Implement on-screen keyboard dialog with QWERTY layout

Builds out uikeyboard/uikeyboardqwerty from placeholders into a working
controller-navigable text entry dialog: title/current-text labels, a flat
QWERTY key grid (letters, space, backspace), and confirm/cancel buttons in
one combined menu so d-pad navigation flows across all of it.

uikeyboardopen_t configures each dialog: onInput/onKeyPress callbacks,
optional cancel button, maxLength (auto-focuses confirm once full),
lineCount for multi-line entry (adds a NEWLINE key, reserves vertical
space up front), a second "are you sure" uiConfirm step, and
trimmed/allowBlank validation on confirm.

Back now deletes the last character first, falling through to close only
when cancel is allowed and the buffer is empty - this needed a general
cancel-intercept callback added to uifocusitem_t/uimenu_t
(uiMenuSetCancelCallback), since the focus system previously only
supported popping or fully swallowing back.

Wired a temporary "LOAD GAME (TEST)" entry into the main menu with
console-logging test callbacks for interactive testing; marked TODO for
removal once the keyboard is wired up somewhere real.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/dusk/ui/dialog/keyboard/uikeyboard.c

@@ -6,16 +6,329 @@
  */
 
 #include "uikeyboard.h"
+#include "ui/widget/uiframe.h"
+#include "ui/widget/uibutton.h"
+#include "ui/dialog/uiconfirm.h"
+#include "assert/assert.h"
+#include "util/memory.h"
+#include "util/string.h"
+#include "util/math.h"
+#include "display/screen/screen.h"
+#include "display/color.h"
+#include "display/text/font.h"
+#include "display/spritebatch/spritebatch.h"
+#include "display/texture/texture.h"
+#include "display/shader/shaderunlit.h"
+
+#define UI_KEYBOARD_BACKDROP_COLOR color4b(0, 0, 0, 160)
+#define UI_KEYBOARD_KEY_WIDTH 20.0f
 
 uikeyboard_t UI_KEYBOARD;
 
+void uiKeyboardFocusConfirm(void) {
+  uint8_t confirmIndex = UI_KEYBOARD.menu.itemCount - (UI_KEYBOARD.cancel ? 2 : 1);
+  uiMenuSetPosition(
+    &UI_KEYBOARD.menu,
+    confirmIndex % UI_KEYBOARD.menu.columns,
+    confirmIndex / UI_KEYBOARD.menu.columns
+  );
+}
+
+bool_t uiKeyboardTextIsBlank(void) {
+  for(const char_t *c = UI_KEYBOARD.text; *c != '\0'; c++) {
+    if(!stringIsWhitespace(*c)) return false;
+  }
+  return true;
+}
+
+void uiKeyboardAppendChar(const char_t c) {
+  size_t length = strlen(UI_KEYBOARD.text);
+  if(length >= UI_KEYBOARD.maxLength) return;
+
+  if(c == '\n') {
+    uint8_t lines = 1;
+    for(size_t i = 0; i < length; i++) {
+      if(UI_KEYBOARD.text[i] == '\n') lines++;
+    }
+    if(lines >= UI_KEYBOARD.lineCount) return;
+  }
+
+  UI_KEYBOARD.text[length] = c;
+  UI_KEYBOARD.text[length + 1] = '\0';
+  UI_KEYBOARD.textLabel.dirty = true;
+  uiLabelRebuffer(&UI_KEYBOARD.textLabel);
+
+  // Nothing more can be typed - jump focus to confirm so accepting is a
+  // single button press away.
+  if(length + 1 >= UI_KEYBOARD.maxLength) uiKeyboardFocusConfirm();
+}
+
+void uiKeyboardBackspace(void) {
+  size_t length = strlen(UI_KEYBOARD.text);
