Partially solve ghostscript rasterize_pdf producing wrong file size

Kludge. Assumes JPEG for now. Messy.

ocrmypdf/exec/ghostscript.py

@@ -7,8 +7,10 @@ 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
 
 
 @lru_cache(maxsize=1)
@@ -33,8 +35,22 @@ 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
+    int_res = round(xres), round(yres)
     with NamedTemporaryFile(delete=True) as tmp:
         args_gs = [
             get_program('gs'),
@@ -46,7 +62,7 @@ def rasterize_pdf(input_file, output_file, xres, yres, raster_device, log,
             '-dFirstPage=%i' % pageno,
             '-dLastPage=%i' % pageno,
             '-o', tmp.name,
-            '-r{0}x{1}'.format(str(round(xres)), str(round(yres))),
+            '-r{0}x{1}'.format(str(int_res[0]), str(int_res[1])),
             input_file
         ]
 
@@ -58,7 +74,13 @@ def rasterize_pdf(input_file, output_file, xres, yres, raster_device, log,
             log.debug(p.stdout)
 
         if p.returncode == 0:
-            copy(tmp.name, output_file)
+            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:
             log.error('Ghostscript rasterizing failed')
             raise SubprocessOutputError()

ocrmypdf/pipeline.py

@@ -445,10 +445,10 @@ def rasterize_with_ghostscript(
         # Ghostscript respects /UserUnit when rasterizing. Rasterize at
         # the true DPI but rewrite the output image to the working DPI.
         ghostscript.rasterize_pdf(
-            input_file, output_file + '.tmp', xres=true_dpi, yres=true_dpi,
+            input_file, output_file + '.jpg', xres=true_dpi, yres=true_dpi,
             raster_device=device, log=log)
 
-        with Image.open(output_file + ".tmp") as im:
+        with Image.open(output_file + ".jpg") as im:
             im.save(output_file, dpi=(working_dpi, working_dpi))
 
 

tests/test_userunit.py

@@ -39,3 +39,13 @@ def poster(resources):
 def test_userunit_ghostscript_fails(poster, no_outpdf):
     p, out, err = run_ocrmypdf(poster, no_outpdf, '--output-type=pdfa')
     assert p.returncode == ExitCode.input_file
+
+
+def test_userunit_qpdf_passes(spoof_tesseract_cache, poster, outpdf):
+    before = PdfInfo(poster)
+    check_ocrmypdf(poster, outpdf, '--output-type=pdf',
+                   env=spoof_tesseract_cache)
+
+    after = PdfInfo(outpdf)
+    assert isclose(before[0].width_inches, after[0].width_inches)
+