Rename gerbonara/gerber package to just gerbonara

1 files changed, 524 insertions, 0 deletions

diff --git a/gerbonara/tests/test_rs274x.py b/gerbonara/tests/test_rs274x.py
new file mode 100644
index 0000000..9beaa7b
--- /dev/null
+++ b/gerbonara/tests/test_rs274x.py
@@ -0,0 +1,524 @@
+#! /usr/bin/env python
+# -*- coding: utf-8 -*-
+# Author: Jan Götte <code@jaseg.de>
+import math
+
+from PIL import Image
+import pytest
+
+from ..rs274x import GerberFile
+from ..cam import FileSettings
+
+from .image_support import *
+from .utils import *
+
+REFERENCE_FILES = [ l.strip() for l in '''
+    board_outline.GKO
+    example_outline_with_arcs.gbr
+    example_two_square_boxes.gbr
+    example_coincident_hole.gbr
+    example_cutin.gbr
+    example_cutin_multiple.gbr
+    example_flash_circle.gbr
+    example_flash_obround.gbr
+    example_flash_polygon.gbr
+    example_flash_rectangle.gbr
+    example_fully_coincident.gbr
+    example_guess_by_content.g0
+    example_holes_dont_clear.gbr
+    example_level_holes.gbr
+    example_not_overlapping_contour.gbr
+    example_not_overlapping_touching.gbr
+    example_overlapping_contour.gbr
+    example_overlapping_touching.gbr
+    example_simple_contour.gbr
+    example_single_contour_1.gbr
+    example_single_contour_2.gbr
+    example_single_contour_3.gbr
+    example_am_exposure_modifier.gbr
+    bottom_copper.GBL
+    bottom_mask.GBS
+    bottom_silk.GBO
+    eagle_files/copper_bottom_l4.gbr
+    eagle_files/copper_inner_l2.gbr
+    eagle_files/copper_inner_l3.gbr
+    eagle_files/copper_top_l1.gbr
+    eagle_files/profile.gbr
+    eagle_files/silkscreen_bottom.gbr
+    eagle_files/silkscreen_top.gbr
+    eagle_files/soldermask_bottom.gbr
+    eagle_files/soldermask_top.gbr
+    eagle_files/solderpaste_bottom.gbr
+    eagle_files/solderpaste_top.gbr
+    multiline_read.ger
+    test_fine_lines_x.gbr
+    test_fine_lines_y.gbr
+    top_copper.GTL
+    top_mask.GTS
+    top_silk.GTO
+    open_outline_altium.gbr
+    easyeda/Gerber_TopSolderMaskLayer.GTS
+    easyeda/Gerber_TopSilkLayer.GTO
+    easyeda/Gerber_BottomSolderMaskLayer.GBS
+    easyeda/Gerber_BoardOutline.GKO
+    easyeda/Gerber_TopLayer.GTL
+    easyeda/Gerber_BottomLayer.GBL
+    easyeda/Gerber_TopPasteMaskLayer.GTP
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_lyr2.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_lyr3.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_fab.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_lyr10_GAF.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_lyr7.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_sps.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_lyr6.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_lyr1_GAF.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_assy.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_smc_GAF.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_lyr4.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_lyr5.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_bslk.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_spc.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_tslk_GAF.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_lyr8.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_sms_GAF.art
+    allegro-2/MinnowMax_RevA1_GAF_Gerber/MinnowMax_lyr9.art
+    eagle-newer/solderpaste_bottom.gbr
+    eagle-newer/silkscreen_bottom.gbr
+    eagle-newer/profile.gbr
+    eagle-newer/copper_bottom.gbr
+    eagle-newer/soldermask_top.gbr
+    eagle-newer/solderpaste_top.gbr
+    eagle-newer/soldermask_bottom.gbr
+    eagle-newer/silkscreen_top.gbr
