emacs/lisp/image.el

;;; image.el --- image API  -*- lexical-binding:t -*-

;; Copyright (C) 1998-2024 Free Software Foundation, Inc.

;; Maintainer: emacs-devel@gnu.org
;; Keywords: multimedia
;; Package: emacs

;; This file is part of GNU Emacs.

;; GNU Emacs 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.

;; GNU Emacs 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 GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

(defgroup image ()
  "Image support."
  :prefix "image-"
  :link '(info-link "(emacs) Image Mode")
  :group 'multimedia)

(declare-function image-flush "image.c" (spec &optional frame))
(declare-function clear-image-cache "image.c"
                  (&optional filter animation-cache))

(defconst image-type-header-regexps
  `(("\\`/[\t\n\r ]*\\*.*XPM.\\*/" . xpm)
    ("\\`P[1-6]\\(?:\
\\(?:\\(?:#[^\r\n]*[\r\n]\\)*[ \t\r\n]\\)+\
\\(?:\\(?:#[^\r\n]*[\r\n]\\)*[0-9]\\)+\
\\)\\{2\\}" . pbm)
    ("\\`GIF8[79]a" . gif)
    ("\\`\x89PNG\r\n\x1a\n" . png)
    ("\\`[\t\n\r ]*#define \\([a-z0-9_]+\\)_width [0-9]+\n\
#define \\1_height [0-9]+\n\\(\
#define \\1_x_hot [0-9]+\n\
#define \\1_y_hot [0-9]+\n\\)?\
static \\(unsigned \\)?char \\1_bits" . xbm)
    ("\\`\\(?:MM\0\\*\\|II\\*\0\\)" . tiff)
    ("\\`[\t\n\r ]*%!PS" . postscript)
    ("\\`\xff\xd8" . jpeg)    ; used to be (image-jpeg-p . jpeg)
    ("\\`RIFF[^z-a][^z-a][^z-a][^z-a]WEBPVP8" . webp)
    (,(let* ((incomment-re "\\(?:[^-]\\|-[^-]\\)")
	     (comment-re (concat "\\(?:!--" incomment-re "*-->[ \t\r\n]*<\\)")))
	(concat "\\(?:<\\?xml[ \t\r\n]+[^>]*>\\)?[ \t\r\n]*<"
		comment-re "*"
		"\\(?:!DOCTYPE[ \t\r\n]+[^>]*>[ \t\r\n]*<[ \t\r\n]*" comment-re "*\\)?"
		"[Ss][Vv][Gg]"))
     . svg)
    ("\\`....ftyp\\(heic\\|heix\\|hevc\\|heim\\|heis\\|hevm\\|hevs\\|mif1\\|msf1\\)" . heic))
  "Alist of (REGEXP . IMAGE-TYPE) pairs used to auto-detect image types.
When the first bytes of an image file match REGEXP, it is assumed to
be of image type IMAGE-TYPE if IMAGE-TYPE is a symbol.  If not a symbol,
IMAGE-TYPE must be a pair (PREDICATE . TYPE).  PREDICATE is called
with one argument, a string containing the image data.  If PREDICATE returns
a non-nil value, TYPE is the image's type.")

(defvar image-type-file-name-regexps
  '(("\\.png\\'" . png)
    ("\\.gif\\'" . gif)
    ("\\.jpe?g\\'" . jpeg)
    ("\\.webp\\'" . webp)
    ("\\.bmp\\'" . bmp)
    ("\\.xpm\\'" . xpm)
    ("\\.pbm\\'" . pbm)
    ("\\.xbm\\'" . xbm)
    ("\\.ps\\'" . postscript)
    ("\\.tiff?\\'" . tiff)
    ("\\.svgz?\\'" . svg)
    ("\\.hei[cf]s?\\'" . heic))
  "Alist of (REGEXP . IMAGE-TYPE) pairs used to identify image files.
When the name of an image file match REGEXP, it is assumed to
be of image type IMAGE-TYPE.")

;; We rely on `auto-mode-alist' to detect xbm and xpm files, instead
;; of content autodetection.  Their contents are just C code, so it is
;; easy to generate false matches.
(defvar image-type-auto-detectable
  '((pbm . t)
    (xbm . nil)
    (bmp . maybe)
    (gif . maybe)
    (png . maybe)
    (xpm . nil)
    (jpeg . maybe)
    (tiff . maybe)
    (svg . maybe)
    (webp . maybe)
    (postscript . nil)
    (heic . maybe))
  "Alist of (IMAGE-TYPE . AUTODETECT) pairs used to auto-detect image files.
\(See `image-type-auto-detected-p').

AUTODETECT can be
 - t      always auto-detect.
 - nil    never auto-detect.
 - maybe  auto-detect only if the image type is available
	    (see `image-type-available-p').")

