Jean-Pierre MartineauandClaude Opus 5.5
b3bf5a6160
The stock image gives an app no text console, so MeshTerm draws its own: the TUI runs in-process with prompt_toolkit's output feeding a small VT parser, the cells are drawn in Terminus 6x12 with MeshTerm's marks over it, and keys go in through a pipe in xterm's spelling. The front end is the only part that differs: framebuffer and evdev on the device (written ahead of the hardware), a Tk window on the desktop. Each handheld's glyph inventory is now named by Platform.font, which replaces ascii_fold; the render-boundary fold derives its accents, emoji, and fallback from that inventory and quantizes colour only where truecolor is off. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
534 lines
20 KiB
Python
534 lines
20 KiB
Python
# SPDX-License-Identifier: Apache-2.0
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"""The terminal the console host draws: a VT byte stream parsed into a grid of cells.
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Small on purpose. Its one producer is MeshTerm itself — prompt_toolkit's ``Vt100_Output``
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and the session's own fast row writer — so it understands what those emit and the handful
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of neighbours a stray library might, and quietly ignores the rest of the VT220/xterm
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universe: cursor movement and addressing, erase and insert/delete, scroll regions, the
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alternate screen, autowrap, and SGR in all three colour depths (16, 256, and truecolor,
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with ``;`` or ``:`` separators). What it does not model it skips by the grammar — a
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whole escape sequence, never part of one — so an unknown sequence can never leak its
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parameters onto the screen as text.
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The grid is the source of truth for the pixels: :class:`Terminal` records which rows
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changed since the host last drew (:meth:`Terminal.take_dirty`), so a keystroke that moves
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the highlight one row repaints two rows of the panel, not fourteen.
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"""
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from __future__ import annotations
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from collections.abc import Callable, Sequence
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from dataclasses import dataclass
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from rich.cells import cell_len
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#: A colour, as 8-bit channels.
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RGB = tuple[int, int, int]
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#: Style flags (:attr:`Style.flags` is a bitmask of these).
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BOLD = 1
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DIM = 2
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ITALIC = 4
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UNDERLINE = 8
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REVERSE = 16
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HIDDEN = 32
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STRIKE = 64
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@dataclass(frozen=True, slots=True)
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class Style:
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"""How a cell is drawn: its colours (``None`` = the terminal's default) and flags."""
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fg: RGB | None = None
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bg: RGB | None = None
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flags: int = 0
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#: The style a fresh or erased cell has.
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PLAIN = Style()
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#: A cell: the character drawn there (``""`` for the right half of a wide character)
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#: and its style.
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Cell = tuple[str, Style]
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_BLANK: Cell = (" ", PLAIN)
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#: A conventional 16-colour palette, for a host that passes none of its own.
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_DEFAULT_PALETTE: tuple[RGB, ...] = (
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(0, 0, 0), (205, 0, 0), (0, 205, 0), (205, 205, 0),
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(0, 0, 238), (205, 0, 205), (0, 205, 205), (229, 229, 229),
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(127, 127, 127), (255, 0, 0), (0, 255, 0), (255, 255, 0),
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(92, 92, 255), (255, 0, 255), (0, 255, 255), (255, 255, 255),
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) # fmt: skip
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_CUBE_LEVELS = (0, 95, 135, 175, 215, 255)
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# Parser states.
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_GROUND, _ESC, _CSI, _OSC, _CHARSET, _STRING = range(6)
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def _xterm_256(index: int, palette: Sequence[RGB]) -> RGB:
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"""The colour xterm's 256-colour index ``index`` names."""
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if index < 16:
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return palette[index]
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if index < 232:
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index -= 16
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return (
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_CUBE_LEVELS[index // 36],
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_CUBE_LEVELS[index // 6 % 6],
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_CUBE_LEVELS[index % 6],
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)
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level = 8 + 10 * (index - 232)
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return (level, level, level)
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class Terminal:
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"""A ``cols`` × ``rows`` character grid driven by a VT byte stream.
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Args:
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cols: Width in cells.
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rows: Height in cells.
