Restoring authorship annotation for <shadchin@yandex-team.ru>. Commit 1 of 2.

1 files changed, 493 insertions, 493 deletions

diff --git a/contrib/python/prompt-toolkit/py3/prompt_toolkit/layout/scrollable_pane.py b/contrib/python/prompt-toolkit/py3/prompt_toolkit/layout/scrollable_pane.py
index a5500d7f7c..57d813d511 100644
--- a/contrib/python/prompt-toolkit/py3/prompt_toolkit/layout/scrollable_pane.py
+++ b/contrib/python/prompt-toolkit/py3/prompt_toolkit/layout/scrollable_pane.py
@@ -1,493 +1,493 @@
-from typing import Dict, List, Optional
-
-from prompt_toolkit.data_structures import Point
-from prompt_toolkit.filters import FilterOrBool, to_filter
-from prompt_toolkit.key_binding import KeyBindingsBase
-from prompt_toolkit.mouse_events import MouseEvent
-
-from .containers import Container, ScrollOffsets
-from .dimension import AnyDimension, Dimension, sum_layout_dimensions, to_dimension
-from .mouse_handlers import MouseHandler, MouseHandlers
-from .screen import Char, Screen, WritePosition
-
-__all__ = ["ScrollablePane"]
-
-# Never go beyond this height, because performance will degrade.
-MAX_AVAILABLE_HEIGHT = 10_000
-
-
-class ScrollablePane(Container):
-    """
-    Container widget that exposes a larger virtual screen to its content and
-    displays it in a vertical scrollbale region.
-
-    Typically this is wrapped in a large `HSplit` container. Make sure in that
-    case to not specify a `height` dimension of the `HSplit`, so that it will
-    scale according to the content.
-
-    .. note::
-
-        If you want to display a completion menu for widgets in this
-        `ScrollablePane`, then it's still a good practice to use a
-        `FloatContainer` with a `CompletionsMenu` in a `Float` at the top-level
-        of the layout hierarchy, rather then nesting a `FloatContainer` in this
-        `ScrollablePane`. (Otherwise, it's possible that the completion menu
-        is clipped.)
-
-    :param content: The content container.
-    :param scrolloffset: Try to keep the cursor within this distance from the
-        top/bottom (left/right offset is not used).
-    :param keep_cursor_visible: When `True`, automatically scroll the pane so
-        that the cursor (of the focused window) is always visible.
-    :param keep_focused_window_visible: When `True`, automatically scroll th e
-        pane so that the focused window is visible, or as much visible as
-        possible if it doen't completely fit the screen.
-    :param max_available_height: Always constraint the height to this amount
-        for performance reasons.
-    :param width: When given, use this width instead of looking at the children.
-    :param height: When given, use this height instead of looking at the children.
-    :param show_scrollbar: When `True` display a scrollbar on the right.
-    """
-
-    def __init__(
-        self,
-        content: Container,
-        scroll_offsets: Optional[ScrollOffsets] = None,
-        keep_cursor_visible: FilterOrBool = True,
-        keep_focused_window_visible: FilterOrBool = True,
-        max_available_height: int = MAX_AVAILABLE_HEIGHT,
-        width: AnyDimension = None,
-        height: AnyDimension = None,
-        show_scrollbar: FilterOrBool = True,
-        display_arrows: FilterOrBool = True,
-        up_arrow_symbol: str = "^",
-        down_arrow_symbol: str = "v",
-    ) -> None:
-        self.content = content
-        self.scroll_offsets = scroll_offsets or ScrollOffsets(top=1, bottom=1)
-        self.keep_cursor_visible = to_filter(keep_cursor_visible)
-        self.keep_focused_window_visible = to_filter(keep_focused_window_visible)
-        self.max_available_height = max_available_height
-        self.width = width
-        self.height = height
-        self.show_scrollbar = to_filter(show_scrollbar)
-        self.display_arrows = to_filter(display_arrows)
-        self.up_arrow_symbol = up_arrow_symbol
-        self.down_arrow_symbol = down_arrow_symbol
-
-        self.vertical_scroll = 0
-
-    def __repr__(self) -> str:
-        return f"ScrollablePane({self.content!r})"
-
-    def reset(self) -> None:
-        self.content.reset()
-
-    def preferred_width(self, max_available_width: int) -> Dimension:
-        if self.width is not None:
-            return to_dimension(self.width)
-
-        # We're only scrolling vertical. So the preferred width is equal to
-        # that of the content.
-        content_width = self.content.preferred_width(max_available_width)
-
-        # If a scrollbar needs to be displayed, add +1 to the content width.
