Adding upstream version 3.0.36.upstream/3.0.36upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 813 insertions, 0 deletions

diff --git a/src/prompt_toolkit/renderer.py b/src/prompt_toolkit/renderer.py
new file mode 100644
index 0000000..d9bb171
--- /dev/null
+++ b/src/prompt_toolkit/renderer.py
@@ -0,0 +1,813 @@
+"""
+Renders the command line on the console.
+(Redraws parts of the input line that were changed.)
+"""
+from asyncio import FIRST_COMPLETED, Future, ensure_future, sleep, wait
+from collections import deque
+from enum import Enum
+from typing import TYPE_CHECKING, Any, Callable, Deque, Dict, Hashable, Optional, Tuple
+
+from prompt_toolkit.application.current import get_app
+from prompt_toolkit.cursor_shapes import CursorShape
+from prompt_toolkit.data_structures import Point, Size
+from prompt_toolkit.filters import FilterOrBool, to_filter
+from prompt_toolkit.formatted_text import AnyFormattedText, to_formatted_text
+from prompt_toolkit.layout.mouse_handlers import MouseHandlers
+from prompt_toolkit.layout.screen import Char, Screen, WritePosition
+from prompt_toolkit.output import ColorDepth, Output
+from prompt_toolkit.styles import (
+    Attrs,
+    BaseStyle,
+    DummyStyleTransformation,
+    StyleTransformation,
+)
+
+if TYPE_CHECKING:
+    from prompt_toolkit.application import Application
+    from prompt_toolkit.layout.layout import Layout
+
+
+__all__ = [
+    "Renderer",
+    "print_formatted_text",
+]
+
+
+def _output_screen_diff(
+    app: "Application[Any]",
+    output: Output,
+    screen: Screen,
+    current_pos: Point,
+    color_depth: ColorDepth,
+    previous_screen: Optional[Screen],
+    last_style: Optional[str],
+    is_done: bool,  # XXX: drop is_done
+    full_screen: bool,
+    attrs_for_style_string: "_StyleStringToAttrsCache",
+    style_string_has_style: "_StyleStringHasStyleCache",
+    size: Size,
+    previous_width: int,
+) -> Tuple[Point, Optional[str]]:
+    """
+    Render the diff between this screen and the previous screen.
+
+    This takes two `Screen` instances. The one that represents the output like
+    it was during the last rendering and one that represents the current
+    output raster. Looking at these two `Screen` instances, this function will
+    render the difference by calling the appropriate methods of the `Output`
+    object that only paint the changes to the terminal.
+
+    This is some performance-critical code which is heavily optimized.
+    Don't change things without profiling first.
+
+    :param current_pos: Current cursor position.
+    :param last_style: The style string, used for drawing the last drawn
+        character.  (Color/attributes.)
+    :param attrs_for_style_string: :class:`._StyleStringToAttrsCache` instance.
+    :param width: The width of the terminal.
+    :param previous_width: The width of the terminal during the last rendering.
+    """
+    width, height = size.columns, size.rows
+
+    #: Variable for capturing the output.
+    write = output.write
+    write_raw = output.write_raw
+
+    # Create locals for the most used output methods.
+    # (Save expensive attribute lookups.)
+    _output_set_attributes = output.set_attributes
+    _output_reset_attributes = output.reset_attributes
+    _output_cursor_forward = output.cursor_forward
+    _output_cursor_up = output.cursor_up
+    _output_cursor_backward = output.cursor_backward
+
+    # Hide cursor before rendering. (Avoid flickering.)
+    output.hide_cursor()
+
+    def reset_attributes() -> None:
+        "Wrapper around Output.reset_attributes."
+        nonlocal last_style
+        _output_reset_attributes()
+        last_style = None  # Forget last char after resetting attributes.
+
+    def move_cursor(new: Point) -> Point:
+        "Move cursor to this `new` point. Returns the given Point."
+        current_x, current_y = current_pos.x, current_pos.y
+
+        if new.y > current_y:
+            # Use newlines instead of CURSOR_DOWN, because this might add new lines.
