Adds an option to make PNG images non-transparent

PNG images with transparency are not officially supported by Kindle,
and often they are displayed incorrectly. Now converter has an option
to make them non-transparent, with white background. By default it's
disabled and can be enabled by <removePngTransparency> config line or
--remove-png-transparency command-line argument.

fb2epub.config

@@ -42,6 +42,7 @@
       <generateAnnotationPage>True</generateAnnotationPage>
       <generateOPFGuide>True</generateOPFGuide>
       <kindleRemovePersonalLabel>True</kindleRemovePersonalLabel>
+      <removePngTransparency>False</removePngTransparency>
       <vignettes>
         <vignette level="default">
           <beforeTitle>profiles/vignettes/title_before.png</beforeTitle>
@@ -79,6 +80,7 @@
       <generateAnnotationPage>True</generateAnnotationPage>
       <generateOPFGuide>True</generateOPFGuide>
       <kindleRemovePersonalLabel>True</kindleRemovePersonalLabel>
+      <removePngTransparency>False</removePngTransparency>
       <vignettes/>
     </profile>
     <profile description="No hyphenation" name="nohyph">
@@ -100,6 +102,7 @@
       <generateAnnotationPage>True</generateAnnotationPage>
       <generateOPFGuide>True</generateOPFGuide>
       <kindleRemovePersonalLabel>True</kindleRemovePersonalLabel>
+      <removePngTransparency>False</removePngTransparency>
       <vignettes/>
     </profile>
     <profile description="Vignettes" name="vignettes">
@@ -121,6 +124,7 @@
       <generateAnnotationPage>True</generateAnnotationPage>
       <generateOPFGuide>True</generateOPFGuide>
       <kindleRemovePersonalLabel>True</kindleRemovePersonalLabel>
+      <removePngTransparency>False</removePngTransparency>
       <vignettes>
         <vignette level="default">
           <beforeTitle>profiles/vignettes/title_before.png</beforeTitle>
@@ -158,6 +162,7 @@
       <generateAnnotationPage>True</generateAnnotationPage>
       <generateOPFGuide>True</generateOPFGuide>
       <kindleRemovePersonalLabel>True</kindleRemovePersonalLabel>
+      <removePngTransparency>False</removePngTransparency>
       <vignettes/>
     </profile>
   </profiles>

fb2mobi.config

@@ -42,6 +42,7 @@
       <generateAnnotationPage>True</generateAnnotationPage>
       <generateOPFGuide>True</generateOPFGuide>
       <kindleRemovePersonalLabel>True</kindleRemovePersonalLabel>
+      <removePngTransparency>False</removePngTransparency>
       <vignettes>
         <vignette level="default">
           <beforeTitle>profiles/vignettes/title_before.png</beforeTitle>
@@ -79,6 +80,7 @@
       <generateAnnotationPage>True</generateAnnotationPage>
       <generateOPFGuide>True</generateOPFGuide>
       <kindleRemovePersonalLabel>True</kindleRemovePersonalLabel>
+      <removePngTransparency>False</removePngTransparency>
       <vignettes/>
     </profile>
     <profile description="No hyphenation" name="nohyph">
@@ -100,6 +102,7 @@
       <generateAnnotationPage>True</generateAnnotationPage>
       <generateOPFGuide>True</generateOPFGuide>
       <kindleRemovePersonalLabel>True</kindleRemovePersonalLabel>
+      <removePngTransparency>False</removePngTransparency>
       <vignettes/>
     </profile>
     <profile description="Vignettes" name="vignettes">
@@ -121,6 +124,7 @@
       <generateAnnotationPage>True</generateAnnotationPage>
       <generateOPFGuide>True</generateOPFGuide>
       <kindleRemovePersonalLabel>True</kindleRemovePersonalLabel>
+      <removePngTransparency>False</removePngTransparency>
       <vignettes>
         <vignette level="default">
           <beforeTitle>profiles/vignettes/title_before.png</beforeTitle>
@@ -158,6 +162,7 @@
       <generateAnnotationPage>True</generateAnnotationPage>
       <generateOPFGuide>True</generateOPFGuide>
       <kindleRemovePersonalLabel>True</kindleRemovePersonalLabel>
+      <removePngTransparency>False</removePngTransparency>
       <vignettes/>
     </profile>
   </profiles>

fb2mobi.py

@@ -483,6 +483,8 @@ def process(args):
             config.current_profile['tocTitle'] = args.toctitle
         if args.chapteronnewpage is not None:
             config.current_profile['chapterOnNewPage'] = args.chapteronnewpage
+        if args.removepngtransparency is not None:
+            config.current_profile['removePngTransparency'] = args.removepngtransparency
         if args.noMOBIoptimization:
             config.noMOBIoptimization = args.noMOBIoptimization
         if args.sendtokindle is not None:
@@ -593,6 +595,10 @@ def process(args):
     tocplace_group.add_argument('--toc-before-body', dest='tocbeforebody', action='store_true', default=None, help='Put TOC at the book beginning')
     tocplace_group.add_argument('--toc-after-body', dest='tocbeforebody', action='store_false', default=None, help='Put TOC at the book end')
 
