Fixed issue #1592 (DXF reader issue) (#1595)

Co-authored-by: Matthias Koefferlein <matthias@klayout.de>

src/plugins/streamers/dxf/db_plugin/dbDXFReader.cc

@@ -816,7 +816,9 @@ De Boor algorithm for NURBS
 static db::DPoint
 b_spline_point (double x, const std::vector<std::pair<db::DPoint, double> > &control_points, int p, const std::vector<double> &t, int &k)
 {
-  k = (int) (std::lower_bound (t.begin (), t.end (), x - 1e-6) - t.begin ());
+  double eps = 1e-12 * (fabs (t.back ()) + fabs (t.front ()));
+
+  k = (int) (std::lower_bound (t.begin (), t.end (), x - eps) - t.begin ());
   --k;
   if (k < p) {
     k = p;
@@ -882,6 +884,12 @@ spline_interpolate (std::list<db::DPoint> &curve_points,
 
   db::DPoint s1 = b_spline_point (t_start + 0.5 * dt, control_points, degree, knots, k1);
   db::DPoint s2 = b_spline_point (t_start + 1.5 * dt, control_points, degree, knots, k2);
+if (s1.to_string () == "-2.60657790172,-1.78843428245") {
+  tl::info << "@@@ BANG!";
+}
+if (s2.to_string () == "-2.60657790172,-1.78843428245") {
+  tl::info << "@@@ BANG!";
+}
 
   db::DVector p1 (s1, *current_curve_point);
   db::DVector p2 (*pm, s1);
@@ -1740,6 +1748,7 @@ DXFReader::read_entities (db::Layout &layout, db::Cell &cell, const db::DVector
       std::string layer;
       unsigned int xy_flag = 0;
       int degree = 1;
+      int flags = 0;
 
       while ((g = read_group_code ()) != 0) {
         if (g == 8) {
@@ -1763,9 +1772,9 @@ DXFReader::read_entities (db::Layout &layout, db::Cell &cell, const db::DVector
 
         } else if (g == 70) {
 
-          int flags = read_int32 ();
-          if (flags != 8 && flags != 12) {
-            warn ("Invalid SPLINE flag (code 70): " + tl::to_string (flags) + ". Only types 8 (non-rational) and 12 (rational) are supported currently.");
+          flags = read_int32 ();
+          if ((flags & 2) != 0) {
+            warn ("Invalid SPLINE flag (code 70): " + tl::to_string (flags) + ". Periodic splines not supported currently.");
           }
 
         } else if (g == 71) {
@@ -1814,6 +1823,13 @@ DXFReader::read_entities (db::Layout &layout, db::Cell &cell, const db::DVector
             }
           }
 
+        } else if ((flags & 1) && m_polyline_mode == 2) {
+
+          //  create a polygon for the spline
+          db::DSimplePolygon p;
+          p.assign_hull (new_points.begin (), new_points.end (), tt);
+          cell.shapes (ll.second).insert (safe_from_double (p));
+
         } else {
 
           //  create a path with width 0 for the spline

src/plugins/streamers/dxf/unit_tests/dbDXFReaderTests.cc

@@ -536,3 +536,20 @@ TEST(35c)
   db::DXFReaderOptions opt;
   run_test_public (_this, "issue_1422c.dxf", "issue_1422c_au.gds.gz", opt);
 }
+
+//  issue #1592, polyline mode 2
+TEST(36a)
+{
+  db::DXFReaderOptions opt;
+  opt.dbu = 1e-5;
+  opt.polyline_mode = 2;
+  run_test_public (_this, "issue_1592.dxf.gz", "issue_1592a_au.oas.gz", opt, true);
+}
+
+//  issue #1592
+TEST(36b)
+{
+  db::DXFReaderOptions opt;
+  opt.dbu = 1e-5;
+  run_test_public (_this, "issue_1592.dxf.gz", "issue_1592b_au.oas.gz", opt, true);
+}