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palette: The 16 colours SGR 30–37/90–97 (and 256-colour indices 0–15) name.
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reply: Called with the bytes a real terminal would answer a query with (a
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cursor-position report, a device-attributes reply); ``None`` drops them.
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"""
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def __init__(
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self,
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cols: int,
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rows: int,
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*,
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palette: Sequence[RGB] = _DEFAULT_PALETTE,
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reply: Callable[[str], None] | None = None,
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) -> None:
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"""Start blank, the cursor home, in the main screen."""
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self.cols = cols
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self.rows = rows
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self.palette = tuple(palette)
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self._reply = reply
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self._main = self._fresh_screen()
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self._alt = self._fresh_screen()
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self.screen = self._main
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self.x = 0
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self.y = 0
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self.style = PLAIN
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self.cursor_visible = True
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self.autowrap = True
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self.application_cursor = False
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self._wrap_pending = False
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self._top = 0
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self._bottom = rows - 1
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self._saved: tuple[int, int, Style] = (0, 0, PLAIN)
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self._state = _GROUND
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self._params = ""
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self._dirty: set[int] = set(range(rows))
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# --- the grid, as the host reads it ------------------------------------------------
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def _fresh_screen(self) -> list[list[Cell]]:
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return [[_BLANK] * self.cols for _ in range(self.rows)]
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def take_dirty(self) -> set[int]:
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"""The rows changed since the last call, which this call forgets."""
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dirty, self._dirty = self._dirty, set()
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return dirty
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def line(self, row: int) -> str:
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"""Row ``row`` as plain text, wide characters once each."""
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return "".join(char for char, _ in self.screen[row])
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def text(self) -> str:
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"""The whole screen as plain text, one line per row."""
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return "\n".join(self.line(row) for row in range(self.rows))
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# --- input --------------------------------------------------------------------------
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def feed(self, data: str) -> None:
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"""Parse ``data``, updating the grid."""
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for char in data:
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state = self._state
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if state == _GROUND:
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if char >= " " and char != "\x7f":
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self._print(char)
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elif char == "\x1b":
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self._state = _ESC
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else:
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self._control(char)
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elif state == _CSI:
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if "\x40" <= char <= "\x7e":
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self._state = _GROUND
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self._csi(self._params, char)
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elif char == "\x1b":
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self._state = _ESC
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elif char in "\x18\x1a":
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self._state = _GROUND # CAN/SUB abort the sequence
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elif char >= " ":
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self._params += char
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else:
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self._control(char) # C0 controls act even mid-sequence
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elif state == _ESC:
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self._escape(char)
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elif state == _OSC:
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if char == "\x07":
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self._state = _GROUND
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elif char == "\x1b":
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self._state = _STRING # ST is ESC \, which _STRING finishes
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elif state == _STRING:
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if char == "\x1b":
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self._state = _ESC
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elif char == "\x07":
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self._state = _GROUND
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else: # _CHARSET: the designator's one final character
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self._state = _GROUND
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def _escape(self, char: str) -> None:
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self._state = _GROUND
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if char == "[":
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self._state, self._params = _CSI, ""
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elif char == "]":
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self._state = _OSC
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elif char in "()*+-./":
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self._state = _CHARSET
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elif char in "P^_X":
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self._state = _STRING
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elif char == "7":
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self._saved = (self.x, self.y, self.style)
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elif char == "8":
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self._restore()
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elif char == "D":
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self._linefeed()
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elif char == "E":
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self.x = 0
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self._linefeed()
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elif char == "M":
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self._reverse_index()
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elif char == "c":
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self.__init__(self.cols, self.rows, palette=self.palette, reply=self._reply)
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# "=", ">", "\\" and anything else: nothing to draw.
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def _control(self, char: str) -> None:
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if char == "\r":
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self.x = 0
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self._wrap_pending = False
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elif char in "\n\x0b\x0c":
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self._linefeed()
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elif char == "\b":
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self.x = max(0, self.x - 1)
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self._wrap_pending = False
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elif char == "\t":
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self.x = min(self.cols - 1, (self.x // 8 + 1) * 8)
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self._wrap_pending = False
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# BEL, SO/SI and the rest draw nothing.
