From cb3482ae27d97af50eb55a74a0783413564881eb Mon Sep 17 00:00:00 2001
From: Tobias Witek <tobi@tobi-wan-kenobi.at>
Date: Sat, 29 Feb 2020 14:05:02 +0100
Subject: [PATCH] [core/decorators] Simplify and test scrolling

---
 core/decorators.py            | 29 +++++++++++++++--------------
 tests/core/test_decorators.py |  6 ++++++
 2 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/core/decorators.py b/core/decorators.py
index 98b2ed9..e7b3b82 100644
--- a/core/decorators.py
+++ b/core/decorators.py
@@ -11,26 +11,27 @@ def scrollable(func):
         if width < 0 or len(text) <= width:
             return text
 
+        start = widget.get('scrolling.start', 0)
         bounce = util.format.asbool(module.parameter('scrolling.bounce', True))
         scroll_speed = util.format.asint(module.parameter('scrolling.speed', 1))
-        start = widget.get('scrolling.start', 0)
-
-        if start + width > len(text):
-            if bounce:
-                widget.set('scrolling.direction', 'left')
-                start -= scroll_speed*2
-            else:
-                start = 0
-        elif start < 0:
-            if bounce:
-                widget.set('scrolling.direction', 'right')
         direction = widget.get('scrolling.direction', 'right')
+
         if direction == 'left':
             scroll_speed = -scroll_speed
-        widget.set('scrolling.start', start + scroll_speed)
-        text = text[start:width+start]
+            if start + scroll_speed <= 0: # bounce back
+                widget.set('scrolling.direction', 'right')
 
-        return text
+        next_start = start + scroll_speed
+        if next_start + width > len(text):
+            if not bounce:
+                next_start = 0
+            else:
+                next_start = start - scroll_speed
+                widget.set('scrolling.direction', 'left')
+
+        widget.set('scrolling.start', next_start)
+
+        return text[start:start+width]
     return wrapper
 
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4
diff --git a/tests/core/test_decorators.py b/tests/core/test_decorators.py
index ddbce8a..8ce115f 100644
--- a/tests/core/test_decorators.py
+++ b/tests/core/test_decorators.py
@@ -44,6 +44,10 @@ class config(unittest.TestCase):
         self.assertEqual('cd', self.module.get(self.widget))
         self.assertEqual('bc', self.module.get(self.widget))
         self.assertEqual('ab', self.module.get(self.widget))
+        self.assertEqual('bc', self.module.get(self.widget))
+        self.assertEqual('cd', self.module.get(self.widget))
+        self.assertEqual('bc', self.module.get(self.widget))
+        self.assertEqual('ab', self.module.get(self.widget))
 
     def test_nobounce(self):
         self.module.set('scrolling.bounce', False)
@@ -53,5 +57,7 @@ class config(unittest.TestCase):
         self.assertEqual('bc', self.module.get(self.widget))
         self.assertEqual('cd', self.module.get(self.widget))
         self.assertEqual('ab', self.module.get(self.widget))
+        self.assertEqual('bc', self.module.get(self.widget))
+        self.assertEqual('cd', self.module.get(self.widget))
 
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4