+    eagle-newer/copper_top.gbr
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.G4
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.G9
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GBL
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GTO
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.G11
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.G1
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GBP
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.G2
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GM15
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GTS
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.G6
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.G7
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.G3
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GPB
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GM1
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.G12
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GBS
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GTL
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.G10
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GM14
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.G5
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GTP
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GBO
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.G8
+    altium-composite-drill/Gerber/LimeSDR-QPCIe_1v2.GPT
+    geda/driver.topmask.gbr
+    geda/controller.top.gbr
+    geda/controller.bottom.gbr
+    geda/driver.bottommask.gbr
+    geda/driver.top.gbr
+    geda/driver.bottom.gbr
+    geda/controller.topsilk.gbr
+    geda/controller.fab.gbr
+    geda/driver.topsilk.gbr
+    geda/controller.group3.gbr
+    geda/controller.topmask.gbr
+    geda/driver.group5.gbr
+    geda/controller.bottommask.gbr
+    geda/driver.fab.gbr
+    pcb-rnd/power-art.gko
+    pcb-rnd/power-art.ast
+    pcb-rnd/power-art.gtl
+    pcb-rnd/power-art.lht
+    pcb-rnd/power-art.gto
+    pcb-rnd/power-art.gtp
+    pcb-rnd/power-art.asb
+    pcb-rnd/power-art.gbp
+    pcb-rnd/power-art.gbs
+    pcb-rnd/power-art.gbl
+    pcb-rnd/power-art.fab
+    pcb-rnd/power-art.gbo
+    pcb-rnd/power-art.gts
+    siemens/80101_0125_F200_L04.gdo
+    siemens/80101_0125_F200_L12_Bottom.gdo
+    siemens/80101_0125_F200_L11.gdo
+    siemens/80101_0125_F200_L10.gdo
+    siemens/80101_0125_F200_SolderPasteTop.gdo
+    siemens/80101_0125_F200_SoldermaskTop.gdo
+    siemens/80101_0125_F200_L06.gdo
+    siemens/80101_0125_F200_L02.gdo
+    siemens/80101_0125_F200_SilkscreenBottom.gdo
+    siemens/80101_0125_F200_SoldermaskBottom.gdo
+    siemens/80101_0125_F200_SolderPasteBottom.gdo
+    siemens/80101_0125_F200_L03.gdo
+    siemens/80101_0125_F200_L01_Top.gdo
+    Target3001/IRNASIoTbank1.2.Bot
+    Target3001/IRNASIoTbank1.2.Outline
+    Target3001/IRNASIoTbank1.2.PasteBot
+    Target3001/IRNASIoTbank1.2.PasteTop
+    Target3001/IRNASIoTbank1.2.PosiBot
+    Target3001/IRNASIoTbank1.2.PosiTop
+    Target3001/IRNASIoTbank1.2.StopBot
+    Target3001/IRNASIoTbank1.2.StopTop
+    Target3001/IRNASIoTbank1.2.Top
+    kicad-older/chibi_2024-Edge.Cuts.gbr
+    kicad-older/chibi_2024-F.SilkS.gbr
+    kicad-older/chibi_2024-B.Paste.gbr
+    kicad-older/chibi_2024-B.Cu.gbr
+    kicad-older/chibi_2024-F.Mask.gbr
+    kicad-older/chibi_2024-B.Mask.gbr
+    kicad-older/chibi_2024-F.Paste.gbr
+    kicad-older/chibi_2024-B.SilkS.gbr
+    kicad-older/chibi_2024-F.Cu.gbr
+    fritzing/combined.gbs
+    fritzing/combined.gm1
+    fritzing/combined.gbl
+    fritzing/combined.gbo
+    fritzing/combined.GKO
+    fritzing/combined.gtl