-        if self.show_scrollbar():
-            return sum_layout_dimensions([Dimension.exact(1), content_width])
-
-        return content_width
-
-    def preferred_height(self, width: int, max_available_height: int) -> Dimension:
-        if self.height is not None:
-            return to_dimension(self.height)
-
-        # Prefer a height large enough so that it fits all the content. If not,
-        # we'll make the pane scrollable.
-        if self.show_scrollbar():
-            # If `show_scrollbar` is set. Always reserve space for the scrollbar.
-            width -= 1
-
-        dimension = self.content.preferred_height(width, self.max_available_height)
-
-        # Only take 'preferred' into account. Min/max can be anything.
-        return Dimension(min=0, preferred=dimension.preferred)
-
-    def write_to_screen(
-        self,
-        screen: Screen,
-        mouse_handlers: MouseHandlers,
-        write_position: WritePosition,
-        parent_style: str,
-        erase_bg: bool,
-        z_index: Optional[int],
-    ) -> None:
-        """
-        Render scrollable pane content.
-
-        This works by rendering on an off-screen canvas, and copying over the
-        visible region.
-        """
-        show_scrollbar = self.show_scrollbar()
-
-        if show_scrollbar:
-            virtual_width = write_position.width - 1
-        else:
-            virtual_width = write_position.width
-
-        # Compute preferred height again.
-        virtual_height = self.content.preferred_height(
-            virtual_width, self.max_available_height
-        ).preferred
-
-        # Ensure virtual height is at least the available height.
-        virtual_height = max(virtual_height, write_position.height)
-        virtual_height = min(virtual_height, self.max_available_height)
-
-        # First, write the content to a virtual screen, then copy over the
-        # visible part to the real screen.
-        temp_screen = Screen(default_char=Char(char=" ", style=parent_style))
-        temp_write_position = WritePosition(
-            xpos=0, ypos=0, width=virtual_width, height=virtual_height
-        )
-
-        temp_mouse_handlers = MouseHandlers()
-
-        self.content.write_to_screen(
-            temp_screen,
-            temp_mouse_handlers,
-            temp_write_position,
-            parent_style,
-            erase_bg,
-            z_index,
-        )
-        temp_screen.draw_all_floats()
-
-        # If anything in the virtual screen is focused, move vertical scroll to
-        from prompt_toolkit.application import get_app
-
-        focused_window = get_app().layout.current_window
-
-        try:
-            visible_win_write_pos = temp_screen.visible_windows_to_write_positions[
-                focused_window
-            ]
-        except KeyError:
-            pass  # No window focused here. Don't scroll.
-        else:
-            # Make sure this window is visible.
-            self._make_window_visible(
-                write_position.height,
-                virtual_height,
-                visible_win_write_pos,
-                temp_screen.cursor_positions.get(focused_window),
-            )
-
-        # Copy over virtual screen and zero width escapes to real screen.
-        self._copy_over_screen(screen, temp_screen, write_position, virtual_width)
-
-        # Copy over mouse handlers.
-        self._copy_over_mouse_handlers(
-            mouse_handlers, temp_mouse_handlers, write_position, virtual_width
-        )
-
-        # Set screen.width/height.
-        ypos = write_position.ypos
-        xpos = write_position.xpos
-
-        screen.width = max(screen.width, xpos + virtual_width)
-        screen.height = max(screen.height, ypos + write_position.height)
-
-        # Copy over window write positions.
-        self._copy_over_write_positions(screen, temp_screen, write_position)
-
-        if temp_screen.show_cursor:
-            screen.show_cursor = True
-
-        # Copy over cursor positions, if they are visible.
-        for window, point in temp_screen.cursor_positions.items():
-            if (
-                0 <= point.x < write_position.width
-                and self.vertical_scroll
-                <= point.y
-                < write_position.height + self.vertical_scroll
-            ):
-                screen.cursor_positions[window] = Point(
-                    x=point.x + xpos, y=point.y + ypos - self.vertical_scroll
-                )
-
-        # Copy over menu positions, but clip them to the visible area.
-        for window, point in temp_screen.menu_positions.items():
-            screen.menu_positions[window] = self._clip_point_to_visible_area(
-                Point(x=point.x + xpos, y=point.y + ypos - self.vertical_scroll),
-                write_position,
-            )
-
-        # Draw scrollbar.
-        if show_scrollbar:
-            self._draw_scrollbar(
-                write_position,
-                virtual_height,
-                screen,
-            )
-
-    def _clip_point_to_visible_area(
-        self, point: Point, write_position: WritePosition
-    ) -> Point:
-        """
-        Ensure that the cursor and menu positions always are always reported
-        """
-        if point.x < write_position.xpos:
-            point = point._replace(x=write_position.xpos)
-        if point.y < write_position.ypos:
-            point = point._replace(y=write_position.ypos)
-        if point.x >= write_position.xpos + write_position.width:
-            point = point._replace(x=write_position.xpos + write_position.width - 1)
-        if point.y >= write_position.ypos + write_position.height:
-            point = point._replace(y=write_position.ypos + write_position.height - 1)
-
-        return point
-
-    def _copy_over_screen(
-        self,
-        screen: Screen,
-        temp_screen: Screen,
-        write_position: WritePosition,
-        virtual_width: int,
-    ) -> None:
-        """
-        Copy over visible screen content and "zero width escape sequences".
