glyph picker

CLAUDE.md

@@ -40,7 +40,7 @@ cargo fmt                                  # format
 `kiln` is a Cargo **workspace** that separates the engine from its front-ends so the same game data can be driven by different UIs:
 
 - **`kiln-core`** — the engine: all core game types (`Board`, `Glyph`, `Archetype`, `GameState`, …) plus `.toml` map-file load/save. No rendering or UI; every front-end depends on it.
-- **`kiln-ui`** — reusable, **game-agnostic** terminal UI widgets on **ratatui** (no `kiln-core` dep). Each widget owns its presentation + input handling and is generic over a host context `Ctx` it mutates only through callbacks. Holds the dialog/text-field system (`dialog::Dialog<Ctx>`), the shared `dim_area` overlay helper, and a hand-written modeless script code editor (`code_editor::CodeEditor`). The **syntect** (highlighting) and **arboard** (clipboard) deps make this crate desktop/terminal-only (not WASM), unlike its ratatui core.
+- **`kiln-ui`** — reusable terminal UI widgets on **ratatui**, mostly **game-agnostic**. Each widget owns its presentation + input handling and is generic over a host context `Ctx` it mutates only through callbacks. Holds the dialog/text-field system (`dialog::Dialog<Ctx>`), the shared `dim_area` overlay helper, a hand-written modeless script code editor (`code_editor::CodeEditor`), and the **glyph picker** (`glyph_dialog::GlyphDialog<Ctx>`). The glyph picker is the **one** widget that depends on `kiln-core` (for `Glyph`/`Rgba8` + the CP437 table); everything else is game-agnostic. The **syntect** (highlighting) and **arboard** (clipboard) deps make this crate desktop/terminal-only (not WASM), unlike its ratatui core.
 - **`kiln-tui`** — a terminal **player + world editor** built on **ratatui 0.30 / crossterm**, depending on both `kiln-core` and `kiln-ui`. Takes a world-file path on the command line; plays a board (arrow keys) and edits it (`Esc` → menu → `e`).
 
 Root `Cargo.toml`: `members = ["kiln-core", "kiln-tui", "kiln-ui"]`, with `ratatui` pinned in `[workspace.dependencies]` so kiln-ui and kiln-tui share one version (their public APIs exchange ratatui types).
@@ -52,6 +52,9 @@ The core types that were formerly monolithic in `game.rs` are now split into foc
 **`kiln-core/src/glyph.rs`** — per-cell visual:
 - `Glyph` (`Copy`, `Eq`, `Hash`) — `tile: u32` (tilesheet index), `fg/bg: Rgba8`. `Glyph::player()` is a `const fn` (tile 64 `@`, white on dark blue); all other glyphs come from map files. `Hash` is hand-implemented via packed `u32` representations so it stays in sync with `Eq`.
 
+**`kiln-core/src/cp437.rs`** — tile-index → character mapping (`pub`):
+- `CP437: [char; 256]` — full code-page-437 table (graphic glyphs for 0x00–0x1F, box-drawing for 0xB0–0xDF, etc.). `tile_to_char(tile: u32) -> char` indexes it for `tile < 256`; falls back to `char::from_u32` then a blank space. Unit-tested. Lives in core (not a front-end) because it is the *meaning* of a tile index under the default font; used by kiln-tui's renderer (`render.rs`) and kiln-ui's glyph picker alike.
+
 **`kiln-core/src/archetype.rs`** — element taxonomy:
 - `Archetype` (`Copy`, `PartialEq`, `Hash`) — enum of named element types: `Empty`, `Wall`, `Crate`, `HCrate`, `VCrate`, `Pusher(Direction)`, `ErrorBlock`. Each variant provides `behavior()`, `name()` (used in map files), and `default_glyph()`. `Crate` pushable any direction (CP437 ■, char 254); `HCrate`/`VCrate` pushable east/west (↔, char 29) / north/south (↕, char 18) only. `Pusher(dir)` (`pusher_north|south|east|west`) is a **map-file keyword only**: at load it expands into a scripted object (see [`builtin_scripts`]), never a terrain cell. `ErrorBlock` is a sentinel for unknown archetype names (yellow `?` on red). `TryFrom<&str>` parses by name; unrecognized names return `Err` (the map loader substitutes `ErrorBlock`).
 
@@ -131,11 +134,11 @@ The core types that were formerly monolithic in `game.rs` are now split into foc
 
 ### kiln-ui modules
 
-Reusable, **game-agnostic** terminal UI widgets on **ratatui** — no `kiln-core` dependency. A widget owns its presentation + input handling and is generic over a host context `Ctx` it mutates *only through callbacks*, so a front-end decides what a choice does without the widget knowing about game/world types. The front-end owns the event loop and routes input to the widget while it is focused.
+Reusable terminal UI widgets on **ratatui**, mostly **game-agnostic**. A widget owns its presentation + input handling and is generic over a host context `Ctx` it mutates *only through callbacks*, so a front-end decides what a choice does without the widget knowing about game/world types. The front-end owns the event loop and routes input to the widget while it is focused. The lone exception is `glyph_dialog`, which depends on `kiln-core` for `Glyph`/`Rgba8` and `cp437::tile_to_char` (the accepted, documented first kiln-core dependency — it would matter only if kiln-ui were ever split into a standalone crate).
 
 **`kiln-ui/src/lib.rs`** — crate root:
 - `dim_area(area, buf)` (`pub`) — dims every cell in `area` (background tint for a modal overlay). Shared scaffolding: used by [`dialog`] here and re-borrowed by kiln-tui's `overlay::render_overlay_frame` so both modal styles dim identically.
-- Modules: `pub mod dialog; pub mod code_editor; pub mod text_field;` (widgets) plus `mod clipboard; mod text;` (`pub(crate)` shared internals — see below).
+- Modules: `pub mod dialog; pub mod code_editor; pub mod text_field; pub mod glyph_dialog;` (widgets) plus `mod clipboard; mod text;` (`pub(crate)` shared internals — see below).
 
 **`kiln-ui/src/clipboard.rs` / `text.rs`** — `pub(crate)` shared internals for the text widgets:
 - `clipboard::Clipboard` — system clipboard via `arboard` when available, always backed by an internal buffer (so copy/paste work headless / on the web); `set`/`get` write-through and prefer-system-on-read. Used by both `code_editor` and `text_field`.
@@ -147,6 +150,11 @@ Reusable, **game-agnostic** terminal UI widgets on **ratatui** — no `kiln-core
 - `handle_event(&Event) -> DialogResult` — `Esc`→`Cancel`; `Enter`→`Submit` only when OK is enabled (always for text; for a list, a valid entry is selected *or* `allow_create` + non-empty); Up/Down move a list's selection; other keys edit the field (and re-clamp the list selection to the new prefix filter). `finish(result, &mut Ctx)` consumes the dialog and fires its callback. The host pattern: `take()` the dialog out of its slot on `Submit`/`Cancel`, then call `finish` so the callback gets an un-borrowed `&mut Ctx`.
 - `Dialog::draw(&self, &mut Frame)` — dims the screen, draws a centered bordered box. A **text** dialog centers its field box (h+v) with a distinct `FIELD_BG` background so it reads as an input box; a **list** dialog puts the filter field atop the scrolling, selection-highlighted list. Both show an `[enter] OK   [esc] Cancel` footer (OK dimmed when disabled). Takes `&mut Frame` (not a `Widget`) because it needs to place a real terminal cursor. Unit-tested (filtering/clamping, OK-enabled rule, Select/Create/Cancel/text outcomes) with a dummy `Ctx`.
 