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# --- drawing --------------------------------------------------------------------------
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def _print(self, char: str) -> None:
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width = cell_len(char)
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row = self.screen[self.y]
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if width == 0:
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# A combining mark rides the cell before it.
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if self.x > 0 or self._wrap_pending:
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col = self.x if self._wrap_pending else self.x - 1
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base, style = row[col]
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row[col] = (base + char, style)
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self._dirty.add(self.y)
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return
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if self._wrap_pending or (width == 2 and self.x == self.cols - 1):
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if self.autowrap:
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self.x = 0
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self._linefeed()
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row = self.screen[self.y]
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self._wrap_pending = False
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x = self.x
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self._unsplit(row, x)
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row[x] = (char, self.style)
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if width == 2 and x + 1 < self.cols:
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self._unsplit(row, x + 1)
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row[x + 1] = ("", self.style)
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self._dirty.add(self.y)
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x += width
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if x >= self.cols:
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self.x = self.cols - 1
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self._wrap_pending = self.autowrap
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else:
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self.x = x
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def _unsplit(self, row: list[Cell], x: int) -> None:
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"""Before ``x`` is overwritten, blank whatever half of a wide character it was."""
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char, style = row[x]
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if char == "" and x > 0:
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row[x - 1] = (" ", row[x - 1][1])
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elif x + 1 < self.cols and row[x + 1][0] == "" and cell_len(char) == 2:
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row[x + 1] = (" ", style)
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def _erase_style(self) -> Style:
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"""What an erased cell carries: the current background, nothing else."""
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return PLAIN if self.style.bg is None else Style(bg=self.style.bg)
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def _erase(self, row: int, first: int, last: int) -> None:
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cell = (" ", self._erase_style())
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line = self.screen[row]
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for x in range(max(0, first), min(self.cols, last + 1)):
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line[x] = cell
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self._dirty.add(row)
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def _linefeed(self) -> None:
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self._wrap_pending = False
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if self.y == self._bottom:
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self._scroll_up(1)
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elif self.y < self.rows - 1:
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self.y += 1
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def _reverse_index(self) -> None:
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self._wrap_pending = False
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if self.y == self._top:
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self._scroll_down(1)
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elif self.y > 0:
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self.y -= 1
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def _scroll_up(self, count: int, top: int | None = None) -> None:
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top = self._top if top is None else top
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bottom = self._bottom
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count = min(count, bottom - top + 1)
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region = self.screen[top : bottom + 1]
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blank = [(" ", self._erase_style())] * self.cols
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region = region[count:] + [list(blank) for _ in range(count)]
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self.screen[top : bottom + 1] = region
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self._dirty.update(range(top, bottom + 1))
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def _scroll_down(self, count: int, top: int | None = None) -> None:
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top = self._top if top is None else top
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bottom = self._bottom
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count = min(count, bottom - top + 1)
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region = self.screen[top : bottom + 1]
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blank = [(" ", self._erase_style())] * self.cols
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region = [list(blank) for _ in range(count)] + region[: len(region) - count]
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self.screen[top : bottom + 1] = region
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self._dirty.update(range(top, bottom + 1))
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def _restore(self) -> None:
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self.x, self.y, self.style = self._saved
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self.x = min(self.x, self.cols - 1)
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self.y = min(self.y, self.rows - 1)
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self._wrap_pending = False
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def _goto(self, x: int, y: int) -> None:
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self.x = min(max(0, x), self.cols - 1)
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self.y = min(max(0, y), self.rows - 1)
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self._wrap_pending = False
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# --- CSI ------------------------------------------------------------------------------
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def _csi(self, raw: str, final: str) -> None:
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private = raw[:1] if raw[:1] in "?<=>" else ""
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body = raw[len(private) :].rstrip(" !\"#$%&'()*+,-./") # intermediates
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params = [part for part in body.split(";")] if body else []
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def arg(index: int, default: int) -> int:
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if index >= len(params):
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return default
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head = params[index].split(":")[0]
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return int(head) if head.isdigit() and int(head) else default
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if private == "?":
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if final in "hl":
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self._private_mode(params, final == "h")
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return
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if private:
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return # secondary DA and kin: nothing to draw
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if final == "m":
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self._sgr(params)
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elif final in "Hf":
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self._goto(arg(1, 1) - 1, arg(0, 1) - 1)
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elif final == "A":