+  if(length == 0) return;
+
+  UI_KEYBOARD.text[length - 1] = '\0';
+  UI_KEYBOARD.textLabel.dirty = true;
+  uiLabelRebuffer(&UI_KEYBOARD.textLabel);
+}
+
+void uiKeyboardMenuClosed(const uimenu_t *menu) {
+  if(UI_KEYBOARD.onInput != NULL) {
+    UI_KEYBOARD.onInput(
+      UI_KEYBOARD.text, UI_KEYBOARD.confirmed, UI_KEYBOARD.user
+    );
+  }
+}
+
+bool_t uiKeyboardMenuCancel(const uimenu_t *menu) {
+  if(strlen(UI_KEYBOARD.text) > 0) {
+    uiKeyboardBackspace();
+    return true;
+  }
+
+  // Nothing left to delete - close, but only if this dialog is even
+  // allowed to be cancelled. Closed explicitly (rather than returning
+  // false to fall through to uiFocusUpdate's default pop) since that
+  // path only pops the focus stack - it never clears UI_KEYBOARD.open,
+  // which would leave uiKeyboardDraw drawing a focus-less dialog forever
+  // and the next uiKeyboardOpen() tripping its already-open assert.
+  if(!UI_KEYBOARD.cancel) return true;
+
+  UI_KEYBOARD.confirmed = false;
+  uiKeyboardClose();
+  return true;
+}
+
+void uiKeyboardConfirmSecondaryResult(const bool_t result, void *user) {
+  if(!result) return;
+
+  UI_KEYBOARD.confirmed = true;
+  uiKeyboardClose();
+}
+
+void uiKeyboardMenuSelected(
+  const uimenu_t *menu,
+  const uint8_t index,
+  const uimenuitem_t *item
+) {
+  uint8_t confirmIndex = menu->itemCount - (UI_KEYBOARD.cancel ? 2 : 1);
+  if(index == confirmIndex) {
+    if(UI_KEYBOARD.trimmed) {
+      stringTrim(UI_KEYBOARD.text);
+      UI_KEYBOARD.textLabel.dirty = true;
+      uiLabelRebuffer(&UI_KEYBOARD.textLabel);
+    }
+    if(!UI_KEYBOARD.allowBlank && uiKeyboardTextIsBlank()) return;
+
+    if(UI_KEYBOARD.confirm) {
+      uiConfirmOpen(
+        UI_KEYBOARD.confirmQuestion, uiKeyboardConfirmSecondaryResult, NULL
+      );
+      return;
+    }
+
+    UI_KEYBOARD.confirmed = true;
+    uiKeyboardClose();
+    return;
+  }
+
+  if(UI_KEYBOARD.cancel && index == menu->itemCount - 1) {
+    UI_KEYBOARD.confirmed = false;
+    uiKeyboardClose();
+    return;
+  }
+
+  const char_t *key = item->button.label.text;
+  if(stringCompare(key, UI_KEYBOARD_QWERTY_KEY_BACKSPACE) == 0) {
+    uiKeyboardBackspace();
+    return;
+  }
+
+  char_t c;
+  if(stringCompare(key, UI_KEYBOARD_QWERTY_KEY_SPACE) == 0) {
+    c = ' ';
+  } else if(
+    UI_KEYBOARD.lineCount > 1 &&
+    stringCompare(key, UI_KEYBOARD_KEY_NEWLINE) == 0
+  ) {
+    c = '\n';
+  } else {
+    c = key[0];
+  }
+
+  if(UI_KEYBOARD.onKeyPress != NULL && !UI_KEYBOARD.onKeyPress(c, UI_KEYBOARD.user)) {
+    return;
+  }
+  uiKeyboardAppendChar(c);
+}
+
 errorret_t uiKeyboardInit(void) {
-  // Nothing to initialize yet -- uikeyboard_t is currently a
+  memoryZero(&UI_KEYBOARD, sizeof(uikeyboard_t));
-  // placeholder with no fields.
+
+  uiLabelInit(
+    &UI_KEYBOARD.titleLabel, UI_KEYBOARD.titleText,
+    UI_KEYBOARD.titleSprites, UI_KEYBOARD_TITLE_SPRITES_MAX
+  );
+  uiLabelInit(
+    &UI_KEYBOARD.textLabel, UI_KEYBOARD.text,
+    UI_KEYBOARD.textSprites, UI_KEYBOARD_TEXT_SPRITES_MAX
+  );
+
   errorOk();
 }
 
