[locale] Refactor long+lat -> x,y mapping

- Move this code to a static method since it only depends on the
  expected image size (which here, is managed by the image list).

src/modules/locale/Tests.cpp

@@ -90,8 +90,7 @@ LocaleTests::testTZImages()
     //
     //
     auto images = TimeZoneImageList::fromDirectory( SOURCE_DIR );
-    QCOMPARE( images.count(), images.zoneCount() );
+    QCOMPARE( images.count(), images.zoneCount );
-    QCOMPARE( images.count(), 38 );  // counted by hand
 
     // All image sizes consistent
     //

src/modules/locale/timezonewidget/TimeZoneImage.cpp

@@ -22,16 +22,17 @@
 
 #include <QDir>
 
-static const char* zoneNames[] =
+static const char* zoneNames[]
-          { "0.0",  "1.0",  "2.0",  "3.0",  "3.5",  "4.0",  "4.5",  "5.0",  "5.5",   "5.75", "6.0",   "6.5",  "7.0",
+    = { "0.0",  "1.0",  "2.0",  "3.0",  "3.5",  "4.0",  "4.5",  "5.0",  "5.5",   "5.75", "6.0",   "6.5",  "7.0",
-            "8.0",  "9.0",  "9.5",  "10.0", "10.5", "11.0", "11.5", "12.0", "12.75", "13.0", "-1.0",  "-2.0", "-3.0",
+        "8.0",  "9.0",  "9.5",  "10.0", "10.5", "11.0", "11.5", "12.0", "12.75", "13.0", "-1.0",  "-2.0", "-3.0",
-            "-3.5", "-4.0", "-4.5", "-5.0", "-5.5", "-6.0", "-7.0", "-8.0", "-9.0",  "-9.5", "-10.0", "-11.0" } ;
+        "-3.5", "-4.0", "-4.5", "-5.0", "-5.5", "-6.0", "-7.0", "-8.0", "-9.0",  "-9.5", "-10.0", "-11.0" };
+static_assert( TimeZoneImageList::zoneCount == ( sizeof( zoneNames ) / sizeof( zoneNames[ 0 ] ) ),
+               "Incorrect number of zones" );
 
-TimeZoneImageList::TimeZoneImageList()
+TimeZoneImageList::TimeZoneImageList() {}
-{
-}
 
-TimeZoneImageList TimeZoneImageList::fromQRC()
+TimeZoneImageList
+TimeZoneImageList::fromQRC()
 {
     TimeZoneImageList l;
     for ( const auto* zoneName : zoneNames )
@@ -43,7 +44,8 @@ TimeZoneImageList TimeZoneImageList::fromQRC()
     return l;
 }
 
-TimeZoneImageList TimeZoneImageList::fromDirectory(const QString& dirName)
+TimeZoneImageList
+TimeZoneImageList::fromDirectory( const QString& dirName )
 {
     TimeZoneImageList l;
     QDir dir( dirName );
@@ -55,14 +57,83 @@ TimeZoneImageList TimeZoneImageList::fromDirectory(const QString& dirName)
 
     for ( const auto* zoneName : zoneNames )
     {
-        l.append( QImage( dir.filePath( QStringLiteral("timezone_" ) + zoneName + ".png" ) ) );
+        l.append( QImage( dir.filePath( QStringLiteral( "timezone_" ) + zoneName + ".png" ) ) );
         l.last().setText( QStringLiteral( "zone" ), zoneName );
     }
 
