Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

Unreleased

Fixed

• Degenerate region contours no longer leak line geometry -- a G36/G37 contour whose points are collinear produced a zero-area MultiLineString from make_valid that flowed into the geometry engine; region expansion now keeps only polygonal parts.

Changed

• Local coverage floor aligned with the CI gate (fail_under 85 -> 90; actual coverage is ~94%).
• Stale documentation corrected: the overlay-PNG colour table no longer lists the removed "yellow" class; SECURITY.md supported versions updated from 0.14.x to 0.29.x; CONTRIBUTING.md blesses conventional-commit prefixes (matching recent history).
• Package __init__ modules for parse, render, diff, and export gained one-line docstrings.

Added

• Documentation site at https://cameronbrooks11.github.io/gerberdiff/ -- MkDocs + Material with mkdocstrings API reference, MathJax for the LaTeX notation already used in the docs, and Changelog/Contributing included via snippets. Built strictly and deployed to GitHub Pages by .github/workflows/docs.yml on every push to main that touches docs or the package.

• Edge-case test suite for the geometry engine's guard paths: block nesting depth limit, invalid layer indices, zero-dimension apertures, degenerate regions and strokes, macro flash dispatch, the equal-geometry attribution guard, and driver diagnostic forwarding.

0.29.1 - 2026-06-13

Changed

• Package metadata reflects both engines -- the PyPI description and the CLI group help text described only the raster engine; both now cover the raster overlay and geometry diff pipelines. Added geometry and shapely to the package keywords. No behaviour changes.

0.29.0 - 2026-06-12

Added

• Geometry diff engine (gerberdiff/geometry/) -- a second, Cairo-free diff pipeline operating on the parsed vector geometry via shapely. Resolution-independent and attributed: each change is classified as added, removed, moved (with dx/dy displacement, down to micrometres), or resized, with net names from %TO.N% attributes propagated onto changes. The raster engine is unchanged; the two are complementary (hybrid architecture). See docs/geometry-diff.md.

• Aperture expansion: exact primitives with adaptive tessellation (<= 1 um chord tolerance); exact Minkowski sums for non-round linear strokes (convex hull of the aperture at both endpoints); all 7 macro primitive types with spec-compliant exposure scoping; region fills with even-odd contour semantics; aperture holes subtracted from the flash only (spec semantics).

• Polarity as ordered boolean replay (dark unions, clear subtracts), including block apertures flattened into the outer replay with renderer-verified global-erase semantics for block-internal clears.
• Exact-cancellation matching: ops carry source-based content signatures (aperture content, not D-code numbering), so unchanged ops cancel exactly and -- via lazy expansion -- never construct geometry at all.
• Boolean added/removed material per layer with snap-rounded differences and a dust filter; full ordered-replay fallback when clear polarity is present.

• Attribution: KD-tree gated matching with tunable tolerances (move_tol, gate_radius, area_tol); orientation-normalised dimension comparison so a 90-degree-rotated footprint classifies as moved, not resized.

• gerberdiff geomdiff CLI subcommand with --move-tol, --gate-radius, --area-tol, --dust-area (mm units), --out-json, --out-svg, --layer, --fail-on-diff, -q/-v.

• JSON report schema version 2 ("mode": "geometry"): per-layer change counts, added/removed areas (mm^2), per-change records with centroid/area/displacement/net, and the tolerances used. Documented in docs/schema.md.

• SVG overlay export (export/svg_export.py, Cairo-free): removed red, added green, moved blue with displacement lines, resized orange; even-odd fill preserves aperture holes.

• Public API: compute_geometry_diff, GeometryChange, LayerGeometryDiff, GeometryDiffResult exported from the top-level package.

• Dependency: shapely >= 2.0 (binary wheels with bundled GEOS; no system library required). Dev dependency types-shapely for mypy.

• 127 new tests, including a differential test pinning resolved geometry to the Cairo renderer's occupancy (>= 99% pixel agreement) and fixture-board integration tests against an independently computed flash-matching oracle.

Changed

• Cairo is now imported lazily. import gerberdiff no longer requires the native cairo library; the parse and geometry pipelines (including gerberdiff geomdiff and gerberdiff parse) work on systems without it. Accessing the rasteriser (render_to_numpy, render_to_surface, compute_diff, or the render/diff CLI commands) raises the underlying OSError only when actually used. Raster-engine tests skip cleanly when cairo is unavailable, which fixes the previously failing Windows CI job.