+bool_t uiKeyboardIsOpen(void) {
+  return UI_KEYBOARD.open;
+}
+
+void uiKeyboardOpen(const uikeyboardopen_t *open) {
+  assertNotNull(open, "Open parameters cannot be NULL");
+  assertFalse(UI_KEYBOARD.open, "Keyboard is already open");
+  assertTrue(
+    open->maxLength <= UI_KEYBOARD_TEXT_MAX - 1,
+    "maxLength exceeds UI_KEYBOARD_TEXT_MAX"
+  );
+  assertTrue(
+    open->lineCount <= UI_KEYBOARD_LINE_COUNT_MAX,
+    "lineCount exceeds UI_KEYBOARD_LINE_COUNT_MAX"
+  );
+
+  stringCopy(
+    UI_KEYBOARD.titleText, UI_KEYBOARD_TITLE_DEFAULT,
+    UI_KEYBOARD_TITLE_TEXT_MAX - 1
+  );
+  UI_KEYBOARD.titleLabel.dirty = true;
+  uiLabelRebuffer(&UI_KEYBOARD.titleLabel);
+
+  UI_KEYBOARD.text[0] = '\0';
+  UI_KEYBOARD.textLabel.dirty = true;
+  uiLabelRebuffer(&UI_KEYBOARD.textLabel);
+
+  UI_KEYBOARD.onInput = open->onInput;
+  UI_KEYBOARD.onKeyPress = open->onKeyPress;
+  UI_KEYBOARD.cancel = open->cancel;
+  UI_KEYBOARD.maxLength = open->maxLength == 0 ?
+    UI_KEYBOARD_TEXT_MAX - 1 : open->maxLength;
+  UI_KEYBOARD.lineCount = open->lineCount == 0 ? 1 : open->lineCount;
+  UI_KEYBOARD.confirm = open->confirm;
+  stringCopy(
+    UI_KEYBOARD.confirmQuestion,
+    open->confirmLabel != NULL ?
+      open->confirmLabel : UI_KEYBOARD_CONFIRM_QUESTION_DEFAULT,
+    UI_KEYBOARD_CONFIRM_QUESTION_MAX - 1
+  );
+  UI_KEYBOARD.trimmed = open->trimmed;
+  UI_KEYBOARD.allowBlank = open->allowBlank;
+  UI_KEYBOARD.user = open->user;
+  UI_KEYBOARD.confirmed = false;
+  UI_KEYBOARD.open = true;
+
+  uint8_t index = uiKeyboardQwertyBuildItems(UI_KEYBOARD.items);
+
+  if(UI_KEYBOARD.lineCount > 1) {
+    UI_KEYBOARD.items[index].type = UI_MENU_WIDGET_TYPE_BUTTON;
+    uiButtonInit(&UI_KEYBOARD.items[index].button, UI_KEYBOARD_KEY_NEWLINE);
+    index++;
+  }
+
+  UI_KEYBOARD.items[index].type = UI_MENU_WIDGET_TYPE_BUTTON;
+  uiButtonInit(&UI_KEYBOARD.items[index].button, UI_KEYBOARD_CONFIRM_LABEL);
+  index++;
+
+  if(UI_KEYBOARD.cancel) {
+    UI_KEYBOARD.items[index].type = UI_MENU_WIDGET_TYPE_BUTTON;
+    uiButtonInit(&UI_KEYBOARD.items[index].button, UI_KEYBOARD_CANCEL_LABEL);
+    index++;
+  }
+
+  uiMenuInit(
+    &UI_KEYBOARD.menu, uiKeyboardMenuSelected, uiKeyboardMenuClosed, NULL
+  );
+  uiMenuSetItems(
+    &UI_KEYBOARD.menu, UI_KEYBOARD.items, index, UI_KEYBOARD_QWERTY_COLUMNS
+  );
+
+  // Back deletes a character rather than closing the dialog outright -
+  // see uiKeyboardMenuCancel.
+  uiMenuSetCancelCallback(&UI_KEYBOARD.menu, uiKeyboardMenuCancel);
+  uiMenuOpen(&UI_KEYBOARD.menu);
+}
+
+void uiKeyboardClose(void) {
+  if(!UI_KEYBOARD.open) return;
+  UI_KEYBOARD.open = false;
+
+  if(uiMenuIsActive(&UI_KEYBOARD.menu)) {
+    uiMenuClose(&UI_KEYBOARD.menu);
+  } else {
+    uiKeyboardMenuClosed(NULL);
+  }
+}
+
 errorret_t uiKeyboardDraw(void) {
+  if(!UI_KEYBOARD.open) errorOk();
+
+  spritebatchsprite_t backdropSprite = {
+    .min = { 0.0f, 0.0f, 0.0f },
+    .max = { (float_t)SCREEN.width, (float_t)SCREEN.height, 0.0f },
+    .uvMin = { 0.0f, 0.0f },
+    .uvMax = { 1.0f, 1.0f }
+  };
+  shadermaterial_t backdropMaterial = {
+    .unlit = {
+      .color = UI_KEYBOARD_BACKDROP_COLOR,
+      .texture = &TEXTURE_WHITE
+    }
+  };
+  errorChain(
+    spriteBatchBuffer(&backdropSprite, 1, &SHADER_UNLIT, backdropMaterial)
+  );
+  errorChain(spriteBatchFlush());
+
+  float_t rowHeight = (float_t)FONT_DEFAULT.tileset->tileHeight;
+  // When multi-line, reserve the full lineCount rows up front so the
+  // dialog doesn't resize as newlines are typed - otherwise fall back to
+  // the label's own measured height (floored at one row for an empty
+  // string, which measures to zero).
+  float_t textHeight = UI_KEYBOARD.lineCount > 1 ?
+    (float_t)UI_KEYBOARD.lineCount * rowHeight :
+    mathMax(rowHeight, (float_t)UI_KEYBOARD.textLabel.height);
+  uint8_t rows = (UI_KEYBOARD.menu.itemCount + UI_KEYBOARD.menu.columns - 1) /
+    UI_KEYBOARD.menu.columns;
+
+  float_t contentWidth = mathMax(
+    mathMax((float_t)UI_KEYBOARD.titleLabel.width, (float_t)UI_KEYBOARD.textLabel.width),
+    (float_t)UI_KEYBOARD.menu.columns * UI_KEYBOARD_KEY_WIDTH
+  );
+  float_t width = contentWidth + (UI_FRAME_START_X * 2);
+  float_t height = (UI_FRAME_START_Y * 2)
+    + rowHeight + UI_FRAME_PADDING_Y
+    + textHeight + UI_FRAME_PADDING_Y
+    + ((float_t)rows * rowHeight);
+
+  float_t x = (float_t)SCREEN.scanX +
+    ((float_t)SCREEN.scanWidth - width) * 0.5f;
+  float_t y = (float_t)SCREEN.scanY +
+    ((float_t)SCREEN.scanHeight - height) * 0.5f;
+
+  errorChain(uiFrameDraw(x, y, width, height));
+
+  float_t contentX = x + UI_FRAME_START_X;
+  float_t contentY = y + UI_FRAME_START_Y;
+
+  uiLabelSetX(&UI_KEYBOARD.titleLabel, contentX);
+  uiLabelSetY(&UI_KEYBOARD.titleLabel, contentY);
+  errorChain(uiLabelRender(&UI_KEYBOARD.titleLabel, COLOR_WHITE));
+
+  float_t textY = contentY + rowHeight + UI_FRAME_PADDING_Y;
+  uiLabelSetX(&UI_KEYBOARD.textLabel, contentX);
+  uiLabelSetY(&UI_KEYBOARD.textLabel, textY);
+  errorChain(uiLabelRender(&UI_KEYBOARD.textLabel, COLOR_WHITE));
+
+  float_t menuY = textY + textHeight + UI_FRAME_PADDING_Y;
+  errorChain(uiMenuDraw(&UI_KEYBOARD.menu, contentX, menuY, contentWidth, rowHeight));
+
+  errorChain(spriteBatchFlush());
   errorOk();
 }
 

