Add todo note.

[lw2-viewer.git] / src / colors.lisp

(uiop:define-package #:lw2.colors
  (:use #:cl #:iterate #:lw2.utils)
  (:import-from #:alexandria #:when-let #:emptyp)
  (:import-from #:parse-float #:parse-float)
  (:export #:-css-color-scanner- #:decode-css-color #:encode-css-color #:safe-color-name #:perceptual-invert-rgba #:perceptual-invert-color-string))

(in-package #:lw2.colors)

;;;; Refer to https://drafts.csswg.org/css-color/#numeric-srgb

(global-vars:define-global-parameter -css-color-scanner- (ppcre:create-scanner "#[0-9a-fA-F]{3,8}|rgba?\\((?:.*?)\\)|hsla?\\((?:.*?)\\)"))

(defparameter *web-colors-list*
  (with-open-file (stream (asdf:system-relative-pathname :lw2-viewer "data/webcolors.json") :direction :input)
    (map 'list
         (lambda (color-data)
           (cons (cdr (assoc :name color-data))
                 (map 'list (lambda (x) (/ (the (integer 0 255) (cdr x)) 255.0d0)) (cdr (assoc :rgb color-data)))))
         (json:decode-json stream))))

(defun parse-multi-hex (string count length &key (start 0) (key #'identity))
  (values-list
   (iter (for i from start below (+ start (* count length)) by length)
         (collect (funcall key (parse-integer string :start i :end (+ i length) :radix 16))))))

(defun parse-css-rgb-value (string)
  (let ((number (parse-integer string :junk-allowed t)))
    (if (ppcre:scan "%$" string)
        (/ number 100.0d0)
        (/ number 255.0d0))))

(defun parse-css-hue-value (string)
  (let ((number (parse-float string :junk-allowed t)))
    (regex-case string
                ("grad$" (* number (/ 360.0d0 400.0d0)))
                ("rad$" (* number (/ 360.0d0 (* 2 pi))))
                ("turn$" (* number 360.0d0))
                ("%$" (* number (/ 360.0d0 100.0d0)))
                (t number))))

(defun parse-css-alpha-value (string)
  (let ((number (and (not (emptyp string)) (parse-float string :junk-allowed t))))
    (if number
        (regex-case string
                    ("%$" (/ number 100d0))
                    (t number))
        1.0d0)))

(defun decode-css-color (color-string)
  ;; TODO: handle CSS variables
  (regex-case color-string
              ("#[0-9a-fA-F]{3}\\s*$" (values* (parse-multi-hex color-string 3 1 :start 1 :key (lambda (x) (declare (type (integer 0 15) x)) (/ (+ x (* x 16)) 255.0d0))) 1.0d0))
              ("#[0-9a-fA-F]{4}\\s*$" (parse-multi-hex color-string 4 1 :start 1 :key (lambda (x) (declare (type (integer 0 15) x)) (/ (+ x (* x 16)) 255.0d0))))
              ("#[0-9a-fA-F]{6}\\s*$" (values* (parse-multi-hex color-string 3 2 :start 1 :key (lambda (x) (declare (type (integer 0 255) x)) (/ x 255.0d0))) 1.0d0))
              ("#[0-9a-fA-F]{8}\\s*$" (parse-multi-hex color-string 4 2 :start 1 :key (lambda (x) (declare (type (integer 0 255) x)) (/ x 255.0d0))))
              ("rgba?\\((.*?)\\)"
               (multiple-value-bind (rgb-list a-list) (firstn (ppcre:split "[ ,]+" (reg 0)) 3)
                 (values* (values-list (map 'list #'parse-css-rgb-value rgb-list))
                          (parse-css-alpha-value (first a-list)))))
              ("hsla?\\((.*?)\\)"
               (destructuring-bind (h s l &optional a) (ppcre:split "[ ,/]+" (reg 0))
                 (values* (dufy/core:hsl-to-rgb (parse-css-hue-value h)
                                                (parse-css-rgb-value s)
                                                (parse-css-rgb-value l))
                          (parse-css-alpha-value a))))
              (t
               (when-let ((color-list (cdr (assoc color-string *web-colors-list* :test #'string-equal))))
                 (values* (values-list color-list) 1.0d0)))))

