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Diffstat (limited to 'modules/nov-reading.el')
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diff --git a/modules/nov-reading.el b/modules/nov-reading.el new file mode 100644 index 000000000..4134f4975 --- /dev/null +++ b/modules/nov-reading.el @@ -0,0 +1,282 @@ +;;; nov-reading.el --- Reading-view theme layer for nov-mode EPUBs -*- lexical-binding: t; -*- +;; author: Craig Jennings <c@cjennings.net> + +;;; Commentary: +;; +;; Layer: 4 (Added features). +;; Category: O (optional commands + faces). +;; Load shape: eager. +;; Eager reason: defines the reading faces and commands the nov launch hook and +;; keymap reference; the faces must exist for theme-studio's inventory too. +;; Top-level side effects: defface x9 (3 palettes + per-palette heading/link), +;; defcustoms, a defgroup, a defvar. +;; Runtime requires: none (face-remap and text-scale are built in). +;; Direct test load: yes. +;; +;; A small theme layer on top of the stock `nov' package (no fork): how an EPUB +;; *reads*, kept buffer-local so it never disturbs the frame or other buffers. +;; Two knobs: +;; +;; - Reading palette -- the background + foreground, as sepia / dark / light, +;; each a face the dupre theme / theme-studio own (registered as the +;; "nov-reading" bespoke app in theme-studio's face_data.py). +;; - Typography -- a serif family and a base height, with +/-/= adjusting the +;; page font size live via a buffer-local text-scale on top of the base. +;; The live size is remembered globally, so every book opens where you left +;; it; "=" returns to the base height. +;; +;; calibredb-epub-config.el owns the library/calibre side and the text-width / +;; centering layout; this module owns reading color and typography. Its launch +;; entry point `cj/nov-reading-setup' is called from that module's nov-mode hook. + +;;; Code: + +(defgroup cj/nov-reading nil + "Reading-view theming for nov-mode EPUBs." + :group 'cj) + +;; ----------------------------- Reading palettes ------------------------------ +;; nov renders through shr and defines no faces, so a palette is a buffer-local +;; face-remap of `default'. Each palette is one face carrying a :background and +;; :foreground, so the theme owns the real colors (the hex defaults here are a +;; starting point to tune in theme-studio). + +(defface cj/nov-reading-sepia + '((t :background "#1f1b16" :foreground "#c9b187")) + "Sepia reading palette for nov-mode: warm dark background, tan text." + :group 'cj/nov-reading) + +(defface cj/nov-reading-dark + '((t :background "#15140f" :foreground "#cfc8b8")) + "Dark reading palette for nov-mode: near-black background, light-gray text." + :group 'cj/nov-reading) + +(defface cj/nov-reading-light + '((t :background "#ece3cf" :foreground "#2a2622")) + "Light reading palette for nov-mode: cream background, near-black text." + :group 'cj/nov-reading) + +;; Structural faces: recolor shr's heading (h1-h6) and link faces per palette, +;; remapped buffer-local so the EPUB's hierarchy reads in the palette's accent +;; while mail/eww (the other shr consumers) keep the theme's shr colors. Heading +;; faces carry :foreground only -- shr's per-level height and weight survive the +;; relative remap; link faces add :underline so the cue reads as a link. + +(defface cj/nov-reading-sepia-heading + '((t :foreground "#e6c98a")) + "Heading accent for the sepia reading palette (recolors shr-h1..h6)." + :group 'cj/nov-reading) + +(defface cj/nov-reading-sepia-link + '((t :foreground "#c98f5a" :underline t)) + "Link accent for the sepia reading palette (recolors shr-link)." + :group 'cj/nov-reading) + +(defface cj/nov-reading-dark-heading + '((t :foreground "#e8e0cc")) + "Heading accent for the dark reading palette (recolors shr-h1..h6)." + :group 'cj/nov-reading) + +(defface cj/nov-reading-dark-link + '((t :foreground "#8fb0c4" :underline t)) + "Link accent for the dark reading palette (recolors shr-link)." + :group 'cj/nov-reading) + +(defface cj/nov-reading-light-heading + '((t :foreground "#5a3d28")) + "Heading accent for the light reading palette (recolors shr-h1..h6)." + :group 'cj/nov-reading) + +(defface