src/dusk/ui/dialog/keyboard/uikeyboard.h

@@ -7,31 +7,267 @@
 
 #pragma once
 #include "error/error.h"
+#include "ui/widget/uilabel.h"
+#include "ui/widget/uimenu.h"
+#include "ui/dialog/keyboard/uikeyboardqwerty.h"
+
+#define UI_KEYBOARD_TITLE_TEXT_MAX 64
+#define UI_KEYBOARD_TITLE_SPRITES_MAX UI_KEYBOARD_TITLE_TEXT_MAX
+#define UI_KEYBOARD_TEXT_MAX 64
+#define UI_KEYBOARD_TEXT_SPRITES_MAX UI_KEYBOARD_TEXT_MAX
+// Room for the active layout's keys plus the newline/confirm/cancel
+// buttons uiKeyboard appends itself - only the QWERTY layout exists
+// today.
+#define UI_KEYBOARD_ITEMS_MAX (UI_KEYBOARD_QWERTY_KEY_COUNT + 3)
+
+// Hardcoded for now - a uiModalOpen-style title/button text override is
+// planned (see uikeyboardopen_t) but not built yet.
+#define UI_KEYBOARD_TITLE_DEFAULT "ENTER YOUR TEXT"
+#define UI_KEYBOARD_CONFIRM_LABEL "CONFIRM"
+#define UI_KEYBOARD_CANCEL_LABEL "CANCEL"
+// Only added to the grid when uikeyboardopen_t.lineCount > 1.
+#define UI_KEYBOARD_KEY_NEWLINE "NEWLINE"
+
+#define UI_KEYBOARD_CONFIRM_QUESTION_MAX 64
+// Used when uikeyboardopen_t.confirmLabel is NULL.
+#define UI_KEYBOARD_CONFIRM_QUESTION_DEFAULT "Is this correct?"
+
+// Maximum number of lines uikeyboardopen_t.lineCount may request.
+#define UI_KEYBOARD_LINE_COUNT_MAX 4
+
+/**
+ * Callback invoked once the keyboard dialog is dismissed.
+ *
+ * @param text The entered text. Only meaningful when confirmed is true;
+ * points at UI_KEYBOARD's own buffer, so copy it out if it needs to
+ * outlive the next uiKeyboardOpen call.
+ * @param confirmed True if the confirm button was picked, false if
+ * cancelled.
+ * @param user Arbitrary pointer passed via uikeyboardopen_t.user.
+ */
+typedef void (*uikeyboardinputcallback_t)(
+  const char_t *text,
+  const bool_t confirmed,
+  void *user
+);
+
+/**
+ * Callback invoked before a key press is applied, giving the caller a
+ * chance to reject it - e.g. an email field rejecting "%".
+ *
+ * @param c The character about to be entered (SPACE included, DEL/
+ * confirm/cancel excluded - those aren't text being entered).
+ * @param user Arbitrary pointer passed via uikeyboardopen_t.user.
+ * @returns True to allow the character, false to reject it (ignored,
+ * nothing is entered).
+ */
+typedef bool_t (*uikeyboardkeypresscallback_t)(const char_t c, void *user);
+
+/**
+ * Parameters for uiKeyboardOpen. Expect this to grow (e.g. title/button
+ * text overrides) as more dialogs start using the keyboard.
+ */
+typedef struct {
+  // Fired once the dialog is dismissed, confirmed or cancelled. May be
+  // NULL.
+  uikeyboardinputcallback_t onInput;
+
+  // Fired for each key press before it's applied. May be NULL to allow
+  // everything.
+  uikeyboardkeypresscallback_t onKeyPress;
+
+  // Whether the cancel button is shown, and whether pressing back with
+  // no text entered closes the dialog - see uiKeyboardMenuCancel.
+  bool_t cancel;
+
+  // Maximum length of the entered text, in characters excluding the
+  // null terminator. 0 defaults to the buffer's full capacity
+  // (UI_KEYBOARD_TEXT_MAX - 1). Must not exceed that.
+  size_t maxLength;
+
+  // When true, picking confirm opens a second uiConfirm "are you sure"
+  // dialog (see confirmLabel) on top of the keyboard before actually
+  // closing it - picking Cancel there returns to the keyboard with the
+  // text untouched.
+  bool_t confirm;
+
+  // Question text/locale message ID for the second confirm dialog when
+  // confirm is true; copied internally, safe to be transient. NULL uses
+  // UI_KEYBOARD_CONFIRM_QUESTION_DEFAULT. Ignored when confirm is false.
+  const char_t *confirmLabel;
+
+  // If true, leading/trailing whitespace is trimmed from the entered
+  // text when confirm is pressed, before it's checked against
+  // allowBlank or passed to onInput.
+  bool_t trimmed;
+
+  // If true, a blank result is accepted when confirm is pressed - blank
+  // means an empty string, or (when trimmed is false) a string of only
+  // spaces. When false, pressing confirm does nothing while the text is
+  // blank - see uiKeyboardTextIsBlank.
+  bool_t allowBlank;
+
+  // Maximum number of lines the entered text can span, from 1 to
+  // UI_KEYBOARD_LINE_COUNT_MAX. 0 defaults to 1. When > 1, a NEWLINE key
+  // is added to the grid, capped at inserting lineCount - 1 newlines.
+  uint8_t lineCount;
+
+  // Arbitrary pointer passed to onInput/onKeyPress.
+  void *user;
+} uikeyboardopen_t;
 
 typedef struct {
+  uilabel_t titleLabel;
+  char_t titleText[UI_KEYBOARD_TITLE_TEXT_MAX];
+  spritebatchsprite_t titleSprites[UI_KEYBOARD_TITLE_SPRITES_MAX];
 