• Project renamed from gerberdelta to gerberdiff (2026-04-25, unreleased at the time). 0.29.0 is the first published release under the new name; no release was ever made as gerberdelta. The rename window also included: docs reorganised to lowercase-kebab filenames with split CLI/API references, an ASCII-only character policy sweep, LaTeX math notation for equations in docs, and strict mypy annotations across the test suite.

0.28.0 - 2026-04-25

Added

• Render/diff regression coverage -- 411 lines of new tests across the renderer, draw-ops, diff engine, and parser: incremental (G91) coordinates, step-and-repeat tiling, layer transforms (LM/LR/LS), clear-polarity compositing, region merge cascade, polygon aperture rotation, macro unit_scale, alignment_offset, and pixel-level render verification. No production code changes.

0.27.0 - 2026-04-25

Changed

• CompiledRender cached per BlockAperture -- repeated flashes of the same block aperture no longer recompile its draw-op groups on every flash. The cache is keyed by id(block_ap) and evicted by a weakref finalizer when the aperture is garbage-collected, so stale ids cannot produce false hits.

0.26.0 - 2026-04-25

Fixed

• Rect/obround stroke width -- D01 strokes with rectangle or obround apertures are drawn with line width max(width, height) instead of min(width, height), so traces whose long axis aligns with the stroke direction (the common case) are no longer under-stroked; documented as an approximation pending geometry-aware rendering.
• Macro evaluation failures no longer abort the render -- a macro aperture whose primitive evaluation raises is skipped with a UserWarning instead of crashing the whole render pass.

0.25.0 - 2026-04-25

Fixed

• Parser correctness sweep --
• arc bounding boxes account for axis-extrema crossings (0/90/180/270 degrees), not just the endpoints;
• step-and-repeat tiles expand the image bounding box and respect layer polarity;
• block aperture (%AB%) parsing isolates state correctly (nested apertures/layers no longer leak into the parent image);
• _apply_format no longer truncates coordinates with more integer digits than the format statement declares;
• referencing an unknown macro in an aperture definition is an Error-severity diagnostic (was silently tolerated).

0.24.0 - 2026-04-25

Changed

• DiffResult.has_changes is a computed property -- derived from the layer results instead of stored at construction, so it cannot drift from the data.
• Excellon parser refactored -- the nonlocal-closure state pattern is replaced with explicit local parser state; behaviour unchanged.

0.23.0 - 2026-04-25

Added

• compute_full_diff -- directory-vs-directory diff as a single public API call (parse, match, diff, assemble DiffResult), with overlay_callback and on_diagnostic hooks.
• All IR and result types exported from the top-level package with an __all__ list; README gains API examples.

Changed

• diff_cmd rewritten on top of compute_full_diff (the CLI no longer duplicates the orchestration logic).

0.22.0 - 2026-04-25

Added

• docs/schema.md -- canonical JSON report schema documentation.
• CI hardening -- coverage gate (--cov-fail-under=90), a Windows test job in the matrix, and a non-ASCII character check.

Changed

• EXCELLON_SUFFIXES is public -- renamed from _EXCELLON_SUFFIXES in diff/layer_matcher.py; it is part of the de-facto API used by the CLI and downstream callers.

0.21.0 - 2026-04-25

Changed

• RegionFill IR redesign -- G36/G37 region fill boundaries are no longer stored as sentinel DrawOp objects with InterpolationMode.RegionStart / RegionEnd. A new RegionFill dataclass (layer_index, net_state_index, segments: list[DrawOp]) is emitted by the parser as a single item. ParsedImage.draw_ops and BlockAperture.draw_ops are now typed list[DrawOp | RegionFill]. InterpolationMode.RegionStart and InterpolationMode.RegionEnd are removed. compiled_render.py handles RegionFill directly without a state-machine sentinel scan. RegionFill is exported from the public API. Unclosed G36 at M02 now correctly emits a Warning diagnostic.

0.20.0 - 2026-04-25

Changed

• _EXCELLON_SUFFIXES consolidated -- the duplicate definition in cli.py is removed; cli.py now imports _EXCELLON_SUFFIXES from diff/layer_matcher.py, which remains the single source of truth.