(defvar image-format-suffixes
  '((image/x-rgb "rgb") (image/x-icon "ico"))
  "An alist associating image types with file name suffixes.
This is used as a hint by the ImageMagick library when detecting
the type of image data (that does not have an associated file name).
Each element has the form (MIME-CONTENT-TYPE EXTENSION).
If `create-image' is called with a :format attribute whose value
equals a content-type found in this list, the ImageMagick library is
told that the data would have the associated suffix if saved to a file.")

(defcustom image-load-path
  (list (file-name-as-directory (expand-file-name "images" data-directory))
        'data-directory 'load-path)
  "List of locations in which to search for image files.
The images for icons shown in the tool bar are also looked up
in these locations.

If an element is a string, it defines a directory to search.
If an element is a variable symbol whose value is a string, that
value defines a directory to search.
If an element is a variable symbol whose value is a list, the
value is used as a list of directories to search.

Subdirectories are not automatically included in the search."
  :type '(repeat (choice directory variable))
  :initialize #'custom-initialize-delay)

(defcustom image-transform-smoothing #'image--default-smoothing
  "Whether to do smoothing when applying transforms to images.
Common transforms are rescaling and rotation.

Valid values are nil (no smoothing), t (smoothing) or a predicate
function that is called with the image specification and should return
either nil or non-nil."
  :type '(choice (const :tag "Do smoothing" t)
                 (const :tag "No smoothing" nil)
                 function)
  :version "28.1")

(defcustom image-use-external-converter nil
  "If non-nil, `create-image' will use external converters for exotic formats.
Emacs handles most of the common image formats (SVG, JPEG, PNG, GIF
and some others) internally, but images that don't have native
support in Emacs can still be displayed if an external conversion
program (like ImageMagick \"convert\", GraphicsMagick \"gm\"
or \"ffmpeg\") is installed."
  :type 'boolean
  :version "27.1")

(define-error 'unknown-image-type "Unknown image type")

(defvar-keymap image-slice-map
  :doc "Map put into text properties on sliced images."
  "i" (define-keymap
        "-" #'image-decrease-size
        "+" #'image-increase-size
        "o" #'image-save
        "c" #'image-crop
        "x" #'image-cut)
  "C-<wheel-down>" #'image-mouse-decrease-size
  "C-<mouse-5>"    #'image-mouse-decrease-size
  "C-<wheel-up>"   #'image-mouse-increase-size
  "C-<mouse-4>"    #'image-mouse-increase-size)

(defvar-keymap image-map
  :doc "Map put into text properties on images."
  :parent image-slice-map
  "i" (define-keymap
        "r" #'image-rotate
        "h" #'image-flip-horizontally
        "v" #'image-flip-vertically))

(defun image-context-menu (menu click)
  "Populate MENU with image-related commands at CLICK."
  (when (mouse-posn-property (event-start click) 'display)
    (define-key menu [image-separator] menu-bar-separator)
    (let ((easy-menu (make-sparse-keymap "Image")))
      (easy-menu-define nil easy-menu nil
        '("Image"
          ["Zoom In" image-increase-size
           :help "Enlarge the image"]
          ["Zoom Out" image-decrease-size
           :help "Shrink the image"]
          ["Rotate Clockwise" image-rotate
           :help "Rotate the image"]
          ["Flip horizontally" image-flip-horizontally
           :help "Flip horizontally"]
          ["Flip vertically" image-flip-vertically
           :help "Flip vertically"]))
      (dolist (item (reverse (lookup-key easy-menu [menu-bar image])))
        (when (consp item)
          (define-key menu (vector (car item)) (cdr item))))))

  menu)

(defun image-load-path-for-library (library image &optional path no-error)
  "Return a suitable search path for images used by LIBRARY.

It searches for IMAGE in `image-load-path' (excluding
\"`data-directory'/images\") and `load-path', followed by a path
suitable for LIBRARY, which includes \"../../etc/images\" and
\"../etc/images\" relative to the library file itself, and then
in \"`data-directory'/images\".

Then this function returns a list of directories which contains
first the directory in which IMAGE was found, followed by the
value of `load-path'.  If PATH is given, it is used instead of
`load-path'.

If NO-ERROR is non-nil and a suitable path can't be found, don't
signal an error.  Instead, return a list of directories as before,
except that nil appears in place of the image directory.

