star-cpr

commit 51b4479b86f195f7aa0e1fc97a25e851ad591db6
parent af9932bc8558765f879ee1419a9cd76aaa7abf4e
Author: Christophe Coustet <christophe.coustet@meso-star.com>
Date:   Tue, 17 Jan 2023 15:27:47 +0100

Fix offset=0 not leaving polygon unchanged

Diffstat:
M
src/scpr_polygon.c
 | 
37
+++++++++++++++++++++----------------
M
src/test_scpr_offset.c
 | 
14
+++++++-------

2 files changed, 28 insertions(+), 23 deletions(-)
diff --git a/src/scpr_polygon.c b/src/scpr_polygon.c
@@ -315,13 +315,14 @@ scpr_offset_polygon
   size_t c;
   Clipper2Lib::PathD tmp;
   Clipper2Lib::PathsD polygon;
-  Clipper2Lib::JoinType cjt;
   res_T res = RES_OK;
 
   if(!poly_desc) {
     res = RES_BAD_ARG;
     goto error;
   }
+
+  /* Check join type */
   switch(join_type) {
     case SCPR_JOIN_SQUARE:
     case SCPR_JOIN_ROUND:
@@ -331,22 +332,26 @@ scpr_offset_polygon
       res = RES_BAD_ARG;
       goto error;
   }
-  cjt = scpr_join_type_to_clipper_join_type(join_type);
-  poly_desc->paths = Clipper2Lib::InflatePaths(poly_desc->paths, offset, cjt,
-      Clipper2Lib::EndType::Polygon);
-
-  /* Rebuild AABB */
-  d2_splat(poly_desc->lower, DBL_MAX);
-  d2_splat(poly_desc->upper,-DBL_MAX);
-  FOR_EACH(c, 0, poly_desc->paths.size()) {
-    size_t i, nverts;
-    nverts = poly_desc->paths[c].size();
 
-    FOR_EACH(i, 0, nverts) {
-      double pos[2];
-      ERR(scpr_polygon_get_position(poly_desc, c, i, pos));
-      d2_min(poly_desc->lower, poly_desc->lower, pos);
-      d2_max(poly_desc->upper, poly_desc->upper, pos);
+  /* Some known problems when offset=0, not leaving polygon unchanged */
+  if(offset != 0) {
+    Clipper2Lib::JoinType cjt = scpr_join_type_to_clipper_join_type(join_type);
+    poly_desc->paths = Clipper2Lib::InflatePaths(poly_desc->paths, offset, cjt,
+        Clipper2Lib::EndType::Polygon);
+
+    /* Rebuild AABB */
+    d2_splat(poly_desc->lower, DBL_MAX);
+    d2_splat(poly_desc->upper,-DBL_MAX);
+    FOR_EACH(c, 0, poly_desc->paths.size()) {
+      size_t i, nverts;
+      nverts = poly_desc->paths[c].size();
+
+      FOR_EACH(i, 0, nverts) {
+        double pos[2];
+        ERR(scpr_polygon_get_position(poly_desc, c, i, pos));
+        d2_min(poly_desc->lower, poly_desc->lower, pos);
+        d2_max(poly_desc->upper, poly_desc->upper, pos);
+      }
     }
   }
 
diff --git a/src/test_scpr_offset.c b/src/test_scpr_offset.c
@@ -54,7 +54,7 @@ test_single(void)
   ctx.coords = coords;
   ctx.nverts = nverts;
   ctx.ncomps = ncomps;
-  
+
   CHK(scpr_polygon_setup_indexed_vertices(polygon, ncomps, pget_nverts, pget_pos, &ctx)
       == RES_OK);
   CHK(scpr_polygon_setup_indexed_vertices(expected, ncomps, pget_nverts, pget_pos, &ctx)
@@ -78,7 +78,7 @@ test_single(void)
   memcpy(*coords, coords0, 2*nverts[0]*sizeof(**coords));
   CHK(scpr_polygon_setup_indexed_vertices(expected, ncomps, pget_nverts, pget_pos, &ctx)
       == RES_OK);
-  
+
   CHK(scpr_offset_polygon(polygon, -1, SCPR_JOIN_MITER) == RES_OK);
   CHK(scpr_polygon_eq(polygon, expected, &eq) == RES_OK);
   CHK(eq);
@@ -160,7 +160,7 @@ test_double(void)
   ctx.coords = coords;
   ctx.nverts = nverts;
   ctx.ncomps = ncomps;
-  
+
   CHK(scpr_polygon_setup_indexed_vertices(polygon, ncomps, pget_nverts, pget_pos, &ctx)
       == RES_OK);
   CHK(scpr_polygon_setup_indexed_vertices(expected, ncomps, pget_nverts, pget_pos, &ctx)
@@ -186,7 +186,7 @@ test_double(void)
   memcpy(*(coords+1), coords1, 2*nverts[1]*sizeof(**coords));
   CHK(scpr_polygon_setup_indexed_vertices(expected, ncomps, pget_nverts, pget_pos, &ctx)
       == RES_OK);
-  
+
   CHK(scpr_offset_polygon(polygon, -1, SCPR_JOIN_MITER) == RES_OK);
   CHK(scpr_polygon_eq(polygon, expected, &eq) == RES_OK);
   CHK(eq);
@@ -280,7 +280,7 @@ test_internal(void)
   ctx.coords = coords;
   ctx.nverts = nverts;
   ctx.ncomps = ncomps;
-  
+
   CHK(scpr_polygon_setup_indexed_vertices(polygon, ncomps, pget_nverts, pget_pos, &ctx)
       == RES_OK);
   CHK(scpr_polygon_setup_indexed_vertices(expected, ncomps, pget_nverts, pget_pos, &ctx)
@@ -306,7 +306,7 @@ test_internal(void)
   memcpy(*(coords+1), coords1, 2*nverts[1]*sizeof(**coords));
   CHK(scpr_polygon_setup_indexed_vertices(expected, ncomps, pget_nverts, pget_pos, &ctx)
       == RES_OK);
-  
+
   CHK(scpr_offset_polygon(polygon, 1, SCPR_JOIN_MITER) == RES_OK);
   CHK(scpr_polygon_eq(polygon, expected, &eq) == RES_OK);
   CHK(eq);
@@ -329,7 +329,7 @@ test_internal(void)
   memcpy(*(coords+1), coords1, 2*nverts[1]*sizeof(**coords));
   CHK(scpr_polygon_setup_indexed_vertices(polygon, ncomps, pget_nverts, pget_pos, &ctx)
       == RES_OK);
-  
+
   ncomps = 0;
   ctx.ncomps = ncomps;
   CHK(scpr_polygon_setup_indexed_vertices(expected, ncomps, pget_nverts, pget_pos, &ctx)