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Ghostscript: refactor image output resizing

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This commit is contained in:
James R. Barlow
2017-05-29 11:42:27 -07:00
parent 6e891f91d3
commit facdd13879
1 changed files with 18 additions and 22 deletions
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40
ocrmypdf/exec/ghostscript.py
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@@ -7,7 +7,6 @@ from shutil import copy
from functools import lru_cache
import re
import sys
from math import isclose
from . import get_program
from ..exceptions import SubprocessOutputError
from PIL import Image
@@ -35,18 +34,6 @@ def _gs_error_reported(stream):
return re.search(r'error', stream, flags=re.IGNORECASE)
def _correct_image_size(input_fp, output_file, res, int_res, log):
# If the output size was reduced due to rounding DPI to an
# integer, resize the image to its expected size
input_fp.seek(0)
with Image.open(input_fp) as im:
expected_size = round(res[0] / int_res[0] * im.size[0]), \
round(res[1] / int_res[1] * im.size[1])
log.info(im.size)
log.info(expected_size)
im.resize(expected_size).save(output_file)
def rasterize_pdf(input_file, output_file, xres, yres, raster_device, log,
pageno=1):
res = xres, yres
@@ -73,18 +60,27 @@ def rasterize_pdf(input_file, output_file, xres, yres, raster_device, log,
else:
log.debug(p.stdout)
if p.returncode == 0:
if isclose(int_res[0], res[0], abs_tol=0.1) and \
isclose(int_res[1], res[1], abs_tol=0.1):
copy(tmp.name, output_file)
else:
# If the output size was reduced due to rounding DPI to an
# integer, resize the image to its expected size
_correct_image_size(tmp, output_file, res, int_res, log)
else:
if p.returncode != 0:
log.error('Ghostscript rasterizing failed')
raise SubprocessOutputError()
tmp.seek(0)
# Ghostscript only accepts integers for output resolution
# if the resolution happens to be fractional, then the discrepancy
# would change the size of the output page, especially if the DPI
# is quite low. Resize the image to the expected size
with Image.open(tmp) as im:
expected_size = round(im.size[0] / int_res[0] * res[0]), \
round(im.size[1] / int_res[1] * res[1])
if expected_size != im.size:
log.debug(
"Ghostscript: resize output image {} -> {}".format(
im.size, expected_size))
im.resize(expected_size).save(output_file)
else:
copy(tmp.name, output_file)
def generate_pdfa(pdf_pages, output_file, compression, log,
threads=1, pdf_version='1.5'):