+**`kiln-ui/src/glyph_dialog.rs`** — the glyph picker (the one kiln-core-dependent widget):
+- `GlyphDialog<Ctx>` — a modal picker for a [`Glyph`] (CP437 tile index + fg/bg colors), same API shape as `Dialog`. Built via `GlyphDialog::new(title, initial: Glyph, on_done)`; `on_done: FnOnce(Option<Glyph>, &mut Ctx)` fires `Some(glyph)` on OK, `None` on cancel. Holds the selected `tile: u32`, two hex-color `TextField`s (`fg`/`bg`, 6 bare hex digits), and a `Focus` (`Grid`/`Fg`/`Bg`).
+- `handle_event(&Event) -> DialogResult` (reuses `dialog::DialogResult`) — `Esc`→`Cancel`; `Enter`→`Submit` only when both color fields parse (`parse_hex6`); `Tab`/`Shift-Tab`/`BackTab` cycle focus; when the grid is focused arrows move the selection in a 32×8 grid (clamped), otherwise keys edit the focused field. `finish(result, &mut Ctx)` fires the callback (a `Submit` with both colors valid yields `Some(Glyph{..})`).
+- `draw(&self, &mut Frame)` — dims + centered bordered box; renders the 256-char grid via `kiln_core::cp437::tile_to_char` (each glyph drawn in the chosen fg/bg when both colors are valid, else gray-on-black; the selected cell is a bright cursor when the grid is focused, else reversed), the labeled `fg`/`bg` swatch fields (focused label's background highlighted; invalid field boxed red), and the standard footer. Places a real terminal cursor in the focused color field. Unit-tested (seed round-trip, focus cycling, grid clamp, invalid-hex disables OK, Submit/Cancel outcomes) with a dummy `Ctx`.
+
 **`kiln-ui/src/text_field.rs`** — a single-line editable text field (a one-line sibling of `code_editor`, used by `dialog`'s text/filter inputs; replaced `tui-input`):
 - `TextField` — `text: String` + a char-indexed `cursor` + a `Clipboard`. `new(initial)`, `value()`, `display_cursor()` (caret's display column), and `handle_key(KeyEvent) -> bool` (`true` if consumed). Handles printable insert, Backspace/Delete, Left/Right (+ ctrl word-moves), Home/End, and `ctrl`/`⌘`+`v` paste (newlines stripped); leaves Esc/Enter/Up/Down to the caller. Presentation is the caller's job (it reads `value()`/`display_cursor()`). No selection yet. Unit-tested (typing, delete, movement, paste, wide-char cursor).
 
@@ -167,24 +175,25 @@ The terminal **player + world editor**, depending on both `kiln-core` and `kiln-
 - `ratatui::init()` → `EnableMouseCapture` → detect `TerminalCaps` → push Kitty flags when supported → `run` loop → pop Kitty flags → `DisableMouseCapture` → `ratatui::restore()`. `game.run_init()` runs object `init()` hooks before the loop.
 - `run` is a ~30 FPS real-time loop: `event::poll`s only until the next frame deadline (so input stays responsive) and otherwise wakes to advance by the real elapsed `dt` via `Ui::tick(dt, mode)`. Acts on `Press`/`Repeat` and ignores `Release` (the Kitty protocol emits these; acting on them double-fires moves). Input is routed by `current_input_mode`: `Menu`→`handle_menu_input`; otherwise (unless `Ignore`) it matches on `Mode` — `Play` → `handle_board_input`/`handle_scroll_input`, `Edit` → `handle_editor_input`/`handle_dialog_input`. After ticking it calls `apply_pending_mode` and exits once `should_quit` is set and no close animation is running.
 - `apply_pending_mode(mode, ui)` — applies a `PendingMode` a menu action requested: reloads the world from `world_path` and swaps `*mode` to `Mode::Edit(EditorState::new(world))` (enter editor) or a fresh `Mode::Play` (play world, re-running `init()`); a reload failure is logged to the play game and leaves the mode unchanged.
-- `draw(frame, mode, ui)` — renders the active mode (`draw_play` or `editor::draw_editor`), then the overlay layer in precedence **animation > menu > (Play: scroll / Edit: dialog)**: an `Overlay`-layer animation via `AnimWidget`, else `MenuWidget`, else the play scroll overlay (`ScrollOverlayWidget`) or the editor dialog (`kiln_ui::dialog::draw`). `draw_play` wraps the board in a bordered `Block` (board-name title; latest log previewed in the bottom border when the panel is closed). `draw_board_area` initializes a pending portal transition (now that the inner area is known) and renders either the board-layer wipe animation or the live board + speech bubbles.
+- `draw(frame, mode, ui)` — renders the active mode (`draw_play` or `editor::draw_editor`), then the overlay layer in precedence **animation > menu > (Play: scroll / Edit: dialog)**: an `Overlay`-layer animation via `AnimWidget`, else `MenuWidget`, else the play scroll overlay (`ScrollOverlayWidget`) or the editor's glyph picker (`GlyphDialog::draw`, when open) / dialog (`Dialog::draw`). `draw_play` wraps the board in a bordered `Block` (board-name title; latest log previewed in the bottom border when the panel is closed). `draw_board_area` initializes a pending portal transition (now that the inner area is known) and renders either the board-layer wipe animation or the live board + speech bubbles.
 
 **`kiln-tui/src/mode.rs`** — top-level application mode:
 - `Mode { Play(GameState), Edit(EditorState) }` — exactly one is live at a time (play and edit are mutually exclusive: entering the editor drops the running game; returning to play rebuilds it fresh from the world file). `PendingMode { EnterEditor, PlayWorld }` — a deferred Play↔Edit switch requested by a menu closure (which only has `&mut Ui`) and applied by the run loop, mirroring the `should_quit` pattern.
 
