From b354e954016963184d6dcaff4f5fa515ba7fd81b Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Wed, 19 Oct 2016 20:15:07 +0530
Subject: [PATCH] Implement cursor movement APIs

---
 kitty/screen.py       | 41 +++++++++++++++++++++++++----------------
 kitty_tests/screen.py | 25 ++++++++++++++++++++++++-
 2 files changed, 49 insertions(+), 17 deletions(-)

diff --git a/kitty/screen.py b/kitty/screen.py
index f3049d46b..49949c728 100644
--- a/kitty/screen.py
+++ b/kitty/screen.py
@@ -66,6 +66,11 @@ class Screen(QObject):
 
     def notify_cursor_position(self, x, y):
         if self._notify_cursor_position:
+            if x >= self.columns:
+                if y < self.lines - 1:
+                    x, y = 0, y + 1
+                else:
+                    x, y = x - 1, y
             self.cursor_position_changed(self.cursor, x, y)
 
     @property
@@ -707,59 +712,63 @@ class Screen(QObject):
         self.cursor.x = max(0, min(self.cursor.x, self.columns - 1))
         self.cursor.y = max(top, min(self.cursor.y, bottom))
 
-    def cursor_up(self, count=None):
+    def cursor_up(self, count=1, do_carriage_return=False, move_direction=-1):
         """Moves cursor up the indicated # of lines in same column.
         Cursor stops at top margin.
 
         :param int count: number of lines to skip.
         """
-        self.cursor.y -= count or 1
+        x, y = self.cursor.x, self.cursor.y
+        self.cursor.y += move_direction * (count or 1)
         self.ensure_bounds(use_margins=True)
+        if do_carriage_return:
+            self.cursor.x = 0
+        if y != self.cursor.y or x != self.cursor.x:
+            self.notify_cursor_position(x, y)
 
-    def cursor_up1(self, count=None):
+    def cursor_up1(self, count=1):
         """Moves cursor up the indicated # of lines to column 1. Cursor
         stops at bottom margin.
 
         :param int count: number of lines to skip.
         """
-        self.cursor_up(count)
-        self.carriage_return()
+        self.cursor_up(count, do_carriage_return=True)
 
-    def cursor_down(self, count=None):
+    def cursor_down(self, count=1):
         """Moves cursor down the indicated # of lines in same column.
         Cursor stops at bottom margin.
 
         :param int count: number of lines to skip.
         """
-        self.cursor.y += count or 1
-        self.ensure_bounds(use_margins=True)
+        self.cursor_up(count, move_direction=1)
 
-    def cursor_down1(self, count=None):
+    def cursor_down1(self, count=1):
         """Moves cursor down the indicated # of lines to column 1.
         Cursor stops at bottom margin.
 
         :param int count: number of lines to skip.
         """
-        self.cursor_down(count)
-        self.carriage_return()
+        self.cursor_up(count, do_carriage_return=True, move_direction=1)
 
-    def cursor_back(self, count=None):
+    def cursor_back(self, count=1, move_direction=-1):
         """Moves cursor left the indicated # of columns. Cursor stops
         at left margin.
 
         :param int count: number of columns to skip.
         """
-        self.cursor.x -= count or 1
+        x = self.cursor.x
+        self.cursor.x += move_direction * (count or 1)
         self.ensure_bounds()
+        if x != self.cursor.x:
+            self.notify_cursor_position(x, self.cursor.y)
 
-    def cursor_forward(self, count=None):
+    def cursor_forward(self, count=1):
         """Moves cursor right the indicated # of columns. Cursor stops
         at right margin.
 
         :param int count: number of columns to skip.
         """
-        self.cursor.x += count or 1
-        self.ensure_bounds()
+        self.cursor_back(count, move_direction=1)
 
     def cursor_position(self, line=None, column=None):
         """Set the cursor to a specific `line` and `column`.
diff --git a/kitty_tests/screen.py b/kitty_tests/screen.py
index 04001ec8c..412b046c8 100644
--- a/kitty_tests/screen.py
+++ b/kitty_tests/screen.py
@@ -64,7 +64,7 @@ class TestScreen(BaseTest):
         self.ae(str(s.linebuf[0]), 'ココx')
         self.ae(str(s.linebuf[1]), 'ニチ ')
         self.ae(str(s.linebuf[2]), 'ハ   ')
-        self.assertChanges(t, ignore='cursor', cells={0: ((5, 5),), 1: ((0, 3),), 2: ((0, 1),)})
+        self.assertChanges(t, ignore='cursor', cells={1: ((0, 3),), 2: ((0, 1),)})
         self.ae(s.cursor.x, 2), self.ae(s.cursor.y, 2)
         s.draw('Ƶ̧\u0308'.encode('utf-8'))
         self.ae(str(s.linebuf[2]), 'ハƵ̧\u0308  ')
@@ -192,3 +192,26 @@ class TestScreen(BaseTest):
         self.ae(s.display, ('     ', '     ', '     ', '     ', '     '))
         self.assertChanges(t, lines=set(range(5)))
         self.assertFalse(s.linebuf[0].cursor_from(1).bold)
+
+    def test_cursor_movement(self):
+        s, t = self.create_screen()
+        s.draw(b'12345' * 5)
+        t.reset()
+        s.cursor_up(2)
+        self.ae((s.cursor.x, s.cursor.y), (4, 2))
+        self.assertChanges(t, ignore='cursor', cells={4: ((4, 4),)})
+        s.cursor_up1()
+        self.ae((s.cursor.x, s.cursor.y), (0, 1))
+        self.assertChanges(t, ignore='cursor', cells={2: ((4, 4),)})
+        s.cursor_forward(3)
+        self.ae((s.cursor.x, s.cursor.y), (3, 1))
+        self.assertChanges(t, ignore='cursor', cells={1: ((0, 0),)})
+        s.cursor_back()
+        self.ae((s.cursor.x, s.cursor.y), (2, 1))
+        self.assertChanges(t, ignore='cursor', cells={1: ((3, 3),)})
+        s.cursor_down()
+        self.ae((s.cursor.x, s.cursor.y), (2, 2))
+        self.assertChanges(t, ignore='cursor', cells={1: ((2, 2),)})
+        s.cursor_down1(5)
+        self.ae((s.cursor.x, s.cursor.y), (0, 4))
+        self.assertChanges(t, ignore='cursor', cells={2: ((2, 2),)})