From b9ffddee71beefbaa200658a414b1563701b9fd7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Motiejus=20Jak=C5=A1tys?= <motiejus@uber.com>
Date: Fri, 26 Feb 2021 16:21:20 +0200
Subject: [PATCH] tests for bends vs inflections

---
 IV/tests.sql | 18 +++++++++++++-----
 IV/wm.sql    |  6 ++++--
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/IV/tests.sql b/IV/tests.sql
index 0592fa6..b981d09 100644
--- a/IV/tests.sql
+++ b/IV/tests.sql
@@ -25,28 +25,36 @@ insert into bends select unnest(detect_bends((select way from figures where name
 insert into bends select unnest(detect_bends((select way from figures where name='fig5')));
 insert into bends select unnest(detect_bends((select way from figures where name='inflection-1')));
 
+-- DETECT BENDS
 do $$
 declare
   vbends geometry[];
 begin
-  -- DETECT BENDS
   select detect_bends((select way from figures where name='fig3')) into vbends;
   perform assert_equals(5, array_length(vbends, 1));
   perform assert_equals('LINESTRING(0 0,12 0,13 4)', st_astext(vbends[1]));
   perform assert_equals('LINESTRING(12 0,13 4,20 2,20 0)', st_astext(vbends[2]));
   perform assert_equals('LINESTRING(20 2,20 0,32 0,33 10)', st_astext(vbends[3]));
   perform assert_equals('LINESTRING(32 0,33 10,38 16,43 15,44 10,44 0)', st_astext(vbends[4]));
-
   perform assert_equals(4, array_length(detect_bends((select way from figures where name='fig3-1')), 1));
-
   select detect_bends((select way from figures where name='fig5')) into vbends;
   perform assert_equals(3, array_length(vbends, 1));
+end $$ language plpgsql;
 
-  -- FIX BEND INFLECTIONS
+-- FIX BEND INFLECTIONS
+do $$
+declare
+  vbends geometry[];
+  vinflections geometry[];
+begin
   select detect_bends((select way from figures where name='inflection-1')) into vbends;
+  select fix_gentle_inflections(vbends) into vinflections;
+
+  perform assert_equals(vbends[1], vinflections[1]); -- unchanged
+  perform assert_equals('LINESTRING(114 20,133 20,145 15,145 0,136 5,123 7,114 7)', st_astext(vinflections[2]));
+  perform assert_equals('LINESTRING(123 7,114 7,111 2)', st_astext(vinflections[3]));
 
   drop table if exists inflections;
   create table inflections (way geometry);
   insert into inflections select unnest(fix_gentle_inflections(vbends));
-
 end $$ language plpgsql;
diff --git a/IV/wm.sql b/IV/wm.sql
index 5ddb216..39b3e32 100644
--- a/IV/wm.sql
+++ b/IV/wm.sql
@@ -98,7 +98,7 @@ begin
     -- Then edges (A,B) and (E,F) are shared with the neighboring bends.
     --
     --
-    -- Assume this curve (figure `inflection-1`):
+    -- Assume this curve (figure `inflection-1`), going clockwise from A:
     --
     --    \______B
     --    A      `-------. C
@@ -110,7 +110,9 @@ begin
     -- After processing the curve following the definition of a bend, the bend
     -- [A-E] would be detected. Assuming inflection point E and F are "small",
     -- the bend needs to be extended by two edges to [A,G].
-    select geom from st_dumppoints(bends[i-1]) order by path[1] asc limit 1 into ptail;
+    select geom from st_dumppoints(bends[i-1])
+      order by path[1] asc limit 1 into ptail;
+
     while true loop
       -- copy last 3 points of bends[i-1] (tail) to ptail
       select array(