Here is an example that uses a common idiom to provide
compatibility with versions of Emacs that lack the variable
`image-load-path':

    ;; Shush compiler.
    (defvar image-load-path)

    (let* ((load-path (image-load-path-for-library \"mh-e\" \"mh-logo.xpm\"))
           (image-load-path (cons (car load-path)
                                  (when (boundp \\='image-load-path)
                                    image-load-path))))
      (mh-tool-bar-folder-buttons-init))"
  (unless library (error "No library specified"))
  (unless image   (error "No image specified"))
  (let (image-directory image-directory-load-path)
    ;; Check for images in image-load-path or load-path.
    (let ((img image)
          (dir (or
                ;; Images in image-load-path.
                (image-search-load-path image)
                ;; Images in load-path.
                (locate-library image)))
          parent)
      ;; Since the image might be in a nested directory (for
      ;; example, mail/attach.pbm), adjust `image-directory'
      ;; accordingly.
      (when dir
        (setq dir (file-name-directory dir))
        (while (setq parent (file-name-directory img))
          (setq img (directory-file-name parent)
                dir (expand-file-name "../" dir))))
      (setq image-directory-load-path dir))

    ;; If `image-directory-load-path' isn't Emacs's image directory,
    ;; it's probably a user preference, so use it. Then use a
    ;; relative setting if possible; otherwise, use
    ;; `image-directory-load-path'.
    (cond
     ;; User-modified image-load-path?
     ((and image-directory-load-path
           (not (equal image-directory-load-path
                       (file-name-as-directory
                        (expand-file-name "images" data-directory)))))
      (setq image-directory image-directory-load-path))
     ;; Try relative setting.
     ((let (library-name d1ei d2ei)
        ;; First, find library in the load-path.
        (setq library-name (locate-library library))
        (if (not library-name)
            (error "Cannot find library %s in load-path" library))
        ;; And then set image-directory relative to that.
        (setq
         ;; Go down 2 levels.
         d2ei (file-name-as-directory
               (expand-file-name
                (concat (file-name-directory library-name) "../../etc/images")))
         ;; Go down 1 level.
         d1ei (file-name-as-directory
               (expand-file-name
                (concat (file-name-directory library-name) "../etc/images"))))
        (setq image-directory
              ;; Set it to nil if image is not found.
              (cond ((file-exists-p (expand-file-name image d2ei)) d2ei)
                    ((file-exists-p (expand-file-name image d1ei)) d1ei)))))
     ;; Use Emacs's image directory.
     (image-directory-load-path
      (setq image-directory image-directory-load-path))
     (no-error
      (message "Could not find image %s for library %s" image library))
     (t
      (error "Could not find image %s for library %s" image library)))

    ;; Return an augmented `path' or `load-path'.
    (nconc (list image-directory)
           (delete image-directory (copy-sequence (or path load-path))))))


;; Used to be in image-type-header-regexps, but now not used anywhere
;; (since 2009-08-28).
(defun image-jpeg-p (data)
  "Value is non-nil if DATA, a string, consists of JFIF image data.
We accept the tag Exif because that is the same format."
  (declare (obsolete "It is unused inside Emacs and will be removed." "27.1"))
  (setq data (ignore-errors (string-to-unibyte data)))
  (when (and data (string-match-p "\\`\xff\xd8" data))
    (catch 'jfif
      (let ((len (length data)) (i 2))
	(while (< i len)
	  (when (/= (aref data i) #xff)
	    (throw 'jfif nil))
	  (setq i (1+ i))
	  (when (>= (+ i 2) len)
	    (throw 'jfif nil))
	  (let ((nbytes (+ (ash (aref data (+ i 1)) 8)
			   (aref data (+ i 2))))
		(code (aref data i)))
	    (when (and (>= code #xe0) (<= code #xef))
	      ;; APP0 LEN1 LEN2 "JFIF\0"
	      (throw 'jfif
		     (string-match-p "JFIF\\|Exif"
				     (substring data i (min (+ i nbytes) len)))))
	    (setq i (+ i 1 nbytes))))))))


;;;###autoload
(defun image-type-from-data (data)
  "Determine the image type from image data DATA.
Value is a symbol specifying the image type or nil if type cannot
be determined."
  (let ((types image-type-header-regexps)
	type)
    (while types
      (let ((regexp (car (car types)))
	    (image-type (cdr (car types))))
	(if (or (and (symbolp image-type)
		     (string-match-p regexp data))
		(and (consp image-type)
		     (funcall (car image-type) data)
		     (setq image-type (cdr image-type))))
	    (setq type image-type
		  types nil)
	  (setq types (cdr types)))))
    type))


;;;###autoload
(defun image-type-from-buffer ()
  "Determine the image type from data in the current buffer.
Value is a symbol specifying the image type or nil if type cannot
be determined."
  (let ((types image-type-header-regexps)
	type
	(opoint (point)))
    (goto-char (point-min))
    (while types
      (let ((regexp (car (car types)))
	    (image-type (cdr (car types)))
	    data)
	(if (or (and (symbolp image-type)
		     (looking-at-p regexp))
		(and (consp image-type)
		     (funcall (car image-type)
			      (or data
				  (setq data
					(buffer-substring
					 (point-min)
					 (min (point-max)
					      (+ (point-min) 8192))))))
		     (setq image-type (cdr image-type))))
	    (setq type image-type
		  types nil)
	  (setq types (cdr types)))))
    (goto-char opoint)
    (and type
	 (boundp 'image-types)
	 (memq type image-types)
	 type)))


