149 lines
4.7 KiB
Python
149 lines
4.7 KiB
Python
# Copyright (c) 2019-2024 Manfred Moitzi
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# License: MIT License
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from __future__ import annotations
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from typing import TYPE_CHECKING, Iterator
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import math
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import numpy as np
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from ezdxf.math import (
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Vec3,
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Matrix44,
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ConstructionArc,
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arc_angle_span_deg,
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)
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from ezdxf.math.transformtools import OCSTransform
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from ezdxf.lldxf.attributes import (
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DXFAttr,
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DXFAttributes,
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DefSubclass,
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group_code_mapping,
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merge_group_code_mappings,
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)
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from ezdxf.lldxf.const import DXF12, SUBCLASS_MARKER
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from .dxfentity import base_class
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from .dxfgfx import acdb_entity
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from .circle import acdb_circle, Circle, merged_circle_group_codes
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from .factory import register_entity
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if TYPE_CHECKING:
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from ezdxf.lldxf.tagwriter import AbstractTagWriter
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__all__ = ["Arc"]
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acdb_arc = DefSubclass(
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"AcDbArc",
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{
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"start_angle": DXFAttr(50, default=0),
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"end_angle": DXFAttr(51, default=360),
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},
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)
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acdb_arc_group_codes = group_code_mapping(acdb_arc)
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merged_arc_group_codes = merge_group_code_mappings(
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merged_circle_group_codes, acdb_arc_group_codes
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)
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@register_entity
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class Arc(Circle):
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"""DXF ARC entity"""
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DXFTYPE = "ARC"
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DXFATTRIBS = DXFAttributes(base_class, acdb_entity, acdb_circle, acdb_arc)
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MERGED_GROUP_CODES = merged_arc_group_codes
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def export_entity(self, tagwriter: AbstractTagWriter) -> None:
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"""Export entity specific data as DXF tags."""
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super().export_entity(tagwriter)
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# AcDbEntity export is done by parent class
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# AcDbCircle export is done by parent class
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if tagwriter.dxfversion > DXF12:
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tagwriter.write_tag2(SUBCLASS_MARKER, acdb_arc.name)
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self.dxf.export_dxf_attribs(tagwriter, ["start_angle", "end_angle"])
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@property
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def start_point(self) -> Vec3:
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"""Returns the start point of the arc in :ref:`WCS`, takes the :ref:`OCS` into
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account.
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"""
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v = list(self.vertices([self.dxf.start_angle]))
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return v[0]
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@property
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def end_point(self) -> Vec3:
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"""Returns the end point of the arc in :ref:`WCS`, takes the :ref:`OCS` into
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account.
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"""
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v = list(self.vertices([self.dxf.end_angle]))
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return v[0]
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def angles(self, num: int) -> Iterator[float]:
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"""Yields `num` angles from start- to end angle in degrees in counter-clockwise
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orientation. All angles are normalized in the range from [0, 360).
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"""
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if num < 2:
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raise ValueError("num >= 2")
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start = self.dxf.start_angle % 360
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stop = self.dxf.end_angle % 360
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if stop <= start:
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stop += 360
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for angle in np.linspace(start, stop, num=num, endpoint=True):
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yield angle % 360
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def flattening(self, sagitta: float) -> Iterator[Vec3]:
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"""Approximate the arc by vertices in :ref:`WCS`, the argument `sagitta`_
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defines the maximum distance from the center of an arc segment to the center of
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its chord.
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.. _sagitta: https://en.wikipedia.org/wiki/Sagitta_(geometry)
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"""
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arc = self.construction_tool()
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ocs = self.ocs()
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elevation = Vec3(self.dxf.center).z
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if ocs.transform:
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to_wcs = ocs.points_to_wcs
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else:
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to_wcs = Vec3.generate
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yield from to_wcs(Vec3(p.x, p.y, elevation) for p in arc.flattening(sagitta))
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def transform(self, m: Matrix44) -> Arc:
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"""Transform ARC entity by transformation matrix `m` inplace.
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Raises ``NonUniformScalingError()`` for non-uniform scaling.
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"""
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ocs = OCSTransform(self.dxf.extrusion, m)
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super()._transform(ocs)
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s: float = self.dxf.start_angle
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e: float = self.dxf.end_angle
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if not math.isclose(arc_angle_span_deg(s, e), 360.0):
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(
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self.dxf.start_angle,
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self.dxf.end_angle,
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) = ocs.transform_ccw_arc_angles_deg(s, e)
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self.post_transform(m)
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return self
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def construction_tool(self) -> ConstructionArc:
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"""Returns the 2D construction tool :class:`ezdxf.math.ConstructionArc` but the
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extrusion vector is ignored.
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"""
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dxf = self.dxf
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return ConstructionArc(
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dxf.center,
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dxf.radius,
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dxf.start_angle,
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dxf.end_angle,
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)
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def apply_construction_tool(self, arc: ConstructionArc) -> Arc:
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"""Set ARC data from the construction tool :class:`ezdxf.math.ConstructionArc`
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but the extrusion vector is ignored.
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"""
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dxf = self.dxf
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dxf.center = Vec3(arc.center)
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dxf.radius = arc.radius
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dxf.start_angle = arc.start_angle
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dxf.end_angle = arc.end_angle
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return self # floating interface
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