option to disable backup compression

aqt/main.py

@@ -322,6 +322,10 @@ the manual for information on how to restore from an automatic backup."))
 
     def backup(self):
         nbacks = self.pm.profile['numBackups']
+        if self.pm.profile.get('compressBackups', True):
+            zipStorage = zipfile.ZIP_DEFLATED
+        else:
+            zipStorage = zipfile.ZIP_STORED
         if not nbacks or os.getenv("ANKIDEV", 0):
             return
         dir = self.pm.backupFolder()
@@ -342,7 +346,7 @@ the manual for information on how to restore from an automatic backup."))
             n = backups[-1][0] + 1
         # do backup
         newpath = os.path.join(dir, "backup-%d.apkg" % n)
-        z = zipfile.ZipFile(newpath, "w", zipfile.ZIP_DEFLATED)
+        z = zipfile.ZipFile(newpath, "w", zipStorage)
         z.write(path, "collection.anki2")
         z.writestr("media", "{}")
         z.close()

aqt/preferences.py

@@ -112,6 +112,7 @@ Not currently enabled; click the sync button in the main window to enable."""))
 
     def setupBackup(self):
         self.form.numBackups.setValue(self.prof['numBackups'])
+        self.form.compressBackups.setChecked(self.prof.get("compressBackups", True))
         self.connect(self.form.openBackupFolder,
                      SIGNAL("linkActivated(QString)"),
                      self.onOpenBackup)
@@ -121,6 +122,7 @@ Not currently enabled; click the sync button in the main window to enable."""))
 
     def updateBackup(self):
         self.prof['numBackups'] = self.form.numBackups.value()
+        self.prof['compressBackups'] = self.form.compressBackups.isChecked()
 
     # Basic & Advanced Options
     ######################################################################

designer/preferences.ui

@@ -349,6 +349,13 @@
          </item>
         </layout>
        </item>
+       <item>
+        <widget class="QCheckBox" name="compressBackups">
+         <property name="text">
+          <string>Compress backups (slower)</string>
+         </property>
+        </widget>
+       </item>
        <item>
         <widget class="QLabel" name="openBackupFolder">
          <property name="text">