 **`kiln-tui/src/editor.rs`** — world editor mode:
-- `EditorState` — a non-ticking editing session over a freshly reloaded `World`: `world`, `board_name` (board being edited), `menu: Vec<MenuLevel>` (sidebar menu stack, for breadcrumb + escape-to-parent), `dialog: Option<Dialog<EditorState>>`, `code_editor: Option<CodeEditor>` (the open script editor; replaces the board view), a blinking `cursor`, `sidebar_width` (mouse-resizable), blink state, `last_board_area` (written at draw, read for right-click hit-testing), and editor-side `log`.
+- `EditorState` — a non-ticking editing session over a freshly reloaded `World`: `world`, `board_name` (board being edited), `menu: Vec<MenuLevel>` (sidebar menu stack, for breadcrumb + escape-to-parent), `dialog: Option<Dialog<EditorState>>`, `code_editor: Option<CodeEditor>` (the open script editor; replaces the board view), `glyph_dialog: Option<GlyphDialog<EditorState>>` (the open glyph picker overlay), a blinking `cursor`, `sidebar_width` (mouse-resizable), blink state, `last_board_area` (written at draw, read for right-click hit-testing), and editor-side `log`.
 - `MenuLevel { World }` — a sidebar menu level; `title()` (breadcrumb segment) and `choices()` (static `(key, label)` list — `[n] Name`, `[e] Entry board`, `[s] Scripts`, `[b] Boards`). The menu is a stack so nested levels can be added later; today only `World` exists and every choice opens a dialog (no sub-menu). Per the design, menus are static letter-keyed lists — picking from a list is always a dialog, so arrow keys never conflict with the board cursor.
 - Methods: `breadcrumb()`, `current_menu()`, `menu_escape(ui)` (pop a level, or at the root open the overlay `editor_menu_items()`), `menu_key(c)` (dispatch a letter → `open_*_dialog`), `menu_value(key)` (the "current value" shown beneath a choice in the sidebar — world name for `n`, start board for `e`), and the `open_{name,entry,scripts,boards}_dialog` builders (name → text dialog writing `world.name`; entry → list dialog writing `world.start`; boards → select-only; scripts → **opens the script in `code_editor`**). `open_script_editor(name)` builds a `CodeEditor` from `world.scripts[name]`; `close_script_editor()` saves its text back into `world.scripts` (in-memory, like the other dialogs).
-- `editor_menu_items()` — the overlay editor menu (`[p]` play, `[q]` quit, `[esc]` resume), opened at the root of the menu tree. `handle_dialog_input(event, ed)` — forwards to the open dialog and, on `Submit`/`Cancel`, `take`s it out and calls `finish(.., ed)`. `handle_code_editor_input(event, ed)` — forwards to the open code editor and, on `Exit` (Esc), calls `close_script_editor()`. `draw_editor(frame, ed, ui)` / `editor_layout(..)` — the **code editor (when open) else** the board (with blinking cursor + coord readout) in the left area, a resizable right-hand sidebar (breadcrumb title + the menu choices, each with its optional current-value line), and the optional full-width log panel.
+- `open_glyph_picker()` — seeds a `GlyphDialog` from `board.glyph_at(cursor)` and opens it; its callback logs the chosen glyph to `ed.log` (no paint tool yet). Bound to **`g`** in `handle_editor_input`.
+- `editor_menu_items()` — the overlay editor menu (`[p]` play, `[q]` quit, `[esc]` resume), opened at the root of the menu tree. `handle_dialog_input(event, ed)` — forwards to the open dialog and, on `Submit`/`Cancel`, `take`s it out and calls `finish(.., ed)`. `handle_glyph_dialog_input(event, ed)` — the same pattern for the open `glyph_dialog`. `handle_code_editor_input(event, ed)` — forwards to the open code editor and, on `Exit` (Esc), calls `close_script_editor()`. `draw_editor(frame, ed, ui)` / `editor_layout(..)` — the **code editor (when open) else** the board (with blinking cursor + coord readout) in the left area, a resizable right-hand sidebar (breadcrumb title + the menu choices, each with its optional current-value line), and the optional full-width log panel.
 
 **`kiln-tui/src/ui.rs`** — front-end presentation state (not on `GameState`):
 - `Ui { log: LogState, overlay: ScrollOverlayState, pending_transition, active_animation: Option<Box<dyn Animation>>, menu: Option<MenuState>, should_quit, world_path, pending_mode }`. While `active_animation` is `Some` all input is suppressed. `tick(dt, mode)` advances the active animation (and, on completion, clears scroll/menu state when returning to `Board`), then ticks the active mode — the game only in `Play` + `Board` input mode (so an open scroll/menu pauses it), the editor's cursor blink in `Edit`; a scroll that appears from a tick starts an open animation.
 - `open_menu(items)` / `begin_close_menu()` — start the menu open/close animations (snapshotting `MenuState`). `begin_close(choice, game)` — set the player's scroll choice and start the scroll close animation. `start_transition(old, new, area)` — build the board-wipe once the inner area is known. `scroll_lines(delta)` / `scroll_menu(delta)` — clamped overlay/menu scrolling.
 
 **`kiln-tui/src/input.rs`** — input mode + dispatch:
-- `InputMode { Board, Scroll, Menu, Editor, Dialog, CodeEditor, Ignore, Frozen }`. `current_input_mode(mode, ui)` — derives the mode: an active animation declares its own (`input_mode_during`); a pending transition → `Ignore`; an open `ui.menu` → `Menu`; else from `Mode` (`Edit` → `Dialog` when a dialog is open, else `CodeEditor` when a script editor is open, else `Editor`; `Play` → `Scroll` when a scroll is active else `Board`).
+- `InputMode { Board, Scroll, Menu, Editor, Dialog, CodeEditor, GlyphDialog, Ignore, Frozen }`. `current_input_mode(mode, ui)` — derives the mode: an active animation declares its own (`input_mode_during`); a pending transition → `Ignore`; an open `ui.menu` → `Menu`; else from `Mode` (`Edit` → `GlyphDialog` when the glyph picker is open, else `Dialog` when a dialog is open, else `CodeEditor` when a script editor is open, else `Editor`; `Play` → `Scroll` when a scroll is active else `Board`).
-- `handle_board_input` (arrows move the player via `try_move_with_transition`, `l` toggles log, `Esc` opens the `pause_menu_items()` overlay, PageUp/Down + mouse scroll/resize the log), `handle_editor_input` (arrows move the cursor, `l` toggles log, `Esc` → `menu_escape`, letters → `menu_key`, right-click moves the cursor, drag resizes the sidebar), `handle_scroll_input` (scroll nav + choice letters via `resolve_choice`), `handle_menu_input` (clone the matched item's action `Rc` to drop the `ui.menu` borrow, then call it). `try_move_with_transition` captures both board `Rc`s into `ui.pending_transition` when a move crosses a portal.
+- `handle_board_input` (arrows move the player via `try_move_with_transition`, `l` toggles log, `Esc` opens the `pause_menu_items()` overlay, PageUp/Down + mouse scroll/resize the log), `handle_editor_input` (arrows move the cursor, `l` toggles log, `g` opens the glyph picker, `Esc` → `menu_escape`, other letters → `menu_key`, right-click moves the cursor, drag resizes the sidebar), `handle_scroll_input` (scroll nav + choice letters via `resolve_choice`), `handle_menu_input` (clone the matched item's action `Rc` to drop the `ui.menu` borrow, then call it). `try_move_with_transition` captures both board `Rc`s into `ui.pending_transition` when a move crosses a portal.
 
 **`kiln-tui/src/animation.rs`** — the animation abstraction:
 - `Animation` trait — `update(dt) -> bool` (done?), `draw(area, buf)`, `layer()`, `input_mode_during()` (default `Ignore`), `input_mode_after()`. `AnimationLayer { Board, Overlay }` (board-area replacement vs. full-screen overlay). `AnimWidget<'a>(&'a dyn Animation)` — adapts an animation to a ratatui `Widget` for `frame.render_widget`.
@@ -201,10 +210,6 @@ The terminal **player + world editor**, depending on both `kiln-core` and `kiln-
 **`kiln-tui/src/scroll_overlay.rs`** — scroll overlay widget:
 - `ScrollOverlayState { offset, max_scroll }` — input/output state threaded through render. `ScrollOverlayWidget<'a>` — `StatefulWidget` for the fully-open overlay (½ width × ¾ height, amber style); `ScrollOpenAnimation`/`ScrollCloseAnimation` implement `Animation` for the open/close transitions. `render_scroll_at(..)` wraps text, centers whitespace-leading lines, prefixes choices with `[a]`/`[b]`, and draws a scrollbar when content overflows.
 