+  uilabel_t textLabel;
+  char_t text[UI_KEYBOARD_TEXT_MAX];
+  spritebatchsprite_t textSprites[UI_KEYBOARD_TEXT_SPRITES_MAX];
+
+  uimenu_t menu;
+  uimenuitem_t items[UI_KEYBOARD_ITEMS_MAX];
+
+  char_t confirmQuestion[UI_KEYBOARD_CONFIRM_QUESTION_MAX];
+
+  uikeyboardinputcallback_t onInput;
+  uikeyboardkeypresscallback_t onKeyPress;
+  void *user;
+  size_t maxLength;
+  uint8_t lineCount;
+  bool_t cancel;
+  bool_t confirm;
+  bool_t trimmed;
+  bool_t allowBlank;
+  bool_t open;
+  bool_t confirmed;
 } uikeyboard_t;
 
 extern uikeyboard_t UI_KEYBOARD;
 
 /**
- * Initializes the on-screen keyboard. Currently a placeholder -- no
+ * Initializes the on-screen keyboard.
- * behavior implemented yet.
  *
  * @return Any error that occurs.
  */
 errorret_t uiKeyboardInit(void);
 
 /**
- * Draws the on-screen keyboard. Currently a placeholder -- no-op.
+ * Draws the on-screen keyboard: a semi-transparent black backdrop
+ * covering the whole screen, then its own centered frame with the title,
+ * currently entered text, and the active layout's key grid. No-op when
+ * not open.
  *
  * @return Any error that occurs.
  */
 errorret_t uiKeyboardDraw(void);
 
+/**
+ * Returns true when the keyboard dialog is currently open.
+ *
+ * @returns True if open.
+ */
+bool_t uiKeyboardIsOpen(void);
+
+/**
+ * Opens the on-screen keyboard with an empty text buffer.
+ *
+ * @param open Parameters for this dialog; copied internally, safe to be
+ * transient. Cannot be NULL.
+ */
+void uiKeyboardOpen(const uikeyboardopen_t *open);
+
+/**
+ * Closes the keyboard dialog, invoking the result callback set by
+ * uiKeyboardOpen as cancelled (confirmed=false) unless the confirm
+ * button was what triggered this close. No-op when already closed.
+ */
+void uiKeyboardClose(void);
+
 /**
  * Disposes of the on-screen keyboard.
  *
  * @return Any error that occurs.
  */
 errorret_t uiKeyboardDispose(void);
+
+/**
+ * Appends a character to the currently entered text, silently ignoring
+ * it once UI_KEYBOARD.maxLength is reached, or (for '\n') once the text
+ * already has UI_KEYBOARD.lineCount - 1 newlines. Does not consult
+ * onKeyPress - that happens in uiKeyboardMenuSelected before this is
+ * called. Moves focus to the confirm button once this append fills the
+ * text to maxLength - see uiKeyboardFocusConfirm.
+ *
+ * @param c The character to append.
+ */
+void uiKeyboardAppendChar(const char_t c);
+
+/**
+ * Moves the menu's focus to the confirm button.
+ */
+void uiKeyboardFocusConfirm(void);
+
+/**
+ * Returns whether the currently entered text counts as blank for
+ * UI_KEYBOARD.allowBlank purposes - an empty string, or (when
+ * UI_KEYBOARD.trimmed is false, so whitespace-only text was never
+ * reduced to empty) a string of only whitespace.
+ *
+ * @returns True if blank.
+ */
+bool_t uiKeyboardTextIsBlank(void);
+
+/**
+ * Removes the last character of the currently entered text. No-op when
+ * already empty.
+ */
+void uiKeyboardBackspace(void);
+
+/**
+ * Internal menu callback - routes a picked key/confirm/cancel item to
+ * uiKeyboardAppendChar/uiKeyboardBackspace/uiKeyboardClose, consulting
+ * onKeyPress before a character key is applied. When UI_KEYBOARD.confirm
+ * is set, picking confirm opens a second uiConfirm dialog (see
+ * uiKeyboardConfirmSecondaryResult) instead of closing immediately.
+ *
+ * @param menu The keyboard's menu.
+ * @param index Index of the picked item.
+ * @param item The picked item.
+ */
+void uiKeyboardMenuSelected(
+  const uimenu_t *menu,
+  const uint8_t index,
+  const uimenuitem_t *item
+);
+
+/**
+ * Result callback for the second "are you sure" uiConfirm dialog opened
+ * when UI_KEYBOARD.confirm is set - see uiKeyboardMenuSelected.
+ *
+ * @param result True if Confirm was picked there, false if Cancel.
+ * @param user Unused.
+ */
+void uiKeyboardConfirmSecondaryResult(const bool_t result, void *user);
+
+/**
+ * Internal menu callback - fires the result callback set by
+ * uiKeyboardOpen once the menu finishes closing.
+ *
+ * @param menu Unused; matches uimenuclosedcallback_t.
+ */
+void uiKeyboardMenuClosed(const uimenu_t *menu);
+
+/**
+ * Internal menu cancel callback (see uiMenuSetCancelCallback): back
+ * deletes the last entered character; with nothing left to delete, it
+ * closes the dialog as cancelled via uiKeyboardClose, but only when
+ * UI_KEYBOARD.cancel allows it - otherwise back is swallowed and does
+ * nothing.
+ *
+ * @param menu The keyboard's menu.
+ * @returns Always true - this always fully handles back itself
+ * (backspace, explicit close, or swallow), never falling through to the
+ * default pop.
+ */
+bool_t uiKeyboardMenuCancel(const uimenu_t *menu);

src/dusk/ui/dialog/keyboard/uikeyboardqwerty.c

@@ -6,17 +6,34 @@
  */
 
 #include "uikeyboardqwerty.h"
+#include "assert/assert.h"
+#include "ui/widget/uibutton.h"
 
 uikeyboardqwerty_t UI_KEYBOARD_QWERTY;
 