• _flush_macro exception severity upgraded to Error -- a failed parse_macro_body call (e.g. non-integer variable index $notanint=...) was silently recorded as a Warning with # pragma: no cover. It is now recorded as DiagnosticSeverity.Error, the # pragma: no cover tag is removed, and a test exercises this path.

• Fixture paths in tests use __file__-relative construction -- all ten Path("tests/fixtures/...") occurrences across seven test files are replaced with Path(__file__).parent / "fixtures" / "...". Tests now pass regardless of the working directory from which pytest is invoked.

• --align-offset Y direction corrected -- positive DY now shifts image B downward (positive screen Y), consistent with DX shifting rightward. Previously positive DY moved the geometry upward, which was the inverse of the expected screen convention. Help text updated to document the convention explicitly.

• CoordState deprecated fields removed -- mirror_state, axis_select, offset_a, offset_b, scale_a, and scale_b were never populated by the parser (the corresponding %MI%, %AS%, %OF%, %SF% commands were handled with pass). CoordState now carries only unit: UnitType.

0.19.0 - 2026-04-25

Added

• Public Python API (gerberdiff/__init__.py) -- parse_gerber, parse_excellon, render_to_surface, render_to_numpy, and compute_diff are now exported from the top-level package with an __all__ list. Added a ## Python API section to README.md with example usage.

Changed

• SingleLayerDiff no longer stores raw pixel arrays -- arr_a, arr_b, and xor (three ~48 MB numpy arrays at 2048^2) have been removed from the dataclass. Callers that need a PNG overlay pass an overlay_callback: Callable[[ndarray, ndarray, ndarray], None] to compute_diff(); the callback is invoked before the arrays are released. The diff CLI uses this callback to write the overlay PNG without ever holding all three arrays simultaneously.

• _parse closure in diff_cmd returns ParsedImage -- the return type annotation was object with # type: ignore[assignment]; it is now correctly typed as ParsedImage, and the ignore comment is removed.

• _GerberParser._block_stack uses _BlockFrame dataclass -- replaces the unnamed 7-tuple (d_code, block_ap, saved_nets, saved_layers, saved_apertures, saved_bbox, saved_layer_idx) with a named _BlockFrame dataclass so that field access is explicit and mypy-checked.

Fixed

• Dead changed/yellow pixel path removed from png_export.py -- both images are rendered with the same colour scheme so the changed mask (pixels present in both A and B with different colour values) is structurally always empty. The unreachable out[changed] = [0, 255, 255, 255] line and the changed variable have been removed.

0.18.0 - 2026-04-25

Changed

• LayerType moved to types.py -- LayerType was defined in diff/layer_matcher.py but is a domain type used across the IR, diff, export, and CLI layers. Moving it to types.py removes the asymmetry and aligns it with all other domain enums.

• LayerStatus StrEnum added (types.py) -- replaces bare str on LayerDiffResult.status and LayerPair.status. Values: Matched, Added, Removed. All construction sites in layer_matcher.py, cli.py, json_report.py, and tests updated. StrEnum ensures JSON serialisation produces the same string values as before.

• LayerDiffResult.layer_type typed as LayerType -- was str with a comment; is now the proper enum. layer_type=pair.layer_type.value call sites simplified to layer_type=pair.layer_type.

Fixed

• InCu classification false-positives (layer_matcher.py) -- the previous check "in" in s and "cu" in s matched any filename containing both substrings (e.g. incident_copper, incoming.Cu). Replaced with re.search(r"\bin\d+[._]cu\b", s) which requires a digit immediately after in and a word boundary on both sides. Four new tests verify correct classification and absence of false positives.

0.17.0 - 2026-04-25

Fixed

• Cairo layer transform order (renderer.py) -- reversed the three conditional blocks in _render_layer from scale->rotation->mirror to mirror->rotation->scale in code order. Cairo post-multiplies each call into the CTM, so the last call in code is the first transform applied to coordinates; the previous order applied transforms to coordinates as mirror->rotation->scale instead of the RS-274X sec.4.9-specified scale->rotation->mirror. A new test (test_layer_transform_order_rotation_plus_mirror) uses a rotation+mirror combination to verify the centroid of rendered pixels lands in the correct screen quadrant.

• Block aperture recursion depth guard (renderer.py) -- _draw_block_flash, _render_layer, and _render_groups now accept a depth: int = 0 parameter. _draw_block_flash returns immediately when depth >= 10, matching the parser's nesting limit and preventing unbounded recursion on malformed input. A new test (test_block_flash_depth_guard_no_recursion_error) verifies that a 15-level nested BlockAperture chain completes without RecursionError.