-**`kiln-tui/src/cp437.rs`** — CP437 → Unicode mapping:
-- `CP437: [char; 256]` — full code-page-437 table (graphic glyphs for 0x00–0x1F, box-drawing for 0xB0–0xDF, etc.).
-- `tile_to_char(tile: u32) -> char` — indexes the table for `tile < 256`; falls back to `char::from_u32` then a blank space. Unit-tested.
-
 **`kiln-tui/src/render.rs`** — board → ratatui buffer:
 - `BoardWidget<'a>` — a `ratatui::widgets::Widget` that draws the board. Per axis, `axis(board_len, view, player) -> (offset, pad, count)` (pub): a board smaller than the viewport is **centered** with screen padding, a larger one **scrolls** to keep the player on screen with no empty margins. Each cell calls `Board::glyph_at`, which already folds in the player glyph at the player's position — no separate player-overlay pass needed.
 - `board_to_screen(area, board, bx, by) -> Option<(u16, u16)>` and its inverse `screen_to_board(area, board, sx, sy) -> Option<(usize, usize)>` (pub) — convert between board cells and terminal coordinates using the same `axis` math, returning `None` off-board. Used by the editor's blinking cursor + right-click hit-testing (and mirrored by `speech::board_screen_pos`).

Cargo.lock

@@ -775,6 +775,8 @@ name = "kiln-ui"
 version = "0.1.0"
 dependencies = [
  "arboard",
+ "color",
+ "kiln-core",
  "ratatui",
  "syntect",
  "unicode-width",

kiln-core/src/cp437.rs

@@ -1,10 +1,12 @@
-//! CP437 → Unicode mapping for rendering glyph tile indices as terminal text.
+//! CP437 → Unicode mapping for interpreting glyph tile indices as characters.
 //!
 //! kiln stores each cell's visual as a `tile: u32` index into a bitmap font.
 //! The default kiln font is IBM CP437, where the tile index equals the CP437
-//! code point. A terminal can't draw the bitmap font, so kiln-tui reinterprets
+//! code point. A terminal can't draw the bitmap font, so a front-end reinterprets
 //! the tile index as a character via this table and prints that character with
-//! the cell's foreground/background colors.
+//! the cell's foreground/background colors. This lives in kiln-core (not a
+//! front-end) because it is the *meaning* of a tile index under the default font,
+//! shared by every renderer and by the editor's glyph picker.
 
 /// CP437 code point → Unicode scalar value.
 ///

kiln-core/src/lib.rs

@@ -2,6 +2,8 @@ mod action;
 mod archetype;
 mod board;
 mod builtin_scripts;
+/// CP437 tile-index → character mapping ([`cp437::tile_to_char`]) for the default font.
+pub mod cp437;
 /// Procedural floor generators ([`floor::FloorGenerator`]).
 pub mod floor;
 /// Core game types: [`board::Board`], [`glyph::Glyph`], [`archetype::Archetype`], etc.

kiln-tui/src/editor.rs

@@ -10,6 +10,7 @@
 
 use kiln_ui::code_editor::{CodeEditor, CodeEditorOutcome};
 use kiln_ui::dialog::{Dialog, DialogResult, ListDialogResponse};
+use kiln_ui::glyph_dialog::GlyphDialog;
 use crate::log::{log_preview_line, LogWidget};
 use crate::render::{board_to_screen, screen_to_board, BoardWidget};
 use crate::ui::Ui;
@@ -55,6 +56,9 @@ pub(crate) struct EditorState {
     /// The open script code editor, if any. While `Some` it replaces the board view and
     /// the editor is in [`InputMode::CodeEditor`](crate::input::InputMode::CodeEditor).
     pub(crate) code_editor: Option<CodeEditor>,
+    /// The open glyph picker overlay, if any. While `Some` the editor is in
+    /// [`InputMode::GlyphDialog`](crate::input::InputMode::GlyphDialog).
+    pub(crate) glyph_dialog: Option<GlyphDialog<EditorState>>,
     /// Cursor position in board cells, clamped to the board bounds.
     cursor: (i32, i32),
     /// Width of the right-hand sidebar in terminal columns (mouse-resizable).
@@ -81,6 +85,7 @@ impl EditorState {
             menu: vec![MenuLevel::Main],
             dialog: None,
             code_editor: None,
+            glyph_dialog: None,
             cursor: (0, 0),
             sidebar_width: DEFAULT_SIDEBAR_WIDTH,
             blink_on: true,
@@ -176,6 +181,27 @@ impl EditorState {
         self.dialog = Some(Dialog::list("Boards", names, false, |_resp, _ed: &mut EditorState| {}));
     }
 
+    /// Opens the glyph picker seeded from the glyph currently under the cursor.
+    /// On OK the chosen glyph is logged (there is no paint tool yet).
+    pub(crate) fn open_glyph_picker(&mut self) {
+        let glyph = {
+            let board = self.board();
+            board.glyph_at(self.cursor.0 as usize, self.cursor.1 as usize)
+        };
+        self.glyph_dialog = Some(GlyphDialog::new(
+            "Glyph",
+            glyph,
+            |chosen, ed: &mut EditorState| {
+                if let Some(g) = chosen {
+                    ed.log.push(LogLine::raw(format!(
+                        "glyph tile={} fg=#{:02X}{:02X}{:02X} bg=#{:02X}{:02X}{:02X}",
+                        g.tile, g.fg.r, g.fg.g, g.fg.b, g.bg.r, g.bg.g, g.bg.b
+                    )));
+                }
+            },
+        ));
+    }
+
     /// Borrows the board currently being edited.
     pub(crate) fn board(&self) -> Ref<'_, Board> {
         self.world.boards[&self.board_name].borrow()
@@ -235,6 +261,24 @@ pub(crate) fn handle_dialog_input(event: Event, ed: &mut EditorState) {
     }
 }
 
+/// Handles an input event while the glyph picker is open ([`InputMode::GlyphDialog`](crate::input::InputMode::GlyphDialog)).
+///
+/// Mirrors [`handle_dialog_input`]: forwards to the picker and, on `Submit`/`Cancel`,
+/// takes it out of [`EditorState::glyph_dialog`] and fires its callback via
+/// [`GlyphDialog::finish`].
+pub(crate) fn handle_glyph_dialog_input(event: Event, ed: &mut EditorState) {
+    let Some(dialog) = ed.glyph_dialog.as_mut() else {
+        return;
+    };
+    match dialog.handle_event(&event) {
+        DialogResult::Continue => {}
+        result => {
+            let dialog = ed.glyph_dialog.take().expect("glyph dialog present");
+            dialog.finish(result, ed);
+        }
+    }
+}
+
 /// Handles an input event while the code editor is open ([`InputMode::CodeEditor`](crate::input::InputMode::CodeEditor)).
 ///
 /// Forwards key/mouse events to the editor; on `Exit` (Esc) it closes and saves the script.