+            # CURSOR_DOWN will never create new lines at the bottom.
+            # Also reset attributes, otherwise the newline could draw a
+            # background color.
+            reset_attributes()
+            write("\r\n" * (new.y - current_y))
+            current_x = 0
+            _output_cursor_forward(new.x)
+            return new
+        elif new.y < current_y:
+            _output_cursor_up(current_y - new.y)
+
+        if current_x >= width - 1:
+            write("\r")
+            _output_cursor_forward(new.x)
+        elif new.x < current_x or current_x >= width - 1:
+            _output_cursor_backward(current_x - new.x)
+        elif new.x > current_x:
+            _output_cursor_forward(new.x - current_x)
+
+        return new
+
+    def output_char(char: Char) -> None:
+        """
+        Write the output of this character.
+        """
+        nonlocal last_style
+
+        # If the last printed character has the same style, don't output the
+        # style again.
+        if last_style == char.style:
+            write(char.char)
+        else:
+            # Look up `Attr` for this style string. Only set attributes if different.
+            # (Two style strings can still have the same formatting.)
+            # Note that an empty style string can have formatting that needs to
+            # be applied, because of style transformations.
+            new_attrs = attrs_for_style_string[char.style]
+            if not last_style or new_attrs != attrs_for_style_string[last_style]:
+                _output_set_attributes(new_attrs, color_depth)
+
+            write(char.char)
+            last_style = char.style
+
+    def get_max_column_index(row: Dict[int, Char]) -> int:
+        """
+        Return max used column index, ignoring whitespace (without style) at
+        the end of the line. This is important for people that copy/paste
+        terminal output.
+
+        There are two reasons we are sometimes seeing whitespace at the end:
+        - `BufferControl` adds a trailing space to each line, because it's a
+          possible cursor position, so that the line wrapping won't change if
+          the cursor position moves around.
+        - The `Window` adds a style class to the current line for highlighting
+          (cursor-line).
+        """
+        numbers = (
+            index
+            for index, cell in row.items()
+            if cell.char != " " or style_string_has_style[cell.style]
+        )
+        return max(numbers, default=0)
+
+    # Render for the first time: reset styling.
+    if not previous_screen:
+        reset_attributes()
+
+    # Disable autowrap. (When entering a the alternate screen, or anytime when
+    # we have a prompt. - In the case of a REPL, like IPython, people can have
+    # background threads, and it's hard for debugging if their output is not
+    # wrapped.)
+    if not previous_screen or not full_screen:
+        output.disable_autowrap()
+
+    # When the previous screen has a different size, redraw everything anyway.
+    # Also when we are done. (We might take up less rows, so clearing is important.)
+    if (
+        is_done or not previous_screen or previous_width != width
+    ):  # XXX: also consider height??
+        current_pos = move_cursor(Point(x=0, y=0))
+        reset_attributes()
+        output.erase_down()
+
+        previous_screen = Screen()
+
+    # Get height of the screen.
+    # (height changes as we loop over data_buffer, so remember the current value.)
+    # (Also make sure to clip the height to the size of the output.)
+    current_height = min(screen.height, height)
+
+    # Loop over the rows.
+    row_count = min(max(screen.height, previous_screen.height), height)
+
+    for y in range(row_count):
+        new_row = screen.data_buffer[y]
+        previous_row = previous_screen.data_buffer[y]
+        zero_width_escapes_row = screen.zero_width_escapes[y]
+
+        new_max_line_len = min(width - 1, get_max_column_index(new_row))
+        previous_max_line_len = min(width - 1, get_max_column_index(previous_row))
+
+        # Loop over the columns.
+        c = 0  # Column counter.
+        while c <= new_max_line_len:
+            new_char = new_row[c]
+            old_char = previous_row[c]
+            char_width = new_char.width or 1
+
+            # When the old and new character at this position are different,
+            # draw the output. (Because of the performance, we don't call
+            # `Char.__ne__`, but inline the same expression.)