-        """
-        ypos = write_position.ypos
-        xpos = write_position.xpos
-
-        for y in range(write_position.height):
-            temp_row = temp_screen.data_buffer[y + self.vertical_scroll]
-            row = screen.data_buffer[y + ypos]
-            temp_zero_width_escapes = temp_screen.zero_width_escapes[
-                y + self.vertical_scroll
-            ]
-            zero_width_escapes = screen.zero_width_escapes[y + ypos]
-
-            for x in range(virtual_width):
-                row[x + xpos] = temp_row[x]
-
-                if x in temp_zero_width_escapes:
-                    zero_width_escapes[x + xpos] = temp_zero_width_escapes[x]
-
-    def _copy_over_mouse_handlers(
-        self,
-        mouse_handlers: MouseHandlers,
-        temp_mouse_handlers: MouseHandlers,
-        write_position: WritePosition,
-        virtual_width: int,
-    ) -> None:
-        """
-        Copy over mouse handlers from virtual screen to real screen.
-
-        Note: we take `virtual_width` because we don't want to copy over mouse
-              handlers that we possibly have behind the scrollbar.
-        """
-        ypos = write_position.ypos
-        xpos = write_position.xpos
-
-        # Cache mouse handlers when wrapping them. Very often the same mouse
-        # handler is registered for many positions.
-        mouse_handler_wrappers: Dict[MouseHandler, MouseHandler] = {}
-
-        def wrap_mouse_handler(handler: MouseHandler) -> MouseHandler:
-            "Wrap mouse handler. Translate coordinates in `MouseEvent`."
-            if handler not in mouse_handler_wrappers:
-
-                def new_handler(event: MouseEvent) -> None:
-                    new_event = MouseEvent(
-                        position=Point(
-                            x=event.position.x - xpos,
-                            y=event.position.y + self.vertical_scroll - ypos,
-                        ),
-                        event_type=event.event_type,
-                        button=event.button,
-                        modifiers=event.modifiers,
-                    )
-                    handler(new_event)
-
-                mouse_handler_wrappers[handler] = new_handler
-            return mouse_handler_wrappers[handler]
-
-        # Copy handlers.
-        mouse_handlers_dict = mouse_handlers.mouse_handlers
-        temp_mouse_handlers_dict = temp_mouse_handlers.mouse_handlers
-
-        for y in range(write_position.height):
-            if y in temp_mouse_handlers_dict:
-                temp_mouse_row = temp_mouse_handlers_dict[y + self.vertical_scroll]
-                mouse_row = mouse_handlers_dict[y + ypos]
-                for x in range(virtual_width):
-                    if x in temp_mouse_row:
-                        mouse_row[x + xpos] = wrap_mouse_handler(temp_mouse_row[x])
-
-    def _copy_over_write_positions(
-        self, screen: Screen, temp_screen: Screen, write_position: WritePosition
-    ) -> None:
-        """
-        Copy over window write positions.
-        """
-        ypos = write_position.ypos
-        xpos = write_position.xpos
-
-        for win, write_pos in temp_screen.visible_windows_to_write_positions.items():
-            screen.visible_windows_to_write_positions[win] = WritePosition(
-                xpos=write_pos.xpos + xpos,
-                ypos=write_pos.ypos + ypos - self.vertical_scroll,
-                # TODO: if the window is only partly visible, then truncate width/height.
-                #       This could be important if we have nested ScrollablePanes.
-                height=write_pos.height,
-                width=write_pos.width,
-            )
-
-    def is_modal(self) -> bool:
-        return self.content.is_modal()
-
-    def get_key_bindings(self) -> Optional[KeyBindingsBase]:
-        return self.content.get_key_bindings()
-
-    def get_children(self) -> List["Container"]:
-        return [self.content]
-
-    def _make_window_visible(
-        self,
-        visible_height: int,
-        virtual_height: int,
-        visible_win_write_pos: WritePosition,
-        cursor_position: Optional[Point],
-    ) -> None:
-        """
-        Scroll the scrollable pane, so that this window becomes visible.
-
-        :param visible_height: Height of this `ScrollablePane` that is rendered.
-        :param virtual_height: Height of the virtual, temp screen.
-        :param visible_win_write_pos: `WritePosition` of the nested window on the
-            temp screen.
-        :param cursor_position: The location of the cursor position of this
-            window on the temp screen.