• Stroke fallback line width (draw_ops.py) -- draw_net_as_stroke now has explicit case ObroundAperture() and case PolygonAperture() branches before case _:. Both use LINE_CAP_ROUND; obround uses min(width, height) and polygon uses outer_diameter. The previous fallback rendered these valid D01 aperture types as a 25 um hairline, producing near-invisible strokes. Two new tests verify the corrected apertures produce > 200 lit pixels.

• CLI assert -> explicit error handling (cli.py) -- replaced three assert statements in diff_cmd that guarded against missing paths on added/removed/matched layers with click.echo(..., err=True) + sys.exit(2) checks. assert is stripped by python -O; the new checks work under all optimisation levels.

0.16.0 - 2026-04-25

Fixed

• Excellon integer-format coordinates -- the parser now correctly handles integer fixed-decimal coordinate encoding produced by Altium, older KiCad, Ultiboard, and most CAM systems. A _FormatSpec dataclass captures the zero-suppression convention (LZ / TZ) and digit counts read from the METRIC / INCH header line; _apply_format() pads and inserts the decimal point accordingly. Explicit digit counts in the header (e.g. METRIC,LZ,0000.0000) override the defaults. Coordinates that contain a decimal point are passed through unchanged, preserving full compatibility with KiCad modern output. Files with no format header emit a DiagnosticSeverity.Warning and default to METRIC,TZ 3.3.
• 13 new tests in tests/test_excellon_parser.py covering _apply_format unit tests (decimal pass-through, METRIC LZ 3.3, INCH TZ 2.4, negative coords, zero) and end-to-end round-trips (inline content and two new fixtures: tests/fixtures/drill-metric-lz.drl, tests/fixtures/drill-inch-tz.drl).

0.15.0 - 2026-04-25

Changed

• License changed from AGPL-3.0 to Apache-2.0 so the tool can be used commercially without copyleft obligations. (Landed immediately before this version's other changes; recorded here for completeness.)

• Domain model rename -- Net renamed to DrawOp and NetState renamed to CoordState throughout the codebase. The term "net" belongs to EDA net-list semantics; the IR types represent drawing primitives and coordinate-system snapshots, not electrical nets.

• ParsedImage.nets -> draw_ops
• ParsedImage.net_states -> coord_states
• BlockAperture.nets -> draw_ops All public and internal references updated; import order re-sorted (ruff I001).

0.14.0 - 2026-04-25

Added

• Block aperture parsing -- %ABD<n>*% / %AB*% extended commands now fully handled in gerber_state.py. The parser maintains a nested block stack (max depth 10) that redirects net emission, layer state, and the bounding box into a BlockAperture while the block is open; on close the completed aperture is registered into the parent aperture dict. Apertures defined before the block open are accessible inside it via a shallow copy of the parent dict.
• layers: list[LayerState] field added to BlockAperture to capture the block's own polarity/layer stack -- matching the reference JS implementation.
• BlockFlash rendering -- _draw_block_flash() helper in renderer.py synthesises a temporary ParsedImage from the block's captured nets/apertures/layers and recursively runs the compile -> render pipeline, translating to the flash position via ctx.translate(x, y).
• Edge-case hardening:
• Empty gerber (no geometry) no longer raises; produces a default centred viewport.
• Boards with coordinates entirely in negative space render and center correctly.
• Step-and-repeat correctness verified -- 2x2 SR produces measurably more lit pixels than a single instance.
• 17 tests in tests/test_block_aperture.py covering: parse registration, net capture, parent isolation, layer capture, parent-aperture inheritance, invalid D-code warnings, stray close warning, BlockFlash compile path, render output, empty block, empty gerber viewport, negative coordinate centering, and step-and-repeat pixel count.
• README.md -- full CLI reference for all three subcommands (parse, render, diff) with option tables, overlay colour-scheme description, JSON report schema, and development commands.

Fixed

• test_negative_coordinate_viewport assertion corrected -- pan_y is legitimately negative for boards in the negative-Y half-plane; test now validates the correct invariant (board centre maps to canvas centre) rather than the sign of pan_y.