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self._goto(self.x, max(self._top if self.y >= self._top else 0, self.y - arg(0, 1)))
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elif final == "B":
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bottom = self._bottom if self.y <= self._bottom else self.rows - 1
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self._goto(self.x, min(bottom, self.y + arg(0, 1)))
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elif final == "C":
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self._goto(self.x + arg(0, 1), self.y)
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elif final == "D":
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self._goto(self.x - arg(0, 1), self.y)
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elif final == "E":
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self._goto(0, self.y + arg(0, 1))
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elif final == "F":
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self._goto(0, self.y - arg(0, 1))
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elif final == "G":
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self._goto(arg(0, 1) - 1, self.y)
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elif final == "d":
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self._goto(self.x, arg(0, 1) - 1)
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elif final == "J":
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self._erase_display(arg(0, 0) if params and params[0] else 0)
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elif final == "K":
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mode = arg(0, 0) if params and params[0] else 0
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if mode == 0:
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self._erase(self.y, self.x, self.cols - 1)
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elif mode == 1:
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self._erase(self.y, 0, self.x)
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else:
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self._erase(self.y, 0, self.cols - 1)
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elif final == "X":
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self._erase(self.y, self.x, self.x + arg(0, 1) - 1)
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elif final == "@":
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self._insert_chars(arg(0, 1))
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elif final == "P":
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self._delete_chars(arg(0, 1))
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elif final == "L":
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if self._top <= self.y <= self._bottom:
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self._scroll_down(arg(0, 1), top=self.y)
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self.x = 0
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elif final == "M":
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if self._top <= self.y <= self._bottom:
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self._scroll_up(arg(0, 1), top=self.y)
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self.x = 0
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elif final == "S":
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self._scroll_up(arg(0, 1))
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elif final == "T":
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self._scroll_down(arg(0, 1))
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elif final == "r":
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top, bottom = arg(0, 1) - 1, arg(1, self.rows) - 1
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if 0 <= top < bottom < self.rows:
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self._top, self._bottom = top, bottom
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self._goto(0, 0)
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elif final == "s":
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self._saved = (self.x, self.y, self.style)
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elif final == "u":
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self._restore()
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elif final == "n" and self._reply is not None:
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if arg(0, 0) == 6:
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self._reply(f"\x1b[{self.y + 1};{self.x + 1}R")
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elif arg(0, 0) == 5:
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self._reply("\x1b[0n")
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elif final == "c" and self._reply is not None:
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self._reply("\x1b[?1;2c")
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# Anything else (window ops, cursor shape, ...) changes nothing here.
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def _erase_display(self, mode: int) -> None:
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if mode == 0:
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self._erase(self.y, self.x, self.cols - 1)
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for row in range(self.y + 1, self.rows):
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self._erase(row, 0, self.cols - 1)
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elif mode == 1:
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for row in range(0, self.y):
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self._erase(row, 0, self.cols - 1)
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self._erase(self.y, 0, self.x)
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else:
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for row in range(self.rows):
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self._erase(row, 0, self.cols - 1)
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def _insert_chars(self, count: int) -> None:
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line = self.screen[self.y]
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count = min(count, self.cols - self.x)
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cell = (" ", self._erase_style())
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line[self.x :] = ([cell] * count + line[self.x :])[: self.cols - self.x]
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self._dirty.add(self.y)
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def _delete_chars(self, count: int) -> None:
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line = self.screen[self.y]
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count = min(count, self.cols - self.x)
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cell = (" ", self._erase_style())
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line[self.x :] = line[self.x + count :] + [cell] * count
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self._dirty.add(self.y)
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def _private_mode(self, params: list[str], on: bool) -> None:
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for raw in params:
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mode = int(raw) if raw.isdigit() else -1
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if mode == 25:
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self.cursor_visible = on
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elif mode == 7:
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self.autowrap = on
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elif mode == 1:
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self.application_cursor = on
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elif mode in (47, 1047, 1049):
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if mode == 1049 and on:
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self._saved = (self.x, self.y, self.style)
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target = self._alt if on else self._main
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if target is not self.screen:
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if on:
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self._alt = self._fresh_screen()
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target = self._alt
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self.screen = target
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self._dirty.update(range(self.rows))
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if mode == 1049 and not on:
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self._restore()
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# --- SGR ------------------------------------------------------------------------------
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def _sgr(self, params: list[str]) -> None:
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if not params:
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params = ["0"]
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# Flatten "38:2::r:g:b" (colon sub-parameters) into the ";" form's sequence.