-        """
-        # Start with maximum allowed scroll range, and then reduce according to
-        # the focused window and cursor position.
-        min_scroll = 0
-        max_scroll = virtual_height - visible_height
-
-        if self.keep_cursor_visible():
-            # Reduce min/max scroll according to the cursor in the focused window.
-            if cursor_position is not None:
-                offsets = self.scroll_offsets
-                cpos_min_scroll = (
-                    cursor_position.y - visible_height + 1 + offsets.bottom
-                )
-                cpos_max_scroll = cursor_position.y - offsets.top
-                min_scroll = max(min_scroll, cpos_min_scroll)
-                max_scroll = max(0, min(max_scroll, cpos_max_scroll))
-
-        if self.keep_focused_window_visible():
-            # Reduce min/max scroll according to focused window position.
-            # If the window is small enough, bot the top and bottom of the window
-            # should be visible.
-            if visible_win_write_pos.height <= visible_height:
-                window_min_scroll = (
-                    visible_win_write_pos.ypos
-                    + visible_win_write_pos.height
-                    - visible_height
-                )
-                window_max_scroll = visible_win_write_pos.ypos
-            else:
-                # Window does not fit on the screen. Make sure at least the whole
-                # screen is occupied with this window, and nothing else is shown.
-                window_min_scroll = visible_win_write_pos.ypos
-                window_max_scroll = (
-                    visible_win_write_pos.ypos
-                    + visible_win_write_pos.height
-                    - visible_height
-                )
-
-            min_scroll = max(min_scroll, window_min_scroll)
-            max_scroll = min(max_scroll, window_max_scroll)
-
-        if min_scroll > max_scroll:
-            min_scroll = max_scroll  # Should not happen.
-
-        # Finally, properly clip the vertical scroll.
-        if self.vertical_scroll > max_scroll:
-            self.vertical_scroll = max_scroll
-        if self.vertical_scroll < min_scroll:
-            self.vertical_scroll = min_scroll
-
-    def _draw_scrollbar(
-        self, write_position: WritePosition, content_height: int, screen: Screen
-    ) -> None:
-        """
-        Draw the scrollbar on the screen.
-
-        Note: There is some code duplication with the `ScrollbarMargin`
-              implementation.
-        """
-
-        window_height = write_position.height
-        display_arrows = self.display_arrows()
-
-        if display_arrows:
-            window_height -= 2
-
-        try:
-            fraction_visible = write_position.height / float(content_height)
-            fraction_above = self.vertical_scroll / float(content_height)
-
-            scrollbar_height = int(
-                min(window_height, max(1, window_height * fraction_visible))
-            )
-            scrollbar_top = int(window_height * fraction_above)
-        except ZeroDivisionError:
-            return
-        else:
-
-            def is_scroll_button(row: int) -> bool:
-                "True if we should display a button on this row."
-                return scrollbar_top <= row <= scrollbar_top + scrollbar_height
-
-            xpos = write_position.xpos + write_position.width - 1
-            ypos = write_position.ypos
-            data_buffer = screen.data_buffer
-
-            # Up arrow.
-            if display_arrows:
-                data_buffer[ypos][xpos] = Char(
-                    self.up_arrow_symbol, "class:scrollbar.arrow"
-                )
-                ypos += 1
-
-            # Scrollbar body.
-            scrollbar_background = "class:scrollbar.background"
-            scrollbar_background_start = "class:scrollbar.background,scrollbar.start"
-            scrollbar_button = "class:scrollbar.button"
-            scrollbar_button_end = "class:scrollbar.button,scrollbar.end"
-
-            for i in range(window_height):
-                style = ""
-                if is_scroll_button(i):
-                    if not is_scroll_button(i + 1):
-                        # Give the last cell a different style, because we want
-                        # to underline this.
-                        style = scrollbar_button_end
-                    else:
-                        style = scrollbar_button
-                else:
-                    if is_scroll_button(i + 1):
-                        style = scrollbar_background_start
-                    else:
-                        style = scrollbar_background
-
-                data_buffer[ypos][xpos] = Char(" ", style)
-                ypos += 1
-
-            # Down arrow
-            if display_arrows:
-                data_buffer[ypos][xpos] = Char(
-                    self.down_arrow_symbol, "class:scrollbar.arrow"
-                )
+from typing import Dict, List, Optional 
+ 
+from prompt_toolkit.data_structures import Point 
+from prompt_toolkit.filters import FilterOrBool, to_filter 
+from prompt_toolkit.key_binding import KeyBindingsBase 
+from prompt_toolkit.mouse_events import MouseEvent 
+ 
+from .containers import Container, ScrollOffsets 
+from .dimension import AnyDimension, Dimension, sum_layout_dimensions, to_dimension 
+from .mouse_handlers import MouseHandler, MouseHandlers 
+from .screen import Char, Screen, WritePosition 
+ 
+__all__ = ["ScrollablePane"] 
+ 
+# Never go beyond this height, because performance will degrade. 
