Wire cg-gaps and cg-bid display through the renderer registry

Makefile

@@ -3,7 +3,7 @@ EMACS   ?= emacs
 PKG      = card-games
 VERSION  = 1.0.50
 # Source files in dependency order (cg-core first).
-EL       = cg-core.el cg-svg.el cg-bid.el cg-gaps.el cg-bid-ui.el card-games.el
+EL       = cg-core.el cg-svg.el cg-render.el cg-bid.el cg-gaps.el cg-bid-ui.el card-games.el
 ELC      = $(EL:.el=.elc)
 PKGDESC  = $(PKG)-pkg.el
 TARDIR   = $(PKG)-$(VERSION)

README.org

@@ -9,24 +9,28 @@ configuring ~card-game-symbols~.
 
 * Games
 - *500 (Bid)* -- the four-handed partnership trick-taking game, against
-  three computer opponents (=M-x cg-bid=).
+  three computer opponents (~M-x cg-bid~).
 - *Gaps / Hell's Half-Acre* -- solitaire; sort each row into one suit
-  running 2..K (=M-x cg-gaps=).
+  running 2..K (~M-x cg-gaps~).
 
-To launch the game-menu press =M-x card-game= or launch a game
-directly by calling it's launcher command.  Launcher commands take the
-form ~cg-GAME~ where ~GAME~ is one of
-- montana - Montana: <SHORT_RULES>
-- gap - Gap: <SHORT_RULES>
-- hha - Hells Half Acre: <SHORT_RULES>
-- bid - Bid, (or 500 Bid): <SHORT_RULES>
+To open the game menu type ~M-x card-game~, or start a game directly
+with its command:
+- ~cg-montana~ -- Montana (also called Gaps).  Each row is anchored by a
+  Two and built upward in one suit, 2 through King; slide cards into the
+  gaps until all four rows are sorted.
+- ~cg-gaps~ -- an alias for ~cg-montana~.
+- ~cg-hells-half-acre~ -- the build-down variant: each row is anchored by
+  a King and built downward, King through 2.
+- ~cg-bid~ -- 500 (Bid).  Win the auction, name the trump suit, then take
+  tricks with your partner to reach 500 points before the opposing pair.
 
 * TODO
-- [ ] documentation
-- [ ] create ~card-game-symbols~ and obey it
-- [ ] refactor to allow games to subclass components (svg)
-- [ ] add manual-control silder for card size (svgfull)
-- [ ] mor games
+- [X] make the suit symbols customizable (~cg-symbols~) and obey them
+- [ ] a Texinfo manual
+- [ ] renderer "skins": let games subclass the display components (text,
+  SVG, full-window SVG)
+- [ ] a manual card-size control for the full-window SVG UI
+- [ ] more games
 
 * Install
 ** From the package tarball
@@ -55,8 +59,11 @@ graphical display.
 
 - 500: ~b~ bid, ~p~ pass, arrows + ~RET~ to play (or click a card),
   ~n~ next hand / new game, ~?~ help.
-- Gaps: arrows or ~hjkl~ to move, ~RET~ to fill a gap (or click it),
-  ~r~ redeal, ~u~ undo, ~n~ new, ~?~ help.
+- Gaps: arrows to move (or ~hjkl~ when ~cg-keys~ is ~classic~), ~RET~ to
+  fill a gap (or click it), ~r~ redeal, ~u~ undo, ~n~ new, ~?~ help.
+
+On a graphical display, ~v~ toggles the full-window SVG table and
+~+~ / ~-~ / ~0~ (Emacs ~text-scale-adjust~) resize the cards.
 
