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.venv/lib/python3.12/site-packages/ezdxf/units.py

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+# Copyright (c) 2019-2023 Manfred Moitzi
+# License: MIT License
+from typing import Optional
+from ezdxf.enums import InsertUnits
+
+# Documentation: https://ezdxf.mozman.at/docs/concepts/units.html#insunits
+
+MSP_METRIC_UNITS_FACTORS = {
+    # length in units / factor = length in meters
+    # length in meters * factor = length in units
+    "km": 0.001,
+    "m": 1.0,
+    "dm": 10.0,
+    "cm": 100.0,
+    "mm": 1000.0,
+    "µm": 1000000.0,
+    "yd": 1.093613298,
+    "ft": 3.280839895,
+    "in": 39.37007874,
+    "mi": 0.00062137119,
+}
+
+IN = 1
+FT = 2
+MI = 3
+MM = 4
+CM = 5
+M = 6
+KM = 7
+YD = 10
+DM = 14
+
+IMPERIAL_UNITS = {
+    InsertUnits.Inches,
+    InsertUnits.Feet,
+    InsertUnits.Miles,
+    InsertUnits.Microinches,
+    InsertUnits.Mils,
+    InsertUnits.Yards,
+    InsertUnits.USSurveyFeet,
+    InsertUnits.USSurveyInch,
+    InsertUnits.USSurveyYard,
+    InsertUnits.USSurveyMile,
+}
+
+# Conversion factor from meters to unit
+# 1 meter is ... [unit]
+METER_FACTOR = [
+    None,  # 0 = Unitless - not supported
+    39.37007874,  # 1 = Inches
+    3.280839895,  # 2 = Feet
+    0.00062137119,  # 3 = Miles
+    1000.0,  # 4 = Millimeters
+    100.0,  # 5 = Centimeters
+    1.0,  # 6 = Meters
+    0.001,  # 7 = Kilometers
+    None,  # 8 = Microinches = 1e-6 in
+    None,  # 9 = Mils = 0.001 in
+    1.093613298,  # 10 = Yards
+    10000000000.0,  # 11 = Angstroms = 1e-10m
+    1000000000.0,  # 12 = Nanometers = 1e-9m
+    1000000.0,  # 13 = Microns = 1e-6m
+    10.0,  # 14 = Decimeters = 0.1m
+    0.1,  # 15 = Decameters = 10m
+    0.01,  # 16 = Hectometers = 100m
+    0.000000001,  # 17 = Gigameters = 1e+9 m
+    1.0 / 149597870700,  # 18 = Astronomical units = 149597870700m
+    1.0 / 9.46e15,  # 19 = Light years = 9.46e15 m
+    1.0 / 3.09e16,  # 20 = Parsecs =  3.09e16 m
+    None,  # 21 = US Survey Feet
+    None,  # 22 = US Survey Inch
+    None,  # 23 = US Survey Yard
+    None,  # 24 = US Survey Mile
+]
+
+
+class DrawingUnits:
+    def __init__(self, base: float = 1.0, unit: str = "m"):
+        self.base = float(base)
+        self.unit = unit.lower()
+        self._units = MSP_METRIC_UNITS_FACTORS
+        self._msp_factor = base * self._units[self.unit]
+
+    def factor(self, unit: str = "m") -> float:
+        return self._msp_factor / self._units[unit.lower()]
+
+    def __call__(self, unit: str) -> float:
+        return self.factor(unit)
+
+
+class PaperSpaceUnits:
+    def __init__(self, msp=DrawingUnits(), unit: str = "mm", scale: float = 1):
+        self.unit = unit.lower()
+        self.scale = scale
+        self._msp = msp
+        self._psp = DrawingUnits(1, self.unit)
+
+    def from_msp(self, value: float, unit: str):
+        drawing_units = value * self._msp(unit.lower())
+        return drawing_units / (self._msp(self.unit) * self.scale)
+
+    def to_msp(self, value: float, unit: str):
+        paper_space_units = value * self.scale * self._psp.factor(unit)
+        model_space_units = paper_space_units * self._msp.factor(self.unit)
+        return model_space_units
+
+
+# Layout units are stored as enum in the associated BLOCK_RECORD: BlockRecord.dxf.units
+# or as  optional XDATA for all DXF versions
+# 1000: "ACAD"
+# 1001: "DesignCenter Data" (optional)
+# 1002: "{"
+# 1070: Autodesk Design Center version number
+# 1070: Insert units: like 'units'
+# 1002: "}"
+
+# The units of the modelspace block record is always 0, the real modelspace
+# units and therefore the document units are stored as enum in the header var
+# $INSUNITS
+
+# units stored as enum in BlockRecord.dxf.units
+# 0 = Unitless
+# 1 = Inches
+# 2 = Feet
+# 3 = Miles
+# 4 = Millimeters
+# 5 = Centimeters
+# 6 = Meters
+# 7 = Kilometers
+# 8 = Microinches = 1e-6 in
+# 9 = Mils = 0.001 in
+# 10 = Yards
+# 11 = Angstroms = 1e-10m
+# 12 = Nanometers = 1e-9m
+# 13 = Microns = 1e-6m
+# 14 = Decimeters = 0.1m
+# 15 = Decameters = 10m
+# 16 = Hectometers = 100m
+# 17 = Gigameters = 1e+9 m
+# 18 = Astronomical units = 149597870700m = 1.58125074e−5 ly =  4.84813681e−6 Parsec
+# 19 = Light years = 9.46e15 m
+# 20 = Parsecs =  3.09e16 m
+# 21 = US Survey Feet
+# 22 = US Survey Inch
+# 23 = US Survey Yard
+# 24 = US Survey Mile
+_unit_spec = [
+    None,
+    "in",
+    "ft",
+    "mi",
+    "mm",
+    "cm",
+    "m",
+    "km",
+    "µin",
+    "mil",
+    "yd",
+    "Å",
+    "nm",
+    "µm",
+    "dm",
+    "dam",
+    "hm",
+    "gm",
+    "au",
+    "ly",
+    "pc",
+    None,
+    None,
+    None,
+    None,
+]
+
+
+def decode(enum: int) -> Optional[str]:
+    return _unit_spec[int(enum)]
+
+
+def conversion_factor(
+    source_units: InsertUnits, target_units: InsertUnits
+) -> float:
+    """Returns the conversion factor to represent `source_units` in
+    `target_units`.
+
+    E.g. millimeter in centimeter :code:`conversion_factor(MM, CM)` returns 0.1,
+    because 1 mm = 0.1 cm
+
+    """
+    try:
+        source_factor = METER_FACTOR[source_units]
+        target_factor = METER_FACTOR[target_units]
+        if source_factor is None or target_factor is None:
+            raise TypeError("Unsupported conversion.")
+        return target_factor / source_factor
+
+    except IndexError:
+        raise ValueError("Invalid unit enum.")
+
+
+def unit_name(enum: int) -> str:
+    """Returns the name of the unit enum."""
+    try:
+        return InsertUnits(enum).name
+    except ValueError:
+        return "unitless"
+
+
+ANGLE_UNITS = {
+    0: "Decimal Degrees",
+    1: "Degrees/Minutes/Seconds",
+    2: "Grad",
+    3: "Radians",
+}
+
+
+def angle_unit_name(enum: int) -> str:
+    """Returns the name of the angle unit enum."""
+    return ANGLE_UNITS.get(enum, f"unknown unit <{enum}>")