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codes: list[int] = []
|
||
for part in params:
|
||
pieces = part.split(":")
|
||
if len(pieces) > 1 and pieces[0] in ("38", "48", "58"):
|
||
head, rest = pieces[0], pieces[1:]
|
||
if rest[:1] == ["2"] and len(rest) == 5:
|
||
rest = ["2", *rest[2:]] # drop the colour-space id
|
||
codes.extend(int(p) if p.isdigit() else 0 for p in (head, *rest))
|
||
else:
|
||
codes.append(int(pieces[0]) if pieces[0].isdigit() else 0)
|
||
fg, bg, flags = self.style.fg, self.style.bg, self.style.flags
|
||
i = 0
|
||
while i < len(codes):
|
||
code = codes[i]
|
||
if code == 0:
|
||
fg, bg, flags = None, None, 0
|
||
elif code == 1:
|
||
flags |= BOLD
|
||
elif code == 2:
|
||
flags |= DIM
|
||
elif code == 3:
|
||
flags |= ITALIC
|
||
elif code in (4, 21):
|
||
flags |= UNDERLINE
|
||
elif code == 7:
|
||
flags |= REVERSE
|
||
elif code == 8:
|
||
flags |= HIDDEN
|
||
elif code == 9:
|
||
flags |= STRIKE
|
||
elif code == 22:
|
||
flags &= ~(BOLD | DIM)
|
||
elif code == 23:
|
||
flags &= ~ITALIC
|
||
elif code == 24:
|
||
flags &= ~UNDERLINE
|
||
elif code == 27:
|
||
flags &= ~REVERSE
|
||
elif code == 28:
|
||
flags &= ~HIDDEN
|
||
elif code == 29:
|
||
flags &= ~STRIKE
|
||
elif 30 <= code <= 37:
|
||
fg = self.palette[code - 30]
|
||
elif 40 <= code <= 47:
|
||
bg = self.palette[code - 40]
|
||
elif 90 <= code <= 97:
|
||
fg = self.palette[code - 90 + 8]
|
||
elif 100 <= code <= 107:
|
||
bg = self.palette[code - 100 + 8]
|
||
elif code == 39:
|
||
fg = None
|
||
elif code == 49:
|
||
bg = None
|
||
elif code in (38, 48, 58):
|
||
colour, used = self._extended(codes, i + 1)
|
||
if code == 38:
|
||
fg = colour
|
||
elif code == 48:
|
||
bg = colour
|
||
i += used
|
||
i += 1
|
||
self.style = Style(fg, bg, flags)
|
||
|
||
def _extended(self, codes: list[int], start: int) -> tuple[RGB | None, int]:
|
||
"""Read an extended colour at ``codes[start:]``: ``(colour, codes consumed)``."""
|
||
kind = codes[start] if start < len(codes) else None
|
||
if kind == 5 and start + 1 < len(codes):
|
||
return _xterm_256(min(255, codes[start + 1]), self.palette), 2
|
||
if kind == 2 and start + 3 < len(codes):
|
||
r, g, b = (min(255, c) for c in codes[start + 1 : start + 4])
|
||
return (r, g, b), 4
|
||
return None, len(codes) - start
|