 * Customization
 ~M-x customize-group RET cg-svg~ and ~RET card-games~:
@@ -66,6 +73,11 @@ graphical display.
 - ~cg-svg-card-width~, ~cg-svg-card-height~, ~cg-svg-card-shadow~,
   ~cg-svg-font-family~ -- card appearance.
 - ~cg-svg-card-back~ -- card-back pattern: dots, rings, or solid.
+- ~cg-symbols~ -- the Unicode suit glyphs (and the joker) drawn on cards.
+- ~cg-svg-four-color~ -- draw a four-colour deck (clubs green, diamonds
+  blue-purple).
+- ~cg-keys~ -- ~emacs~ (default) or ~classic~ (adds vi-style ~hjkl~ and
+  ~SPC~).
 - ~cg-bid-animate~, ~cg-bid-ai-delay~, ~cg-bid-trick-pause~ -- pace the
   500 AI so play is watchable and completed tricks linger.
 - ~M-x card-games-set-theme~ -- apply a preset (classic, dark, contrast).

card-games-pkg.el

@@ -3,7 +3,7 @@
   "Play card games in Emacs (console UNICODE and graphical SVG)."
   '((emacs "26.1"))
   :keywords '("games")
-  :url "https://github.com/corwin/card-games"
+  :url "https://code.bru.st/corwin/card-game.el"
   :authors '(("Corwin Brust" . "corwin@bru.st"))
   :maintainer '("Corwin Brust" . "corwin@bru.st"))
 ;;; card-games-pkg.el ends here

card-games.el

@@ -7,7 +7,7 @@
 ;; Version: 1.0.50
 ;; Package-Requires: ((emacs "26.1"))
 ;; Keywords: games
-;; URL: https://github.com/corwin/card-games
+;; URL: https://code.bru.st/corwin/card-game.el
 
 ;; This program is free software; you can redistribute it and/or modify
 ;; it under the terms of the GNU General Public License as published by
@@ -39,6 +39,7 @@
 ;;; Code:
 
 (require 'cg-core)
+(require 'cg-render)
 (require 'cg-gaps)
 (require 'cg-bid-ui)
 

cg-bid-ui.el

@@ -7,7 +7,7 @@
 ;; Version: 1.0.50
 ;; Package-Requires: ((emacs "26.1"))
 ;; Keywords: games
-;; URL: https://github.com/corwin/card-games
+;; URL: https://code.bru.st/corwin/card-game.el
 
 ;; This program is free software; you can redistribute it and/or modify
 ;; it under the terms of the GNU General Public License as published by
@@ -33,6 +33,7 @@
 (require 'cg-core)
 (require 'cg-bid)
 (require 'cg-svg)
+(require 'cg-render)
 (require 'svg)
 (require 'color)
 
@@ -388,17 +389,37 @@ Folds the controls into the single action-button row (see
   (cg-bid--button "[Help]" #'cg-bid-help "Show help")
   (insert "\n"))
 
+(cl-defmethod cg-renderer-draw ((_renderer cg-text-renderer) (game cg-bid-game))
+  "Draw the 500 GAME as UNICODE text with the action buttons."
+  (insert (cg-render game))
+  (cg-bid--insert-buttons game))
+
+(cl-defmethod cg-renderer-draw ((_renderer cg-svg-renderer) (game cg-bid-game))
+  "Draw the 500 GAME as an SVG table with the action buttons."
+  (cg-bid--insert-graphical game)
+  (cg-bid--insert-buttons game))
+
+(cl-defmethod cg-renderer-draw ((_renderer cg-svg-fill-renderer) (game cg-bid-game))
+  "Draw the 500 GAME as a frameless full-window SVG table."
+  (cg-bid--insert-svg-ui game))
+
+(defun cg-bid--treatment ()
+  "Return the display treatment symbol for the current 500 buffer.
+Honours `cg-bid-svg-ui' and whether the display is graphical."
+  (cond ((and cg-bid-svg-ui (display-graphic-p)) 'svg-fill)
+        ((display-graphic-p) 'svg)
+        (t 'text)))
+
 (defun cg-bid--redisplay ()
-  "Redraw the current 500 buffer (SVG table on a graphical display)."
-  (let ((inhibit-read-only t) (game cg-bid--game))
+  "Redraw the current 500 buffer through its renderer.
+The treatment is chosen by `cg-bid--treatment' and dispatched with
+`cg-renderer-draw'."
+  (let* ((inhibit-read-only t)
+         (game cg-bid--game)
+         (renderer (cg-render-set-treatment game (cg-bid--treatment))))
     (setq-local mode-line-process (cg-bid--mode-line game))
     (erase-buffer)
-    (if (and cg-bid-svg-ui (display-graphic-p))
-        (cg-bid--insert-svg-ui game)
-      (if (display-graphic-p)
-          (cg-bid--insert-graphical game)
-        (insert (cg-render game)))
-      (cg-bid--insert-buttons game))
+    (cg-renderer-draw renderer game)
     (goto-char (point-min))))
 
