def test_rasterize_rotated(francais, outdir, caplog):
path, pdf = francais
page_size_pts = (pdf.pages[0].MediaBox[2], pdf.pages[0].MediaBox[3])
assert pdf.pages[0].MediaBox[0] == pdf.pages[0].MediaBox[1] == 0
page_size = (page_size_pts[0] / Decimal(72),
page_size_pts[1] / Decimal(72))
target_size = Decimal('50.0'), Decimal('30.0')
forced_dpi = Resolution(42.0, 4242.0)
caplog.set_level(logging.DEBUG)
rasterize_pdf(
path,
outdir / 'out.png',
raster_device='pngmono',
raster_dpi=Resolution(target_size[0] / page_size[0],
target_size[1] / page_size[1]),
page_dpi=forced_dpi,
rotation=90,
)
with Image.open(outdir / 'out.png') as im:
assert im.size == (target_size[1], target_size[0])
assert im.info['dpi'] == forced_dpi.flip_axis()
def rasterize_pdf(
input_file: os.PathLike,
output_file: os.PathLike,
*,
raster_device: str,
raster_dpi: Resolution,
pageno: int = 1,
page_dpi: Resolution = None,
rotation: int = None,
filter_vector: bool = False,
):
"""Rasterize one page of a PDF at resolution raster_dpi in canvas units."""
raster_dpi = raster_dpi.round(6)
if not page_dpi:
page_dpi = raster_dpi
args_gs = ([
GS,
'-dQUIET',
'-dSAFER',
'-dBATCH',
'-dNOPAUSE',
f'-sDEVICE={raster_device}',
f'-dFirstPage={pageno}',
f'-dLastPage={pageno}',
f'-r{raster_dpi.x:f}x{raster_dpi.y:f}',
] + (['-dFILTERVECTOR'] if filter_vector else []) + [
'-o',
'-',
'-sstdout=%stderr',
'-dAutoRotatePages=/None', # Probably has no effect on raster
'-f',
fspath(input_file),
])
try:
p = run(args_gs, stdout=PIPE, stderr=PIPE, check=True)
except CalledProcessError as e:
log.error(e.stderr.decode(errors='replace'))
raise SubprocessOutputError('Ghostscript rasterizing failed')
else:
stderr = p.stderr.decode(errors='replace')
if _gs_error_reported(stderr):
log.error(stderr)
elif stderr:
log.debug(stderr)
with Image.open(BytesIO(p.stdout)) as im:
if rotation is not None:
log.debug("Rotating output by %i", rotation)
# rotation is a clockwise angle and Image.ROTATE_* is
# counterclockwise so this cancels out the rotation
if rotation == 90:
im = im.transpose(Image.ROTATE_90)
elif rotation == 180:
im = im.transpose(Image.ROTATE_180)
elif rotation == 270:
im = im.transpose(Image.ROTATE_270)
if rotation % 180 == 90:
page_dpi = page_dpi.flip_axis()
im.save(fspath(output_file), dpi=page_dpi)