+    fritzing/combined.gts
+    fritzing/combined.gto
+    siemens-2/Gerber/SoldermaskTop.gdo
+    siemens-2/Gerber/EtchLayerTop.gdo
+    siemens-2/Gerber/DrillDrawingThrough.gdo
+    siemens-2/Gerber/SoldermaskBottom.gdo
+    siemens-2/Gerber/SolderPasteBottom.gdo
+    siemens-2/Gerber/SolderPasteTop.gdo
+    siemens-2/Gerber/EtchLayerBottom.gdo
+    siemens-2/Gerber/GerberPlot.gpf
+    siemens-2/Gerber/BoardOutlline.gdo
+    upverter/design_export.gko
+    upverter/design_export.gtl
+    upverter/design_export.gbp
+    upverter/design_export.gtp
+    upverter/design_export.gbl
+    upverter/design_export.gto
+    upverter/design_export.gbs
+    upverter/design_export.gts
+    upverter/design_export.gbo
+    eagle_files/solderpaste_bottom.gbr
+    eagle_files/silkscreen_bottom.gbr
+    eagle_files/profile.gbr
+    eagle_files/copper_inner_l2.gbr
+    eagle_files/copper_top_l1.gbr
+    eagle_files/soldermask_top.gbr
+    eagle_files/copper_inner_l3.gbr
+    eagle_files/solderpaste_top.gbr
+    eagle_files/soldermask_bottom.gbr
+    eagle_files/copper_bottom_l4.gbr
+    eagle_files/silkscreen_top.gbr
+    diptrace/panel_BoardOutline.gbr
+    diptrace/keyboard_BottomSilk.gbr
+    diptrace/keyboard_Bottom.gbr
+    diptrace/mainboard_Top.gbr
+    diptrace/mainboard_TopMask.gbr
+    diptrace/mainboard_BoardOutline.gbr
+    diptrace/mainboard_Bottom.gbr
+    diptrace/mainboard_BottomMask.gbr
+    diptrace/keyboard_BottomMask.gbr
+    diptrace/panel_Bottom.gbr
+    diptrace/keyboard_BoardOutline.gbr
+    diptrace/panel_BottomSilk.gbr
+    diptrace/panel_BottomMask.gbr
+    diptrace/mainboard_TopSilk.gbr
+'''.splitlines() if l ]
+
+MIN_REFERENCE_FILES = [
+    'example_two_square_boxes.gbr',
+    'example_outline_with_arcs.gbr',
+    'example_flash_circle.gbr',
+    'example_flash_polygon.gbr',
+    'example_flash_rectangle.gbr',
+    'example_simple_contour.gbr',
+    'example_am_exposure_modifier.gbr',
+    'bottom_copper.GBL',
+    'bottom_silk.GBO',
+    'eagle_files/copper_bottom_l4.gbr'
+    ]
+
+HAS_ZERO_SIZE_APERTURES = [
+    'bottom_copper.GBL',
+    'bottom_silk.GBO',
+    'top_copper.GTL',
+    'top_silk.GTO',
+    'board_outline.GKO',
+    'silkscreen_top.gbr',
+    'combined.GKO',
+    'combined.gto',
+    'EtchLayerTop.gdo',
+    'EtchLayerBottom.gdo',
+    'BoardOutlline.gdo',
+    ]
+
+
+@filter_syntax_warnings
+@pytest.mark.parametrize('reference', REFERENCE_FILES, indirect=True)
+def test_round_trip(reference, tmpfile):
+    tmp_gbr = tmpfile('Output gerber', '.gbr')
+
+    GerberFile.open(reference).save(tmp_gbr)
+
+    mean, _max, hist = gerber_difference(reference, tmp_gbr, diff_out=tmpfile('Difference', '.png'))
+    assert mean < 5e-5
+    assert hist[9] == 0
+    assert hist[3:].sum() < 5e-5*hist.size
+
+@filter_syntax_warnings
+@pytest.mark.parametrize('reference', REFERENCE_FILES, indirect=True)
+def test_idempotence(reference, tmpfile):
+    tmp_gbr_1 = tmpfile('First generation output', '.gbr')
+    tmp_gbr_2 = tmpfile('Second generation output', '.gbr')
+
+    GerberFile.open(reference).save(tmp_gbr_1)
+    GerberFile.open(tmp_gbr_1).save(tmp_gbr_2)
+    assert tmp_gbr_1.read_text() == tmp_gbr_2.read_text()
+
+
+TEST_ANGLES = [90, 180, 270, 30, 1.5, 10, 360, 1024, -30, -90]
+TEST_OFFSETS = [(0, 0), (100, 0), (0, 100), (2, 0), (10, 100)]
+
+@filter_syntax_warnings
+@pytest.mark.parametrize('reference', MIN_REFERENCE_FILES, indirect=True)
+@pytest.mark.parametrize('angle', TEST_ANGLES)
+def test_rotation(reference, angle, tmpfile):
+    if 'flash_rectangle' in str(reference) and angle == 1024:
+        # gerbv's rendering of this is broken, the hole is missing.
