15.1 Keyboard State🔗ℹ

(when (key-pressed? 'escape)

(quit!))

(when (key-pressed? 'w)

(move-forward!))

This is useful for checking multiple keys efficiently in a game loop.

15.2 Modifier Keys🔗ℹ

(define mods (get-mod-state))

(when (mod-state-has? mods 'ctrl)

(printf "Control is held~n"))

15.3 Keyboard Enumeration🔗ℹ

15.4 Text Input🔗ℹ

Text input allows receiving Unicode text from the user, including IME (Input Method Editor) support for non-Latin scripts.

Once enabled, text-input-event will be generated when the user types text. This is separate from key events—key events give you raw key presses, while text input gives you the resulting characters (including those composed via dead keys or IME).

(start-text-input! win)

;; Now text-input-event will fire when user types

Call this when you no longer need text input (e.g., when leaving a text field) to allow the IME to close.

15.5 Key Symbol Conversion🔗ℹ

These functions convert between Racket symbols and SDL scancodes/keycodes.

Scancodes represent physical key positions on the keyboard, independent of the current keyboard layout.

Keycodes represent the logical key based on the current keyboard layout. For example, on a QWERTY layout the ’Q’ position produces keycode for ’q’, but on an AZERTY layout it produces keycode for ’a’.

15.6 Low-Level Key Utilities🔗ℹ

These functions provide direct access to SDL’s scancode and keycode APIs.