kiln-tui/src/input.rs

@@ -33,6 +33,8 @@ pub enum InputMode {
     Dialog,
     /// The script code editor is open; all input drives the editor.
     CodeEditor,
+    /// The glyph picker is open over the editor; all input drives the picker.
+    GlyphDialog,
     /// An animation is running and has not claimed any input mode; all input is discarded.
     Ignore,
     /// Reserved for a post-transition freeze; nothing currently produces this mode.
@@ -54,7 +56,9 @@ pub(crate) fn current_input_mode(mode: &Mode, ui: &Ui) -> InputMode {
     }
     match mode {
         Mode::Edit(ed) => {
-            if ed.dialog.is_some() {
+            if ed.glyph_dialog.is_some() {
+                InputMode::GlyphDialog
+            } else if ed.dialog.is_some() {
                 InputMode::Dialog
             } else if ed.code_editor.is_some() {
                 InputMode::CodeEditor
@@ -122,6 +126,8 @@ pub(crate) fn handle_editor_input(event: Event, term_w: u16, ed: &mut EditorStat
             KeyCode::Left => ed.move_cursor(-1, 0),
             KeyCode::Right => ed.move_cursor(1, 0),
             KeyCode::Char('l') => ui.log.toggle(),
+            // `g` opens the glyph picker for the cell under the cursor.
+            KeyCode::Char('g') => ed.open_glyph_picker(),
             // A menu letter opens its dialog; unmatched letters are ignored.
             KeyCode::Char(c) => {
                 ed.menu_key(c);

kiln-tui/src/main.rs

@@ -5,10 +5,9 @@
 //! (or HJKL). There is no editor — this is a play-only front-end.
 //!
 //! Rendering is text-based: kiln's bitmap-font tile indices are reinterpreted
-//! as characters (see [`cp437`]) and drawn with each cell's RGB colors.
+//! as characters (see [`kiln_core::cp437`]) and drawn with each cell's RGB colors.
 
 mod animation;
-mod cp437;
 mod editor;
 mod input;
 mod log;
@@ -25,7 +24,10 @@ mod utils;
 mod editor_menu;
 
 use crate::animation::{AnimWidget, AnimationLayer};
-use crate::editor::{EditorState, draw_editor, handle_code_editor_input, handle_dialog_input};
+use crate::editor::{
+    EditorState, draw_editor, handle_code_editor_input, handle_dialog_input,
+    handle_glyph_dialog_input,
+};
 use crate::input::{
     InputMode, current_input_mode, handle_board_input, handle_editor_input, handle_menu_input,
     handle_scroll_input,
@@ -170,6 +172,7 @@ fn run(terminal: &mut ratatui::DefaultTerminal, mode: &mut Mode, ui: &mut Ui) ->
                     Mode::Edit(ed) => match input_mode {
                         InputMode::Editor => handle_editor_input(event, size.width, ed, ui),
                         InputMode::Dialog => handle_dialog_input(event, ed),
+                        InputMode::GlyphDialog => handle_glyph_dialog_input(event, ed),
                         InputMode::CodeEditor => handle_code_editor_input(event, ed),
                         _ => unreachable!(
                             "Menu and Ignore handled above; Board/Scroll/Frozen input modes only occur in Play mode"
@@ -263,9 +266,11 @@ fn draw(frame: &mut Frame, mode: &mut Mode, ui: &mut Ui) {
                     );
                 }
             }
-            // The dialog overlay only exists while editing.
+            // The dialog / glyph-picker overlays only exist while editing.
             Mode::Edit(ed) => {
-                if let Some(d) = &ed.dialog {
+                if let Some(g) = &ed.glyph_dialog {
+                    g.draw(frame);
+                } else if let Some(d) = &ed.dialog {
                     d.draw(frame);
                 }
             }

kiln-tui/src/render.rs

@@ -1,11 +1,11 @@
 //! Rendering a kiln [`Board`] into a ratatui buffer as colored text.
 //!
 //! Each board cell becomes one terminal cell: the glyph's tile index is mapped
-//! to a character (see [`crate::cp437`]) and drawn with the glyph's foreground
+//! to a character (see [`kiln_core::cp437`]) and drawn with the glyph's foreground
 //! and background colors. Objects are drawn over their floor cell, and the
 //! player is drawn on top of everything.
 
-use crate::cp437::tile_to_char;
+use kiln_core::cp437::tile_to_char;
 use kiln_core::Board;
 use ratatui::buffer::Buffer;
 use ratatui::layout::Rect;

kiln-ui/Cargo.toml

@@ -4,6 +4,9 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+# First kiln-core dependency in kiln-ui: the glyph picker needs `Glyph`/`Rgba8`.
+kiln-core = { path = "../kiln-core" }
+color = "0.3.3"
 # text-only clipboard: drop the default `image-data` deps (image/tiff/jpeg), add Linux Wayland support
 arboard = { version = "3", default-features = false, features = ["wayland-data-control"] }
 ratatui = { workspace = true }