(defun encode-css-color (r g b a)
  (format nil "#~6,'0X~2,'0X" (dufy/core:rgb-to-rgbpack r g b) (round (* a 255))))

(defun safe-color-name (r g b a)
  (format nil "~6,'0X~2,'0X" (dufy/core:rgb-to-rgbpack r g b) (round (* a 255))))

(defun gamma-invert-lightness (l &optional gamma)
  (declare (double-float l)
           (type (or null (double-float 0d0)) gamma))
  (let ((gamma (or gamma 1.7d0)))
    (cond ((>= l 1d0) 0d0)
          ((<= l 0d0) 1d0)
          (t (expt (the (double-float 0d0) (- 1d0 l)) (/ gamma))))))

(defun linear-to-srgb (r g b)
  (declare (optimize (debug 0))
           (double-float r g b))
  (flet ((f (x)
           (declare (double-float x))
           (if (>= x 0.0031308d0)
               (- (* 1.055d0 (expt x (/ 2.4d0))) 0.055d0)
               (* 12.92d0 x))))
    (declare (inline f))
    (values (f r) (f g) (f b))))

(defun linear-to-simple-srgb (r g b)
  (declare (double-float r g b))
  (flet ((f (x) (if (plusp x) (expt x (/ 2.2d0)) 0d0)))
    (values (f r) (f g) (f b))))

(defun srgb-to-linear (r g b)
  (declare (optimize (debug 0))
           (double-float r g b))
  (flet ((f (x)
           (declare (double-float x))
           (if (>= x 0.04045d0)
               (expt (/ (+ x 0.055d0) 1.055d0) 2.4d0)
               (/ x 12.92d0))))
    (declare (inline f))
    (values (f r) (f g) (f b))))

(defun simple-srgb-to-linear (r g b)
  (declare (double-float r g b))
  (flet ((f (x)
           (if (plusp x) (expt x 2.2d0) 0d0)))
    (values (f r) (f g) (f b))))

(declaim (ftype (function (double-float double-float double-float) (values double-float double-float double-float))
                linear-srgb-to-oklab
                oklab-to-linear-srgb))

(defun linear-srgb-to-oklab (r g b)
  (declare (optimize (debug 0))
           (type (double-float 0d0) r g b))
  (flet ((soft-cbrt (x)
           (declare (type (double-float 0d0) x))
           (let* ((image-cutoff 0.1d0)
                  (arg-cutoff (expt image-cutoff 3)))
             (if (> x arg-cutoff)
                 (* (expt arg-cutoff 1/3) (expt (- (* (/ arg-cutoff) x) 1) (/ 3.0d0)))
                 (* (/ arg-cutoff image-cutoff) x)))))
    (declare (inline soft-cbrt))
    (let ((l (soft-cbrt (+ (* 0.4122214708 r) (* 0.5363325363 g) (* 0.0514459929 b))))
          (m (soft-cbrt (+ (* 0.2119034982 r) (* 0.6806995451 g) (* 0.1073969566 b))))
          (s (soft-cbrt (+ (* 0.0883024619 r) (* 0.2817188376 g) (* 0.6299787005 b)))))
      (values (+ (* 0.2104542553 l) (* +0.7936177850 m) (* -0.0040720468 s))
              (+ (* 1.9779984951 l) (* -2.4285922050 m) (* +0.4505937099 s))
              (+ (* 0.0259040371 l) (* +0.7827717662 m) (* -0.8086757660 s))))))

(declaim (ftype (function (double-float double-float) (values double-float double-float))
                ab-to-ch ch-to-ab))

(defun ab-to-ch (a b)
  (declare (type (double-float #.(- pi) #.pi) a b))
  (values (sqrt (+ (expt a 2) (expt b 2)))
          (atan b a)))

(defun ch-to-ab (c h)
  (declare (type (double-float #.(- pi) #.pi) c h))
  (values (* c (cos h))
          (* c (sin h))))