 (defun cg-bid--refresh ()

cg-bid.el

@@ -7,7 +7,7 @@
 ;; Version: 1.0.50
 ;; Package-Requires: ((emacs "26.1"))
 ;; Keywords: games
-;; URL: https://github.com/corwin/card-games
+;; URL: https://code.bru.st/corwin/card-game.el
 
 ;; This program is free software; you can redistribute it and/or modify
 ;; it under the terms of the GNU General Public License as published by
@@ -65,7 +65,7 @@
   (cond
    ((null card) "--")
    ((cg-bid-joker-p card) "Jk")
-   (t (concat (aref cg-bid-ranks (cdr card)) (aref cg-suits (car card))))))
+   (t (concat (aref cg-bid-ranks (cdr card)) (cg-suit-glyph (car card))))))
 
 (defun cg-bid--full-deck ()
   "Return the 45-card deck as a list of cards."

cg-core.el

@@ -7,7 +7,7 @@
 ;; Version: 1.0.50
 ;; Package-Requires: ((emacs "26.1"))
 ;; Keywords: games
-;; URL: https://github.com/corwin/card-games
+;; URL: https://code.bru.st/corwin/card-game.el
 
 ;; This program is free software; you can redistribute it and/or modify
 ;; it under the terms of the GNU General Public License as published by
@@ -60,7 +60,9 @@ and SPC as an action key.  Takes effect the next time a game starts."
   ((name :initarg :name :initform "game" :type string
          :documentation "Human-readable game name.")
    (env  :initarg :env  :initform nil
-         :documentation "Mutable per-game data, stored as a plist."))
+         :documentation "Mutable per-game data, stored as a plist.")
+   (renderer :initarg :renderer :initform nil
+             :documentation "Current `cg-renderer', or nil for the default."))
   "Abstract base class for card games."
   :abstract t)
 
@@ -80,13 +82,78 @@ and SPC as an action key.  Takes effect the next time a game starts."
   value)
 
 
+;;;; Renderer "skins"
+
+;; A renderer (a "skin") is a display treatment: it knows how to draw a
+;; game and how to map a click back to a game action.  Treatments are
+;; EIEIO classes registered by name in `cg-renderers'; a game holds the
+;; one it is currently drawn with.  This lets a single game be shown as
+;; plain text, as SVG, or as a full-window SVG table without subclassing
+;; the game itself once per treatment.  Concrete treatments and the
+;; game-specific drawing methods live in cg-render.el and the games.
+
+(defclass cg-renderer ()
+  ((name :initarg :name :initform 'text :type symbol
+         :documentation "Symbol naming this treatment."))
+  "Abstract base class for a display treatment (a \"skin\")."
+  :abstract t)
+
+(cl-defgeneric cg-renderer-draw (renderer game)
+  "Draw GAME under RENDERER by inserting into the current buffer.")
+
+(cl-defgeneric cg-renderer-hit (renderer game position)
+  "Map POSITION under RENDERER to an action on GAME.
+Return non-nil when the click was handled.")
+
+(cl-defmethod cg-renderer-draw ((renderer cg-renderer) (game cg-game))
+  "Default method: report that no drawing method exists for this pair."
+  (error "No `cg-renderer-draw' for %s under the `%s' renderer"
+         (eieio-object-class-name game) (oref renderer name)))
+
+(cl-defmethod cg-renderer-hit ((_renderer cg-renderer) (_game cg-game) _position)
+  "Default method: treat the click as unhandled."
+  nil)
+
+(defvar cg-renderers nil
+  "Alist mapping a treatment name (a symbol) to a `cg-renderer' subclass.
+Populate it with `cg-register-renderer' and look entries up with
+`cg-make-renderer'.")
+
+(defun cg-register-renderer (name class)
+  "Register renderer CLASS (an EIEIO class) under the treatment NAME."
+  (setf (alist-get name cg-renderers) class))
+
+(defun cg-make-renderer (name)
+  "Return a fresh renderer instance for treatment NAME, or nil if unknown."
+  (let ((class (alist-get name cg-renderers)))
+    (and class (make-instance class :name name))))
+
+(defun cg-renderer-names ()
+  "Return the registered treatment names."
+  (mapcar #'car cg-renderers))
+
+
 ;;;; Cards and colours
 