kiln-ui/src/glyph_dialog.rs

@@ -0,0 +1,499 @@
+//! A modal **glyph picker** dialog: choose a [`Glyph`] (a CP437 tile index plus
+//! foreground/background colors) from a 32×8 character grid and two hex color fields.
+//!
+//! This mirrors the [`dialog`](crate::dialog) API — build a [`GlyphDialog`], route
+//! events to [`handle_event`](GlyphDialog::handle_event), [`draw`](GlyphDialog::draw)
+//! it, and on dismissal call [`finish`](GlyphDialog::finish), which fires a stored
+//! callback with the chosen [`Glyph`] (or `None` on cancel) plus `&mut Ctx`.
+//!
+//! It is the first kiln-ui widget that depends on `kiln-core` (for [`Glyph`]/`Rgba8`
+//! and the [`tile_to_char`] table); kiln-ui is otherwise game-agnostic.
+
+use color::Rgba8;
+use kiln_core::cp437::tile_to_char;
+use kiln_core::glyph::Glyph;
+use ratatui::Frame;
+use ratatui::crossterm::event::{Event, KeyCode, KeyModifiers};
+use ratatui::layout::{Constraint, Layout, Rect};
+use ratatui::style::{Color, Modifier, Style};
+use ratatui::text::{Line, Span};
+use ratatui::widgets::{Block, Clear, Paragraph};
+
+use crate::dialog::DialogResult;
+use crate::dim_area;
+use crate::text_field::TextField;
+
+/// Background color filling the dialog window (matches [`crate::dialog`]).
+const BG: Color = Color::Rgb(10, 15, 35);
+/// Border color for the dialog window.
+const BORDER: Color = Color::Rgb(80, 130, 210);
+/// Background highlight applied to the *label* of the currently focused color field.
+const LABEL_FOCUS_BG: Color = Color::Rgb(40, 60, 110);
+/// Color for the bracketed key hints in the footer.
+const KEY: Color = Color::Rgb(150, 200, 255);
+/// Background of the selected grid cell while the grid is focused (a bright cursor).
+const CURSOR_BG: Color = Color::Rgb(255, 215, 0);
+
+/// Number of columns in the character grid (32 cols × 8 rows = 256 tiles).
+const GRID_COLS: u32 = 32;
+/// Number of rows in the character grid.
+const GRID_ROWS: u32 = 8;
+
+/// Which sub-control of the picker currently has keyboard focus.
+#[derive(Clone, Copy, PartialEq, Eq)]
+enum Focus {
+    /// The 32×8 character grid (arrow keys move the selection).
+    Grid,
+    /// The foreground-color hex field.
+    Fg,
+    /// The background-color hex field.
+    Bg,
+}
+
+/// Boxed callback fired once when the picker is dismissed: `Some(glyph)` on OK,
+/// `None` on cancel.
+type GlyphCallback<Ctx> = Box<dyn FnOnce(Option<Glyph>, &mut Ctx)>;
+
+/// An open glyph-picker dialog, generic over the host context `Ctx` its callback mutates.
+pub struct GlyphDialog<Ctx> {
+    /// Title shown in the window's top border.
+    title: String,
+    /// The currently selected tile index (`0..256`).
+    tile: u32,
+    /// Foreground color as bare hex digits (6 chars when valid, no `#`).
+    fg: TextField,
+    /// Background color as bare hex digits (6 chars when valid, no `#`).
+    bg: TextField,
+    /// Which sub-control currently has focus.
+    focus: Focus,
+    /// The callback fired exactly once on dismissal.
+    callback: GlyphCallback<Ctx>,
+}
+
+impl<Ctx> GlyphDialog<Ctx> {
+    /// Builds a glyph picker seeded from `initial`. The tile selection starts at
+    /// `initial.tile` and the two hex fields are pre-filled from `initial.fg`/`initial.bg`
+    /// (6 uppercase hex digits). `on_done` receives `Some(glyph)` on OK or `None` on
+    /// cancel, plus `&mut Ctx`.
+    pub fn new(
+        title: impl Into<String>,
+        initial: Glyph,
+        on_done: impl FnOnce(Option<Glyph>, &mut Ctx) + 'static,
+    ) -> Self {
+        Self {
+            title: title.into(),
+            tile: initial.tile,
+            fg: TextField::sized(hex6(initial.fg), 6usize),
+            bg: TextField::sized(hex6(initial.bg), 6usize),
+            focus: Focus::Grid,
+            callback: Box::new(on_done),
+        }
+    }
+
+    /// Updates the picker for an input event and reports whether it should close.
+    ///
+    /// `Esc` → [`DialogResult::Cancel`]; `Enter` → [`DialogResult::Submit`] only when
+    /// both color fields are valid hex; `Tab`/`Shift-Tab` cycle focus; arrow keys move
+    /// the grid selection when the grid is focused, otherwise edit the focused field.
+    pub fn handle_event(&mut self, event: &Event) -> DialogResult {
+        let Event::Key(key) = event else {
+            return DialogResult::Continue;
+        };
+        let shift = key.modifiers.contains(KeyModifiers::SHIFT);
+        match key.code {
+            KeyCode::Esc => DialogResult::Cancel,
+            KeyCode::Enter => {
+                if self.ok_enabled() {
+                    DialogResult::Submit
+                } else {
+                    DialogResult::Continue
+                }
+            }
+            // Tab cycles focus forward; Shift-Tab (or BackTab) cycles backward.
+            KeyCode::Tab if shift => self.cycle_focus(false),
+            KeyCode::Tab => self.cycle_focus(true),
+            KeyCode::BackTab => self.cycle_focus(false),
+            // Everything else either moves the grid cursor or edits the focused field.
+            _ => {
+                match self.focus {
+                    Focus::Grid => self.move_grid(key.code),
+                    Focus::Fg => {
+                        self.fg.handle_key(*key);
+                    }
+                    Focus::Bg => {
+                        self.bg.handle_key(*key);
+                    }
+                }
+                DialogResult::Continue
+            }
+        }
+    }
+
+    /// Consumes the dialog and fires its callback. `result` must be the
+    /// [`DialogResult`] just returned by [`handle_event`](GlyphDialog::handle_event);
+    /// only [`DialogResult::Submit`] with both colors valid yields `Some(glyph)`.
+    pub fn finish(self, result: DialogResult, ctx: &mut Ctx) {
+        let chosen = if matches!(result, DialogResult::Submit) {
+            self.glyph()
+        } else {
+            None
+        };
+        (self.callback)(chosen, ctx);
+    }
+
+    /// The chosen [`Glyph`], or `None` if either color field is currently invalid.
+    fn glyph(&self) -> Option<Glyph> {
+        let fg = parse_hex6(self.fg.value())?;
+        let bg = parse_hex6(self.bg.value())?;
+        Some(Glyph {
+            tile: self.tile,
+            fg,
+            bg,
+        })
+    }
+
+    /// Whether OK is currently allowed (both color fields parse as valid hex).
+    fn ok_enabled(&self) -> bool {
+        parse_hex6(self.fg.value()).is_some() && parse_hex6(self.bg.value()).is_some()
+    }
+
+    /// Moves focus to the next (or previous) sub-control, wrapping around.
+    fn cycle_focus(&mut self, forward: bool) -> DialogResult {
+        self.focus = match (self.focus, forward) {
+            (Focus::Grid, true) => Focus::Fg,
+            (Focus::Fg, true) => Focus::Bg,
+            (Focus::Bg, true) => Focus::Grid,
+            (Focus::Grid, false) => Focus::Bg,
+            (Focus::Fg, false) => Focus::Grid,
+            (Focus::Bg, false) => Focus::Fg,
+        };
+        DialogResult::Continue
+    }
+
+    /// Moves the grid selection one cell for an arrow key, clamped at the edges.
+    fn move_grid(&mut self, code: KeyCode) {
+        let (col, row) = (self.tile % GRID_COLS, self.tile / GRID_COLS);
+        let (col, row) = match code {
+            KeyCode::Left => (col.saturating_sub(1), row),
+            KeyCode::Right => ((col + 1).min(GRID_COLS - 1), row),
+            KeyCode::Up => (col, row.saturating_sub(1)),
+            KeyCode::Down => (col, (row + 1).min(GRID_ROWS - 1)),
+            _ => (col, row),
+        };
+        self.tile = row * GRID_COLS + col;
+    }
+
+    /// Draws the picker centered over the whole frame: dims the background, then
+    /// renders the bordered window, the character grid, the two color fields, and the
+    /// OK/Cancel footer. Takes `&mut Frame` (not a `Widget`) so it can place a real
+    /// terminal cursor in the focused color field.
+    pub fn draw(&self, frame: &mut Frame) {
+        let area = frame.area();
+        dim_area(area, frame.buffer_mut());
+
+        // Size the window: wide enough for the 32-cell grid, tall enough for the grid
+        // (8) + a gap + the fields row + the footer, all within borders.
+        let want_w = 40u16;
+        let want_h = 14u16;
+        let w = want_w.min(area.width.saturating_sub(2)).max(8);
+        let h = want_h.min(area.height.saturating_sub(2)).max(5);
+        let rect = Rect {
+            x: area.x + area.width.saturating_sub(w) / 2,
+            y: area.y + area.height.saturating_sub(h) / 2,
+            width: w,
+            height: h,
+        };
+
+        // Window frame: clear underlying content, then a bordered titled block.
+        frame.render_widget(Clear, rect);
+        let block = Block::bordered()
+            .title(format!(" {} ", self.title))
+            .border_style(Style::default().fg(BORDER).bg(BG))
+            .style(Style::default().bg(BG));
+        let inner = block.inner(rect);
+        frame.render_widget(block, rect);
+
+        // Stack: grid (8 rows), gap, fields row, filler, footer.
+        let [grid_area, _gap, fields_area, _filler, footer_area] = Layout::vertical([
+            Constraint::Length(GRID_ROWS as u16),
+            Constraint::Length(1),
+            Constraint::Length(1),
+            Constraint::Min(0),
+            Constraint::Length(1),
+        ])
+        .areas(inner);
+
+        // Both colors must be valid for the grid to preview them; otherwise gray-on-black.
+        let colors = parse_hex6(self.fg.value()).zip(parse_hex6(self.bg.value()));
+
+        self.draw_grid(frame, grid_area, colors);
+        let field_cursor = self.draw_fields(frame, fields_area);
+        self.draw_footer(frame, footer_area);
+
+        // Place a real terminal cursor in the focused field (none when the grid is focused).
+        if let Some((cx, cy)) = field_cursor {
+            frame.set_cursor_position((cx, cy));
+        }
+    }
+
+    /// Draws the 32×8 character grid into `area`, centered horizontally. When `colors`
+    /// is `Some((fg, bg))` each glyph is drawn in those colors; otherwise gray-on-black.
+    /// The selected cell is shown reversed (a bright cursor when the grid is focused).
