+G01 X4.55748 Y-3.82974
+G01 X4.55527 Y-3.83041
+G01 X4.55298 Y-3.83064
+G01 X4.50602 Y-3.83073
+G01 X4.50217 Y-3.83028
+G01 X4.49875 Y-3.82900
+G01 X4.49736 Y-3.82832
+G01 X4.49608 Y-3.82746
+G01 X4.49356 Y-3.82509
+G01 X4.49209 Y-3.82329
+G01 X4.49100 Y-3.82125
+G01 X4.49026 Y-3.81948
+G01 X4.48959 Y-3.81726
+G01 X4.48936 Y-3.81496
+G01 X4.48936 Y-3.81304
+G01 X4.48959 Y-3.81074
+G01 X4.49026 Y-3.80852
+G01 X4.49100 Y-3.80675
+G01 X4.49209 Y-3.80470
+G01 X4.49356 Y-3.80291
+G01 X4.49608 Y-3.80054
+G01 X4.49736 Y-3.79968
 G01 X4.50000 Y-3.79848
 G01 X4.50000 Y-3.78613
-G01 X4.50041 Y-3.78601
 G01 X4.50499 Y-3.78555
 G01 X4.55195 Y-3.78546
-G01 X4.55431 Y-3.78557
+G01 X4.55527 Y-3.78566
 G01 X4.55870 Y-3.78626
-G01 X4.56200 Y-3.78735
+G01 X4.56377 Y-3.78808
 G01 X4.56654 Y-3.78945
 G01 X4.56911 Y-3.79117
 G01 X4.57144 Y-3.79320
@@ -511,7 +554,7 @@ G01 X4.57999 Y-3.81957
 G01 X4.57865 Y-3.82400
 G01 X4.57655 Y-3.82855
 G01 X4.57483 Y-3.83111
-G01 X4.57144 Y-3.83480
+G01 X4.57280 Y-3.83344
 G01 X4.56911 Y-3.83683
 G01 X4.56654 Y-3.83855
 G01 X4.56200 Y-3.84065
@@ -559,65 +602,19 @@ G01 X4.59226 Y-3.81304
 G01 X4.59226 Y-3.81496
 G01 X4.59158 Y-3.82187
 G01 X4.58956 Y-3.82852
+G01 X4.58883 Y-3.83029
 G01 X4.58678 Y-3.83445
 G01 X4.58420 Y-3.83830
-G01 X4.58115 Y-3.84179
+G01 X4.57979 Y-3.84315
 G01 X4.57630 Y-3.84620
 G01 X4.57245 Y-3.84878
-G01 X4.56829 Y-3.85083
 G01 X4.56652 Y-3.85156
 G01 X4.55991 Y-3.85357
 G01 X4.55303 Y-3.85426
 G01 X4.50607 Y-3.85435
 G01 X4.50253 Y-3.85418
 G01 X4.50000 Y-3.85382
-G01 X4.50000 Y-3.82952
-G01 X4.49736 Y-3.82832
-G01 X4.49608 Y-3.82746
-G01 X4.49356 Y-3.82509
-G01 X4.49209 Y-3.82329
-G01 X4.49100 Y-3.82125
-G01 X4.49026 Y-3.81948
-G01 X4.48959 Y-3.81726
-G01 X4.48936 Y-3.81496
-G01 X4.48936 Y-3.81304
-G01 X4.48959 Y-3.81074
-G01 X4.49026 Y-3.80852
-G01 X4.49100 Y-3.80675
-G01 X4.49209 Y-3.80470
-G01 X4.49356 Y-3.80291
-G01 X4.49608 Y-3.80054
-G01 X4.49736 Y-3.79968
-G01 X4.50052 Y-3.79826
-G01 X4.50272 Y-3.79759
-G01 X4.50502 Y-3.79736
-G01 X4.55198 Y-3.79727
-G01 X4.55412 Y-3.79742
-G01 X4.55583 Y-3.79772
-G01 X4.55748 Y-3.79826
-G01 X4.56064 Y-3.79968
-G01 X4.56192 Y-3.80054
-G01 X4.56309 Y-3.80156
-G01 X4.56444 Y-3.80291
-G01 X4.56591 Y-3.80470
-G01 X4.56700 Y-3.80675
-G01 X4.56774 Y-3.80852
-G01 X4.56841 Y-3.81074
-G01 X4.56864 Y-3.81304
-G01 X4.56864 Y-3.81496
-G01 X4.56841 Y-3.81726
-G01 X4.56774 Y-3.81948
-G01 X4.56700 Y-3.82125
-G01 X4.56591 Y-3.82329
-G01 X4.56444 Y-3.82509
-G01 X4.56192 Y-3.82746
-G01 X4.56064 Y-3.82832
-G01 X4.55748 Y-3.82974
-G01 X4.55527 Y-3.83041
-G01 X4.55298 Y-3.83064
-G01 X4.50602 Y-3.83073
-G01 X4.50217 Y-3.83028
-G01 X4.50000 Y-3.82952
+G01 X4.50000 Y-3.84186
 G01 X4.50000 Y-3.86577
 G01 X4.50610 Y-3.86617
 G01 X4.55305 Y-3.86607

testing/gerbv_example/multivibrator-contentions/expected/back.ngc

@@ -646,6 +646,9 @@ G01 X-3.07738 Y-2.38904
 G01 X-3.07188 Y-2.39515
 G01 X-3.05891 Y-2.41116
 G01 X-3.04769 Y-2.42844
+G01 X-3.05000 Y-2.42489
+G01 X-3.05717 Y-2.42687
+G01 X-3.05000 Y-2.42488
 G01 X-3.05891 Y-2.41116
 G01 X-3.07188 Y-2.39515
 G01 X-3.07738 Y-2.38904
@@ -657,8 +660,6 @@ G01 X-3.12729 Y-2.35811
 G01 X-3.12488 Y-2.35000
 G01 X-3.05000 Y-2.35000
 G01 X-3.05000 Y-2.42489
-G01 X-3.05717 Y-2.42687
-G01 X-3.05000 Y-2.42489
 G01 X-3.04769 Y-2.42844
 G01 X-3.04357 Y-2.43557
 G01 X-3.03422 Y-2.45393