From b97531447c4a0d8b0e7c4d3c672b49984c304305 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Motiejus=20Jak=C5=A1tys?= <motiejus@uber.com>
Date: Fri, 26 Feb 2021 18:19:23 +0200
Subject: [PATCH] fix gentle inflections -- both tests pass

---
 IV/tests.sql | 28 ++++++++++++++--------------
 IV/wm.sql    | 25 +++++++++++++++++++++----
 2 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/IV/tests.sql b/IV/tests.sql
index 0e61339..8b2f35c 100644
--- a/IV/tests.sql
+++ b/IV/tests.sql
@@ -43,20 +43,20 @@ end $$ language plpgsql;
 
 drop table if exists inflections;
 create table inflections (name text, way geometry);
---insert into inflections select 'fig3', unnest(fix_gentle_inflections(detect_bends((select way from figures where name='fig3'))));
+insert into inflections select 'fig3', unnest(fix_gentle_inflections(detect_bends((select way from figures where name='fig3'))));
 insert into inflections select 'fig5', unnest(fix_gentle_inflections(detect_bends((select way from figures where name='fig5'))));
---insert into inflections select 'inflection-1', unnest(fix_gentle_inflections(detect_bends((select way from figures where name='inflection-1'))));
+insert into inflections select 'inflection-1', unnest(fix_gentle_inflections(detect_bends((select way from figures where name='inflection-1'))));
 
 -- FIX BEND INFLECTIONS
---do $$
---declare
---  vbends geometry[];
---  vinflections geometry[];
---begin
---  select detect_bends((select way from figures where name='inflection-1')) into vbends;
---  select fix_gentle_inflections(vbends) into vinflections;
---
---  perform assert_equals(vbends[1], vinflections[1]); -- unchanged
---  perform assert_equals('LINESTRING(114 20,133 20,145 15,145 0,136 5,123 7,114 7)', st_astext(vinflections[2]));
---  perform assert_equals('LINESTRING(123 7,114 7,111 2)', st_astext(vinflections[3]));
---end $$ language plpgsql;
+do $$
+declare
+  vbends geometry[];
+  vinflections geometry[];
+begin
+  select detect_bends((select way from figures where name='inflection-1')) into vbends;
+  select fix_gentle_inflections(vbends) into vinflections;
+
+  perform assert_equals(vbends[1], vinflections[1]); -- unchanged
+  perform assert_equals('LINESTRING(114 20,133 20,145 15,145 0,136 5,123 7,114 7)', st_astext(vinflections[2]));
+  perform assert_equals('LINESTRING(123 7,114 7,111 2)', st_astext(vinflections[3]));
+end $$ language plpgsql;
diff --git a/IV/wm.sql b/IV/wm.sql
index e5fd175..5ab7326 100644
--- a/IV/wm.sql
+++ b/IV/wm.sql
@@ -76,10 +76,21 @@ $$ language plpgsql;
 -- commulative inflection angle small (see variable below).
 create or replace function fix_gentle_inflections(INOUT bends geometry[]) as $$
 declare
+  len int4;
   bends1 geometry[];
+  bends2 geometry[];
 begin
+  len = array_length(bends, 1);
+
   bends1 = fix_gentle_inflections1(bends);
-  bends1 = array_reverse(fix_gentle_inflections1(array_reverse(bends1)));
+  for i in 1..len loop
+    bends2[i] = st_reverse(bends1[len-i+1]);
+  end loop;
+  bends2 = fix_gentle_inflections1(bends2);
+
+  for i in 1..len loop
+    bends[i] = st_reverse(bends2[len-i+1]);
+  end loop;
 end
 $$ language plpgsql;
 
@@ -134,13 +145,19 @@ begin
       exit when array_length(phead, 1) < 3;
 
       -- if inflection angle between ptail[1:3] "large", stop processing this bend
-      exit when abs(st_angle(phead[1], phead[2], phead[3]) - pi) > small_angle;
+      if abs(st_angle(phead[1], phead[2], phead[3]) - pi) > small_angle then
+        --raise notice 'quitting % because angle between % % %', st_astext(ptail), st_astext(phead[1]), st_astext(phead[2]), st_astext(phead[3]);
+        exit;
+      end if;
 
       -- distance from head's first vertex should be larger than from second vertex
-      exit when st_distance(ptail, phead[2]) < st_distance(ptail, phead[3]);
+      if st_distance(ptail, phead[2]) < st_distance(ptail, phead[3]) then
+        --raise notice 'quitting % because distance', st_astext(ptail);
+        exit;
+      end if;
 
       -- detected a gentle inflection. Move head of the tail to the tail of head
-      raise notice 'fixing a gentle inflection of angle %', degrees(abs(st_angle(phead[1], phead[2], phead[3]) - pi));
+      --raise notice 'fixing a gentle inflection of angle %', degrees(abs(st_angle(phead[1], phead[2], phead[3]) - pi));
 
       bends[i] = st_removepoint(bends[i], 0);
       bends[i-1] = st_addpoint(bends[i-1], phead[3]);