-(defconst cg-suits ["♠" "♣" "♦" "♥"]
-  "Suit glyphs indexed 0..3: spades, clubs, diamonds, hearts.")
+(defcustom cg-symbols
+  '((0 . "♠") (1 . "♣") (2 . "♦") (3 . "♥") (joker . "★"))
+  "Glyphs used to draw suits, both as text and inside the SVG cards.
+The value is an alist mapping a suit index (0 spades, 1 clubs,
+2 diamonds, 3 hearts) or the symbol `joker' to the string drawn for it.
+Customize this to use alternative Unicode symbols, for example the
+outlined suits \"♤\" \"♧\" \"♢\" \"♡\"."
+  :type '(alist :key-type sexp :value-type string)
+  :group 'card-games)
 
 (defconst cg-suit-names ["Spades" "Clubs" "Diamonds" "Hearts"]
-  "Suit names indexed to match `cg-suits'.")
+  "Suit names indexed 0..3 to match the suit indices used throughout.")
+
+(defun cg-suit-glyph (suit)
+  "Return the glyph drawn for SUIT, a suit index 0-3 or the symbol `joker'.
+The glyphs are taken from `cg-symbols'."
+  (or (cdr (assoc suit cg-symbols))
+      (and (integerp suit) (aref cg-suit-names suit))
+      "?"))
 
 (defsubst cg-red-suit-p (suit)
   "Return non-nil when SUIT index denotes a red suit."

cg-gaps.el

@@ -7,7 +7,7 @@
 ;; Version: 1.0.50
 ;; Package-Requires: ((emacs "26.1"))
 ;; Keywords: games
-;; URL: https://github.com/corwin/card-games
+;; URL: https://code.bru.st/corwin/card-game.el
 
 ;; This program is free software; you can redistribute it and/or modify
 ;; it under the terms of the GNU General Public License as published by
@@ -49,6 +49,7 @@
 
 (require 'cg-core)
 (require 'cg-svg)
+(require 'cg-render)
 
 
 ;;;; Cards
@@ -73,7 +74,7 @@
   (if (null card)
       "·"
     (concat (aref cg-gaps-ranks (cdr card))
-            (aref cg-suits (car card)))))
+            (cg-suit-glyph (car card)))))
 
 
 ;;;; Games — an abstract base and two subclasses
@@ -419,23 +420,37 @@ buttons (the keyboard hint *is* the button)."
   (cg-gaps--key-button "?"   "help"   #'cg-gaps-help   "Show the rules and keys")
   (insert "\n"))
 
