radselect: Add option to display radicals in decreasing frequency order

BUG: 431866

radselect/buttongrid.cpp

@@ -27,6 +27,7 @@ ButtonGrid::ButtonGrid( QWidget *parent, RadicalFile *radicalInfo )
 : QWidget( parent )
 , CurrentMode( Selection )
 , m_radicalInfo( radicalInfo )
+, m_sortByFrequency( false )
 {
   if ( m_radicalInfo )
   {
@@ -76,7 +77,8 @@ void ButtonGrid::buildRadicalButtons()
     int row_index = 1;
 
     QList<Radical> radicals = radicalMap->values( strokeCount );
-    std::sort( radicals.begin(), radicals.end(), Radical::compareIndices );
+    std::sort( radicals.begin(), radicals.end(),
+               m_sortByFrequency ? Radical::compareFrequencies : Radical::compareIndices );
     foreach( const Radical &radical, radicals )
     {
       //Make the button
@@ -98,6 +100,15 @@ void ButtonGrid::buildRadicalButtons()
   updateButtons();
 }
 
+void ButtonGrid::setSortByFrequency( bool enable )
+{
+  if( m_sortByFrequency != enable )
+  {
+    m_sortByFrequency = enable;
+    buildRadicalButtons();
+  }
+}
+
 void ButtonGrid::clearSelections()
 {
   m_selectedRadicals.clear();

radselect/buttongrid.h

@@ -48,6 +48,8 @@ class ButtonGrid : public QWidget
      */
     void clearSelections();
 
+    void setSortByFrequency( bool enable );
+
   private:
     void buildRadicalButtons();
     void updateButtons();
@@ -64,6 +66,7 @@ class ButtonGrid : public QWidget
     QString        m_relationalRadical;
     QSet<QString>  m_selectedRadicals;
     RadicalFile   *m_radicalInfo;
+    bool           m_sortByFrequency;
 
     //Radical -> Button Mapping
     QHash<QString, RadicalButton*> m_buttons;

radselect/radical.cpp

@@ -5,6 +5,8 @@
     SPDX-License-Identifier: LGPL-2.0-or-later
 */
 
+#include <tuple>
+
 #include "radical.h"
 
 Radical::Radical()
@@ -43,3 +45,10 @@ bool Radical::compareIndices( const Radical &a, const Radical &b )
 {
   return a.idx < b.idx;
 }
+
+bool Radical::compareFrequencies( const Radical &a, const Radical &b )
+{
+  // Negative frequency results in a descending order
+  return std::make_tuple( - a.getKanji().size(), a.idx ) <
+         std::make_tuple( - b.getKanji().size(), b.idx );
+}

radselect/radical.h

@@ -26,6 +26,7 @@ class Radical
     unsigned int         strokes() const;
 
     static bool          compareIndices( const Radical &a, const Radical &b );
+    static bool          compareFrequencies( const Radical &a, const Radical &b );
 
   protected:
     QString       string;

radselect/radselectconfig.kcfg

@@ -16,6 +16,10 @@
       <default>resultListFnt</default>
     </entry>
     <entry key="font" type="Font"></entry>
+    <entry key="sortByFrequency" type="Bool">
+      <label>Display radicals in descending frequency order</label>
+      <default>true</default>
+    </entry>
     <entry key="closeOnSearch" type="Bool">
       <label>Do we close this program when searching?</label>
       <default>false</default>

radselect/radselectprefdialog.ui

@@ -25,6 +25,13 @@
           </property>
         </widget>
       </item>
+      <item>
+        <widget class="QCheckBox" name="kcfg_sortByFrequency" >
+          <property name="text">
+            <string>Display radicals in descending frequency order</string>
+          </property>
+        </widget>
+      </item>
       <item>
         <layout class="QGridLayout" >
           <property name="margin" >

radselect/radselectview.cpp

@@ -207,6 +207,8 @@ void RadSelectView::loadSettings()
   //Suggested options: Lookup in Kiten, Add to Search Bar, Copy to Clipboard
   selected_radicals->setFont( RadSelectConfigSkeleton::self()->resultListFont() );
   m_buttongrid->setFont( RadSelectConfigSkeleton::self()->font() );
+
+  m_buttongrid->setSortByFrequency( RadSelectConfigSkeleton::self()->sortByFrequency() );
 }
 
 void RadSelectView::strokeLimitChanged( int newvalue )