Fix memory leak from repeatedly resetting the font (#9326)

* Fix memory leak from repeatedly resetting the font

* Reduce ruleset recompilation by MainMenuScreen background changes

core/src/com/unciv/ui/components/Fonts.kt

@@ -204,6 +204,10 @@ object Fonts {
     fun resetFont() {
         val settings = GUI.getSettings()
         fontImplementation.setFontFamily(settings.fontFamilyData, settings.getFontSize())
+        if (::font.isInitialized) {
+            (font.data as? NativeBitmapFontData)?.dispose()  // See #9325
+            // Don't font.dispose() even it it seems obvious -> leaves only black rectangles
+        }
         font = fontImplementation.getBitmapFont()
         font.data.markupEnabled = true
     }

core/src/com/unciv/ui/images/ImageGetter.kt

@@ -75,7 +75,7 @@ object ImageGetter {
         TileSetCache.assembleTileSetConfigs(ruleset.mods)
         SkinCache.assembleSkinConfigs(ruleset.mods)
 
-        Fonts.resetFont()
+        BaseScreen.setSkin()
         Fonts.addRulesetImages(ruleset)
     }
 

core/src/com/unciv/ui/screens/mainmenuscreen/MainMenuScreen.kt

@@ -60,6 +60,8 @@ import kotlin.math.min
 class MainMenuScreen: BaseScreen(), RecreateOnResize {
     private val backgroundStack = Stack()
     private val singleColumn = isCrampedPortrait()
+
+    private val backgroundMapRuleset: Ruleset
     private var easterEggRuleset: Ruleset? = null  // Cache it so the next 'egg' can be found in Civilopedia
 
     private var backgroundMapGenerationJob: Job? = null
@@ -68,7 +70,7 @@ class MainMenuScreen: BaseScreen(), RecreateOnResize {
     companion object {
         const val mapFadeTime = 1.3f
         const val mapFirstFadeTime = 0.3f
-        const val mapReplaceDelay = 15f
+        const val mapReplaceDelay = 20f
     }
 
     /** Create one **Main Menu Button** including onClick/key binding
@@ -117,7 +119,15 @@ class MainMenuScreen: BaseScreen(), RecreateOnResize {
 
         // If we were in a mod, some of the resource images for the background map we're creating
         // will not exist unless we reset the ruleset and images
-        ImageGetter.ruleset = RulesetCache.getVanillaRuleset()
+        val baseRuleset = RulesetCache.getVanillaRuleset()
+        ImageGetter.ruleset = baseRuleset
+
+        if (game.settings.enableEasterEggs) {
+            val easterEggMod = EasterEggRulesets.getTodayEasterEggRuleset()
+            if (easterEggMod != null)
+                easterEggRuleset = RulesetCache.getComplexRuleset(baseRuleset, listOf(easterEggMod))
+        }
+        backgroundMapRuleset = easterEggRuleset ?: baseRuleset
 
         // This is an extreme safeguard - should an invalid settings.tileSet ever make it past the
         // guard in UncivGame.create, simply omit the background so the user can at least get to options
@@ -209,13 +219,7 @@ class MainMenuScreen: BaseScreen(), RecreateOnResize {
                 scale = min(scale, 20f)
             }
 
-            val baseRuleset = RulesetCache.getVanillaRuleset()
+            val newMap = MapGenerator(backgroundMapRuleset, this)
-            easterEggRuleset = EasterEggRulesets.getTodayEasterEggRuleset()?.let {
-                RulesetCache.getComplexRuleset(baseRuleset, listOf(it))
-            }
-            val mapRuleset = if (game.settings.enableEasterEggs) easterEggRuleset ?: baseRuleset else baseRuleset
-
-            val newMap = MapGenerator(mapRuleset, this)
                 .generateMap(MapParameters().apply {
                     shape = MapShape.rectangular
                     mapSize = MapSizeNew(MapSize.Small)
@@ -226,7 +230,7 @@ class MainMenuScreen: BaseScreen(), RecreateOnResize {
                 })
 
             launchOnGLThread { // for GL context
-                ImageGetter.setNewRuleset(mapRuleset)
+                ImageGetter.setNewRuleset(backgroundMapRuleset)
                 val mapHolder = EditorMapHolder(
                     this@MainMenuScreen,
                     newMap