+(cl-defmethod cg-renderer-draw ((_renderer cg-text-renderer) (game cg-gaps-game))
+  "Draw the Gaps GAME as UNICODE text with the control line."
+  (insert (cg-render game))
+  (cg-gaps--insert-controls))
+
+(cl-defmethod cg-renderer-draw ((_renderer cg-svg-renderer) (game cg-gaps-game))
+  "Draw the Gaps GAME as an inline SVG board with the control line."
+  (cg-gaps--insert-graphical game)
+  (cg-gaps--insert-controls))
+
+(cl-defmethod cg-renderer-draw ((_renderer cg-svg-fill-renderer) (game cg-gaps-game))
+  "Draw the Gaps GAME as a full-window SVG table."
+  (cg-gaps--insert-svg-ui game))
+
+(defun cg-gaps--treatment ()
+  "Return the display treatment symbol for the current Gaps buffer.
+Honours `cg-gaps-svg-ui' and whether the display is graphical."
+  (cond ((and cg-gaps-svg-ui (display-graphic-p)) 'svg-fill)
+        ((display-graphic-p) 'svg)
+        (t 'text)))
+
 (defun cg-gaps--redisplay ()
-  "Redraw the current Gaps buffer.
-Full-buffer SVG when `cg-gaps-svg-ui'; otherwise an inline SVG board (or
-UNICODE text on a terminal), each followed by the single control line."
-  (let ((game cg-gaps--game)
-        (inhibit-read-only t))
+  "Redraw the current Gaps buffer through its renderer.
+The treatment is chosen by `cg-gaps--treatment' and dispatched with
+`cg-renderer-draw'."
+  (let* ((game cg-gaps--game)
+         (inhibit-read-only t)
+         (renderer (cg-render-set-treatment game (cg-gaps--treatment))))
     (setq-local mode-line-process (cg-gaps--mode-line game))
     (erase-buffer)
-    (cond
-     ((and cg-gaps-svg-ui (display-graphic-p))
-      (cg-gaps--insert-svg-ui game))
-     ((display-graphic-p)
-      (cg-gaps--insert-graphical game)
-      (cg-gaps--insert-controls))
-     (t
-      (insert (cg-render game))
-      (cg-gaps--insert-controls)))
+    (cg-renderer-draw renderer game)
     (if (display-graphic-p)
         (goto-char (point-min))
       (let ((cur (cg-get game :cursor)))

cg-render.el

@@ -0,0 +1,98 @@
+;;; cg-render.el --- Renderer "skins" for card games  -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2026  Corwin Brust
+
+;; Author: Corwin Brust <corwin@bru.st>
+;; Maintainer: Corwin Brust <corwin@bru.st>
+;; Version: 1.0.50
+;; Package-Requires: ((emacs "26.1"))
+;; Keywords: games
+;; URL: https://code.bru.st/corwin/card-game.el
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Concrete display treatments ("skins") built on the `cg-renderer'
+;; protocol from cg-core.  Each treatment is a small EIEIO class that
+;; registers itself by name:
+;;
+;;   text      plain UNICODE text (works in a terminal and on Android)
+;;   svg       SVG cards on a graphical display
+;;   svg-fill  a full-window SVG table that grows with the window
+;;
+;; A game draws itself by calling `cg-render-game', which selects the
+;; game's current renderer (falling back to a default treatment chosen
+;; for the display) and dispatches `cg-renderer-draw'.  The actual,
+;; game-specific drawing is supplied as methods specialised on a
+;; (TREATMENT GAME) pair in the individual game files.
+
+;;; Code:
+
+(require 'cg-core)
+
+(defgroup cg-render nil
+  "Display treatments (\"skins\") for card games."
+  :group 'card-games
+  :prefix "cg-render-")
+
+(defclass cg-text-renderer (cg-renderer)
+  ((name :initform 'text))
+  "Plain UNICODE text treatment.")
+
+(defclass cg-svg-renderer (cg-renderer)
+  ((name :initform 'svg))
+  "SVG cards on a graphical display.")
+
+(defclass cg-svg-fill-renderer (cg-svg-renderer)
+  ((name :initform 'svg-fill))
+  "Full-window SVG table that grows to fill the window.")
+
+(cg-register-renderer 'text     'cg-text-renderer)
+(cg-register-renderer 'svg      'cg-svg-renderer)
+(cg-register-renderer 'svg-fill 'cg-svg-fill-renderer)
+
+(defcustom cg-render-default-treatment 'auto
+  "Default display treatment for games.
+The value `auto' chooses `svg' on a graphical display and `text'
+otherwise.  It may instead name a treatment registered in
+`cg-renderers', such as `text', `svg', or `svg-fill'."
+  :type '(choice (const :tag "Automatic (svg if graphical, else text)" auto)
+                 (const text) (const svg) (const svg-fill)
+                 (symbol :tag "Other registered treatment"))
+  :group 'cg-render)
+
+(defun cg-render-resolve-treatment (&optional name)
+  "Return a concrete treatment name, resolving `auto' and NAME for this display.
+NAME defaults to `cg-render-default-treatment'."
+  (let ((n (or name cg-render-default-treatment)))
+    (if (eq n 'auto)
+        (if (display-graphic-p) 'svg 'text)
+      n)))
+
+(defun cg-render-game (game)
+  "Draw GAME with its current renderer, creating a default one if needed.
+The default treatment comes from `cg-render-resolve-treatment'."
+  (let ((r (or (oref game renderer)
+               (let ((new (cg-make-renderer (cg-render-resolve-treatment))))
+                 (oset game renderer new)
+                 new))))
+    (cg-renderer-draw r game)))
+
+(defun cg-render-set-treatment (game name)
+  "Switch GAME to the treatment NAME and return its new renderer."
+  (oset game renderer (cg-make-renderer name)))
+
+(provide 'cg-render)
+;;; cg-render.el ends here