+MAX_AVAILABLE_HEIGHT = 10_000 
+ 
+ 
+class ScrollablePane(Container): 
+    """ 
+    Container widget that exposes a larger virtual screen to its content and 
+    displays it in a vertical scrollbale region. 
+ 
+    Typically this is wrapped in a large `HSplit` container. Make sure in that 
+    case to not specify a `height` dimension of the `HSplit`, so that it will 
+    scale according to the content. 
+ 
+    .. note:: 
+ 
+        If you want to display a completion menu for widgets in this 
+        `ScrollablePane`, then it's still a good practice to use a 
+        `FloatContainer` with a `CompletionsMenu` in a `Float` at the top-level 
+        of the layout hierarchy, rather then nesting a `FloatContainer` in this 
+        `ScrollablePane`. (Otherwise, it's possible that the completion menu 
+        is clipped.) 
+ 
+    :param content: The content container. 
+    :param scrolloffset: Try to keep the cursor within this distance from the 
+        top/bottom (left/right offset is not used). 
+    :param keep_cursor_visible: When `True`, automatically scroll the pane so 
+        that the cursor (of the focused window) is always visible. 
+    :param keep_focused_window_visible: When `True`, automatically scroll th e 
+        pane so that the focused window is visible, or as much visible as 
+        possible if it doen't completely fit the screen. 
+    :param max_available_height: Always constraint the height to this amount 
+        for performance reasons. 
+    :param width: When given, use this width instead of looking at the children. 
+    :param height: When given, use this height instead of looking at the children. 
+    :param show_scrollbar: When `True` display a scrollbar on the right. 
+    """ 
+ 
+    def __init__( 
+        self, 
+        content: Container, 
+        scroll_offsets: Optional[ScrollOffsets] = None, 
+        keep_cursor_visible: FilterOrBool = True, 
+        keep_focused_window_visible: FilterOrBool = True, 
+        max_available_height: int = MAX_AVAILABLE_HEIGHT, 
+        width: AnyDimension = None, 
+        height: AnyDimension = None, 
+        show_scrollbar: FilterOrBool = True, 
+        display_arrows: FilterOrBool = True, 
+        up_arrow_symbol: str = "^", 
+        down_arrow_symbol: str = "v", 
+    ) -> None: 
+        self.content = content 
+        self.scroll_offsets = scroll_offsets or ScrollOffsets(top=1, bottom=1) 
+        self.keep_cursor_visible = to_filter(keep_cursor_visible) 
+        self.keep_focused_window_visible = to_filter(keep_focused_window_visible) 
+        self.max_available_height = max_available_height 
+        self.width = width 
+        self.height = height 
+        self.show_scrollbar = to_filter(show_scrollbar) 
+        self.display_arrows = to_filter(display_arrows) 
+        self.up_arrow_symbol = up_arrow_symbol 
+        self.down_arrow_symbol = down_arrow_symbol 
+ 
+        self.vertical_scroll = 0 
+ 
+    def __repr__(self) -> str: 
+        return f"ScrollablePane({self.content!r})" 
+ 
+    def reset(self) -> None: 
+        self.content.reset() 
+ 
+    def preferred_width(self, max_available_width: int) -> Dimension: 
+        if self.width is not None: 
+            return to_dimension(self.width) 
+ 
+        # We're only scrolling vertical. So the preferred width is equal to 
+        # that of the content. 
+        content_width = self.content.preferred_width(max_available_width) 
+ 
+        # If a scrollbar needs to be displayed, add +1 to the content width. 
+        if self.show_scrollbar(): 
+            return sum_layout_dimensions([Dimension.exact(1), content_width]) 
+ 
+        return content_width 
+ 
+    def preferred_height(self, width: int, max_available_height: int) -> Dimension: 
+        if self.height is not None: 
+            return to_dimension(self.height) 
+ 
+        # Prefer a height large enough so that it fits all the content. If not, 
+        # we'll make the pane scrollable. 
+        if self.show_scrollbar(): 
+            # If `show_scrollbar` is set. Always reserve space for the scrollbar. 
+            width -= 1 
+ 
+        dimension = self.content.preferred_height(width, self.max_available_height) 
+ 
+        # Only take 'preferred' into account. Min/max can be anything. 
+        return Dimension(min=0, preferred=dimension.preferred) 
+ 
+    def write_to_screen( 
+        self, 
+        screen: Screen, 
+        mouse_handlers: MouseHandlers, 
+        write_position: WritePosition, 
+        parent_style: str, 
+        erase_bg: bool, 
+        z_index: Optional[int], 
+    ) -> None: 
+        """ 
+        Render scrollable pane content. 
