feat(standards): ISO-25 and ANSI dimension, text and leader style presets as pinned data

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd

engineering/standards/textstyles.py

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+"""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),
+    }