cg-svg.el

@@ -7,7 +7,7 @@
 ;; Version: 1.0.50
 ;; Package-Requires: ((emacs "26.1"))
 ;; Keywords: games
-;; URL: https://github.com/corwin/card-games
+;; URL: https://code.bru.st/corwin/card-game.el
 
 ;; This program is free software; you can redistribute it and/or modify
 ;; it under the terms of the GNU General Public License as published by
@@ -79,8 +79,9 @@
   :type 'string :group 'cg-svg)
 
 (defcustom cg-svg-theme-colors t
-  "When non-nil, derive the highlight ring and card back from the
-active Emacs theme (with the colour variables below as fallbacks)."
+  "Derive the highlight ring and card back from the active theme.
+When non-nil, colours are taken from the active Emacs theme, with the
+colour variables below as fallbacks."
   :type 'boolean :group 'cg-svg)
 
 (defcustom cg-svg-card-back 'dots
@@ -88,8 +89,9 @@ active Emacs theme (with the colour variables below as fallbacks)."
   :type '(choice (const dots) (const rings) (const solid)) :group 'cg-svg)
 
 (defcustom cg-svg-four-color nil
-  "When non-nil use a four-colour deck: clubs green, diamonds blue-purple
-\(spades stay black, hearts red)."
+  "Use a four-colour deck when non-nil.
+Clubs are drawn green and diamonds blue-purple; spades stay black and
+hearts red."
   :type 'boolean :group 'cg-svg)
 
 (defconst cg-svg-corner-radius 6
@@ -164,8 +166,9 @@ Pips with a Y fraction above 0.5 are drawn rotated 180 degrees.")
         (t cg-svg-black-color)))
 
 (defun cg-svg--suit-glyph (suit)
-  "Return the glyph for SUIT (0-3 or the symbol `joker')."
-  (if (eq suit 'joker) "★" (aref cg-suits suit)))
+  "Return the glyph for SUIT (0-3 or the symbol `joker').
+Defers to `cg-suit-glyph', so it honours `cg-symbols'."
+  (cg-suit-glyph suit))
 
 (defun cg-svg--text (svg str x y size color &optional bold transform)
   "Add centred text STR to SVG at X, Y with SIZE, COLOR, BOLD, TRANSFORM."
@@ -178,7 +181,8 @@ Pips with a Y fraction above 0.5 are drawn rotated 180 degrees.")
 