+            if new_char.char != old_char.char or new_char.style != old_char.style:
+                current_pos = move_cursor(Point(x=c, y=y))
+
+                # Send injected escape sequences to output.
+                if c in zero_width_escapes_row:
+                    write_raw(zero_width_escapes_row[c])
+
+                output_char(new_char)
+                current_pos = Point(x=current_pos.x + char_width, y=current_pos.y)
+
+            c += char_width
+
+        # If the new line is shorter, trim it.
+        if previous_screen and new_max_line_len < previous_max_line_len:
+            current_pos = move_cursor(Point(x=new_max_line_len + 1, y=y))
+            reset_attributes()
+            output.erase_end_of_line()
+
+    # Correctly reserve vertical space as required by the layout.
+    # When this is a new screen (drawn for the first time), or for some reason
+    # higher than the previous one. Move the cursor once to the bottom of the
+    # output. That way, we're sure that the terminal scrolls up, even when the
+    # lower lines of the canvas just contain whitespace.
+
+    # The most obvious reason that we actually want this behaviour is the avoid
+    # the artifact of the input scrolling when the completion menu is shown.
+    # (If the scrolling is actually wanted, the layout can still be build in a
+    # way to behave that way by setting a dynamic height.)
+    if current_height > previous_screen.height:
+        current_pos = move_cursor(Point(x=0, y=current_height - 1))
+
+    # Move cursor:
+    if is_done:
+        current_pos = move_cursor(Point(x=0, y=current_height))
+        output.erase_down()
+    else:
+        current_pos = move_cursor(screen.get_cursor_position(app.layout.current_window))
+
+    if is_done or not full_screen:
+        output.enable_autowrap()
+
+    # Always reset the color attributes. This is important because a background
+    # thread could print data to stdout and we want that to be displayed in the
+    # default colors. (Also, if a background color has been set, many terminals
+    # give weird artifacts on resize events.)
+    reset_attributes()
+
+    if screen.show_cursor or is_done:
+        output.show_cursor()
+
+    return current_pos, last_style
+
+
+class HeightIsUnknownError(Exception):
+    "Information unavailable. Did not yet receive the CPR response."
+
+
+class _StyleStringToAttrsCache(Dict[str, Attrs]):
+    """
+    A cache structure that maps style strings to :class:`.Attr`.
+    (This is an important speed up.)
+    """
+
+    def __init__(
+        self,
+        get_attrs_for_style_str: Callable[["str"], Attrs],
+        style_transformation: StyleTransformation,
+    ) -> None:
+
+        self.get_attrs_for_style_str = get_attrs_for_style_str
+        self.style_transformation = style_transformation
+
+    def __missing__(self, style_str: str) -> Attrs:
+        attrs = self.get_attrs_for_style_str(style_str)
+        attrs = self.style_transformation.transform_attrs(attrs)
+
+        self[style_str] = attrs
+        return attrs
+
+
+class _StyleStringHasStyleCache(Dict[str, bool]):
+    """
+    Cache for remember which style strings don't render the default output
+    style (default fg/bg, no underline and no reverse and no blink). That way
+    we know that we should render these cells, even when they're empty (when
+    they contain a space).
+
+    Note: we don't consider bold/italic/hidden because they don't change the
+    output if there's no text in the cell.
+    """
+
+    def __init__(self, style_string_to_attrs: Dict[str, Attrs]) -> None:
+        self.style_string_to_attrs = style_string_to_attrs
+
+    def __missing__(self, style_str: str) -> bool:
+        attrs = self.style_string_to_attrs[style_str]
+        is_default = bool(
+            attrs.color
+            or attrs.bgcolor
+            or attrs.underline
+            or attrs.strike
+            or attrs.blink
+            or attrs.reverse
+        )
+
+        self[style_str] = is_default
+        return is_default
+
+
+class CPR_Support(Enum):
+    "Enum: whether or not CPR is supported."