     return l;
 }
 
-int TimeZoneImageList::zoneCount()
+QPoint
+TimeZoneImageList::getLocationPosition( double longitude, double latitude )
 {
-    return sizeof(zoneNames) / sizeof(zoneNames[0]);
+    constexpr double MAP_Y_OFFSET = 0.125;
+    constexpr double MAP_X_OFFSET = -0.0370;
+    constexpr double MATH_PI = 3.14159265;
+
+    const int width = imageSize.width();
+    const int height = imageSize.height();
+
+    double x = ( width / 2.0 + ( width / 2.0 ) * longitude / 180.0 ) + MAP_X_OFFSET * width;
+    double y = ( height / 2.0 - ( height / 2.0 ) * latitude / 90.0 ) + MAP_Y_OFFSET * height;
+
+    // Far north, the MAP_Y_OFFSET no longer holds, cancel the Y offset; it's noticeable
+    // from 62 degrees north, so scale those 28 degrees as if the world is flat south
+    // of there, and we have a funny "rounded" top of the world. In practice the locations
+    // of the different cities / regions looks ok -- at least Thule ends up in the right
+    // country, and Inuvik isn't in the ocean.
+    if ( latitude > 70.0 )
+    {
+        y -= sin( MATH_PI * ( latitude - 70.0 ) / 56.0 ) * MAP_Y_OFFSET * height * 0.8;
+    }
+    if ( latitude > 74.0 )
+    {
+        y += 4;
+    }
+    if ( latitude > 69.0 )
+    {
+        y -= 2;
+    }
+    if ( latitude > 59.0 )
+    {
+        y -= 4 * int( ( latitude - 54.0 ) / 5.0 );
+    }
+    if ( latitude > 54.0 )
+    {
+        y -= 2;
+    }
+    if ( latitude > 49.0 )
+    {
+        y -= int( ( latitude - 44.0 ) / 5.0 );
+    }
+    // Far south, some stretching occurs as well, but it is less pronounced.
+    // Move down by 1 pixel per 5 degrees past 10 south
+    if ( latitude < 0 )
+    {
+        y += int( ( -latitude ) / 5.0 );
+    }
+    // Antarctica isn't shown on the map, but you could try clicking there
+    if ( latitude < -60 )
+    {
+        y = height - 1;
+    }
+
+    if ( x < 0 )
+    {
+        x = width + x;
+    }
+    if ( x >= width )
+    {
+        x -= width;
+    }
+    if ( y < 0 )
+    {
+        y = height + y;
+    }
+    if ( y >= height )
+    {
+        y -= height;
+    }
+
+    return QPoint( int( x ), int( y ) );
 }

src/modules/locale/timezonewidget/TimeZoneImage.h

@@ -33,6 +33,7 @@ class TimeZoneImageList : public QList< TimeZoneImage >
 {
 private:
     TimeZoneImageList();
+
 public:
     /** @brief loads all the images from QRC.
      *
@@ -46,8 +47,19 @@ public:
      */
     static TimeZoneImageList fromDirectory( const QString& dirName );
 
+    /** @brief Map longitude and latitude to pixel positions
+     *
+     * The image is flat, and stretched at the poles and generally
+     * a bit weird, so this maps the global coordinates (as found in
+     * the zones table as a floating-point longitude and latitude value)
+     * to an x,y position.
+     */
+    static QPoint getLocationPosition( double longitude, double latitude );
+
     /// @brief The **expected** number of zones in the list.
-    static int zoneCount();
+    static constexpr const int zoneCount = 38;
+    /// @brief The expected size of each zone image.
+    static constexpr const QSize imageSize = QSize( 780, 340 );
 };
 
 #endif

src/modules/locale/timezonewidget/timezonewidget.cpp

@@ -31,10 +31,6 @@
 // Pixel value indicating that a spot is outside of a zone
 #define RGB_TRANSPARENT 0
 
-static constexpr double MAP_Y_OFFSET = 0.125;
-static constexpr double MAP_X_OFFSET = -0.0370;
-constexpr static double MATH_PI = 3.14159265;
-
 #ifdef DEBUG_TIMEZONES
 // Adds a label to the timezone with this name
 #define ZONE_NAME QStringLiteral( "zone" )
@@ -134,78 +130,6 @@ TimeZoneWidget::setCurrentLocation( const CalamaresUtils::Locale::TZZone* locati
 //### Private
 //###
 
