Fixed issue #578 (CIF writer issue with arbitrary angle) (#581)

* Fixed isse #578 (CIF writer issue with arbitrary angle)

* Added missing files.

src/plugins/streamers/cif/db_plugin/dbCIFWriter.cc

@@ -165,23 +165,18 @@ CIFWriter::write (db::Layout &layout, tl::OutputStream &stream, const db::SaveLa
           }
           
           double a = t.angle();
-          while (a < 0) {
-            a += 360.0;
-          }
-          double ya = 0.0, xa = 0.0;
-          if (a < 45 || a > 315) {
-            xa = 1.0;
-            ya = tan(a / 180.0 * M_PI);
-          } else if (a < 135) {
-            xa = 1.0 / tan(a / 180.0 * M_PI);
-            ya = 1.0;
-          } else if (a < 225) {
-            xa = -1.0;
-            ya = tan(a / 180.0 * M_PI);
+          double xa = cos(a / 180.0 * M_PI);
+          double ya = sin(a / 180.0 * M_PI);
+
+          //  normalize xa or ya whichever is better
+          double n;
+          if (fabs (xa) >= M_SQRT1_2) {
+            n = 1.0 / fabs (xa);
           } else {
-            xa = 1.0 / tan(a / 180.0 * M_PI);
-            ya = -1.0;
-          } 
+            n = 1.0 / fabs (ya);
+          }
+          xa *= n;
+          ya *= n;
 
           //  TODO: that can be done smarter ...
           for (int n = 0; n < 20 && (fabs (xa - floor (0.5 + xa)) > 1e-3 || fabs (ya - floor (0.5 + ya)) > 1e-3); ++n) {

src/plugins/streamers/cif/unit_tests/dbCIFReader.cc

@@ -200,3 +200,9 @@ TEST(rot_instances)
 {
   run_test (_this, tl::testsrc (), "issue_568.cif", "issue_568_au.gds");
 }
+
+//  Issue #578
+TEST(rot_instances2)
+{
+  run_test (_this, tl::testsrc (), "issue_578.cif", "issue_578_au.gds");
+}

testdata/cif/issue_578.cif

@@ -0,0 +1,18 @@
+(CIF file written 2020-06-04 16:17:46 by KLayout);
+DS 1 1 10;
+9 F;
+L L1D0;
+P 0,0 0,7000 4000,7000 4000,6000 1000,6000 1000,4000 2000,4000 2000,3000 1000,3000 1000,0;
+DF;
+DS 2 1 10;
+9 ALL;
+C1 R1,0 T0,0;
+C1 R1,1 T0,0;
+C1 R0,1 T0,0;
+C1 R-1,-1 T0,0;
+C1 R-1,0 T0,0;
+C1 R-1,1 T0,0;
+C1 R0,-1 T0,0;
+C1 R1,-1 T0,0;
+DF;
+E