Add ^Up and ^Down for scrolling the screen by one line

babi.py

@@ -502,6 +502,18 @@ class File:
         self.cursor_y = len(self.lines) - 1
         self._scroll_screen_if_needed(margin)
 
+    @action
+    def ctrl_up(self, margin: Margin) -> None:
+        self.file_y = max(0, self.file_y - 1)
+        self.cursor_y = min(self.cursor_y, self.file_y + margin.body_lines - 1)
+        self._set_x_after_vertical_movement()
+
+    @action
+    def ctrl_down(self, margin: Margin) -> None:
+        self.file_y = min(len(self.lines) - 1, self.file_y + 1)
+        self.cursor_y = max(self.cursor_y, self.file_y)
+        self._set_x_after_vertical_movement()
+
     @action
     def go_to_line(self, lineno: int, margin: Margin) -> None:
         self.x = self.x_hint = 0
@@ -627,6 +639,8 @@ class File:
         b'^V': page_down,
         b'kHOM5': ctrl_home,
         b'kEND5': ctrl_end,
+        b'kUP5': ctrl_up,
+        b'kDN5': ctrl_down,
     }
 
     @edit_action('text')
@@ -807,14 +821,16 @@ SEQUENCE_KEY = {
     '\x1bOF': curses.KEY_END,
 }
 SEQUENCE_KEYNAME = {
-    '\x1b[1;5H': b'kHOM5',  # C-Home
-    '\x1b[1;5F': b'kEND5',  # C-End
+    '\x1b[1;5H': b'kHOM5',  # ^Home
+    '\x1b[1;5F': b'kEND5',  # ^End
     '\x1bOH': b'KEY_HOME',
     '\x1bOF': b'KEY_END',
     '\x1b[1;3A': b'kUP3',  # M-Up
     '\x1b[1;3B': b'kDN3',  # M-Down
     '\x1b[1;3C': b'kRIT3',  # M-Right
     '\x1b[1;3D': b'kLFT3',  # M-Left
+    '\x1b[1;5A': b'kUP5',  # ^Up
+    '\x1b[1;5B': b'kDN5',  # ^Down
 }
 
 

tests/babi_test.py

@@ -649,6 +649,81 @@ def test_scrolling_arrow_key_movement(ten_lines):
         h.await_text('line_0')
 
 
+def test_ctrl_down_beginning_of_file(ten_lines):
+    with run(str(ten_lines), height=5) as h, and_exit(h):
+        h.press('^Down')
+        h.await_text('line_3')
+        h.await_cursor_position(x=0, y=1)
+        assert h.get_cursor_line() == 'line_1'
+
+
+def test_ctrl_up_moves_screen_up_one_line(ten_lines):
+    with run(str(ten_lines), height=5) as h, and_exit(h):
+        h.press('^Down')
+        h.press('^Up')
+        h.await_text('line_0')
+        h.await_text('line_2')
+        h.await_cursor_position(x=0, y=2)
+
+
+def test_ctrl_up_at_beginning_of_file_does_nothing(ten_lines):
+    with run(str(ten_lines), height=5) as h, and_exit(h):
+        h.press('^Up')
+        h.await_text('line_0')
+        h.await_text('line_2')
+        h.await_cursor_position(x=0, y=1)
+
+
+def test_ctrl_up_at_bottom_of_screen(ten_lines):
+    with run(str(ten_lines), height=5) as h, and_exit(h):
+        h.press('^Down')
+        h.press('Down')
+        h.press('Down')
+        h.await_text('line_1')
+        h.await_text('line_3')
+        h.await_cursor_position(x=0, y=3)
+        h.press('^Up')
+        h.await_text('line_0')
+        h.await_cursor_position(x=0, y=3)
+
+
+def test_ctrl_down_at_end_of_file(ten_lines):
+    with run(str(ten_lines), height=5) as h, and_exit(h):
+        h.press('^End')
+        for i in range(4):
+            h.press('^Down')
+        h.press('Up')
+        h.await_text('line_9')
+        assert h.get_cursor_line() == 'line_9'
+
+
+def test_ctrl_down_causing_cursor_movement_should_fix_x(tmpdir):
+    f = tmpdir.join('f')
+    f.write('1\n\n2\n\n3\n\n4\n')
+
+    with run(str(f), height=5) as h, and_exit(h):
+        h.press('Right')
+        h.press('^Down')
+        h.await_text_missing('\n1\n')
+        h.await_cursor_position(x=0, y=1)
+
+
+def test_ctrl_up_causing_cursor_movement_should_fix_x(tmpdir):
+    f = tmpdir.join('f')
+    f.write('1\n\n2\n\n3\n\n4\n')
+
+    with run(str(f), height=5) as h, and_exit(h):
+        h.press('^Down')
+        h.press('^Down')
+        h.press('Down')
+        h.press('Down')
+        h.press('Right')
+        h.await_text('3')
+        h.press('^Up')
+        h.await_text_missing('3')
+        h.await_cursor_position(x=0, y=3)
+
+
 @pytest.mark.parametrize('k', ('End', '^E'))
 def test_end_key(tmpdir, k):
     f = tmpdir.join('f')