0.13.0 - 2026-04-25

Added

• diff CLI subcommand (gerberdiff diff BEFORE_DIR AFTER_DIR) with options:
• --layer NAME (repeatable) -- restrict diff to named layers
• --width / --height -- canvas dimensions (default 2048)
• --min-pixels -- minimum pixel count for a reported region (default 4)
• --merge-tolerance -- region merge padding in inches (default 0.05)
• --out-json PATH -- write JSON diff report
• --out-png DIR -- write per-layer overlay PNGs
• --overwrite -- allow replacing existing output files
• --png-show-common -- shade unchanged geometry grey in PNG overlays
• --align-offset X,Y -- translate board B by (X, Y) inches before diffing
• --fail-on-diff -- exit 1 if any changes detected
• --quiet / --verbose
• Exit codes: 0 = no diff (or diff without --fail-on-diff), 1 = diff found with --fail-on-diff, 2 = parse/IO error.
• gerberdiff/export/json_report.py -- build_report(diff_result) -> dict and write_report(diff_result, path, overwrite) producing a versioned JSON schema (version: 1) with summary (changed_layers, total_regions, has_changes) and per-layer region detail. Raises FileExistsError when the target exists and overwrite=False. Parent directories created automatically.
• gerberdiff/export/png_export.py -- build_overlay_png(arr_a, arr_b, xor, path, ...). Colour scheme (BGRA ARGB32): removed -> red [0,0,255,255], added -> green [0,255,0,255], changed (both non-zero, different value) -> yellow [0,255,255,255], common (opt-in) -> grey [128,128,128,255]. Written via cairocffi.ImageSurface.create_for_data.
• DiffResult and LayerDiffResult types added to gerberdiff/types.py (has_changes is a stored field, not a property, so added/removed layers correctly drive has_changes=True regardless of pixel count).
• 14 tests in tests/test_json_report.py and 8 tests in tests/test_png_export.py.
• 11 fixture-based integration tests in tests/test_cli_diff.py (guarded with pytest.mark.skipif when fixtures are absent).

0.12.0 - 2026-04-25

Added

• gerberdiff/diff/layer_matcher.py -- match_layers(before_dir, after_dir) -> list[LayerPair] pairs layers by file stem across two directories. Unmatched files are reported as status="added" or status="removed". Results are sorted by a canonical _LAYER_TYPE_ORDER (FCu -> BCu -> inner Cu -> masks -> paste -> silk -> edge cuts -> drill -> unknown).
• LayerType StrEnum with 14 values: FCu, BCu, InCu, FMask, BMask, FPaste, BPaste, FSilk, BSilk, EdgeCuts, NPTH, PTH, Drill, Unknown.
• LayerPair dataclass: name, before_path, after_path, layer_type, status.
• classify_layer(path) -> LayerType -- classifies a single file by name/suffix heuristics.
• 29 tests in tests/test_layer_matcher.py.
• scipy-stubs>=1.17.1.4 added to the [dependency-groups].dev group.

0.11.0 - 2026-04-25

Added

• gerberdiff/diff/diff_engine.py -- pixel-based diff pipeline:
• Renders both images to a shared viewport (merge_bounding_boxes + compute_viewport).
• XORs RGB channels to produce a boolean change mask.
• _ccl_and_extract() -- scipy.ndimage.label (4-connectivity) -> find_objects -> center_of_mass -> list[Region] with world-space (inch) centroid and bounding box.
• merge_overlapping_regions() -- iterative weighted-centroid merge within a tolerance.
• SingleLayerDiff dataclass: arr_a, arr_b, xor, regions, viewport, changed_pixel_count, total_pixel_count.
• compute_diff(image_a, image_b, width, height, alignment_offset, min_pixel_count, merge_tolerance) -> SingleLayerDiff.
• Region, LayerDiffResult, DiffResult types added to gerberdiff/types.py.
• coordinate_offset: tuple[float, float] | None parameter added to render_to_surface() and render_to_numpy() -- applied as ctx.translate() after viewport scale, enabling panel-offset alignment.
• 17 tests in tests/test_diff_engine.py.

0.10.0 - 2026-04-25

Added

• render CLI subcommand (gerberdiff render FILE --out-png PATH) with options: --width, --height, --overwrite, --quiet, --verbose. Accepts both Gerber and Excellon files (auto-detected by suffix). Prints render timing under --verbose.
• Memory warning for canvases exceeding 16 777 216 pixels (~64 MB) -- non-blocking advisory message to stderr.
• 9 tests in tests/test_cli_render.py.

