GUI: Editable combo box with most common character encodings instead of fully free form text entry. This still allows users to specify encodings that are not part of the common list.

src/calibre/gui2/convert/__init__.py

@@ -191,7 +191,9 @@ class Widget(QWidget):
             if not val: val = ''
             getattr(g, 'setPlainText', g.setText)(val)
             getattr(g, 'setCursorPosition', lambda x: x)(0)
-        elif isinstance(g, QComboBox) and val:
+        elif isinstance(g, QComboBox):
+            if not val:
+                val = ''
             idx = g.findText(val, Qt.MatchFixedString)
             if idx < 0:
                 g.addItem(val)

src/calibre/gui2/convert/look_and_feel.ui

@@ -84,7 +84,7 @@
         <string>...</string>
        </property>
        <property name="icon">
-        <iconset resource="../../../../resources/images.qrc">
+        <iconset>
          <normaloff>:/images/wizard.png</normaloff>:/images/wizard.png</iconset>
        </property>
        <property name="iconSize">
@@ -122,14 +122,8 @@
      <property name="text">
       <string>Input character &amp;encoding:</string>
      </property>
-     <property name="buddy">
-      <cstring>opt_input_encoding</cstring>
-     </property>
     </widget>
    </item>
-   <item row="5" column="1" colspan="3">
-    <widget class="QLineEdit" name="opt_input_encoding"/>
-   </item>
    <item row="6" column="0" colspan="2">
     <widget class="QCheckBox" name="opt_remove_paragraph_spacing">
      <property name="text">
@@ -244,8 +238,22 @@
      </property>
     </widget>
    </item>
+   <item row="5" column="1" colspan="3">
+    <widget class="EncodingComboBox" name="opt_input_encoding">
+     <property name="editable">
+      <bool>true</bool>
+     </property>
+    </widget>
+   </item>
   </layout>
  </widget>
+ <customwidgets>
+  <customwidget>
+   <class>EncodingComboBox</class>
+   <extends>QComboBox</extends>
+   <header>widgets.h</header>
+  </customwidget>
+ </customwidgets>
  <resources>
   <include location="../../../../resources/images.qrc"/>
   <include location="../../../../resources/images.qrc"/>

src/calibre/gui2/convert/pdb_output.ui

@@ -55,10 +55,21 @@
     </widget>
    </item>
    <item row="1" column="1">
-    <widget class="QLineEdit" name="opt_output_encoding"/>
+    <widget class="EncodingComboBox" name="opt_output_encoding">
+     <property name="editable">
+      <bool>true</bool>
+     </property>
+    </widget>
    </item>
   </layout>
  </widget>
+ <customwidgets>
+  <customwidget>
+   <class>EncodingComboBox</class>
+   <extends>QComboBox</extends>
+   <header>widgets.h</header>
+  </customwidget>
+ </customwidgets>
  <resources/>
  <connections/>
 </ui>

src/calibre/gui2/convert/pmlz_output.ui

@@ -14,7 +14,7 @@
    <string>Form</string>
   </property>
   <layout class="QGridLayout" name="gridLayout">
-   <item row="3" column="0">
+   <item row="4" column="0">
     <spacer name="verticalSpacer">
      <property name="orientation">
       <enum>Qt::Vertical</enum>
@@ -27,32 +27,47 @@
      </property>
     </spacer>
    </item>
-   <item row="1" column="0">
+   <item row="2" column="0">
     <widget class="QCheckBox" name="opt_inline_toc">
      <property name="text">
       <string>&amp;Inline TOC</string>
      </property>
     </widget>
    </item>
-   <item row="2" column="0">
+   <item row="3" column="0">
     <widget class="QCheckBox" name="opt_full_image_depth">
      <property name="text">
       <string>Do not reduce image size and depth</string>
      </property>
     </widget>
    </item>
-   <item row="0" column="0">
+   <item row="1" column="0">
+    <layout class="QHBoxLayout" name="horizontalLayout">
+     <item>
       <widget class="QLabel" name="label">
        <property name="text">
         <string>Output Encoding:</string>
        </property>
       </widget>
      </item>
-   <item row="0" column="1">
-    <widget class="QLineEdit" name="opt_output_encoding"/>
+     <item>
+      <widget class="EncodingComboBox" name="opt_output_encoding">
+       <property name="editable">
+        <bool>true</bool>
+       </property>
+      </widget>
+     </item>
+    </layout>
    </item>
   </layout>
  </widget>
+ <customwidgets>
+  <customwidget>
+   <class>EncodingComboBox</class>
+   <extends>QComboBox</extends>
+   <header>widgets.h</header>
+  </customwidget>
+ </customwidgets>
  <resources/>
  <connections/>
 </ui>

src/calibre/gui2/convert/txt_output.ui

@@ -96,10 +96,21 @@
     </widget>
    </item>
    <item row="2" column="1">
-    <widget class="QLineEdit" name="opt_output_encoding"/>
+    <widget class="EncodingComboBox" name="opt_output_encoding">
+     <property name="editable">
+      <bool>true</bool>
+     </property>
+    </widget>
    </item>
   </layout>
  </widget>
+ <customwidgets>
+  <customwidget>
+   <class>EncodingComboBox</class>
+   <extends>QComboBox</extends>
+   <header>widgets.h</header>
+  </customwidget>
+ </customwidgets>
  <resources/>
  <connections/>
 </ui>

src/calibre/gui2/widgets.py

@@ -616,6 +616,32 @@ class ComboBoxWithHelp(QComboBox):
         QComboBox.hidePopup(self)
         self.set_state()
 
+
+class EncodingComboBox(QComboBox):
+    '''
+    A combobox that holds text encodings support
+    by Python. This is only populated with the most
+    common and standard encodings. There is no good
+    way to programatically list all supported encodings
+    using encodings.aliases.aliases.keys(). It
+    will not work.
+    '''
+
+    ENCODINGS = ['', 'ascii', 'big5', 'cp1250', 'cp1251',  'cp1252', 'cp1253',
+        'cp1254', 'cp1255', 'cp1256', 'euc_jp', 'euc_kr', 'gb2312', 'gb18030',
+        'hz', 'iso2022_jp', 'iso2022_kr', 'iso8859_5', 'latin_1', 'shift_jis',
+        'utf_8',
+    ]
+    
+    def __init__(self, parent=None):
+        QComboBox.__init__(self, parent)
+        self.setEditable(True)
+        self.setLineEdit(EnLineEdit(self))
+        
+        for item in self.ENCODINGS:
+            self.addItem(item)
+    
+
 class PythonHighlighter(QSyntaxHighlighter):
 
     Rules = []