+    pngtransparency_group = argparser.add_mutually_exclusive_group()
+    pngtransparency_group.add_argument('--remove-png-transparency', dest='removepngtransparency', action='store_true', default=None, help='Remove transparency in PNG images')
+    pngtransparency_group.add_argument('--no-remove-png-transparency', dest='removepngtransparency', action='store_false', default=None, help='Do not remove transparency in PNG images')
+
     # Для совместимости с MyHomeLib добавляем аргументы, которые передает MHL в fb2mobi.exe
     argparser.add_argument('-nc', action='store_true', default=False, help='For MyHomeLib compatibility')
     argparser.add_argument('-cl', action='store_true', help='For MyHomeLib compatibility')

modules/config.py

@@ -64,6 +64,7 @@ def __init__(self, config_file):
         self.profiles['default']['generateAnnotationPage'] = True
         self.profiles['default']['generateOPFGuide'] = True
         self.profiles['default']['kindleRemovePersonalLabel'] = True
+        self.profiles['default']['removePngTransparency'] = False
 
         self.current_profile = {}
         self.mhl = False
@@ -171,6 +172,7 @@ def _load(self):
                     self.profiles[prof_name]['generateOPFGuide'] = True
                     self.profiles[prof_name]['flatTOC'] = True
                     self.profiles[prof_name]['kindleRemovePersonalLabel'] = True
+                    self.profiles[prof_name]['removePngTransparency'] = False
 
                     for p in prof:
                         if p.tag == 'hyphens':
@@ -209,6 +211,9 @@ def _load(self):
                         elif p.tag == 'kindleRemovePersonalLabel':
                             self.profiles[prof_name]['kindleRemovePersonalLabel'] = p.text.lower() == 'true'
 
+                        elif p.tag == 'removePngTransparency':
+                            self.profiles[prof_name]['removePngTransparency'] = p.text.lower() == 'true'
+
                         elif p.tag == 'generateAnnotationPage':
                             self.profiles[prof_name]['generateAnnotationPage'] = p.text.lower() == 'true'
 
@@ -309,6 +314,7 @@ def _getProfiles(self):
                             E('generateAnnotationPage', str(self.profiles[p]['generateAnnotationPage'])),
                             E('generateOPFGuide', str(self.profiles[p]['generateOPFGuide'])),
                             E('kindleRemovePersonalLabel', str(self.profiles[p]['kindleRemovePersonalLabel'])),
+                            E('removePngTransparency', str(self.profiles[p]['removePngTransparency'])),
                             E('vignettes',
                               *self._getVignettes(p)
                               ),

modules/fb2html.py

@@ -119,6 +119,8 @@ def __init__(self, fb2file, mobifile, tempdir, config):
         self.vignettes = config.current_profile['vignettes']
         self.vignette_files = []
 
+        self.removepngtransparency = config.current_profile['removePngTransparency']  # Remove transparency in PNG images
+
         self.annotation_title = config.current_profile['annotationTitle']  # Заголовок для раздела аннотации
         self.toc_title = config.current_profile['tocTitle']  # Заголовок для раздела содержания
 
@@ -224,6 +226,8 @@ def generate(self):
             elif ns_tag(child.tag) == 'binary':
                 self.parse_binary(child)
 
+        if self.removepngtransparency:
+            self.remove_png_transparency()
         self.correct_links()
         if self.generate_toc_page:
             self.generate_toc()
@@ -281,6 +285,39 @@ def replace_url(url):
         else:
             copy_file(self.css_file, os.path.join(self.temp_content_dir, 'stylesheet.css'))
 
+    def remove_png_transparency(self):
+        self.log.info('Removing PNG transparency...')
+        for img_rel_path in self.image_file_list:
+            if os.path.splitext(img_rel_path)[1] == '.png':
+                self.log.debug('Processing file "{}"'.format(img_rel_path))
+
+                try:
+                    filename = os.path.split(img_rel_path)[1]
+                    img_full_path = os.path.join(self.temp_content_dir, 'images', filename)
+                    img = Image.open(img_full_path)
+
+                    if img.format == 'PNG' and (img.mode in ('RGBA', 'LA')
+                            or (img.mode in ('RGB', 'L', 'P') and 'transparency' in img.info)):
+
+                        if img.mode == "P" and type(img.info.get("transparency")) is bytes:
+                            img = img.convert("RGBA")
+
+                        if img.mode in ("L", "LA"):
+                            bg = Image.new("L", img.size, 255)
+                        else:
+                            bg = Image.new("RGB", img.size, (255, 255, 255))
+
+                        alpha = img.convert("RGBA").split()[-1]
+                        bg.paste(img, mask=alpha)
+
+                        img_temp_path = os.path.splitext(img_full_path)[0] + "-o.png"
+                        bg.save(img_temp_path, dpi=img.info.get("dpi"))
+                        os.replace(img_temp_path, img_full_path)
+
+                except:
+                    self.log.warning('Error while removing transparency in file "{}"'.format(img_rel_path))
+                    self.log.debug('Getting details:', exc_info=True)
+
     def correct_links(self):
         for fl in self.html_file_list:
             parser = etree.XMLParser(encoding='utf-8')