+// String literals have static storage duration, so these stay valid for
+// as long as the process runs - safe for uiButtonInit's non-copying
+// label contract.
+static const char_t *const UI_KEYBOARD_QWERTY_KEYS[UI_KEYBOARD_QWERTY_KEY_COUNT] = {
+  "Q", "W", "E", "R", "T", "Y", "U", "I", "O", "P",
+  "A", "S", "D", "F", "G", "H", "J", "K", "L",
+  "Z", "X", "C", "V", "B", "N", "M",
+  UI_KEYBOARD_QWERTY_KEY_SPACE, UI_KEYBOARD_QWERTY_KEY_BACKSPACE
+};
+
 errorret_t uiKeyboardQwertyInit(void) {
-  // Nothing to initialize yet -- uikeyboardqwerty_t is currently a
-  // placeholder with no fields.
   errorOk();
 }
 
-errorret_t uiKeyboardQwertyDraw(void) {
+uint8_t uiKeyboardQwertyBuildItems(uimenuitem_t *items) {
-  errorOk();
+  assertNotNull(items, "Items cannot be NULL");
+
+  for(uint8_t i = 0; i < UI_KEYBOARD_QWERTY_KEY_COUNT; i++) {
+    items[i].type = UI_MENU_WIDGET_TYPE_BUTTON;
+    uiButtonInit(&items[i].button, UI_KEYBOARD_QWERTY_KEYS[i]);
+  }
+
+  return UI_KEYBOARD_QWERTY_KEY_COUNT;
 }
 
 errorret_t uiKeyboardQwertyDispose(void) {

src/dusk/ui/dialog/keyboard/uikeyboardqwerty.h

@@ -7,6 +7,20 @@
 
 #pragma once
 #include "error/error.h"
+#include "ui/widget/uimenu.h"
+
+// 26 letters plus SPACE and DEL, laid out as one flat columns-wide grid
+// rather than the staggered rows a physical QWERTY keyboard uses - the
+// menu/focus grid only supports uniform columns today, so exact row
+// staggering is left for later.
+#define UI_KEYBOARD_QWERTY_COLUMNS 10
+#define UI_KEYBOARD_QWERTY_KEY_COUNT 28
+
+// Labels uiKeyboard checks for by pointer/string compare (see
+// uiKeyboardQwertyBuildItems) to tell the space/backspace keys apart from
+// an ordinary single-letter key.
+#define UI_KEYBOARD_QWERTY_KEY_SPACE "SPACE"
+#define UI_KEYBOARD_QWERTY_KEY_BACKSPACE "DEL"
 
 typedef struct {
 
@@ -15,22 +29,29 @@ typedef struct {
 extern uikeyboardqwerty_t UI_KEYBOARD_QWERTY;
 
 /**
- * Initializes the QWERTY keyboard layout. Currently a placeholder --
+ * Initializes the QWERTY keyboard layout. Currently a no-op - the key
- * no behavior implemented yet.
+ * labels are static string literals with no per-instance state.
  *
  * @return Any error that occurs.
  */
 errorret_t uiKeyboardQwertyInit(void);
 
 /**
- * Draws the QWERTY keyboard layout. Currently a placeholder -- no-op.
+ * Builds the QWERTY layout's key buttons (26 letters, then SPACE and
+ * DEL) into items, starting at index 0, one UI_MENU_WIDGET_TYPE_BUTTON
+ * per key. Each button's label is either a single uppercase letter or the
+ * literal UI_KEYBOARD_QWERTY_KEY_SPACE/UI_KEYBOARD_QWERTY_KEY_BACKSPACE -
+ * uiKeyboard reads a selected item's own label back to know which key it
+ * was, rather than this function returning a separate mapping.
  *
- * @return Any error that occurs.
+ * @param items Destination array; must have room for at least
+ * UI_KEYBOARD_QWERTY_KEY_COUNT entries.
+ * @returns The number of items written (UI_KEYBOARD_QWERTY_KEY_COUNT).
  */
-errorret_t uiKeyboardQwertyDraw(void);
+uint8_t uiKeyboardQwertyBuildItems(uimenuitem_t *items);
 
 /**
- * Disposes of the QWERTY keyboard layout.
+ * Disposes of the QWERTY keyboard layout. Currently a no-op.
  *
  * @return Any error that occurs.
  */

src/dusk/ui/focus/uifocus.c

@@ -153,6 +153,7 @@ void uiFocusUpdate(void) {
   }
 
   if(inputPressed(INPUT_ACTION_CANCEL)) {
+    if(item->cancel != NULL && item->cancel(item)) return;
     if(!item->disableBack) uiFocusPop();
     return;
   }

src/dusk/ui/focus/uifocusitem.h

@@ -53,10 +53,19 @@ struct uifocusitem_s {
   uifocusitemcallback_t changed;
   uifocusitemcallback_t closed;
   uifocusitemdirectioncallback_t direction;
+
+  // Called when INPUT_ACTION_CANCEL is pressed, before disableBack/the
+  // default pop is applied; may be NULL. Returns true if fully handled
+  // (e.g. it did something else instead, or popped itself), which skips
+  // the default pop; false to fall through to the default disableBack/
+  // pop behavior below.
+  uifocusitemcallback_t cancel;
+
   void *user;
 
