Files
autocad-mcp-pro/engineering/standards/textstyles.py
T

101 lines
3.8 KiB
Python

"""Text style presets: the four fonts the standards data refers to by name.
``TEXT_PRESETS`` maps a style name to ``(font file, width factor, oblique
degrees)``. ISOCP is AutoCAD's ISO 3098 type B lettering as an SHX shape
file; ISOCPEUR is the TrueType twin with accented characters; ARIAL is the
general-purpose TrueType face; ROMANS is AutoCAD's simplex roman, the face
ASME Y14.2 Gothic lettering is usually drawn with. A DXF stores only the font
*name*, so an unknown file is never refused here: ``resolve_font`` says
whether it is a bundled preset, the backend adds whether its font path has
it, and the caller sees ``font_resolved``.
"""
from __future__ import annotations
from pathlib import PurePath
__all__ = [
"MAX_OBLIQUE_DEG",
"TEXT_PRESETS",
"resolve_font",
"validate_textstyle",
]
TEXT_PRESETS: dict[str, tuple[str, float, float]] = {
"ISOCP": ("isocp.shx", 1.0, 0.0),
"ISOCPEUR": ("isocpeur.ttf", 1.0, 0.0),
"ARIAL": ("arial.ttf", 1.0, 0.0),
"ROMANS": ("romans.shx", 1.0, 0.0),
}
#: AutoCAD's own limit for the STYLE command's obliquing angle.
MAX_OBLIQUE_DEG = 85.0
_ILLEGAL_NAME_CHARS = frozenset('<>/\\":;?*|,=`')
def resolve_font(font: str) -> tuple[str, bool]:
"""``(font_file, known)``: a preset name or file resolves to the bundled
file with ``known=True``; anything else is passed through with ``False``.
Accepts the style name (``ISOCP``), the file (``isocp.shx``) or the stem
(``isocp``), case-insensitively. Refuses an empty string or control
characters — the only inputs a DXF cannot hold.
"""
if not isinstance(font, str):
raise TypeError(f"font: expected a string, got {type(font).__name__}")
text = font.strip()
if not text:
raise ValueError("font: a font file name cannot be empty")
if any(ord(ch) < 32 for ch in text):
raise ValueError("font: control characters are refused")
upper = text.upper()
if upper in TEXT_PRESETS:
return TEXT_PRESETS[upper][0], True
for font_file, _width, _oblique in TEXT_PRESETS.values():
if upper in (font_file.upper(), PurePath(font_file).stem.upper()):
return font_file, True
return text, False
def validate_textstyle(
name: str,
font: str,
height: float = 0.0,
width_factor: float = 1.0,
oblique_deg: float = 0.0,
) -> dict:
"""The typed request both engines write, or a ``ValueError``/``TypeError``
naming the field. ``height`` 0 is AutoCAD's "prompt per text" and is legal;
the width factor must be positive; the oblique angle is AutoCAD's ±85°."""
if not isinstance(name, str) or not name.strip():
raise ValueError("name: a text style name cannot be empty")
clean = name.strip()
bad = sorted(set(clean) & _ILLEGAL_NAME_CHARS)
if bad:
raise ValueError(f"name: {clean!r} contains characters DXF forbids in a name: {bad}")
font_file, known = resolve_font(font)
for key, value in (
("height", height),
("width_factor", width_factor),
("oblique_deg", oblique_deg),
):
if isinstance(value, bool) or not isinstance(value, (int, float)):
raise TypeError(f"{key}: expected a number, got {type(value).__name__}")
if float(height) < 0.0:
raise ValueError(f"height: {height!r} is negative; 0 means 'ask per text'")
if float(width_factor) <= 0.0:
raise ValueError(f"width_factor: {width_factor!r} must be greater than 0")
if abs(float(oblique_deg)) > MAX_OBLIQUE_DEG:
raise ValueError(
f"oblique_deg: {oblique_deg!r} is outside AutoCAD's +/-{MAX_OBLIQUE_DEG:g} degrees"
)
return {
"name": clean,
"font_file": font_file,
"known": known,
"height": float(height),
"width_factor": float(width_factor),
"oblique_deg": float(oblique_deg),
}