(defun oklab-to-linear-srgb (l a b)
  (declare (optimize (debug 0))
           (type double-float l)
           (type (double-float #.(- pi) #.pi) a b))
  (flet ((soft-cube (x)
           (declare (type double-float x))
           (let* ((arg-cutoff 0.1d0)
                  (image-cutoff (expt arg-cutoff 3)))
             (if (> x arg-cutoff)
                 (+ image-cutoff (* (- 1 image-cutoff) (expt x 3)))
                 (* (/ image-cutoff arg-cutoff) x)))))
    (declare (inline soft-cube))
    (let ((l (soft-cube (+ l (* 0.3963377774 a) (* 0.2158037573 b))))
          (m (soft-cube (- l (* 0.1055613458 a) (* 0.0638541728 b))))
          (s (soft-cube (- l (* 0.0894841775 a) (* 1.2914855480 b)))))
      (values (+ (* +4.0767416621 l) (* -3.3077115913 m) (* +0.2309699292 s))
              (+ (* -1.2684380046 l) (* +2.6097574011 m) (* -0.3413193965 s))
              (+ (* -0.0041960863 l) (* -0.7034186147 m) (* +1.7076147010 s))))))

(defun oklab-to-srgb (l a b)
  (declare (optimize (debug 0))
           (double-float l a b))
  (flet ((in-gamut (l a b)
           (multiple-value-bind (r g b) (multiple-value-call #'linear-to-srgb (oklab-to-linear-srgb l a b))
             (and (not (> (max r g b) 1.0d0))
                  (not (< (min r g b) 0.0d0))))))
    (if (in-gamut l a b)
        (multiple-value-call #'linear-to-srgb (oklab-to-linear-srgb l a b))
        (let ((array (cl-grnm:grnm-optimize
                      (lambda (array)
                        (let ((c-l (aref array 0))
                              (c-a (aref array 1))
                              (c-b (aref array 2)))
                          (declare (double-float c-l c-a c-b))
                          (if (in-gamut c-l c-a c-b)
                              (+ (* 10.0d0 (the double-float (expt (- l c-l) 2)))
                                 (expt (- a c-a) 2)
                                 (expt (- b c-b) 2))
                              most-positive-double-float)))
                      (vector (* (+ 0.05d0 (max 0.0d0 (min 1.0d0 l))) 0.9d0) 0.0d0 0.0d0)
                      :max-function-calls 10000)))
          (let ((l (aref array 0))
                (a (aref array 1))
                (b (aref array 2)))
            (multiple-value-call #'linear-to-srgb (oklab-to-linear-srgb l a b)))))))

(defun perceptual-invert-rgba (r g b alpha &optional gamma)
  (multiple-value-bind (l a b)
      (multiple-value-call #'linear-srgb-to-oklab (srgb-to-linear r g b))
    (multiple-value-bind (c h)
        (ab-to-ch a b)
      (multiple-value-bind (a b)
          (ch-to-ab c (if (< -1.5591128900152316d0 h 2.372773855360125d0)
                          h
                          (+ (* (mod (- h 2.372773855360125d0) (* 2 pi))
                                0.11248729401633725d0)
                             2.372773855360125d0)))
        (multiple-value-call #'values
          (oklab-to-srgb (gamma-invert-lightness l gamma) a b)
          alpha)))))

(defun perceptual-invert-color-string (color-string &optional gamma)
  (multiple-value-call #'encode-css-color (multiple-value-call #'perceptual-invert-rgba (decode-css-color color-string) gamma)))

(defun rewrite-css-colors (in-stream out-stream fn)
  (flet ((replacer (target-string start end match-start match-end reg-starts reg-ends)
           (declare (ignore start end reg-starts reg-ends))
           (funcall fn (substring target-string match-start match-end))))
    (declare (dynamic-extent #'replacer))
    (loop for in-line = (read-line in-stream nil)
       while in-line
       do (let ((out-line (ppcre:regex-replace-all -css-color-scanner- in-line #'replacer)))
            (write-line out-line out-stream)))))