4fad89288e
- "engine/output/dxf.py" - "engine/api/routes.py" - "engine/tests/test_output.py" GSD-Task: S01/T01
116 lines
3.8 KiB
Python
116 lines
3.8 KiB
Python
"""DXF output generator — AC1015+ DXF from PostProcessResult using ezdxf."""
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from __future__ import annotations
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import io
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from typing import Literal
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import ezdxf
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from pipeline.postprocess import PathInfo, PostProcessResult
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# DXF $INSUNITS codes per the HEADER variable specification
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_INSUNITS_MAP: dict[str, int] = {
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"inches": 1,
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"mm": 4,
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}
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# $MEASUREMENT: 0 = Imperial (inches), 1 = Metric (mm)
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_MEASUREMENT_MAP: dict[str, int] = {
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"inches": 0,
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"mm": 1,
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}
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def _add_path_to_msp(
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msp: ezdxf.layouts.BaseLayout,
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path: PathInfo,
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layer: str = "0",
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scale_factor: float = 1.0,
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) -> None:
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"""Add a single PathInfo as an LWPOLYLINE entity to the modelspace.
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Closed paths get the LWPOLYLINE close flag set.
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Islands are placed on a separate "ISLANDS" layer for downstream CAM tools.
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When *scale_factor* is not 1.0, all coordinates are multiplied by it
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to convert from pixel space to real-world units.
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"""
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coords = path.simplified_coords
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if len(coords) < 2:
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return
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target_layer = "ISLANDS" if path.is_island else layer
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# LWPOLYLINE uses (x, y[, start_width, end_width, bulge]) tuples
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points = [(x * scale_factor, y * scale_factor) for x, y in coords]
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# Remove duplicate close point if the polyline close flag handles it
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if path.is_closed and len(points) > 1 and points[0] == points[-1]:
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points = points[:-1]
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msp.add_lwpolyline(
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points,
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dxfattribs={"layer": target_layer},
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close=path.is_closed,
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)
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def generate_dxf(
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result: PostProcessResult,
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*,
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units: Literal["inches", "mm"] | None = None,
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scale_factor: float = 1.0,
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layer_map: dict[int, str] | None = None,
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) -> bytes:
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"""Generate an AC1015 (AutoCAD R2000) DXF file from post-processed path data.
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Creates LWPOLYLINE entities from simplified coordinate data. Islands (holes)
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are placed on an "ISLANDS" layer; outer contours on the default "0" layer.
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Args:
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result: PostProcessResult from the post-processing pipeline.
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units: Target unit system — ``'inches'`` or ``'mm'``. When set, the
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``$INSUNITS`` and ``$MEASUREMENT`` DXF header variables are written
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so downstream tools (Inkscape, LightBurn, AutoCAD) interpret
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coordinate values in the correct unit.
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scale_factor: Multiplier applied to every coordinate. Use this to
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convert from pixel space to real-world units (e.g. 1/96 for
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96 PPI → inches, 25.4/96 for 96 PPI → mm).
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layer_map: Optional mapping of path index → DXF layer name. Paths
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whose index is absent fall back to the default layer logic
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(``"ISLANDS"`` for islands, ``"0"`` for outer contours).
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Returns:
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DXF file content as bytes.
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"""
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doc = ezdxf.new(dxfversion="R2000") # AC1015
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# --- Unit metadata in DXF header ---
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if units is not None:
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doc.header["$INSUNITS"] = _INSUNITS_MAP[units]
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doc.header["$MEASUREMENT"] = _MEASUREMENT_MAP[units]
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msp = doc.modelspace()
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# Create ISLANDS layer for hole/island paths
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doc.layers.add("ISLANDS", color=1) # color 1 = red in AutoCAD
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# Create any custom layers requested by layer_map
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if layer_map:
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for layer_name in set(layer_map.values()):
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if layer_name not in ("0", "ISLANDS"):
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doc.layers.add(layer_name)
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for idx, path in enumerate(result.paths):
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# Determine the base layer: explicit layer_map entry, or default logic
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if layer_map and idx in layer_map:
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base_layer = layer_map[idx]
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else:
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base_layer = "0"
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_add_path_to_msp(msp, path, layer=base_layer, scale_factor=scale_factor)
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# Write to string buffer, then encode to bytes
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stream = io.StringIO()
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doc.write(stream)
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return stream.getvalue().encode("utf-8")
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