+        pytest.skip()
+
+    tmp_gbr = tmpfile('Output gerber', '.gbr')
+
+    f = GerberFile.open(reference)
+    f.rotate(math.radians(angle))
+    f.save(tmp_gbr)
+
+    cx, cy = 0, to_gerbv_svg_units(10, unit='inch')
+    mean, _max, hist = gerber_difference(reference, tmp_gbr, diff_out=tmpfile('Difference', '.png'),
+            svg_transform=f'rotate({angle} {cx} {cy})')
+    assert mean < 1e-3 # relax mean criterion compared to above.
+    assert hist[9] == 0
+
+@filter_syntax_warnings
+@pytest.mark.parametrize('reference', MIN_REFERENCE_FILES, indirect=True)
+@pytest.mark.parametrize('angle', TEST_ANGLES)
+@pytest.mark.parametrize('center', [(0, 0), (-10, -10), (10, 10), (10, 0), (0, -10), (-10, 10), (10, 20)])
+def test_rotation_center(reference, angle, center, tmpfile):
+    if 'flash_rectangle' in str(reference) and angle in (30, 1024):
+        # gerbv's rendering of this is broken, the hole is missing.
+        pytest.skip()
+
+    tmp_gbr = tmpfile('Output gerber', '.gbr')
+
+    f = GerberFile.open(reference)
+    f.rotate(math.radians(angle), center=center)
+    f.save(tmp_gbr)
+
+    # calculate circle center in SVG coordinates 
+    size = (10, 10) # inches
+    cx, cy = to_gerbv_svg_units(center[0]), to_gerbv_svg_units(size[1], 'inch')-to_gerbv_svg_units(center[1], 'mm')
+    mean, _max, hist = gerber_difference(reference, tmp_gbr, diff_out=tmpfile('Difference', '.png'),
+            svg_transform=f'rotate({angle} {cx} {cy})',
+            size=size)
+    assert mean < 1e-3
+    assert hist[9] < 50
+    assert hist[3:].sum() < 1e-3*hist.size
+
+@filter_syntax_warnings
+@pytest.mark.parametrize('reference', MIN_REFERENCE_FILES, indirect=True)
+@pytest.mark.parametrize('offset', TEST_OFFSETS)
+def test_offset(reference, offset, tmpfile):
+    tmp_gbr = tmpfile('Output gerber', '.gbr')
+
+    f = GerberFile.open(reference)
+    f.offset(*offset)
+    f.save(tmp_gbr, settings=FileSettings(unit=f.unit, number_format=(4,7)))
+
+    # flip y offset since svg's y axis is flipped compared to that of gerber
+    dx, dy = to_gerbv_svg_units(offset[0]), -to_gerbv_svg_units(offset[1])
+    mean, _max, hist = gerber_difference(reference, tmp_gbr, diff_out=tmpfile('Difference', '.png'),
+            svg_transform=f'translate({dx} {dy})')
+    assert mean < 1e-4
+    assert hist[9] == 0
+
+@filter_syntax_warnings
+@pytest.mark.parametrize('reference', MIN_REFERENCE_FILES, indirect=True)
+@pytest.mark.parametrize('angle', TEST_ANGLES)
+@pytest.mark.parametrize('center', [(0, 0), (10, 0), (0, -10), (10, 20)])
+@pytest.mark.parametrize('offset', [(0, 0), (100, 0), (0, 100), (100, 100), (100, 10)])
+def test_combined(reference, angle, center, offset, tmpfile):
+    if 'flash_rectangle' in str(reference) and angle in (30, 1024):
+        # gerbv's rendering of this is broken, the hole is missing.
