From ce403e1f75f9b8de6153d13eaf7796a07883e113 Mon Sep 17 00:00:00 2001
From: Alexander Iljin <ajsoft@yandex.ru>
Date: Sun, 22 Jan 2017 02:34:29 +0300
Subject: [PATCH] charts.lines: fix edge cases for fix-left-chunk and
 fix-right-chunk

---
 lines/lines-tests.factor |  6 ++++--
 lines/lines.factor       | 10 ++++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/lines/lines-tests.factor b/lines/lines-tests.factor
index 670322e82f..b8214f45ed 100644
--- a/lines/lines-tests.factor
+++ b/lines/lines-tests.factor
@@ -79,6 +79,8 @@ IN: charts.lines.tests
     -3 3 fix-left-chunk
 ] unit-test
 
+! TODO: add more tests for the recently discovered bugs in fix-left-chunk and fix-right-chunk
+
 ! fix-right-chunk: y coord = top limit
 {
     { { 5 3 } { 6 0 } }
@@ -192,8 +194,8 @@ IN: charts.lines.tests
 ! single-element sequences, same x coord
 {
     {
-        { { 0 0 } }
-        { { 0 3 } }
+        { { 0 0 } { 0 3 } }
+        { { 0 3 } { 0 0 } }
     }
 } [
     { { 0 -2 } { 0 0 } { 0 5 } { 0 3 } { 0 -1 } } { 0 3 }
diff --git a/lines/lines.factor b/lines/lines.factor
index 9edb0029b6..644f5fe22f 100644
--- a/lines/lines.factor
+++ b/lines/lines.factor
@@ -127,7 +127,10 @@ ALIAS: y second
 :: fix-left-chunk ( left right ymin ymax -- left' )
     left last :> left-point
     right first :> right-point
-    left-point y { [ ymin = ] [ ymax = ] } 1|| [
+    left-point y right-point y {
+        [ { [ drop ymin = ] [ > ] } 2&& ]
+        [ { [ drop ymax = ] [ < ] } 2&& ]
+    } 2|| [
         left
     ] [
         left-point y right-point y > ymin ymax ? :> y-coord
@@ -143,7 +146,10 @@ ALIAS: y second
 :: fix-right-chunk ( left right ymin ymax -- right' )
     left last :> left-point
     right first :> right-point
-    right-point y { [ ymin = ] [ ymax = ] } 1|| [
+    left-point y right-point y {
+        [ { [ ymin = nip ] [ < ] } 2&& ]
+        [ { [ ymax = nip ] [ > ] } 2&& ]
+    } 2|| [
         right
     ] [
         left-point y right-point y < ymin ymax ? :> y-coord