Comic Input: Change default colors to 256 and add option to generate comic pages in PNG or JPEG formats. Fixes #3529 (Comics display badly on Adobe Digital Editions and some prs-505 models due to colour depth)

src/calibre/ebooks/comic/input.py

@@ -173,7 +173,7 @@ class PageProcessor(list):
                     p.MagickDespeckleImage(wand)
 
                 p.MagickQuantizeImage(wand, self.opts.colors, p.RGBColorspace, 0, 1, 0)
-                dest = '%d_%d.png'%(self.num, i)
+                dest = '%d_%d.%s'%(self.num, i, self.opts.output_format)
                 dest = os.path.join(self.dest, dest)
                 p.MagickWriteImage(wand, dest+'8')
                 os.rename(dest+'8', dest)
@@ -270,8 +270,10 @@ class ComicInput(InputFormatPlugin):
     is_image_collection = True
 
     options = set([
-        OptionRecommendation(name='colors', recommended_value=64,
+        OptionRecommendation(name='colors', recommended_value=256,
-            help=_('Number of colors for grayscale image conversion. Default: %default')),
+            help=_('Number of colors for grayscale image conversion. Default: '
+                '%default. Values of less than 256 may result in blurred text '
+                'on your device if you are creating your comics in EPUB format.')),
         OptionRecommendation(name='dont_normalize', recommended_value=False,
             help=_('Disable normalize (improve contrast) color range '
             'for pictures. Default: False')),
@@ -298,6 +300,10 @@ class ComicInput(InputFormatPlugin):
               help=_("Don't sort the files found in the comic "
               "alphabetically by name. Instead use the order they were "
               "added to the comic.")),
+        OptionRecommendation(name='output_format', choices=['png', 'jpg'],
+            recommended_value='png', help=_('The format that images in the created ebook '
+                'are converted to. You can experiment to see which format gives '
+                'you optimal size and look on your device.')),
         OptionRecommendation(name='no_process', recommended_value=False,
               help=_("Apply no processing to the image")),
         ])
@@ -365,7 +371,8 @@ class ComicInput(InputFormatPlugin):
                 '(run with --verbose to see why):')
                 for f in failures:
                     self.log.warning('\t', f)
-            thumbnail = os.path.join(tdir2, 'thumbnail.png')
+            thumbnail = os.path.join(tdir2,
+                    'thumbnail.'+self.opts.output_format.lower())
             if not os.access(thumbnail, os.R_OK):
                 thumbnail = None
         return new_pages

src/calibre/gui2/convert/comic_input.py

@@ -19,9 +19,11 @@ class PluginWidget(Widget, Ui_Form):
         Widget.__init__(self, parent, 'comic_input',
                 ['colors', 'dont_normalize', 'keep_aspect_ratio', 'right2left',
                     'despeckle', 'no_sort', 'no_process', 'landscape',
-                    'dont_sharpen', 'disable_trim', 'wide']
+                    'dont_sharpen', 'disable_trim', 'wide', 'output_format']
                 )
         self.db, self.book_id = db, book_id
+        for x in get_option('output_format').option.choices:
+            self.opt_output_format.addItem(x)
         self.initialize_options(get_option, get_help, db, book_id)
         self.opt_no_process.toggle()
         self.opt_no_process.toggle()

src/calibre/gui2/convert/comic_input.ui

@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>599</width>
-    <height>305</height>
+    <height>343</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -100,7 +100,7 @@
      </property>
     </widget>
    </item>
-   <item row="11" column="0">
+   <item row="12" column="0">
     <spacer name="verticalSpacer">
      <property name="orientation">
       <enum>Qt::Vertical</enum>
@@ -120,6 +120,19 @@
      </property>
     </widget>
    </item>
+   <item row="11" column="0">
+    <widget class="QLabel" name="label">
+     <property name="text">
+      <string>&amp;Output format:</string>
+     </property>
+     <property name="buddy">
+      <cstring>opt_output_format</cstring>
+     </property>
+    </widget>
+   </item>
+   <item row="11" column="1">
+    <widget class="QComboBox" name="opt_output_format"/>
+   </item>
   </layout>
  </widget>
  <resources/>
@@ -263,8 +276,8 @@
      <y>15</y>
     </hint>
     <hint type="destinationlabel">
-     <x>52</x>
+     <x>56</x>
-     <y>225</y>
+     <y>248</y>
     </hint>
    </hints>
   </connection>
@@ -300,5 +313,21 @@
     </hint>
    </hints>
   </connection>
+  <connection>
+   <sender>opt_no_process</sender>
+   <signal>toggled(bool)</signal>
+   <receiver>opt_output_format</receiver>
+   <slot>setDisabled(bool)</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>237</x>
+     <y>12</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>370</x>
+     <y>308</y>
+    </hint>
+   </hints>
+  </connection>
  </connections>
 </ui>