Merge branch 'rohlfing_add_jpeg_compression' into 'master'

Add JPEG compression of watermarked PDF pages

See merge request rwthmoodle/exam-scan!29

tests/test_watermark.py

@@ -24,6 +24,7 @@ class MainTest(unittest.TestCase):
         # Prepare parameter
         in_dir = './pdfs'
         dpi = 250
+        quality = 75
         pdf_file = '123456_Nachname.pdf'
 
         tmp_dir = os.path.join(self.test_dir, 'tmp')
@@ -33,7 +34,8 @@ class MainTest(unittest.TestCase):
         os.mkdir(out_dir)
 
         # Call function
-        watermark.watermark_pdf(in_dir, tmp_dir, out_dir, dpi, pdf_file)
+        watermark.watermark_pdf(in_dir, tmp_dir, out_dir,
+                                dpi, quality, pdf_file)
 
         self.assertTrue(os.listdir(out_dir)[0], '123456_Nachname_w.pdf')
 

watermark.py

@@ -126,7 +126,8 @@ def remove_transparency(im, bg_colour=(255, 255, 255)):
     else:
         return im
 
-def watermark_img(img_file, template, dpi):
+
+def watermark_img(img_file, template, dpi, quality):
     """Watermarks image with watermark template
 
     Args:
@@ -152,7 +153,7 @@ def watermark_img(img_file, template, dpi):
 
     # Save image as PDF and delete original image file
     pdf_file = os.path.splitext(img_file)[0] + '.pdf'
-    out.save(pdf_file, resolution=dpi)
+    out.save(pdf_file, resolution=dpi, quality=quality)
     if os.path.isfile(img_file):
         os.remove(img_file)
 
@@ -188,7 +189,7 @@ def combine_all_pdfs(pdf_pages, out_dir):
     return pdf_file
 
 
-def watermark_pdf(input_dir, tmp_dir, output_dir, dpi, pdf_file):
+def watermark_pdf(input_dir, tmp_dir, output_dir, dpi, quality, pdf_file):
     """Watermarkes each page of a given PDF file
 
     Args:
@@ -214,7 +215,7 @@ def watermark_pdf(input_dir, tmp_dir, output_dir, dpi, pdf_file):
     template = create_watermark_template(img_files[0], matnum, dpi)
     pdf_files = []
     for img_file in img_files:
-        pdf_file = watermark_img(img_file, template, dpi)
+        pdf_file = watermark_img(img_file, template, dpi, quality)
         pdf_files.append(pdf_file)
 
     # Combining watermarked PDF pages into one PDF
@@ -255,6 +256,8 @@ def main(args):
         help="tmp folder. Default: ./tmp/")
     parser.add_argument("-d", "--dpi", default="250",
         help="dpi parameter for conversion from pdf to images. Default: 250")
+    parser.add_argument("-q", "--quality", default="75",
+        help="quality parameter for jpeg. Default: 75")
 
     args = parser.parse_args(args)
     infolder = args.infolder
@@ -262,6 +265,7 @@ def main(args):
     cores = int(args.cores)
     tmpdir = args.tmp
     dpi = int(args.dpi)
+    quality = int(args.quality)
 
     # Print status
     starttime = time.time()
@@ -280,7 +284,7 @@ Parallel execution with {:d} cores from now on.
     if cores > 1:
         pool = Pool(cores)
         watermark_fun = partial(
-            watermark_pdf, infolder, tmpdir, outfolder, dpi)
+            watermark_pdf, infolder, tmpdir, outfolder, dpi, quality)
         pdf_files_w = pool.map(watermark_fun, pdf_files)
         pool.close()
         pool.join()
@@ -288,7 +292,7 @@ Parallel execution with {:d} cores from now on.
         pdf_files_w = []
         for pdf_file in pdf_files:
             pdf_file_w = watermark_pdf(
-                infolder, tmpdir, outfolder, dpi, pdf_file)
+                infolder, tmpdir, outfolder, dpi, quality, pdf_file)
             pdf_files_w.append(pdf_file_w)
 
     # Print status