Added castability highlighting for cards in hand

forge-gui-desktop/src/main/java/forge/screens/home/settings/CSubmenuPreferences.java

@@ -155,6 +155,7 @@ public void initialize() {
         lstControls.add(Pair.of(view.getCbOpenPacksIndiv(), FPref.UI_OPEN_PACKS_INDIV));
         lstControls.add(Pair.of(view.getCbTokensInSeparateRow(), FPref.UI_TOKENS_IN_SEPARATE_ROW));
         lstControls.add(Pair.of(view.getCbStackCreatures(), FPref.UI_STACK_CREATURES));
+        lstControls.add(Pair.of(view.getCbShowCastableBorder(), FPref.UI_SHOW_CASTABLE_BORDER));
         lstControls.add(Pair.of(view.getCbManaLostPrompt(), FPref.UI_MANA_LOST_PROMPT));
         lstControls.add(Pair.of(view.getCbEscapeEndsTurn(), FPref.UI_ALLOW_ESC_TO_END_TURN));
         lstControls.add(Pair.of(view.getCbDetailedPaymentDesc(), FPref.UI_DETAILED_SPELLDESC_IN_PROMPT));

forge-gui-desktop/src/main/java/forge/screens/home/settings/VSubmenuPreferences.java

@@ -109,6 +109,7 @@ public enum VSubmenuPreferences implements IVSubmenu<CSubmenuPreferences> {
     private final JCheckBox cbOpenPacksIndiv = new OptionsCheckBox(localizer.getMessage("cbOpenPacksIndiv"));
     private final JCheckBox cbTokensInSeparateRow = new OptionsCheckBox(localizer.getMessage("cbTokensInSeparateRow"));
     private final JCheckBox cbStackCreatures = new OptionsCheckBox(localizer.getMessage("cbStackCreatures"));
+    private final JCheckBox cbShowCastableBorder = new OptionsCheckBox(localizer.getMessage("cbShowCastableBorder"));
     private final JCheckBox cbFilterLandsByColorId = new OptionsCheckBox(localizer.getMessage("cbFilterLandsByColorId"));
     private final JCheckBox cbShowStormCount = new OptionsCheckBox(localizer.getMessage("cbShowStormCount"));
     private final JCheckBox cbRemindOnPriority = new OptionsCheckBox(localizer.getMessage("cbRemindOnPriority"));
@@ -423,6 +424,9 @@ public enum VSubmenuPreferences implements IVSubmenu<CSubmenuPreferences> {
         pnlPrefs.add(cbStackCreatures, titleConstraints);
         pnlPrefs.add(new NoteLabel(localizer.getMessage("nlStackCreatures")), descriptionConstraints);
 
+        pnlPrefs.add(cbShowCastableBorder, titleConstraints);
+        pnlPrefs.add(new NoteLabel(localizer.getMessage("nlShowCastableBorder")), descriptionConstraints);
+
         pnlPrefs.add(cbTimedTargOverlay, titleConstraints);
         pnlPrefs.add(new NoteLabel(localizer.getMessage("nlTimedTargOverlay")), descriptionConstraints);
 
@@ -973,6 +977,10 @@ public final JCheckBox getCbStackCreatures() {
         return cbStackCreatures;
     }
 
+    public final JCheckBox getCbShowCastableBorder() {
+        return cbShowCastableBorder;
+    }
+
     public final JCheckBox getCbManaLostPrompt() {
     	return cbManaLostPrompt;
     }

forge-gui-desktop/src/main/java/forge/view/arcane/CardPanel.java

@@ -45,6 +45,7 @@
 import javax.swing.JRootPane;
 import javax.swing.SwingUtilities;
 
+import forge.ai.ComputerUtilMana;
 import forge.CachedCardImage;
 import forge.StaticData;
 import forge.card.CardEdition;
@@ -55,6 +56,7 @@
 import forge.game.card.CardView.CardStateView;
 import forge.game.card.CounterType;
 import forge.game.keyword.Keyword;
+import forge.game.spellability.SpellAbility;
 import forge.game.zone.ZoneType;
 import forge.gui.CardContainer;
 import forge.gui.FThreads;
@@ -299,6 +301,13 @@ protected final void paintComponent(final Graphics g) {
             g2d.fillRoundRect(cardXOffset - n2, (cardYOffset - n2) + offset, cardWidth + (n2 * 2), cardHeight + (n2 * 2), cornerSize + n2, cornerSize + n2);
         }
 