 (defun cg-svg--index (svg x y w h rank glyph color flip)
   "Draw a stacked RANK/GLYPH index in COLOR on SVG.
-Top-left normally; bottom-right and upside-down when FLIP is non-nil."
+X, Y and W, H give the card's top-left corner and size.  The index sits
+top-left normally, and bottom-right and upside-down when FLIP is non-nil."
   (let* ((rs (max 8 (round (* h 0.18))))
          (gs (max 7 (round (* h 0.15))))
          (ix (+ x (round (* w 0.16))))
@@ -207,14 +211,16 @@ Top-left normally; bottom-right and upside-down when FLIP is non-nil."
                    ps glyph color (> (cdr pos) 0.5)))))
 
 (defun cg-svg--draw-ace (svg x y w h glyph color)
-  "Draw a single large central pip (an ace) in COLOR on SVG."
+  "Draw a single large central pip (an ace) of GLYPH in COLOR on SVG.
+X, Y and W, H give the card's top-left corner and size."
   (cg-svg--pip svg (+ x (/ w 2.0)) (+ y (/ h 2.0)) (round (* h 0.42))
                glyph color nil))
 
 (defun cg-svg--draw-court (svg x y w h rank glyph color suit)
   "Draw a framed court card (RANK letter + GLYPH) of SUIT in COLOR on SVG.
-The inner panel has a quarter-circle scallop cut into each corner; the
-scallop radius is 8.5% of the panel height (17% diameter)."
+X, Y and W, H give the card's top-left corner and size.  The inner panel
+has a quarter-circle scallop cut into each corner; the scallop radius is
+8.5% of the panel height (17% diameter)."
   (let* ((mx (round (* w 0.15))) (my (round (* h 0.16)))
          (bx (+ x mx)) (by (+ y my))
          (bw (- w (* 2 mx))) (bh (- h (* 2 my)))
@@ -238,7 +244,8 @@ scallop radius is 8.5% of the panel height (17% diameter)."
     (cg-svg--text svg glyph (+ x (/ w 2.0)) (+ y (* h 0.76)) (* h 0.20) color)))
 
 (defun cg-svg--draw-joker (svg x y w h color)
-  "Draw the joker face in COLOR on SVG."
+  "Draw the joker face in COLOR on SVG.
+X, Y and W, H give the card's top-left corner and size."
   (cg-svg--text svg "★" (+ x (/ w 2.0)) (+ y (* h 0.52)) (* h 0.40) color)
   (cg-svg--text svg "JOKER" (+ x (/ w 2.0)) (+ y (* h 0.74)) (* h 0.135) color t))
 

test/card-games-tests.el

@@ -15,6 +15,26 @@
 (ert-deftest cgt-core-color-fallback ()
   (should (equal "#123456" (cg-color 'no-such-face-xyzzy :background "#123456"))))
 
+(ert-deftest cgt-core-suit-glyph ()
+  (let ((cg-symbols '((0 . "S") (1 . "C") (2 . "D") (3 . "H") (joker . "JK"))))
+    (should (equal "S" (cg-suit-glyph 0)))
+    (should (equal "JK" (cg-suit-glyph 'joker))))
+  (should (equal "♠" (cg-suit-glyph 0))))
+
+;;;; Renderer skins
+
+(ert-deftest cgt-render-registry ()
+  (should (memq 'text (cg-renderer-names)))
+  (should (memq 'svg (cg-renderer-names)))
+  (should (memq 'svg-fill (cg-renderer-names)))
+  (should (object-of-class-p (cg-make-renderer 'svg) 'cg-svg-renderer))
+  (should (object-of-class-p (cg-make-renderer 'svg-fill) 'cg-svg-renderer))
+  (should-not (cg-make-renderer 'no-such-treatment)))
+
+(ert-deftest cgt-render-resolve ()
+  (should (eq 'text (cg-render-resolve-treatment 'text)))
+  (should (memq (cg-render-resolve-treatment 'auto) '(text svg))))
+
 ;;;; Gaps
 
 (ert-deftest cgt-gaps-deal ()