   // When true, INPUT_ACTION_CANCEL is ignored while this item is the
   // topmost focus item - it does not pop. Does not affect a
-  // programmatic uiFocusPop()/uiFocusPopItem() call.
+  // programmatic uiFocusPop()/uiFocusPopItem() call. Only consulted
+  // when cancel is unset or returns false.
   bool_t disableBack;
 };

src/dusk/ui/screen/mainmenu/uimainmenu.c

@@ -16,11 +16,15 @@
 #include "locale/localemanager.h"
 #include "asset/loader/locale/assetlocaleloader.h"
 #include "ui/dialog/uiconfirm.h"
+#include "ui/dialog/keyboard/uikeyboard.h"
 #include "scene/mainmenu/scenemainmenu.h"
+#include "console/console.h"
 
 #define UI_MAIN_MENU_INDEX_START_GAME 0
 #define UI_MAIN_MENU_INDEX_OPTIONS 1
 #define UI_MAIN_MENU_INDEX_QUIT 2
+// TODO: temporary - see UI_MAIN_MENU_ITEM_COUNT in uimainmenu.h.
+#define UI_MAIN_MENU_INDEX_LOAD_GAME_TEST 3
 
 uimainmenu_t UI_MAIN_MENU;
 
@@ -28,6 +32,22 @@ void uiMainMenuQuitConfirmed(const bool_t result, void *user) {
   if(result) ENGINE.running = false;
 }
 
+bool_t uiMainMenuKeyboardTestKeyPress(const char_t c, void *user) {
+  consolePrint("uiKeyboard onKeyPress: '%c'", c);
+  return true;
+}
+
+void uiMainMenuKeyboardTestInput(
+  const char_t *text,
+  const bool_t confirmed,
+  void *user
+) {
+  consolePrint(
+    "uiKeyboard onInput: confirmed=%s text='%s'",
+    confirmed ? "true" : "false", text
+  );
+}
+
 void uiMainMenuSelected(
   const uimenu_t *menu,
   const uint8_t index,
@@ -48,6 +68,20 @@ void uiMainMenuSelected(
       uiConfirmOpen("main_menu.quit_confirm", uiMainMenuQuitConfirmed, NULL);
       break;
 
+    case UI_MAIN_MENU_INDEX_LOAD_GAME_TEST: {
+      uikeyboardopen_t open = {
+        .onInput = uiMainMenuKeyboardTestInput,
+        .onKeyPress = uiMainMenuKeyboardTestKeyPress,
+        .cancel = false,
+        .confirm = true,
+        .user = NULL,
+        .maxLength = 6,
+        .lineCount = 2
+      };
+      uiKeyboardOpen(&open);
+      break;
+    }
+
     default:
       break;
   }
@@ -84,6 +118,8 @@ errorret_t uiMainMenuInit(void) {
   MENU_BUTTON(UI_MAIN_MENU.startGameLabel);
   MENU_BUTTON(UI_MAIN_MENU.optionsLabel);
   MENU_BUTTON(UI_MAIN_MENU.quitLabel);
+  // TODO: temporary - see UI_MAIN_MENU_ITEM_COUNT in uimainmenu.h.
+  MENU_BUTTON("LOAD GAME (TEST)");
   MENU_END(UI_MAIN_MENU.items, 1);
 
   // The main menu is the root screen once past the initial boot check -

src/dusk/ui/screen/mainmenu/uimainmenu.h

@@ -9,9 +9,12 @@
 #include "error/error.h"
 #include "ui/widget/uimenu.h"
 
-#define UI_MAIN_MENU_ITEM_COUNT 3
+// TODO: item count/height bumped for the temporary "LOAD GAME (TEST)"
+// keyboard test entry in uiMainMenuSelected - drop back to 3/160 once
+// the keyboard is wired up somewhere real and this is removed.
+#define UI_MAIN_MENU_ITEM_COUNT 4
 #define UI_MAIN_MENU_WIDTH 200.0f
-#define UI_MAIN_MENU_HEIGHT 160.0f
+#define UI_MAIN_MENU_HEIGHT 200.0f
 #define UI_MAIN_MENU_LABEL_MAX 32
 
 typedef struct {
@@ -49,3 +52,29 @@ errorret_t uiMainMenuDraw(void);
  * @return Any error that occurs.
  */
 errorret_t uiMainMenuDispose(void);
+
+// TODO: temporary keyboard test hooks - see UI_MAIN_MENU_INDEX_LOAD_GAME_TEST
+// in uimainmenu.c. Remove once the keyboard is wired up somewhere real.
+
+/**
+ * Test onKeyPress callback - console-prints every key press and allows
+ * all of them.
+ *
+ * @param c The character about to be entered.
+ * @param user Unused.
+ * @returns Always true.
+ */
+bool_t uiMainMenuKeyboardTestKeyPress(const char_t c, void *user);
+
+/**
+ * Test onInput callback - console-prints the final result.
+ *
+ * @param text The entered text.
+ * @param confirmed Whether confirm (vs cancel) was picked.
+ * @param user Unused.
+ */
+void uiMainMenuKeyboardTestInput(
+  const char_t *text,
+  const bool_t confirmed,
+  void *user
+);