+        // Yellow border for cards in hand that can be cast with available mana
+        if (isPreferenceEnabled(FPref.UI_SHOW_CASTABLE_BORDER) && canCastCard()) {
+            g2d.setColor(Color.YELLOW);
+            final int n = Math.max(1, Math.round(cardWidth * CardPanel.SELECTED_BORDER_SIZE));
+            g2d.fillRoundRect(cardXOffset - n, (cardYOffset - n) + offset, cardWidth + (n * 2), cardHeight + (n * 2), cornerSize + n , cornerSize + n);
+        }
+
         // Green outline for hover
         if (isSelected) {
             g2d.setColor(Color.green);
@@ -352,6 +361,71 @@ protected final void paintComponent(final Graphics g) {
         }
     }
 
+    /*
+     * Checks if the card in this panel can be cast with available mana.
+     * Returns true if the card is in hand and has at least one spell ability that can be played.
+     * This method is used to highlight castable cards with a yellow border.
+     */
+    private boolean canCastCard() {
+        try {
+            // Only check cards in hand
+            if (card == null || !ZoneType.Hand.equals(card.getZone())) {
+                return false;
+            }
+
+            // Get the game view to access the actual Game object
+            final var gameView = matchUI.getGameView();
+            if (gameView == null) {
+                return false;
+            }
+
+            final var game = gameView.getGame();
+            if (game == null) {
+                return false;
+            }
+
+            // Find the actual Card object 
+            Card actualCard = game.findByView(card);
+            if (actualCard == null) {
+                return false;
+            }
+
+            // Get all spell abilities for this card
+            final var abilities = actualCard.getSpellAbilities();
+            if (abilities == null || abilities.isEmpty()) {
+                return false;
+            }
+
+            // Get the player who owns this card
+            final var player = actualCard.getOwner();
+            if (player == null) {
+                return false;
+            }
+
+            for (final SpellAbility sa : abilities) {
+                // First check if the spell can be played (timing, restrictions, etc.)
+                if (!sa.canPlay(true)) {
+                    continue;
+                }
+
+                // Set the activating player for the spell ability
+                sa.setActivatingPlayer(player);
+
+                // Check if the player can actually pay the mana cost from available sources
+                if (ComputerUtilMana.canPayManaCost(sa, player, 0, false)) {
+                    return true;
+                }
+            }
+            //If no costs can be met
+            return false;
+
+        } catch (Exception e) {
+            // If any exception occurs (NullPointerException, etc.), safely return false
+            return false;
+        }
+    }
+
+
     private void drawManaCost(final Graphics g, final ManaCost cost, final int deltaY) {
         final int width = CardFaceSymbols.getWidth(cost);
         final int height = CardFaceSymbols.getHeight();

forge-gui/res/languages/en-US.properties

@@ -135,6 +135,7 @@ cbCardTextHideReminder=Hide Reminder Text for Card Text Renderer
 cbOpenPacksIndiv=Open Packs Individually
 cbTokensInSeparateRow=Display Tokens in a Separate Row
 cbStackCreatures=Stack Creatures
+cbShowCastableBorder=Enable Castability Highlighting
 cbFilterLandsByColorId=Filter Lands by Color in Activated Abilities
 cbShowStormCount=Show Storm Count in Prompt Pane
 cbRemindOnPriority=Visually Alert on Receipt of Priority
@@ -240,6 +241,7 @@ nlCardTextHideReminder=When render card images, skip rendering reminder text.
 nlOpenPacksIndiv=When opening Fat Packs and Booster Boxes, booster packs will be opened and displayed one at a time.
 nlTokensInSeparateRow=Displays tokens in a separate row on the battlefield below the non-token creatures.
 nlStackCreatures=Stacks identical creatures on the battlefield like lands, artifacts, and enchantments.
+nlShowCastableBorder=Enables a yellow border that highlights cards that can currently be cast (considering available mana, timing, etc.)
 nlTimedTargOverlay=Enables throttling-based optimization of targeting overlay to reduce CPU use (only disable if you experience choppiness on older hardware, requires starting a new match).
 nlCounterDisplayType=Selects the style of the in-game counter display for cards. Text-based is a new tab-like display on the cards. Image-based is the old counter image. Hybrid displays both at once.
 nlCounterDisplayLocation=Determines where to position the text-based counters on the card: close to the top or close to the bottom.

forge-gui/src/main/java/forge/localinstance/properties/ForgePreferences.java

@@ -77,6 +77,7 @@ public enum FPref implements PreferencesStore.IPref {
         UI_AVATARS ("0,1"),
         UI_SLEEVES ("0,1"),
         UI_SHOW_CARD_OVERLAYS ("true"),
+        UI_SHOW_CASTABLE_BORDER ("false"),
         UI_OVERLAY_CARD_NAME ("true"),
         UI_OVERLAY_CARD_POWER ("true"),
         UI_OVERLAY_CARD_MANA_COST ("true"),