-
-QPoint
-TimeZoneWidget::getLocationPosition( double longitude, double latitude )
-{
-    const int width = this->width();
-    const int height = this->height();
-
-    double x = ( width / 2.0 + ( width / 2.0 ) * longitude / 180.0 ) + MAP_X_OFFSET * width;
-    double y = ( height / 2.0 - ( height / 2.0 ) * latitude / 90.0 ) + MAP_Y_OFFSET * height;
-
-    // Far north, the MAP_Y_OFFSET no longer holds, cancel the Y offset; it's noticeable
-    // from 62 degrees north, so scale those 28 degrees as if the world is flat south
-    // of there, and we have a funny "rounded" top of the world. In practice the locations
-    // of the different cities / regions looks ok -- at least Thule ends up in the right
-    // country, and Inuvik isn't in the ocean.
-    if ( latitude > 70.0 )
-    {
-        y -= sin( MATH_PI * ( latitude - 70.0 ) / 56.0 ) * MAP_Y_OFFSET * height * 0.8;
-    }
-    if ( latitude > 74.0 )
-    {
-        y += 4;
-    }
-    if ( latitude > 69.0 )
-    {
-        y -= 2;
-    }
-    if ( latitude > 59.0 )
-    {
-        y -= 4 * int( ( latitude - 54.0 ) / 5.0 );
-    }
-    if ( latitude > 54.0 )
-    {
-        y -= 2;
-    }
-    if ( latitude > 49.0 )
-    {
-        y -= int( ( latitude - 44.0 ) / 5.0 );
-    }
-    // Far south, some stretching occurs as well, but it is less pronounced.
-    // Move down by 1 pixel per 5 degrees past 10 south
-    if ( latitude < 0 )
-    {
-        y += int( ( -latitude ) / 5.0 );
-    }
-    // Antarctica isn't shown on the map, but you could try clicking there
-    if ( latitude < -60 )
-    {
-        y = height - 1;
-    }
-
-    if ( x < 0 )
-    {
-        x = width + x;
-    }
-    if ( x >= width )
-    {
-        x -= width;
-    }
-    if ( y < 0 )
-    {
-        y = height + y;
-    }
-    if ( y >= height )
-    {
-        y -= height;
-    }
-
-    return QPoint( int( x ), int( y ) );
-}
-
-
 void
 TimeZoneWidget::paintEvent( QPaintEvent* )
 {
@@ -229,7 +153,7 @@ TimeZoneWidget::paintEvent( QPaintEvent* )
         QPen p( y_lat ? Qt::black : Qt::red );
         p.setWidth( 0 );
         painter.setPen( p );
-        QPoint latLine0( getLocationPosition( 0, y_lat ) );
+        QPoint latLine0( TimeZoneImageList::getLocationPosition( 0, y_lat ) );
         painter.drawLine( 0, latLine0.y(), this->width() - 1, latLine0.y() );
     }
     // Just a dot in the selected location, no label
@@ -309,7 +233,7 @@ TimeZoneWidget::mousePressEvent( QMouseEvent* event )
                 const auto* zone = dynamic_cast< const TZZone* >( zone_p );
                 if ( zone )
                 {
-                    QPoint locPos = getLocationPosition( zone->longitude(), zone->latitude() );
+                    QPoint locPos = TimeZoneImageList::getLocationPosition( zone->longitude(), zone->latitude() );
 
                     if ( ( abs( mX - locPos.x() ) + abs( mY - locPos.y() ) < abs( mX - nX ) + abs( mY - nY ) ) )
                     {

src/modules/locale/timezonewidget/timezonewidget.h

@@ -59,8 +59,10 @@ private:
     TimeZoneImageList timeZoneImages;
     const TZZone* m_currentLocation = nullptr;  // Not owned by me
 
-    QPoint getLocationPosition( const TZZone* l ) { return getLocationPosition( l->longitude(), l->latitude() ); }
+    QPoint getLocationPosition( const TZZone* l )
-    QPoint getLocationPosition( double longitude, double latitude );
+    {
+        return timeZoneImages.getLocationPosition( l->longitude(), l->latitude() );
+    }
 
     void paintEvent( QPaintEvent* event );
     void mousePressEvent( QMouseEvent* event );