+    fn draw_grid(&self, frame: &mut Frame, area: Rect, colors: Option<(Rgba8, Rgba8)>) {
+        // Center the fixed-width grid within whatever inner width we got.
+        let grid_x = area.x + area.width.saturating_sub(GRID_COLS as u16) / 2;
+        let base = match colors {
+            Some((fg, bg)) => Style::default().fg(to_color(fg)).bg(to_color(bg)),
+            None => Style::default().fg(Color::Gray).bg(Color::Black),
+        };
+        let buf = frame.buffer_mut();
+        for tile in 0..(GRID_COLS * GRID_ROWS) {
+            let x = grid_x + (tile % GRID_COLS) as u16;
+            let y = area.y + (tile / GRID_COLS) as u16;
+            // Skip cells that would fall outside the (possibly clamped) grid area.
+            if x >= area.right() || y >= area.bottom() {
+                continue;
+            }
+            let style = if tile == self.tile {
+                if self.focus == Focus::Grid {
+                    // Bright cursor so the selection reads even against the colored grid.
+                    Style::default().fg(Color::Black).bg(CURSOR_BG)
+                } else {
+                    base.add_modifier(Modifier::REVERSED)
+                }
+            } else {
+                base
+            };
+            if let Some(cell) = buf.cell_mut((x, y)) {
+                cell.set_symbol(&tile_to_char(tile).to_string());
+                cell.set_style(style);
+            }
+        }
+    }
+
+    /// Draws the `fg`/`bg` labeled hex fields into `area`, centered. Returns the screen
+    /// position of the terminal cursor for the focused field (or `None` if the grid is
+    /// focused), so the caller can place it after dropping the buffer borrow.
+    fn draw_fields(&self, frame: &mut Frame, area: Rect) -> Option<(u16, u16)> {
+        // Each field box is at least 6 wide, growing if the (invalid) value is longer.
+        let fg_w = self.fg.value().chars().count().max(6) as u16;
+        let bg_w = self.bg.value().chars().count().max(6) as u16;
+        // Layout: "fg " + field + "  " + "bg " + field.
+        let total = 3 + fg_w + 2 + 3 + bg_w;
+        let start_x = area.x + area.width.saturating_sub(total) / 2;
+        let y = area.y;
+
+        let fg_label_x = start_x;
+        let fg_field_x = fg_label_x + 3;
+        let bg_label_x = fg_field_x + fg_w + 2;
+        let bg_field_x = bg_label_x + 3;
+
+        let buf = frame.buffer_mut();
+        draw_label(buf, fg_label_x, y, "fg ", self.focus == Focus::Fg);
+        draw_swatch(buf, fg_field_x, y, fg_w, self.fg.value());
+        draw_label(buf, bg_label_x, y, "bg ", self.focus == Focus::Bg);
+        draw_swatch(buf, bg_field_x, y, bg_w, self.bg.value());
+
+        // The terminal cursor goes in the focused field, clamped to its box.
+        match self.focus {
+            Focus::Fg => Some((fg_field_x + (self.fg.display_cursor() as u16).min(fg_w - 1), y)),
+            Focus::Bg => Some((bg_field_x + (self.bg.display_cursor() as u16).min(bg_w - 1), y)),
+            Focus::Grid => None,
+        }
+    }
+
+    /// Draws the `[enter] OK   [esc] Cancel` footer (OK dimmed when disabled).
+    fn draw_footer(&self, frame: &mut Frame, area: Rect) {
+        let ok_style = if self.ok_enabled() {
+            Style::default().fg(Color::White).bg(BG)
+        } else {
+            Style::default().fg(Color::DarkGray).bg(BG)
+        };
+        let key_style = Style::default().fg(KEY).bg(BG);
+        let footer = Line::from(vec![
+            Span::styled("[enter] ", key_style),
+            Span::styled("OK   ", ok_style),
+            Span::styled("[esc] ", key_style),
+            Span::styled("Cancel", Style::default().fg(Color::White).bg(BG)),
+        ]);
+        frame.render_widget(Paragraph::new(footer), area);
+    }
+}
+
+/// Draws a field label, highlighting its background when the field is focused.
+fn draw_label(buf: &mut ratatui::buffer::Buffer, x: u16, y: u16, text: &str, focused: bool) {
+    let style = if focused {
+        Style::default().fg(Color::White).bg(LABEL_FOCUS_BG)
+    } else {
+        Style::default().fg(Color::Gray).bg(BG)
+    };
+    buf.set_string(x, y, text, style);
+}
+
+/// Draws a color swatch box of width `w`: the parsed color as background with
+/// contrasting text when `value` is valid hex, otherwise a red "invalid" box.
+fn draw_swatch(buf: &mut ratatui::buffer::Buffer, x: u16, y: u16, w: u16, value: &str) {
+    let style = match parse_hex6(value) {
+        Some(c) => Style::default().fg(contrast(c)).bg(to_color(c)),
+        None => Style::default().fg(Color::White).bg(Color::Rgb(150, 30, 30)),
+    };
+    // Left-align the value in a fixed-width box so the swatch fills the whole field.
+    let shown = format!("{value:<width$}", width = w as usize);
+    buf.set_string(x, y, shown, style);
+}
+
+/// Formats an [`Rgba8`] as 6 uppercase hex digits (no `#`); alpha is dropped.
+fn hex6(c: Rgba8) -> String {
+    format!("{:02X}{:02X}{:02X}", c.r, c.g, c.b)
+}
+
+/// Parses exactly 6 hex digits (no `#`) into an opaque [`Rgba8`], or `None` if the
+/// string is not exactly six hex characters.
+fn parse_hex6(s: &str) -> Option<Rgba8> {
+    if s.len() != 6 || !s.bytes().all(|b| b.is_ascii_hexdigit()) {
+        return None;
+    }
+    Some(Rgba8 {
+        r: u8::from_str_radix(&s[0..2], 16).ok()?,
+        g: u8::from_str_radix(&s[2..4], 16).ok()?,
+        b: u8::from_str_radix(&s[4..6], 16).ok()?,
+        a: 255,
+    })
+}
+
+/// Converts a core [`Rgba8`] to a ratatui [`Color`] (alpha dropped).
+fn to_color(c: Rgba8) -> Color {
+    Color::Rgb(c.r, c.g, c.b)
+}
+
+/// Picks black or white for legible text on a `c` background, by luminance.
+fn contrast(c: Rgba8) -> Color {
+    // Rec. 601 luma; > ~50% brightness reads better with black text.
+    let luma = 0.299 * c.r as f32 + 0.587 * c.g as f32 + 0.114 * c.b as f32;
+    if luma > 128.0 {
+        Color::Black
+    } else {
+        Color::White
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ratatui::crossterm::event::{KeyEvent, KeyModifiers};
+
+    /// A glyph with distinct, valid colors for seeding tests.
+    fn sample() -> Glyph {
+        Glyph {
+            tile: 5,
+            fg: Rgba8 {
+                r: 0xFF,
+                g: 0x00,
+                b: 0x00,
+                a: 255,
+            },
+            bg: Rgba8 {
+                r: 0x00,
+                g: 0x00,
+                b: 0xFF,
+                a: 255,
+            },
+        }
+    }
+
+    /// Builds a key-press event with no modifiers.
+    fn key(code: KeyCode) -> Event {
+        Event::Key(KeyEvent::new(code, KeyModifiers::NONE))
+    }
+
+    #[test]
+    fn seed_round_trips_tile_and_colors() {
+        let d: GlyphDialog<()> = GlyphDialog::new("t", sample(), |_, _| {});
+        assert_eq!(d.tile, 5);
+        assert_eq!(d.fg.value(), "FF0000");
+        assert_eq!(d.bg.value(), "0000FF");
+        assert!(d.ok_enabled());
+    }
+
+    #[test]
+    fn tab_cycles_focus_both_ways() {
+        let mut d: GlyphDialog<()> = GlyphDialog::new("t", sample(), |_, _| {});
+        assert!(d.focus == Focus::Grid);
+        d.handle_event(&key(KeyCode::Tab));
+        assert!(d.focus == Focus::Fg);
+        d.handle_event(&key(KeyCode::Tab));
+        assert!(d.focus == Focus::Bg);
+        d.handle_event(&key(KeyCode::Tab));
+        assert!(d.focus == Focus::Grid);
+        // BackTab goes the other way.
+        d.handle_event(&key(KeyCode::BackTab));
+        assert!(d.focus == Focus::Bg);
+    }
+
+    #[test]
+    fn arrows_move_grid_selection_and_clamp() {
+        let mut g = sample();
+        g.tile = 0;
+        let mut d: GlyphDialog<()> = GlyphDialog::new("t", g, |_, _| {});
+        d.handle_event(&key(KeyCode::Right));
+        assert_eq!(d.tile, 1);
+        d.handle_event(&key(KeyCode::Down));
+        assert_eq!(d.tile, 1 + GRID_COLS);
+        d.handle_event(&key(KeyCode::Left));
+        assert_eq!(d.tile, GRID_COLS);
+        d.handle_event(&key(KeyCode::Up));
+        assert_eq!(d.tile, 0);
+        // Clamps at the top-left corner.
+        d.handle_event(&key(KeyCode::Up));
+        d.handle_event(&key(KeyCode::Left));
+        assert_eq!(d.tile, 0);
+    }
+
+    #[test]
+    fn invalid_hex_disables_ok_and_blocks_enter() {
+        let mut d: GlyphDialog<()> = GlyphDialog::new("t", sample(), |_, _| {});
+        // Focus the fg field and delete a digit → "FF000" (5 chars) is invalid.
+        d.handle_event(&key(KeyCode::Tab));
+        d.handle_event(&key(KeyCode::Backspace));
+        assert_eq!(d.fg.value(), "FF000");
+        assert!(!d.ok_enabled());
+        assert!(matches!(
+            d.handle_event(&key(KeyCode::Enter)),
+            DialogResult::Continue
+        ));
+        // Type the digit back → valid again.
+        d.handle_event(&key(KeyCode::Char('0')));
+        assert_eq!(d.fg.value(), "FF0000");
+        assert!(d.ok_enabled());
+    }
+
+    #[test]
+    fn submit_yields_glyph_cancel_yields_none() {
+        // Submit returns the chosen glyph.
+        let mut out: Option<Option<Glyph>> = None;
+        let mut d: GlyphDialog<Option<Option<Glyph>>> =
+            GlyphDialog::new("t", sample(), |g, c| *c = Some(g));
+        d.handle_event(&key(KeyCode::Right)); // tile 5 -> 6
+        let res = d.handle_event(&key(KeyCode::Enter));
+        d.finish(res, &mut out);
+        let chosen = out.unwrap().unwrap();
+        assert_eq!(chosen.tile, 6);
+        assert_eq!(chosen.fg, sample().fg);
+        assert_eq!(chosen.bg, sample().bg);
+
+        // Cancel returns None.
+        let mut out2: Option<Option<Glyph>> = None;
+        let d2: GlyphDialog<Option<Option<Glyph>>> =
+            GlyphDialog::new("t", sample(), |g, c| *c = Some(g));
+        d2.finish(DialogResult::Cancel, &mut out2);
+        assert!(out2.unwrap().is_none());
+    }
+
+    #[test]
+    fn parse_hex6_validation() {
+        assert!(parse_hex6("FF0000").is_some());
+        assert!(parse_hex6("ff00 aa").is_none()); // space / wrong length
+        assert!(parse_hex6("FF00").is_none()); // too short
+        assert!(parse_hex6("GGGGGG").is_none()); // non-hex
+    }
+}

