/game-ui-ux

name: game-ui-ux
description: >
  Design and build game UI/UX — HUDs, menus, and overlays — that survive every screen: anchor-
  based responsive layout, resolution/aspect scaling and safe areas, keyboard/gamepad focus
  navigation, a screen/menu state stack, and event-driven (not polled) HUD updates. Engine-
  neutral patterns that pair with the detected engine's UI skill. Use when the user mentions
  HUD, health bar, main menu, pause menu, settings screen, UI layout, anchors, UI scaling,
  aspect ratio, safe area, controller/keyboard menu navigation, or wiring UI to game state.

Game UI/UX

Build HUDs and menus that stay correct on a phone, an ultrawide monitor, and a TV across a gamepad and a mouse. This skill owns the engine-neutral UI architecture — responsive layout, scaling, focus navigation, screen flow, and how UI talks to game state — and defers the concrete widget API to the engine UI skill.

When to use

• Use when building a HUD (health/ammo/score), a menu (main/pause/settings), an inventory or

shop screen, or any overlay, and you want it to scale and navigate correctly.

• Use to fix UI that breaks at other resolutions/aspect ratios, ignores notches/safe areas,

can't be used with a controller, or is wired to game state by per-frame polling.

• Use to structure screen flow (title → game → pause → settings) as a stack, not flag soup.

**When *not* to use:** for the engine's concrete UI nodes/components and styling, use `godot-ui-control` or Unity UI (UGUI/UI Toolkit). For *visual* punch (button pop, damage numbers, shake) use `game-feel`. For branching conversation UI use `dialogue-systems`. For translating UI strings, that is localization (see `references/` and `input-systems` for rebinding screens). For card/board layout specifics, the `card-game` genre composes this skill.

Core workflow

1. **Pick a layout model: anchors + containers, never absolute pixels.** Anchor elements to edges/corners/center and let containers (rows, columns, grids) flow children. Absolute `(x, y)` positions break at the first new resolution. 2. **Choose a scaling strategy** for the whole UI: a reference resolution that scales to fit (most games), plus a policy for extra width/height on other aspect ratios (letterbox, expand, or anchor HUD corners outward). 3. **Respect the safe area.** Inset critical UI from screen edges so notches, rounded corners, and TV overscan don't clip it. 4. **Make every screen keyboard/gamepad navigable.** Set an initial focused control per screen, define focus order/neighbors, and show a clear focus highlight. Mouse and focus must coexist. 5. **Model screens as a stack.** Push (pause over game), pop (resume), with input + visibility handed to the top screen. This makes overlays and "back" trivial. 6. **Drive the HUD from events, not polling.** The HUD subscribes to `health_changed`, `score_changed`, etc. and updates only when they fire — it does not read game state every frame. 7. **Verify across screens and devices.** Resize the window, switch aspect ratios, unplug the mouse and navigate by gamepad only, and confirm focus, scaling, and safe-area insets. Report what you actually observed at which resolutions.

Patterns

1. Anchors + containers, not absolute coordinates

# Godot 4.7. Anchor a HUD label to the TOP-LEFT; let a container flow a row of hearts.
func _ready() -> void:
    $Score.set_anchors_preset(Control.PRESET_TOP_LEFT)   # sticks to the corner at any size
    # An HBoxContainer auto-lays-out children left-to-right; never position hearts by hand.
    for i in lives:
        $Hearts.add_child(make_heart())                   # HBoxContainer spaces them for you
# Unity 6.3 LTS uGUI: set RectTransform anchors to the corner; use a HorizontalLayoutGroup.
# RIGHT: anchors + layout groups. WRONG: rect.anchoredPosition = new Vector2(640, 360) (1080p-only).

2. Scale to a reference resolution (one UI, many screens)

# Godot 4.7 — Project Settings > Display > Window > Stretch:
#   Mode = "canvas_items", Aspect = "expand", reference size e.g. 1920x1080.
#   UI scales to the window; "expand" reveals extra space you anchor HUD corners into.
# Unity 6.3 LTS — Canvas > CanvasScaler:
#   UI Scale Mode = "Scale With Screen Size", Reference Resolution = 1920x1080,
#   Match = 0.5 (blend width/height) — pick 1.0 if your HUD is height-critical.
# Unity 6.3 LTS — UI Toolkit: the same three settings live on the PanelSettings asset
#   (Scale Mode = Scale With Screen Size, Reference Resolution, Screen Match Mode/Match).

3. Safe-area inset for notches / overscan

# Godot 4.7. Inset a MarginContainer to the OS safe rect. Only Android and iOS report a real
# safe area; elsewhere Godot returns the screen's usable rect, so desktop margins are ~0.
func _apply_safe_area() -> void:
    var safe := Rect2(DisplayServer.get_display_safe_area())           # screen pixels
    var win := Rect2(Rect2i(DisplayServer.window_get_position(), DisplayServer.window_get_size()))
    var inner := safe.intersection(win)
    var to_ui := get_viewport_rect().size / win.size    # window pixels -> UI units under stretch
    $Margin.add_theme_constant_override("margin_left", int((inner.position.x - win.position.x) * to_ui.x))
    $Margin.add_theme_constant_override("margin_top", int((inner.position.y - win.position.y) * to_ui.y))
    $Margin.add_theme_constant_override("margin_right", int((win.end.x - inner.end.x) * to_ui.x))
    $Margin.add_theme_constant_override("margin_bottom", int((win.end.y - inner.end.y) * to_ui.y))
# Unity 6.3 LTS: read Screen.safeArea (Rect in pixels) and set a panel's anchorMin/anchorMax to
# safeArea.position / (position+size) normalized by Screen.width/height.

4. Gamepad/keyboard focus (UI is unusable on a controller without it)

# Godot 4.7. Give each screen a default focus; Godot guesses neighbors from layout, so set
# them only where its guess is wrong (g