+    SUPPORTED = "SUPPORTED"
+    NOT_SUPPORTED = "NOT_SUPPORTED"
+    UNKNOWN = "UNKNOWN"
+
+
+class Renderer:
+    """
+    Typical usage:
+
+    ::
+
+        output = Vt100_Output.from_pty(sys.stdout)
+        r = Renderer(style, output)
+        r.render(app, layout=...)
+    """
+
+    CPR_TIMEOUT = 2  # Time to wait until we consider CPR to be not supported.
+
+    def __init__(
+        self,
+        style: BaseStyle,
+        output: Output,
+        full_screen: bool = False,
+        mouse_support: FilterOrBool = False,
+        cpr_not_supported_callback: Optional[Callable[[], None]] = None,
+    ) -> None:
+
+        self.style = style
+        self.output = output
+        self.full_screen = full_screen
+        self.mouse_support = to_filter(mouse_support)
+        self.cpr_not_supported_callback = cpr_not_supported_callback
+
+        self._in_alternate_screen = False
+        self._mouse_support_enabled = False
+        self._bracketed_paste_enabled = False
+        self._cursor_key_mode_reset = False
+
+        # Future set when we are waiting for a CPR flag.
+        self._waiting_for_cpr_futures: Deque[Future[None]] = deque()
+        self.cpr_support = CPR_Support.UNKNOWN
+
+        if not output.responds_to_cpr:
+            self.cpr_support = CPR_Support.NOT_SUPPORTED
+
+        # Cache for the style.
+        self._attrs_for_style: Optional[_StyleStringToAttrsCache] = None
+        self._style_string_has_style: Optional[_StyleStringHasStyleCache] = None
+        self._last_style_hash: Optional[Hashable] = None
+        self._last_transformation_hash: Optional[Hashable] = None
+        self._last_color_depth: Optional[ColorDepth] = None
+
+        self.reset(_scroll=True)
+
+    def reset(self, _scroll: bool = False, leave_alternate_screen: bool = True) -> None:
+
+        # Reset position
+        self._cursor_pos = Point(x=0, y=0)
+
+        # Remember the last screen instance between renderers. This way,
+        # we can create a `diff` between two screens and only output the
+        # difference. It's also to remember the last height. (To show for
+        # instance a toolbar at the bottom position.)
+        self._last_screen: Optional[Screen] = None
+        self._last_size: Optional[Size] = None
+        self._last_style: Optional[str] = None
+        self._last_cursor_shape: Optional[CursorShape] = None
+
+        # Default MouseHandlers. (Just empty.)
+        self.mouse_handlers = MouseHandlers()
+
+        #: Space from the top of the layout, until the bottom of the terminal.
+        #: We don't know this until a `report_absolute_cursor_row` call.
+        self._min_available_height = 0
+
+        # In case of Windows, also make sure to scroll to the current cursor
+        # position. (Only when rendering the first time.)
+        # It does nothing for vt100 terminals.
+        if _scroll:
+            self.output.scroll_buffer_to_prompt()
+
+        # Quit alternate screen.
+        if self._in_alternate_screen and leave_alternate_screen:
+            self.output.quit_alternate_screen()
+            self._in_alternate_screen = False
+
+        # Disable mouse support.
+        if self._mouse_support_enabled:
+            self.output.disable_mouse_support()
+            self._mouse_support_enabled = False
+
+        # Disable bracketed paste.
+        if self._bracketed_paste_enabled:
+            self.output.disable_bracketed_paste()
+            self._bracketed_paste_enabled = False
+
+        self.output.reset_cursor_shape()
+
+        # NOTE: No need to set/reset cursor key mode here.
+
+        # Flush output. `disable_mouse_support` needs to write to stdout.
+        self.output.flush()
+
+    @property
+    def last_rendered_screen(self) -> Optional[Screen]:
+        """
+        The `Screen` class that was generated during the last rendering.
+        This can be `None`.
+        """
+        return self._last_screen
+
+    @property
+    def height_is_known(self) -> bool:
+        """
+        True when the height from the cursor until the bottom of the terminal
+        is known. (It's often nicer to draw bottom toolbars only if the height
+        is known, in order to avoid flickering when the CPR response arrives.)
