From df3d0ec8a58874e37e0868ce64de9b4c75325319 Mon Sep 17 00:00:00 2001
From: Alexander Iljin <ajsoft@yandex.ru>
Date: Sat, 21 Jan 2017 22:24:04 +0300
Subject: [PATCH] charts.lines: add clip-data tests, fix implementation of
 left-cut-x

---
 lines/lines-tests.factor | 42 +++++++++++++++++++++++++++++++++++++++-
 lines/lines.factor       |  2 +-
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/lines/lines-tests.factor b/lines/lines-tests.factor
index 29efcbf197..0e8ee00b56 100644
--- a/lines/lines-tests.factor
+++ b/lines/lines-tests.factor
@@ -257,4 +257,44 @@ IN: charts.lines.tests
     } clip-data
 ] unit-test
 
-! TODO: add tests where after search there is no adjustment necessary, so that extra adjustment would take bad elements. Also, add tests for sequences fully outside the range.
+! no points within the viewport, complete calculation
+{
+    { { 1 1 } { 4 4 } }
+} [
+    { { 1 4 } { 1 4 } }
+    { { 0 0 } { 5 5 } } clip-data
+] unit-test
+
+! no points within the viewport, complete calculation
+{
+    { { 1 4 } { 4 1 } }
+} [
+    { { 1 4 } { 1 4 } }
+    { { 0 5 } { 5 0 } } clip-data
+] unit-test
+
+! no points within the viewport, complete calculation
+{
+    { { 1 3 } { 4 3 } }
+} [
+    { { 1 4 } { 1 4 } }
+    { { 0 3 } { 5 3 } } clip-data
+] unit-test
+
+! all data are to the left of viewport
+{
+    { }
+} [
+    { { 1 4 } { 1 4 } }
+    { { -1 0 } { 0 1 } { 0.5 1 } } clip-data
+] unit-test
+
+! all data are to the right of viewport
+{
+    { }
+} [
+    { { 1 4 } { 1 4 } }
+    { { 4.5 0 } { 5 1 } { 6 1 } } clip-data
+] unit-test
+
+! TODO: add tests where after search there is no adjustment necessary, so that extra adjustment would take bad elements.
diff --git a/lines/lines.factor b/lines/lines.factor
index a119463bd1..9edb0029b6 100644
--- a/lines/lines.factor
+++ b/lines/lines.factor
@@ -71,7 +71,7 @@ ALIAS: y second
 ! pairs is <= xmin, and if the first is < xmin, then the second is
 ! > xmin. Otherwise the first one would be = xmin.
 : left-cut-x ( xmin pairs -- seq )
-    2dup first x < [
+    2dup first x > [
         [ dupd first2 y-at 2array ] keep rest-slice swap prefix
     ] [
         nip