src/dusk/ui/uielementlist.c

@@ -101,6 +101,11 @@ uielement_t UI_ELEMENTS[] = {
     .update = uiTextboxMiniListUpdate,
     .draw = uiTextboxMiniListDraw
   },
+  {
+    .init = uiKeyboardInit,
+    .draw = uiKeyboardDraw,
+    .dispose = uiKeyboardDispose
+  },
   {
     .init = uiModalInit,
     .draw = uiModalDraw,
@@ -110,11 +115,6 @@ uielement_t UI_ELEMENTS[] = {
     .init = uiConfirmInit,
     .dispose = uiConfirmDispose
   },
-  {
-    .init = uiKeyboardInit,
-    .draw = uiKeyboardDraw,
-    .dispose = uiKeyboardDispose
-  },
 
   // ===========================================================================
   // Overlayed components, can even outdraw all UI things.

src/dusk/ui/widget/uimenu.c

@@ -68,6 +68,7 @@ void uiMenuOpen(uimenu_t *menu) {
     menu
   );
   menu->focusItem->disableBack = menu->disableBack;
+  menu->focusItem->cancel = menu->cancel != NULL ? uiMenuFocusCancel : NULL;
 }
 
 void uiMenuClose(uimenu_t *menu) {
@@ -83,6 +84,14 @@ void uiMenuSetDisableBack(uimenu_t *menu, const bool_t disableBack) {
   if(menu->focusItem != NULL) menu->focusItem->disableBack = disableBack;
 }
 
+void uiMenuSetCancelCallback(uimenu_t *menu, uimenucancelcallback_t cancel) {
+  assertNotNull(menu, "Menu cannot be NULL");
+  menu->cancel = cancel;
+  if(menu->focusItem != NULL) {
+    menu->focusItem->cancel = cancel != NULL ? uiMenuFocusCancel : NULL;
+  }
+}
+
 bool_t uiMenuIsActive(const uimenu_t *menu) {
   assertNotNull(menu, "Menu cannot be NULL");
   return menu->focusItem != NULL;
@@ -259,6 +268,14 @@ bool_t uiMenuFocusDirection(
   return false;
 }
 
+bool_t uiMenuFocusCancel(const uifocusitem_t *focusItem) {
+  assertNotNull(focusItem, "Focus item cannot be NULL");
+  assertNotNull(focusItem->user, "Focus item user cannot be NULL");
+  uimenu_t *menu = (uimenu_t *)focusItem->user;
+  if(menu->cancel == NULL) return false;
+  return menu->cancel(menu);
+}
+
 uint8_t uiMenuFocusableCount(const uimenu_t *menu) {
   assertNotNull(menu, "Menu cannot be NULL");
   uint8_t count = 0;

src/dusk/ui/widget/uimenu.h

@@ -55,6 +55,16 @@ typedef void (*uimenuchangedcallback_t)(
 
 typedef void (*uimenuclosedcallback_t)(const uimenu_t *menu);
 
+/**
+ * Callback invoked when INPUT_ACTION_CANCEL is pressed while the menu is
+ * focused - see uiMenuSetCancelCallback.
+ *
+ * @param menu The menu that was cancelled.
+ * @returns True if fully handled (skips the default disableBack/pop
+ * behavior); false to fall through to it.
+ */
+typedef bool_t (*uimenucancelcallback_t)(const uimenu_t *menu);
+
 typedef struct uimenu_s {
   uimenuitem_t *items;
   uint8_t itemCount;
@@ -64,6 +74,7 @@ typedef struct uimenu_s {
   uimenuselectedcallback_t selected;
   uimenuclosedcallback_t closed;
   uimenuchangedcallback_t changed;
+  uimenucancelcallback_t cancel;
 
   void *user;
 
@@ -138,6 +149,17 @@ void uiMenuClose(uimenu_t *menu);
  */
 void uiMenuSetDisableBack(uimenu_t *menu, const bool_t disableBack);
 
+/**
+ * Sets a callback given first refusal of INPUT_ACTION_CANCEL while this
+ * menu is the topmost focus item, before disableBack/the default pop is
+ * applied. Safe to call before or after uiMenuOpen().
+ *
+ * @param menu The menu to update.
+ * @param cancel The callback to install, or NULL to remove it and
+ * restore default disableBack/pop behavior.
+ */
+void uiMenuSetCancelCallback(uimenu_t *menu, uimenucancelcallback_t cancel);
+
 /**
  * Returns whether the menu is currently active (on the UI focus stack).
  *
@@ -230,6 +252,15 @@ bool_t uiMenuFocusDirection(
   const uifocusdirection_t direction
 );
 
+/**
+ * Internal focus callback  -  forwards INPUT_ACTION_CANCEL to the menu's
+ * cancel handler, if one is set.
+ *
+ * @param focusItem The active focus item; user field must point to uimenu_t.
+ * @returns The cancel handler's result, or false if none is set.
+ */
+bool_t uiMenuFocusCancel(const uifocusitem_t *focusItem);
+
 // Helper macros
 #define MENU_BEGIN(menuPtr, itemsArray, selected, closed, changed) \
   uimenu_t *menu = (menuPtr); \