Encoding combobox optimization

MainWindow.cpp

@@ -76,11 +76,22 @@ MainWindow::MainWindow(QWidget *parent)
         qtAvaEcs.removeOne(top); }
     encodingList += qtAvaEcs;
 
+    ui->comboBox_EncodingSrc->blockSignals(true);
+    ui->comboBox_EncodingDest->blockSignals(true);
+    QFontMetrics fm = fontMetrics();
+    int cbboxMaxWidth = 0;
     for (auto &ec: encodingList) {
         QStringList aliases = ec.split(" / ");
         ui->comboBox_EncodingSrc->addItem(ec, aliases.first());
         ui->comboBox_EncodingDest->addItem(ec, aliases.first());
+        int tmp = fm.width(ec + "   ");  // 3 space to distinguish with " / "
+        if (tmp > cbboxMaxWidth)
+            cbboxMaxWidth = tmp;
     }
+    ui->comboBox_EncodingSrc->blockSignals(false);
+    ui->comboBox_EncodingDest->blockSignals(false);
+    ui->comboBox_EncodingSrc->view()->setFixedWidth(cbboxMaxWidth + 20);  // 20: scroll bar width
+    ui->comboBox_EncodingDest->view()->setFixedWidth(cbboxMaxWidth + 20);
 
     sIniPath = "config.ini";
     IniSetting cfg(sIniPath);

MainWindow.ui

@@ -6,7 +6,7 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>800</width>
+    <width>820</width>
     <height>500</height>
    </rect>
   </property>
@@ -30,6 +30,9 @@
        </item>
        <item row="0" column="1">
         <widget class="QComboBox" name="comboBox_EncodingSrc">
+         <property name="sizeAdjustPolicy">
+          <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
+         </property>
          <item>
           <property name="text">
            <string>Auto detect (Support UTF and System encoding)</string>
@@ -47,7 +50,11 @@
        <item row="1" column="1">
         <layout class="QHBoxLayout" name="horizontalLayout_3" stretch="1,0">
          <item>
-          <widget class="QComboBox" name="comboBox_EncodingDest"/>
+          <widget class="QComboBox" name="comboBox_EncodingDest">
+           <property name="sizeAdjustPolicy">
+            <enum>QComboBox::AdjustToMinimumContentsLengthWithIcon</enum>
+           </property>
+          </widget>
          </item>
          <item>
           <widget class="QCheckBox" name="checkBox_BomDest">