+ 
+        This works by rendering on an off-screen canvas, and copying over the 
+        visible region. 
+        """ 
+        show_scrollbar = self.show_scrollbar() 
+ 
+        if show_scrollbar: 
+            virtual_width = write_position.width - 1 
+        else: 
+            virtual_width = write_position.width 
+ 
+        # Compute preferred height again. 
+        virtual_height = self.content.preferred_height( 
+            virtual_width, self.max_available_height 
+        ).preferred 
+ 
+        # Ensure virtual height is at least the available height. 
+        virtual_height = max(virtual_height, write_position.height) 
+        virtual_height = min(virtual_height, self.max_available_height) 
+ 
+        # First, write the content to a virtual screen, then copy over the 
+        # visible part to the real screen. 
+        temp_screen = Screen(default_char=Char(char=" ", style=parent_style)) 
+        temp_write_position = WritePosition( 
+            xpos=0, ypos=0, width=virtual_width, height=virtual_height 
+        ) 
+ 
+        temp_mouse_handlers = MouseHandlers() 
+ 
+        self.content.write_to_screen( 
+            temp_screen, 
+            temp_mouse_handlers, 
+            temp_write_position, 
+            parent_style, 
+            erase_bg, 
+            z_index, 
+        ) 
+        temp_screen.draw_all_floats() 
+ 
+        # If anything in the virtual screen is focused, move vertical scroll to 
+        from prompt_toolkit.application import get_app 
+ 
+        focused_window = get_app().layout.current_window 
+ 
+        try: 
+            visible_win_write_pos = temp_screen.visible_windows_to_write_positions[ 
+                focused_window 
+            ] 
+        except KeyError: 
+            pass  # No window focused here. Don't scroll. 
+        else: 
+            # Make sure this window is visible. 
+            self._make_window_visible( 
+                write_position.height, 
+                virtual_height, 
+                visible_win_write_pos, 
+                temp_screen.cursor_positions.get(focused_window), 
+            ) 
+ 
+        # Copy over virtual screen and zero width escapes to real screen. 
+        self._copy_over_screen(screen, temp_screen, write_position, virtual_width) 
+ 
+        # Copy over mouse handlers. 
+        self._copy_over_mouse_handlers( 
+            mouse_handlers, temp_mouse_handlers, write_position, virtual_width 
+        ) 
+ 
+        # Set screen.width/height. 
+        ypos = write_position.ypos 
+        xpos = write_position.xpos 
+ 
+        screen.width = max(screen.width, xpos + virtual_width) 
+        screen.height = max(screen.height, ypos + write_position.height) 
+ 
+        # Copy over window write positions. 
+        self._copy_over_write_positions(screen, temp_screen, write_position) 
+ 
+        if temp_screen.show_cursor: 
+            screen.show_cursor = True 
+ 
+        # Copy over cursor positions, if they are visible. 
+        for window, point in temp_screen.cursor_positions.items(): 
+            if ( 
+                0 <= point.x < write_position.width 
+                and self.vertical_scroll 
+                <= point.y 
+                < write_position.height + self.vertical_scroll 
+            ): 
+                screen.cursor_positions[window] = Point( 
+                    x=point.x + xpos, y=point.y + ypos - self.vertical_scroll 
+                ) 
+ 
+        # Copy over menu positions, but clip them to the visible area. 
+        for window, point in temp_screen.menu_positions.items(): 
+            screen.menu_positions[window] = self._clip_point_to_visible_area( 
+                Point(x=point.x + xpos, y=point.y + ypos - self.vertical_scroll), 
+                write_position, 
+            ) 
+ 
+        # Draw scrollbar. 
+        if show_scrollbar: 
+            self._draw_scrollbar( 
+                write_position, 
+                virtual_height, 
+                screen, 
+            ) 
+ 
+    def _clip_point_to_visible_area( 
+        self, point: Point, write_position: WritePosition 
+    ) -> Point: 
+        """ 
+        Ensure that the cursor and menu positions always are always reported 
+        """ 
+        if point.x < write_position.xpos: 
+            point = point._replace(x=write_position.xpos) 
+        if point.y < write_position.ypos: 
+            point = point._replace(y=write_position.ypos) 
+        if point.x >= write_position.xpos + write_position.width: 
+            point = point._replace(x=write_position.xpos + write_position.width - 1) 
+        if point.y >= write_position.ypos + write_position.height: 
+            point = point._replace(y=write_position.ypos + write_position.height - 1) 
+ 
+        return point 
+ 
+    def _copy_over_screen( 
+        self, 
+        screen: Screen, 
+        temp_screen: Screen, 
+        write_position: WritePosition, 
+        virtual_width: int, 
+    ) -> None: 
+        """ 
+        Copy over visible screen content and "zero width escape sequences". 