kiln-ui/src/lib.rs

@@ -23,6 +23,7 @@ use ratatui::style::{Color, Style};
 mod clipboard;
 pub mod code_editor;
 pub mod dialog;
+pub mod glyph_dialog;
 mod text;
 pub mod text_field;
 

kiln-ui/src/text_field.rs

@@ -18,6 +18,8 @@ pub struct TextField {
     cursor: usize,
     /// Clipboard for `ctrl`/`⌘`+`v` paste.
     clipboard: Clipboard,
+    /// How long we will allow the string to be:
+    max_length: Option<usize>,
 }
 
 impl TextField {
@@ -25,7 +27,14 @@ impl TextField {
     pub fn new(initial: impl Into<String>) -> Self {
         let text = initial.into();
         let cursor = text.chars().count();
-        Self { text, cursor, clipboard: Clipboard::new() }
+        Self { text, cursor, clipboard: Clipboard::new(), max_length: None }
+    }
+
+    pub fn sized(initial: impl Into<String>, max_length: usize) -> Self {
+        let mut text = initial.into();
+        text.truncate(max_length);
+        let cursor = text.chars().count();
+        Self { text, cursor, clipboard: Clipboard::new(), max_length: Some(max_length) }
     }
 
     /// The current text.
@@ -70,8 +79,13 @@ impl TextField {
 
     fn insert(&mut self, c: char) {
         let b = byte_of(&self.text, self.cursor);
-        self.text.insert(b, c);
+        if self.max_length.is_none_or(|max_length| max_length > self.text.len() ) {
-        self.cursor += 1;
+            self.text.insert(b, c);
+        }
+
+        if self.max_length.is_none_or(|max_length| max_length > self.cursor ) {
+            self.cursor += 1;
+        }
     }
 
     fn backspace(&mut self) -> bool {
@@ -168,6 +182,35 @@ mod tests {
         assert_eq!(f.display_cursor(), 0);
     }
 
+    #[test]
+    fn sized_truncates_overlong_initial_value() {
+        // `sized` clamps the seed text to the max length up front.
+        let f = TextField::sized("FF0000extra", 6);
+        assert_eq!(f.value(), "FF0000");
+    }
+
+    #[test]
+    fn max_length_caps_typed_input() {
+        // Typing into a sized field fills up to the cap, then further input is dropped.
+        let mut f = TextField::sized("", 3);
+        for c in "abcd".chars() {
+            f.handle_key(key(KeyCode::Char(c)));
+        }
+        assert_eq!(f.value(), "abc");
+
+        // A field seeded at its cap ignores further typing (the glyph picker's hex fields).
+        let mut g = TextField::sized("FF0000", 6);
+        g.handle_key(key(KeyCode::Char('9')));
+        assert_eq!(g.value(), "FF0000");
+
+        // An unsized field is unbounded.
+        let mut u = TextField::new("");
+        for c in "abcdef".chars() {
+            u.handle_key(key(KeyCode::Char(c)));
+        }
+        assert_eq!(u.value(), "abcdef");
+    }
+
     #[test]
     fn unhandled_keys_return_false() {
         let mut f = TextField::new("x");