+        """
+        if self.full_screen or self._min_available_height > 0:
+            return True
+        try:
+            self._min_available_height = self.output.get_rows_below_cursor_position()
+            return True
+        except NotImplementedError:
+            return False
+
+    @property
+    def rows_above_layout(self) -> int:
+        """
+        Return the number of rows visible in the terminal above the layout.
+        """
+        if self._in_alternate_screen:
+            return 0
+        elif self._min_available_height > 0:
+            total_rows = self.output.get_size().rows
+            last_screen_height = self._last_screen.height if self._last_screen else 0
+            return total_rows - max(self._min_available_height, last_screen_height)
+        else:
+            raise HeightIsUnknownError("Rows above layout is unknown.")
+
+    def request_absolute_cursor_position(self) -> None:
+        """
+        Get current cursor position.
+
+        We do this to calculate the minimum available height that we can
+        consume for rendering the prompt. This is the available space below te
+        cursor.
+
+        For vt100: Do CPR request. (answer will arrive later.)
+        For win32: Do API call. (Answer comes immediately.)
+        """
+        # Only do this request when the cursor is at the top row. (after a
+        # clear or reset). We will rely on that in `report_absolute_cursor_row`.
+        assert self._cursor_pos.y == 0
+
+        # In full-screen mode, always use the total height as min-available-height.
+        if self.full_screen:
+            self._min_available_height = self.output.get_size().rows
+            return
+
+        # For Win32, we have an API call to get the number of rows below the
+        # cursor.
+        try:
+            self._min_available_height = self.output.get_rows_below_cursor_position()
+            return
+        except NotImplementedError:
+            pass
+
+        # Use CPR.
+        if self.cpr_support == CPR_Support.NOT_SUPPORTED:
+            return
+
+        def do_cpr() -> None:
+            # Asks for a cursor position report (CPR).
+            self._waiting_for_cpr_futures.append(Future())
+            self.output.ask_for_cpr()
+
+        if self.cpr_support == CPR_Support.SUPPORTED:
+            do_cpr()
+            return
+
+        # If we don't know whether CPR is supported, only do a request if
+        # none is pending, and test it, using a timer.
+        if self.waiting_for_cpr:
+            return
+
+        do_cpr()
+
+        async def timer() -> None:
+            await sleep(self.CPR_TIMEOUT)
+
+            # Not set in the meantime -> not supported.
+            if self.cpr_support == CPR_Support.UNKNOWN:
+                self.cpr_support = CPR_Support.NOT_SUPPORTED
+
+                if self.cpr_not_supported_callback:
+                    # Make sure to call this callback in the main thread.
+                    self.cpr_not_supported_callback()
+
+        get_app().create_background_task(timer())
+
+    def report_absolute_cursor_row(self, row: int) -> None:
+        """
+        To be called when we know the absolute cursor position.
+        (As an answer of a "Cursor Position Request" response.)
+        """
+        self.cpr_support = CPR_Support.SUPPORTED
+
+        # Calculate the amount of rows from the cursor position until the
+        # bottom of the terminal.
+        total_rows = self.output.get_size().rows
+        rows_below_cursor = total_rows - row + 1
+
+        # Set the minimum available height.
+        self._min_available_height = rows_below_cursor
+
+        # Pop and set waiting for CPR future.
+        try:
+            f = self._waiting_for_cpr_futures.popleft()
+        except IndexError:
+            pass  # Received CPR response without having a CPR.
+        else:
+            f.set_result(None)
+
+    @property
+    def waiting_for_cpr(self) -> bool:
+        """
+        Waiting for CPR flag. True when we send the request, but didn't got a
+        response.
+        """
+        return bool(self._waiting_for_cpr_futures)
+
+    async def wait_for_cpr_responses(self, timeout: int = 1) -> None:
+        """
+        Wait for a CPR response.
+        """
+        cpr_futures = list(self._waiting_for_cpr_futures)  # Make copy.
+
+        # When there are no CPRs in the queue. Don't do anything.