+        pytest.skip()
+
+    tmp_gbr = tmpfile('Output gerber', '.gbr')
+
+    f = GerberFile.open(reference)
+    f.rotate(math.radians(angle), center=center)
+    f.offset(*offset)
+    f.save(tmp_gbr, settings=FileSettings(unit=f.unit, number_format=(4,7)))
+
+    size = (10, 10) # inches
+    cx, cy = to_gerbv_svg_units(center[0]), to_gerbv_svg_units(size[1], 'inch')-to_gerbv_svg_units(center[1], 'mm')
+    dx, dy = to_gerbv_svg_units(offset[0]), -to_gerbv_svg_units(offset[1])
+    mean, _max, hist = gerber_difference(reference, tmp_gbr, diff_out=tmpfile('Difference', '.png'),
+            svg_transform=f'translate({dx} {dy}) rotate({angle} {cx} {cy})',
+            size=size)
+    assert mean < 1e-3
+    assert hist[9] < 100
+    assert hist[3:].sum() < 1e-3*hist.size
+
+@filter_syntax_warnings
+@pytest.mark.parametrize('file_a', MIN_REFERENCE_FILES)
+@pytest.mark.parametrize('file_b', [
+    'example_two_square_boxes.gbr',
+    'example_outline_with_arcs.gbr',
+    'example_am_exposure_modifier.gbr',
+    'bottom_silk.GBO',
+    'eagle_files/copper_bottom_l4.gbr', ])
+@pytest.mark.parametrize('angle', [0, 10, 90])
+@pytest.mark.parametrize('offset', [(0, 0, 0, 0), (100, 0, 0, 0), (0, 0, 0, 100), (100, 0, 0, 100)])
+def test_compositing(file_a, file_b, angle, offset, tmpfile, print_on_error):
+
+    # TODO bottom_silk.GBO renders incorrectly with gerbv: the outline does not exist in svg. In GUI, the logo only
+    # renders at very high magnification. Skip, and once we have our own SVG export maybe use that instead. Or just use
+    # KiCAD's gerbview.
+    # TODO check if this and the issue with aperture holes not rendering in test_combined actually are bugs in gerbv
+    # and fix/report upstream.
+    if file_a == 'bottom_silk.GBO' or file_b == 'bottom_silk.GBO':
+        pytest.skip()
+
+    ref_a = reference_path(file_a)
+    print_on_error('Reference file a:', ref_a)
+    ref_b = reference_path(file_b)
+    print_on_error('Reference file b:', ref_b)
+
+    ax, ay, bx, by = offset
+    grb_a = GerberFile.open(ref_a)
+    grb_a.rotate(math.radians(angle))
+    grb_a.offset(ax, ay)
+
+    grb_b = GerberFile.open(ref_b)
+    grb_b.offset(bx, by)
+
+    grb_a.merge(grb_b)
+    tmp_gbr = tmpfile('Output gerber', '.gbr')
+    grb_a.save(tmp_gbr, settings=FileSettings(unit=grb_a.unit, number_format=(4,7)))
+
+    size = (10, 10) # inches
+    ax, ay = to_gerbv_svg_units(ax), -to_gerbv_svg_units(ay)
+    bx, by = to_gerbv_svg_units(bx), -to_gerbv_svg_units(by)
+    # note that we have to specify cx, cy even if we rotate around the origin since gerber's origin lies at (x=0
+    # y=+document size) in SVG's coordinate space because svg's y axis is flipped compared to gerber's.
+    cx, cy = 0, to_gerbv_svg_units(size[1], 'inch')
+    mean, _max, hist = gerber_difference_merge(ref_a, ref_b, tmp_gbr,
+            composite_out=tmpfile('Composite', '.svg'), diff_out=tmpfile('Difference', '.png'),
+            svg_transform1=f'translate({ax} {ay}) rotate({angle} {cx} {cy})',
+            svg_transform2=f'translate({bx} {by})',
+            size=size)
+    assert mean < 1e-3
+    assert hist[9] < 100
+    assert hist[3:].sum() < 1e-3*hist.size
+
+@filter_syntax_warnings
+@pytest.mark.parametrize('reference', REFERENCE_FILES, indirect=True)
+def test_svg_export(reference, tmpfile):
+    if reference.name in ('silkscreen_bottom.gbr', 'silkscreen_top.gbr', 'top_silk.GTO'):
+        # Some weird svg rendering artifact. Might be caused by mismatching svg units between gerbv and us. Result looks
+        # fine though.
+        pytest.skip()
+
+    if reference.name == 'MinnowMax_assy.art':
+        # This leads to worst-case performance in resvg, this testcase takes over 1h to finish. So skip.