+        """ 
+        ypos = write_position.ypos 
+        xpos = write_position.xpos 
+ 
+        for y in range(write_position.height): 
+            temp_row = temp_screen.data_buffer[y + self.vertical_scroll] 
+            row = screen.data_buffer[y + ypos] 
+            temp_zero_width_escapes = temp_screen.zero_width_escapes[ 
+                y + self.vertical_scroll 
+            ] 
+            zero_width_escapes = screen.zero_width_escapes[y + ypos] 
+ 
+            for x in range(virtual_width): 
+                row[x + xpos] = temp_row[x] 
+ 
+                if x in temp_zero_width_escapes: 
+                    zero_width_escapes[x + xpos] = temp_zero_width_escapes[x] 
+ 
+    def _copy_over_mouse_handlers( 
+        self, 
+        mouse_handlers: MouseHandlers, 
+        temp_mouse_handlers: MouseHandlers, 
+        write_position: WritePosition, 
+        virtual_width: int, 
+    ) -> None: 
+        """ 
+        Copy over mouse handlers from virtual screen to real screen. 
+ 
+        Note: we take `virtual_width` because we don't want to copy over mouse 
+              handlers that we possibly have behind the scrollbar. 
+        """ 
+        ypos = write_position.ypos 
+        xpos = write_position.xpos 
+ 
+        # Cache mouse handlers when wrapping them. Very often the same mouse 
+        # handler is registered for many positions. 
+        mouse_handler_wrappers: Dict[MouseHandler, MouseHandler] = {} 
+ 
+        def wrap_mouse_handler(handler: MouseHandler) -> MouseHandler: 
+            "Wrap mouse handler. Translate coordinates in `MouseEvent`." 
+            if handler not in mouse_handler_wrappers: 
+ 
+                def new_handler(event: MouseEvent) -> None: 
+                    new_event = MouseEvent( 
+                        position=Point( 
+                            x=event.position.x - xpos, 
+                            y=event.position.y + self.vertical_scroll - ypos, 
+                        ), 
+                        event_type=event.event_type, 
+                        button=event.button, 
+                        modifiers=event.modifiers, 
+                    ) 
+                    handler(new_event) 
+ 
+                mouse_handler_wrappers[handler] = new_handler 
+            return mouse_handler_wrappers[handler] 
+ 
+        # Copy handlers. 
+        mouse_handlers_dict = mouse_handlers.mouse_handlers 
+        temp_mouse_handlers_dict = temp_mouse_handlers.mouse_handlers 
+ 
+        for y in range(write_position.height): 
+            if y in temp_mouse_handlers_dict: 
+                temp_mouse_row = temp_mouse_handlers_dict[y + self.vertical_scroll] 
+                mouse_row = mouse_handlers_dict[y + ypos] 
+                for x in range(virtual_width): 
+                    if x in temp_mouse_row: 
+                        mouse_row[x + xpos] = wrap_mouse_handler(temp_mouse_row[x]) 
+ 
+    def _copy_over_write_positions( 
+        self, screen: Screen, temp_screen: Screen, write_position: WritePosition 
+    ) -> None: 
+        """ 
+        Copy over window write positions. 
+        """ 
+        ypos = write_position.ypos 
+        xpos = write_position.xpos 
+ 
+        for win, write_pos in temp_screen.visible_windows_to_write_positions.items(): 
+            screen.visible_windows_to_write_positions[win] = WritePosition( 
+                xpos=write_pos.xpos + xpos, 
+                ypos=write_pos.ypos + ypos - self.vertical_scroll, 
+                # TODO: if the window is only partly visible, then truncate width/height. 
+                #       This could be important if we have nested ScrollablePanes. 
+                height=write_pos.height, 
+                width=write_pos.width, 
+            ) 
+ 
+    def is_modal(self) -> bool: 
+        return self.content.is_modal() 
+ 
+    def get_key_bindings(self) -> Optional[KeyBindingsBase]: 
+        return self.content.get_key_bindings() 
+ 
+    def get_children(self) -> List["Container"]: 
+        return [self.content] 
+ 
+    def _make_window_visible( 
+        self, 
+        visible_height: int, 
+        virtual_height: int, 
+        visible_win_write_pos: WritePosition, 
+        cursor_position: Optional[Point], 
+    ) -> None: 
+        """ 
+        Scroll the scrollable pane, so that this window becomes visible. 
+ 
+        :param visible_height: Height of this `ScrollablePane` that is rendered. 
+        :param virtual_height: Height of the virtual, temp screen. 
+        :param visible_win_write_pos: `WritePosition` of the nested window on the 
+            temp screen. 