+        if not cpr_futures or self.cpr_support == CPR_Support.NOT_SUPPORTED:
+            return None
+
+        async def wait_for_responses() -> None:
+            for response_f in cpr_futures:
+                await response_f
+
+        async def wait_for_timeout() -> None:
+            await sleep(timeout)
+
+            # Got timeout, erase queue.
+            for response_f in cpr_futures:
+                response_f.cancel()
+            self._waiting_for_cpr_futures = deque()
+
+        tasks = {
+            ensure_future(wait_for_responses()),
+            ensure_future(wait_for_timeout()),
+        }
+        _, pending = await wait(tasks, return_when=FIRST_COMPLETED)
+        for task in pending:
+            task.cancel()
+
+    def render(
+        self, app: "Application[Any]", layout: "Layout", is_done: bool = False
+    ) -> None:
+        """
+        Render the current interface to the output.
+
+        :param is_done: When True, put the cursor at the end of the interface. We
+                won't print any changes to this part.
+        """
+        output = self.output
+
+        # Enter alternate screen.
+        if self.full_screen and not self._in_alternate_screen:
+            self._in_alternate_screen = True
+            output.enter_alternate_screen()
+
+        # Enable bracketed paste.
+        if not self._bracketed_paste_enabled:
+            self.output.enable_bracketed_paste()
+            self._bracketed_paste_enabled = True
+
+        # Reset cursor key mode.
+        if not self._cursor_key_mode_reset:
+            self.output.reset_cursor_key_mode()
+            self._cursor_key_mode_reset = True
+
+        # Enable/disable mouse support.
+        needs_mouse_support = self.mouse_support()
+
+        if needs_mouse_support and not self._mouse_support_enabled:
+            output.enable_mouse_support()
+            self._mouse_support_enabled = True
+
+        elif not needs_mouse_support and self._mouse_support_enabled:
+            output.disable_mouse_support()
+            self._mouse_support_enabled = False
+
+        # Create screen and write layout to it.
+        size = output.get_size()
+        screen = Screen()
+        screen.show_cursor = False  # Hide cursor by default, unless one of the
+        # containers decides to display it.
+        mouse_handlers = MouseHandlers()
+
+        # Calculate height.
+        if self.full_screen:
+            height = size.rows
+        elif is_done:
+            # When we are done, we don't necessary want to fill up until the bottom.
+            height = layout.container.preferred_height(
+                size.columns, size.rows
+            ).preferred
+        else:
+            last_height = self._last_screen.height if self._last_screen else 0
+            height = max(
+                self._min_available_height,
+                last_height,
+                layout.container.preferred_height(size.columns, size.rows).preferred,
+            )
+
+        height = min(height, size.rows)
+
+        # When the size changes, don't consider the previous screen.
+        if self._last_size != size:
+            self._last_screen = None
+
+        # When we render using another style or another color depth, do a full
+        # repaint. (Forget about the previous rendered screen.)
+        # (But note that we still use _last_screen to calculate the height.)
+        if (
+            self.style.invalidation_hash() != self._last_style_hash
+            or app.style_transformation.invalidation_hash()
+            != self._last_transformation_hash
+            or app.color_depth != self._last_color_depth
+        ):
+            self._last_screen = None
+            self._attrs_for_style = None
+            self._style_string_has_style = None
+
+        if self._attrs_for_style is None:
+            self._attrs_for_style = _StyleStringToAttrsCache(
+                self.style.get_attrs_for_style_str, app.style_transformation
+            )
+        if self._style_string_has_style is None:
+            self._style_string_has_style = _StyleStringHasStyleCache(
+                self._attrs_for_style
+            )
+
+        self._last_style_hash = self.style.invalidation_hash()
+        self._last_transformation_hash = app.style_transformation.invalidation_hash()
+        self._last_color_depth = app.color_depth
+
+        layout.container.write_to_screen(
+            screen,
+            mouse_handlers,
+            WritePosition(xpos=0, ypos=0, width=size.columns, height=height),
+            parent_style="",
+            erase_bg=False,
+            z_index=None,
+        )
+        screen.draw_all_floats()
+
+        # When grayed. Replace all styles in the new screen.