+        pytest.skip()
+
+    grb = GerberFile.open(reference)
+
+    bounds = (0.0, 0.0), (6.0, 6.0) # bottom left, top right
+
+    out_svg = tmpfile('Output', '.svg')
+    with open(out_svg, 'w') as f:
+        f.write(str(grb.to_svg(force_bounds=bounds, arg_unit='inch', fg='black', bg='white')))
+
+    # NOTE: Instead of having gerbv directly export a PNG, we ask gerbv to output SVG which we then rasterize using
+    # resvg. We have to do this since gerbv's built-in cairo-based PNG export has severe aliasing issues. In contrast,
+    # using resvg for both allows an apples-to-apples comparison of both results.
+    ref_svg = tmpfile('Reference export', '.svg')
+    ref_png = tmpfile('Reference render', '.png')
+    gerbv_export(reference, ref_svg, origin=bounds[0], size=bounds[1], fg='#000000', bg='#ffffff')
+    svg_to_png(ref_svg, ref_png, dpi=300, bg='white')
+
+    out_png = tmpfile('Output render', '.png')
+    svg_to_png(out_svg, out_png, dpi=300, bg='white')
+
+    if reference.name in HAS_ZERO_SIZE_APERTURES:
+        # gerbv does not render these correctly.
+        return
+
+    mean, _max, hist = image_difference(ref_png, out_png, diff_out=tmpfile('Difference', '.png'))
+    assert hist[9] < 1
+    if 'Minnow' in reference.name or 'LimeSDR' in reference.name or '80101_0125_F200' in reference.name:
+        # This is a dense design with lots of traces, leading to lots of aliasing artifacts.
+        assert mean < 10e-3
+        assert hist[4:].sum() < 1e-2*hist.size
+    else:
+        assert mean < 1.2e-3
+        assert hist[3:].sum() < 1e-3*hist.size
+
+# FIXME test svg margin, bounding box computation
+
+@filter_syntax_warnings
+@pytest.mark.parametrize('reference', REFERENCE_FILES, indirect=True)
+def test_bounding_box(reference, tmpfile):
+    if reference.name == 'MinnowMax_assy.art':
+        # This leads to worst-case performance in resvg, this testcase takes over 1h to finish. So skip.
+        pytest.skip()
+    # skip this check on files that contain lines with a zero-size aperture at the board edge
+    if any(reference.match(f'*/{f}') for f in HAS_ZERO_SIZE_APERTURES):
+        pytest.skip()
+
+    margin = 1.0 # inch
+    dpi = 200
+    margin_px = int(dpi*margin) # intentionally round down to avoid aliasing artifacts
+
+    grb = GerberFile.open(reference)
+
+    if grb.is_empty:
+        pytest.skip()
+
+    out_svg = tmpfile('Output', '.svg')
+    with open(out_svg, 'w') as f:
+        f.write(str(grb.to_svg(margin=margin, arg_unit='inch', fg='white', bg='black')))
+
+    out_png = tmpfile('Render', '.png')
+    svg_to_png(out_svg, out_png, dpi=dpi)
+
+    img = np.array(Image.open(out_png))
+    img = img[:, :, :3].mean(axis=2) # drop alpha and convert to grayscale
+    img = np.round(img).astype(int) # convert to int
+    assert (img > 0).any() # there must be some content, none of the test gerbers are completely empty.
+    cols = img.sum(axis=1)
+    rows = img.sum(axis=0)
+    col_prefix, col_suffix = np.argmax(cols > 0), np.argmax(cols[::-1] > 0)
+    row_prefix, row_suffix = np.argmax(rows > 0), np.argmax(rows[::-1] > 0)
+    print('cols:', col_prefix, col_suffix)
+    print('rows:', row_prefix, row_suffix)
+
+    # Check that all margins are completely black and that the content touches the margins. Allow for some tolerance to
+    # allow for antialiasing artifacts and for things like very thin features.
+    assert margin_px-2 <= col_prefix <= margin_px+2
+    assert margin_px-2 <= col_suffix <= margin_px+2
+    assert margin_px-2 <= row_prefix <= margin_px+2
+    assert margin_px-2 <= row_suffix <= margin_px+2
+
+@filter_syntax_warnings
+def test_syntax_error():
+    ref = reference_path('test_syntax_error.gbr')
+    with pytest.raises(SyntaxError) as exc_info:
+        GerberFile.open(ref)
+
+    assert 'test_syntax_error.gbr' in exc_info.value.msg
+    assert '7' in exc_info.value.msg # lineno
+