Changed

• scipy promoted to core required dependency (scipy>=1.10 in [project].dependencies). Previously treated as an optional extra; made core because diff_engine.py requires scipy.ndimage and there is no meaningful fallback.

0.9.0 - 2026-04-25

Added

• gerberdiff/render/compiled_render.py -- single-pass compile stage that walks the flat nets list and groups operations into typed batch objects:
• FlashBatch -- simple flashes sharing one aperture (no hole, no macro/block)
• StrokeBatch -- D01 strokes sharing one aperture
• RegionGroup -- G36/G37 region fill
• HoledFlash -- flash for an aperture with a punch-through hole
• MacroFlash -- flash for a macro aperture (one per net)
• BlockFlash -- flash for a block aperture (one per net; rendered in 0.14.0)
• CompiledLayer, CompiledRender containers.
• gerberdiff/render/renderer.py -- two-pass Cairo rasteriser:
• render_to_surface(parsed_image, viewport, draw_color, coordinate_offset) -> cairo.ImageSurface
• render_to_numpy(parsed_image, viewport, draw_color, coordinate_offset) -> np.ndarray (shape (H, W, 4) uint8, BGRA; .copy() called to detach from Cairo buffer before returning)
• Polarity compositing via OPERATOR_OVER (dark) / OPERATOR_DEST_OUT (clear).
• Per-layer transforms: scale, rotation, mirror.
• Step-and-repeat rendered by nested ctx.translate loops.
• 14 tests in tests/test_renderer.py.

0.8.0 - 2026-04-25

Added

• gerberdiff/render/macro_renderer.py -- all 7 RS-274X aperture macro primitive types:
• 1 -- Circle
• 20 -- Vector line
• 21 -- Center line
• 4 -- Outline
• 5 -- Polygon
• 6 -- Moire
• 7 -- Thermal
• draw_macro_flash(ctx, x, y, aperture: MacroAperture) -- evaluates macro expressions, renders each primitive with correct rotation and polarity into the current Cairo context.
• compute_macro_bounding_radius(aperture: MacroAperture) -> float -- conservative radius estimate used for bounding-box expansion.
• 14 tests in tests/test_macro_renderer.py.

0.7.0 - 2026-04-25

Added

• gerberdiff/render/viewport.py:
• Viewport dataclass (width, height, pan_x, pan_y, zoom).
• compute_viewport(bbox, width, height) -> Viewport -- fits the bounding box with a 10% margin, Y-flipped so Gerber's mathematical Y-up maps to screen Y-down.
• merge_bounding_boxes(a, b) -> BoundingBox -- axis-aligned union of two boxes.
• screen_to_world(px, py, vp) -> tuple[float, float] -- inverse viewport transform.
• gerberdiff/render/draw_ops.py:
• draw_arc_path(ctx, arc_segment, start_x, start_y) -- draws a Cairo arc path from a resolved ArcSegment.
• draw_net_segment_in_region(ctx, net) -- adds a net's segment to an open region path.
• draw_net_as_stroke(ctx, net, aperture) -- strokes a D01 net with aperture-derived line width and cap style.
• draw_flash(ctx, net, aperture) -- fills/strokes a D03 flash for all standard aperture shapes (circle, rectangle, obround, polygon).
• 9 tests in tests/test_viewport.py and 13 tests in tests/test_draw_ops.py.

0.6.0 - 2026-04-25

Added

• gerberdiff/parse/excellon_parser.py -- Excellon NC drill format parser. Supports tool definitions (T<n>C<dia>), drill hits (D03 / no D-code with coordinates), routed slots (G00 move + G01 linear route), metric/imperial unit modes, and leading/trailing zero suppression. Emits ParsedImage with the same IR as the Gerber parser.
• parse CLI subcommand (gerberdiff parse FILE) with options: --dump-ir (JSON summary to stdout), --quiet, --verbose. Auto-detects Gerber vs. Excellon by file suffix. Exit code 2 on parse errors.
• 8 tests in tests/test_excellon_parser.py and 6 tests in tests/test_cli_parse.py.