+        if app.exit_style:
+            screen.append_style_to_content(app.exit_style)
+
+        # Process diff and write to output.
+        self._cursor_pos, self._last_style = _output_screen_diff(
+            app,
+            output,
+            screen,
+            self._cursor_pos,
+            app.color_depth,
+            self._last_screen,
+            self._last_style,
+            is_done,
+            full_screen=self.full_screen,
+            attrs_for_style_string=self._attrs_for_style,
+            style_string_has_style=self._style_string_has_style,
+            size=size,
+            previous_width=(self._last_size.columns if self._last_size else 0),
+        )
+        self._last_screen = screen
+        self._last_size = size
+        self.mouse_handlers = mouse_handlers
+
+        # Handle cursor shapes.
+        new_cursor_shape = app.cursor.get_cursor_shape(app)
+        if (
+            self._last_cursor_shape is None
+            or self._last_cursor_shape != new_cursor_shape
+        ):
+            output.set_cursor_shape(new_cursor_shape)
+            self._last_cursor_shape = new_cursor_shape
+
+        # Flush buffered output.
+        output.flush()
+
+        # Set visible windows in layout.
+        app.layout.visible_windows = screen.visible_windows
+
+        if is_done:
+            self.reset()
+
+    def erase(self, leave_alternate_screen: bool = True) -> None:
+        """
+        Hide all output and put the cursor back at the first line. This is for
+        instance used for running a system command (while hiding the CLI) and
+        later resuming the same CLI.)
+
+        :param leave_alternate_screen: When True, and when inside an alternate
+            screen buffer, quit the alternate screen.
+        """
+        output = self.output
+
+        output.cursor_backward(self._cursor_pos.x)
+        output.cursor_up(self._cursor_pos.y)
+        output.erase_down()
+        output.reset_attributes()
+        output.enable_autowrap()
+
+        output.flush()
+
+        self.reset(leave_alternate_screen=leave_alternate_screen)
+
+    def clear(self) -> None:
+        """
+        Clear screen and go to 0,0
+        """
+        # Erase current output first.
+        self.erase()
+
+        # Send "Erase Screen" command and go to (0, 0).
+        output = self.output
+
+        output.erase_screen()
+        output.cursor_goto(0, 0)
+        output.flush()
+
+        self.request_absolute_cursor_position()
+
+
+def print_formatted_text(
+    output: Output,
+    formatted_text: AnyFormattedText,
+    style: BaseStyle,
+    style_transformation: Optional[StyleTransformation] = None,
+    color_depth: Optional[ColorDepth] = None,
+) -> None:
+    """
+    Print a list of (style_str, text) tuples in the given style to the output.
+    """
+    fragments = to_formatted_text(formatted_text)
+    style_transformation = style_transformation or DummyStyleTransformation()
+    color_depth = color_depth or output.get_default_color_depth()
+
+    # Reset first.
+    output.reset_attributes()
+    output.enable_autowrap()
+    last_attrs: Optional[Attrs] = None
+
+    # Print all (style_str, text) tuples.
+    attrs_for_style_string = _StyleStringToAttrsCache(
+        style.get_attrs_for_style_str, style_transformation
+    )
+
+    for style_str, text, *_ in fragments:
+        attrs = attrs_for_style_string[style_str]
+
+        # Set style attributes if something changed.
+        if attrs != last_attrs:
+            if attrs:
+                output.set_attributes(attrs, color_depth)
+            else:
+                output.reset_attributes()
+        last_attrs = attrs
+
+        # Print escape sequences as raw output
+        if "[ZeroWidthEscape]" in style_str:
+            output.write_raw(text)
+        else:
+            # Eliminate carriage returns
+            text = text.replace("\r", "")
+            # Insert a carriage return before every newline (important when the
+            # front-end is a telnet client).
+            text = text.replace("\n", "\r\n")
+            output.write(text)
+
+    # Reset again.
+    output.reset_attributes()
+    output.flush()