cj/nov-reading-light-link + '((t :foreground "#8a5a2a" :underline t)) + "Link accent for the light reading palette (recolors shr-link)." + :group 'cj/nov-reading) + +(defcustom cj/nov-reading-palettes + '(("sepia" :face cj/nov-reading-sepia + :heading cj/nov-reading-sepia-heading + :link cj/nov-reading-sepia-link) + ("dark" :face cj/nov-reading-dark + :heading cj/nov-reading-dark-heading + :link cj/nov-reading-dark-link) + ("light" :face cj/nov-reading-light + :heading cj/nov-reading-light-heading + :link cj/nov-reading-light-link)) + "Alist of reading-palette NAME -> face property list for nov-mode. +Each entry's plist supplies the palette's colors, all theme-owned faces: + :face reading-view :background and :foreground, remapped onto `default' + :heading recolors shr's heading faces (h1-h6) for this palette + :link recolors shr's link face for this palette +The selector and cycle commands choose among these names. Add an entry to add a +palette; omit :heading or :link to leave that element at the theme's default." + :type '(alist :key-type string + :value-type + (plist :options ((:face face) (:heading face) (:link face)))) + :group 'cj/nov-reading) + +(defcustom cj/nov-reading-default-palette "sepia" + "Reading palette applied to a fresh nov-mode buffer. +A key in `cj/nov-reading-palettes', or nil for the theme's normal rendering." + :type '(choice (const :tag "None (theme default)" nil) string) + :group 'cj/nov-reading) + +(defvar-local cj/nov--reading-remap-cookies nil + "List of `face-remap-add-relative' cookies for the active reading palette. +Covers the `default' remap and any shr heading/link remaps, so switching +palettes can remove them all at once.") + +(defvar-local cj/nov--reading-palette nil + "Name of the reading palette active in this buffer, or nil for none.") + +(defun cj/nov--reading-palette-plist (name) + "Return the face property list for palette NAME, or nil when unknown. +NAME nil (the no-palette state) and unknown names both yield nil." + (cdr (assoc name cj/nov-reading-palettes))) + +(defun cj/nov--reading-palette-face (name) + "Return the base (bg/fg) face for palette NAME, or nil when NAME is unknown." + (plist-get (cj/nov--reading-palette-plist name) :face)) + +(defun cj/nov--next-reading-palette (current names) + "Return the palette after CURRENT in the cycle NAMES then nil, wrapping. +CURRENT nil is the no-palette state, and a returned nil means no palette. An +unknown CURRENT falls back to the first palette." + (let* ((cycle (append names (list nil))) + (tail (cdr (member current cycle)))) + (car (or tail cycle)))) + +(defun cj/nov--apply-reading-palette (name) + "Apply reading palette NAME buffer-local; NAME nil removes any palette. +Remaps `default' to the palette's :face, and (when present) shr's heading faces +h1-h6 to its :heading face and shr-link to its :link face. Removes the previous +palette's remaps first so switching never stacks, and leaves the typography +remap (a separate `default' remap) untouched." + (mapc #'face-remap-remove-relative cj/nov--reading-remap-cookies) + (setq cj/nov--reading-remap-cookies nil) + (let* ((plist (cj/nov--reading-palette-plist name)) + (face (plist-get plist :face))) + (when face + (push (face-remap-add-relative 'default face) + cj/nov--reading-remap-cookies) + (let ((heading (plist-get plist :heading))) + (when heading + (dolist (h '(shr-h1 shr-h2 shr-h3 shr-h4 shr-h5 shr-h6)) + (push (face-remap-add-relative h heading) + cj/nov--reading-remap-cookies)))) + (let ((link (plist-get plist :link))) + (when link + (push (face-remap-add-relative 'shr-link link) + cj/nov--reading-remap-cookies)))) + (setq cj/nov--reading-palette (and face name)))) + +(defun cj/nov-set-reading-palette (name) + "Choose reading palette NAME for this nov buffer; \"none\" clears it. +Interactively prompts among `cj/nov-reading-palettes' plus \"none\"." + (interactive + (list (completing-read "Reading palette: " + (cons "none" (mapcar #'car cj/nov-reading-palettes)) + nil t))) + (unless (derived-mode-p 'nov-mode) + (user-error "Not in a nov-mode buffer")) + (cj/nov--apply-reading-palette (unless (equal name "none") name)) + (message "Reading palette: %s" (or cj/nov--reading-palette "none"))) + +(defun cj/nov-cycle-reading-palette () + "Cycle to the next reading palette, then the no-palette state, wrapping." + (interactive) + (unless (derived-mode-p 'nov-mode) + (user-error "Not in a nov-mode buffer")) + (let ((next (cj/nov--next-reading-palette + cj/nov--reading-palette + (mapcar #'car cj/nov-reading-palettes)))) + (cj/nov--apply-reading-palette next) + (message "Reading palette: %s" (or next "none")))) + +;; ------------------------------- Typography ---------------------------------- + +(defcustom cj/nov-reading-font-family "Merriweather" + "Variable-pitch serif family for the EPUB reading view." + :type 'string + :group 'cj/nov-reading) + +(defcustom cj/nov-reading-text-height 180 + "Base `default'-face height (1/10 pt) the reading view renders at. +The +/-/= keys adjust the page size from here with a buffer-local text-scale. +That adjustment is remembered globally (see `cj/nov-reading-text-scale-file'): +every book and every session opens at the size you last left it, and `=' +returns to this base." + :type 'integer + :group 'cj/nov-reading) + +(defvar cj/nov-reading-text-scale-file + (expand-file-name "data/nov-reading-text-scale" user-emacs-directory) + "File persisting the global reading text-scale offset across sessions. +A single integer: the buffer-local `text-scale-mode-amount' the +/-/= keys +last set, applied on top of `cj/nov-reading-text-height' when a book opens.") + +(defun cj/nov-reading--parse-text-scale (s) + "Parse S (a string or nil) as an integer text-scale offset; 0 when invalid. +Surrounding whitespace is tolerated; non-integer content yields 0." + (let ((trimmed (and (stringp s) (string-trim s)))) + (if (and trimmed (string-match-p "\\`[+-]?[0-9]+\\'" trimmed)) + (string-to-number trimmed) + 0))) + +(defun cj/nov-reading--load-text-scale () + "Return the persisted reading text-scale offset, or 0 when none is saved." + (if (file-readable-p cj/nov-reading-text-scale-file) + (cj/nov-reading--parse-text-scale + (with-temp-buffer + (insert-file-contents cj/nov-reading-text-scale-file) + (buffer-string))) + 0)) + +(defun cj/nov-reading--save-text-scale (amount) + "Persist AMOUNT as the global reading text-scale offset. +Creates the data directory when absent." + (make-directory (file-name-directory cj/nov-reading-text-scale-file) t) + (with-temp-file cj/nov-reading-text-scale-file + (insert (number-to-string amount)))) + +(defun cj/nov-reading-apply-typography () + "Apply the reading family and base height buffer-local. +Remaps `variable-pitch', `default', and `fixed-pitch' so nov's shr output reads +as a comfortably-sized serif page." + (face-remap-add-relative 'variable-pitch + :family cj/nov-reading-font-family :height 1.0) + (face-remap-add-relative 'default + :family cj/nov-reading-font-family + :height cj/nov-reading-text-height) + (face-remap-add-relative 'fixed-pitch :height cj/nov-reading-text-height)) + +(defun cj/nov-reading-text-bigger () + "Increase the page font size and remember it across books and sessions." + (interactive) + (text-scale-increase 1) + (cj/nov-reading--save-text-scale text-scale-mode-amount)) + +(defun cj/nov-reading-text-smaller () + "Decrease the page font size and remember it across books and sessions." + (interactive) + (text-scale-decrease 1) + (cj/nov-reading--save-text-scale text-scale-mode-amount)) + +(defun cj/nov-reading-text-reset () + "Reset the page font size to the base reading height; clears the saved offset." + (interactive) + (text-scale-set 0) + (cj/nov-reading--save-text-scale 0)) + +;; ------------------------------- Launch hook --------------------------------- + +(defun cj/nov-reading-setup () + "Apply the reading view (typography + default palette) to this nov buffer. +Restores the remembered page font size on top of the base height. +Called from the nov-mode launch hook in calibredb-epub-config.el." + (cj/nov-reading-apply-typography) + (text-scale-set (cj/nov-reading--load-text-scale)) + (when cj/nov-reading-default-palette + (cj/nov--apply-reading-palette cj/nov-reading-default-palette))) + +(provide 'nov-reading) +;;; nov-reading.el ends here |