+        :param cursor_position: The location of the cursor position of this 
+            window on the temp screen. 
+        """ 
+        # Start with maximum allowed scroll range, and then reduce according to 
+        # the focused window and cursor position. 
+        min_scroll = 0 
+        max_scroll = virtual_height - visible_height 
+ 
+        if self.keep_cursor_visible(): 
+            # Reduce min/max scroll according to the cursor in the focused window. 
+            if cursor_position is not None: 
+                offsets = self.scroll_offsets 
+                cpos_min_scroll = ( 
+                    cursor_position.y - visible_height + 1 + offsets.bottom 
+                ) 
+                cpos_max_scroll = cursor_position.y - offsets.top 
+                min_scroll = max(min_scroll, cpos_min_scroll) 
+                max_scroll = max(0, min(max_scroll, cpos_max_scroll)) 
+ 
+        if self.keep_focused_window_visible(): 
+            # Reduce min/max scroll according to focused window position. 
+            # If the window is small enough, bot the top and bottom of the window 
+            # should be visible. 
+            if visible_win_write_pos.height <= visible_height: 
+                window_min_scroll = ( 
+                    visible_win_write_pos.ypos 
+                    + visible_win_write_pos.height 
+                    - visible_height 
+                ) 
+                window_max_scroll = visible_win_write_pos.ypos 
+            else: 
+                # Window does not fit on the screen. Make sure at least the whole 
+                # screen is occupied with this window, and nothing else is shown. 
+                window_min_scroll = visible_win_write_pos.ypos 
+                window_max_scroll = ( 
+                    visible_win_write_pos.ypos 
+                    + visible_win_write_pos.height 
+                    - visible_height 
+                ) 
+ 
+            min_scroll = max(min_scroll, window_min_scroll) 
+            max_scroll = min(max_scroll, window_max_scroll) 
+ 
+        if min_scroll > max_scroll: 
+            min_scroll = max_scroll  # Should not happen. 
+ 
+        # Finally, properly clip the vertical scroll. 
+        if self.vertical_scroll > max_scroll: 
+            self.vertical_scroll = max_scroll 
+        if self.vertical_scroll < min_scroll: 
+            self.vertical_scroll = min_scroll 
+ 
+    def _draw_scrollbar( 
+        self, write_position: WritePosition, content_height: int, screen: Screen 
+    ) -> None: 
+        """ 
+        Draw the scrollbar on the screen. 
+ 
+        Note: There is some code duplication with the `ScrollbarMargin` 
+              implementation. 
+        """ 
+ 
+        window_height = write_position.height 
+        display_arrows = self.display_arrows() 
+ 
+        if display_arrows: 
+            window_height -= 2 
+ 
+        try: 
+            fraction_visible = write_position.height / float(content_height) 
+            fraction_above = self.vertical_scroll / float(content_height) 
+ 
+            scrollbar_height = int( 
+                min(window_height, max(1, window_height * fraction_visible)) 
+            ) 
+            scrollbar_top = int(window_height * fraction_above) 
+        except ZeroDivisionError: 
+            return 
+        else: 
+ 
+            def is_scroll_button(row: int) -> bool: 
+                "True if we should display a button on this row." 
+                return scrollbar_top <= row <= scrollbar_top + scrollbar_height 
+ 
+            xpos = write_position.xpos + write_position.width - 1 
+            ypos = write_position.ypos 
+            data_buffer = screen.data_buffer 
+ 
+            # Up arrow. 
+            if display_arrows: 
+                data_buffer[ypos][xpos] = Char( 
+                    self.up_arrow_symbol, "class:scrollbar.arrow" 
+                ) 
+                ypos += 1 
+ 
+            # Scrollbar body. 
+            scrollbar_background = "class:scrollbar.background" 
+            scrollbar_background_start = "class:scrollbar.background,scrollbar.start" 
+            scrollbar_button = "class:scrollbar.button" 
+            scrollbar_button_end = "class:scrollbar.button,scrollbar.end" 
+ 
+            for i in range(window_height): 
+                style = "" 
+                if is_scroll_button(i): 
+                    if not is_scroll_button(i + 1): 
+                        # Give the last cell a different style, because we want 
+                        # to underline this. 
+                        style = scrollbar_button_end 
+                    else: 
+                        style = scrollbar_button 
+                else: 
+                    if is_scroll_button(i + 1): 
+                        style = scrollbar_background_start 
+                    else: 
+                        style = scrollbar_background 
+ 
+                data_buffer[ypos][xpos] = Char(" ", style) 
+                ypos += 1 
+ 
+            # Down arrow 
+            if display_arrows: 
+                data_buffer[ypos][xpos] = Char( 
+                    self.down_arrow_symbol, "class:scrollbar.arrow" 
+                )