Tweak to restrict list of output formats

Add a tweak to restrict the list of output formats available in the
conversion dialog. Go to Preferences->Tweaks to change it.

resources/default_tweaks.py

@@ -537,3 +537,10 @@ many_libraries = 10
 # highlight with this tweak. Set it to 'transparent' to disable highlighting.
 highlight_virtual_library = 'yellow'
 
+#: Choose available output formats for conversion
+# Restrict the list of available output formats in the conversion dialogs.
+# For example, if you only want to convert to EPUB and AZW3, change this to
+# restrict_output_formats = ['EPUB', 'AZW3']. The default value of None causes
+# all available output formats to be present.
+restrict_output_formats = None
+

src/calibre/gui2/convert/bulk.py

@@ -9,8 +9,7 @@ import shutil
 from PyQt4.Qt import QString, SIGNAL
 
 from calibre.gui2.convert.single import (Config, sort_formats_by_preference,
-    GroupModel, gprefs)
+    GroupModel, gprefs, get_output_formats)
-from calibre.customize.ui import available_output_formats
 from calibre.gui2 import ResizableDialog
 from calibre.gui2.convert.look_and_feel import LookAndFeelWidget
 from calibre.gui2.convert.heuristics import HeuristicsWidget
@@ -43,7 +42,6 @@ class BulkConfig(Config):
             'values saved in a previous conversion (if they exist) instead '
             'of using the defaults specified in the Preferences'))
 
-
         self.connect(self.output_formats, SIGNAL('currentIndexChanged(QString)'),
                 self.setup_pipeline)
         self.connect(self.groups, SIGNAL('activated(QModelIndex)'),
@@ -96,7 +94,8 @@ class BulkConfig(Config):
 
         while True:
             c = self.stack.currentWidget()
-            if not c: break
+            if not c:
+                break
             self.stack.removeWidget(c)
 
         widgets = [lf, hw, ps, sd, toc, sr]
@@ -118,17 +117,14 @@ class BulkConfig(Config):
         except:
             pass
 
-
     def setup_output_formats(self, db, preferred_output_format):
         if preferred_output_format:
             preferred_output_format = preferred_output_format.lower()
-        output_formats = sorted(available_output_formats(),
+        output_formats = get_output_formats(preferred_output_format)
-                key=lambda x:{'EPUB':'!A', 'MOBI':'!B'}.get(x.upper(), x))
-        output_formats.remove('oeb')
         preferred_output_format = preferred_output_format if \
             preferred_output_format and preferred_output_format \
             in output_formats else sort_formats_by_preference(output_formats,
-                    prefs['output_format'])[0]
+                    [prefs['output_format']])[0]
         self.output_formats.addItems(list(map(QString, [x.upper() for x in
             output_formats])))
         self.output_formats.setCurrentIndex(output_formats.index(preferred_output_format))
@@ -149,3 +145,4 @@ class BulkConfig(Config):
                 bytearray(self.saveGeometry())
         return ResizableDialog.done(self, r)
 
+

src/calibre/gui2/convert/single.py

@@ -29,7 +29,7 @@ from calibre.ebooks.conversion.plumber import (Plumber,
 from calibre.ebooks.conversion.config import delete_specifics
 from calibre.customize.ui import available_output_formats
 from calibre.customize.conversion import OptionRecommendation
-from calibre.utils.config import prefs
+from calibre.utils.config import prefs, tweaks
 from calibre.utils.logging import Log
 
 class NoSupportedInputFormats(Exception):
@@ -48,6 +48,20 @@ def sort_formats_by_preference(formats, prefs):
         return len(prefs)
     return sorted(formats, key=key)
 
+def get_output_formats(preferred_output_format):
+    all_formats = {x.upper() for x in available_output_formats()}
+    all_formats.discard('OEB')
+    pfo = preferred_output_format.upper() if preferred_output_format else ''
+    restrict = tweaks['restrict_output_formats']
+    if restrict:
+        fmts = [x.upper() for x in restrict]
+        if pfo and pfo not in fmts and pfo in all_formats:
+            fmts.append(pfo)
+    else:
+        fmts = list(sorted(all_formats,
+                key=lambda x:{'EPUB':'!A', 'MOBI':'!B'}.get(x.upper(), x)))
+    return fmts
+
 class GroupModel(QAbstractListModel):
 
     def __init__(self, widgets):
@@ -239,15 +253,13 @@ class Config(ResizableDialog, Ui_Dialog):
             preferred_output_format):
         if preferred_output_format:
             preferred_output_format = preferred_output_format.lower()
-        output_formats = sorted(available_output_formats(),
+        output_formats = get_output_formats(preferred_output_format)
-                key=lambda x:{'EPUB':'!A', 'MOBI':'!B'}.get(x.upper(), x))
-        output_formats.remove('oeb')
         input_format, input_formats = get_input_format_for_book(db, book_id,
                 preferred_input_format)
         preferred_output_format = preferred_output_format if \
             preferred_output_format in output_formats else \
             sort_formats_by_preference(output_formats,
-                    prefs['output_format'])[0]
+                    [prefs['output_format']])[0]
         self.input_formats.addItems(list(map(QString, [x.upper() for x in
             input_formats])))
         self.output_formats.addItems(list(map(QString, [x.upper() for x in