0.5.0 - 2026-04-25

Added

• gerberdiff/parse/gerber_state.py -- full RS-274X stateful parser:
• Format statement (%FS...%) and unit mode (%MO...%)
• All aperture definitions via parse_aperture_definition (phases 3-4)
• Macro definitions (%AM...%) collected and parsed via parse_macro_body
• Layer polarity (%LP...%), mirror (%LM...%), rotation (%LR...%), scale (%LS...%), name (%LN...%)
• Step-and-repeat (%SR...%) with SRX<n>Y<n>I<step>J<step> syntax
• Absolute / incremental coordinate modes (G90/G91)
• Arc modes single-quadrant G74 / multi-quadrant G75
• Region fill G36/G37
• Object and aperture attributes (%TO...%, %TA...%, %TD...%, %TF...%)
• Deprecated codes (G54/55/70/71, %IA...%, %AS...%, %MI...%, %OF...%, %SF...%) handled gracefully
• parse_gerber(content, source_path) -> ParsedImage
• 12 tests in tests/test_gerber_state.py.

0.4.0 - 2026-04-25

Added

• gerberdiff/parse/arc_math.py -- geometry helpers for both arc modes:
• compute_arc_single_quadrant(sx, sy, ex, ey, i, j, clockwise) -> ArcSegment | None
• compute_arc_multi_quadrant(sx, sy, ex, ey, i, j, clockwise) -> ArcSegment | None
• gerberdiff/parse/macro_parser.py -- RS-274X aperture macro parser and evaluator:
• Expression AST with literal, variable ($n), binary operators, and unary minus nodes.
• parse_macro_body(name, body) -> MacroDef
• All 7 primitive types parsed into MacroPrimitive dataclasses.
• evaluate_macro_expression(node, params) -> float
• MacroDef, MacroPrimitive, MacroExpression type hierarchy.
• 8 tests in tests/test_arc_math.py and 19 tests in tests/test_macro_parser.py.

0.3.0 - 2026-04-25

Added

• gerberdiff/parse/tokenizer.py -- RS-274X tokenizer:
• TokenType StrEnum: GCode, DCode, Coordinate, EndOfBlock, Extended, EndOfFile, Unknown.
• Token dataclass: type, raw, numeric_value, line.
• tokenize_gerber(content) -> Iterator[Token]
• gerberdiff/parse/gerber_parser.py -- stateless gerber parser utilities:
• FormatStatement dataclass.
• parse_format_statement(body) -> FormatStatement | None
• parse_aperture_definition(body, unit, macro_map) -> tuple[int, Aperture] | None -- handles circle, rectangle, obround, polygon, and macro apertures with optional hole diameters and unit scaling (inch -> mm).
• convert_coordinate(raw_int, raw_str, int_digits, dec_digits, zero_omission, unit) -> float converting raw token values to inches.
• 13 tests in tests/test_tokenizer.py and 17 tests in tests/test_gerber_parser.py.

0.2.0 - 2026-04-25

Added

• gerberdiff/types.py -- complete intermediate representation (IR) type system:
• Enums (all StrEnum): ApertureType, ApertureState, InterpolationMode, Polarity, MirrorState, UnitType, ZeroOmission, CoordinateMode, DiagnosticSeverity.
• Geometric primitives: ArcSegment, BoundingBox (with expand() and is_valid).
• Drawing state: StepAndRepeat, LayerState, NetState, Net, Diagnostic.
• Aperture types: CircleAperture, RectangleAperture, ObroundAperture, PolygonAperture, MacroAperture, BlockAperture.
• Aperture union TypeAlias.
• ParsedImage top-level IR container.
• 11 tests in tests/test_types.py.

0.1.0 - 2026-04-24

Added

• Package scaffold: pyproject.toml (hatchling build), uv.lock, gerberdiff/__init__.py with __version__ = "0.1.0".
• CLI entry point gerberdiff = "gerberdiff.cli:cli" (stub group with version option).
• Subpackage directories with __init__.py: parse/, render/, diff/, export/.
• Core runtime dependencies: click>=8, numpy>=1.24, cairocffi>=1.6.
• Optional extra gerberdiff[rich] for rich>=13.
• Dev toolchain in [dependency-groups].dev: pytest>=8, pytest-cov>=5, ruff>=0.4, mypy>=1.10.
• Ruff rules: E, F, I, UP, B, C4, RUF; ignores E501. known-first-party = ["gerberdiff"].
• mypy strict=true, warn_unused_ignores=true, cairocffi.* override for missing stubs.
• 2 smoke tests in tests/test_scaffold.py.