;;;###autoload
(defun image-type-from-file-header (file)
  "Determine the type of image file FILE from its first few bytes.
Value is a symbol specifying the image type, or nil if type cannot
be determined."
  (unless (or (file-readable-p file)
	      (file-name-absolute-p file))
    (setq file (image-search-load-path file)))
  (and file
       (file-readable-p file)
       (with-temp-buffer
	 (set-buffer-multibyte nil)
	 (insert-file-contents-literally file nil 0 8192)
	 (image-type-from-buffer))))


;;;###autoload
(defun image-type-from-file-name (file)
  "Determine the type of image file FILE from its name.
Value is a symbol specifying the image type, or nil if type cannot
be determined."
  (declare (obsolete image-supported-file-p "29.1"))
  (let (type first (case-fold-search t))
    (catch 'found
      (dolist (elem image-type-file-name-regexps first)
	(when (string-match-p (car elem) file)
	  (if (image-type-available-p (setq type (cdr elem)))
	      (throw 'found type)
	    ;; If nothing seems to be supported, return first type that matched.
	    (or first (setq first type))))))))

 ;;;###autoload
(defun image-supported-file-p (file)
  "Say whether Emacs has native support for displaying TYPE.
The value is a symbol specifying the image type, or nil if type
cannot be determined (or if Emacs doesn't have built-in support
for the image type)."
  (let ((case-fold-search t)
        type)
    (catch 'found
      (dolist (elem image-type-file-name-regexps)
	(when (and (string-match-p (car elem) file)
                   (image-type-available-p (setq type (cdr elem))))
	  (throw 'found type))))))

(declare-function image-convert-p "image-converter.el"
                  (source &optional image-format))
(declare-function image-convert "image-converter.el"
                  (image &optional image-format))

;;;###autoload
(defun image-type (source &optional type data-p)
  "Determine and return image type.
SOURCE is an image file name or image data.
Optional TYPE is a symbol describing the image type.  If TYPE is omitted
or nil, try to determine the image type from its first few bytes
of image data.  If that doesn't work, and SOURCE is a file name,
use its file extension as image type.

Optional DATA-P non-nil means SOURCE is a string containing image
data.  If DATA-P is a symbol with a name on the format
`image/jpeg', that may be used as a hint to determine the image
type if we can't otherwise guess it."
  (when (and (not data-p) (not (stringp source)))
    (error "Invalid image file name `%s'" source))
  (unless type
    (setq type (if data-p
		   (or (image-type-from-data source)
                       (and image-use-external-converter
                            (progn
                              (require 'image-converter)
                              (image-convert-p source data-p))))
		 (or (image-type-from-file-header source)
		     (image-supported-file-p source)
                     (and image-use-external-converter
                          (progn
                            (require 'image-converter)
                            (image-convert-p source))))))
    (unless type
      (signal 'unknown-image-type '("Cannot determine image type"))))
  (when (and (not (eq type 'image-convert))
             (not (memq type (and (boundp 'image-types) image-types))))
    (error "Invalid image type `%s'" type))
  type)

;;;###autoload
(defun image-type-available-p (type)
  "Return t if image type TYPE is available.
Image types are symbols like `xbm' or `jpeg'."
  (and (fboundp 'init-image-library)
       (init-image-library type)))


;;;###autoload
(defun image-type-auto-detected-p ()
  "Return t if the current buffer contains an auto-detectable image.
This function is intended to be used from `magic-fallback-mode-alist'.

The buffer is considered to contain an auto-detectable image if
its beginning matches an image type in `image-type-header-regexps',
and that image type is present in `image-type-auto-detectable' with a
non-nil value.  If that value is non-nil, but not t, then the image type
must be available."
  (let* ((type (image-type-from-buffer))
	 (auto (and type (cdr (assq type image-type-auto-detectable)))))
    (and auto
	 (or (eq auto t) (image-type-available-p type)))))

(defvar image-convert-to-format)

;;;###autoload
(defun create-image (file-or-data &optional type data-p &rest props)
  "Create an image from FILE-OR-DATA.
FILE-OR-DATA is an image file name or image data.  If it is a relative
file name, the function will look for it along `image-load-path'.

Optional TYPE is a symbol describing the image type.  If TYPE is omitted
or nil, try to determine the image type from its first few bytes
of image data.  If that doesn't work, and FILE-OR-DATA is a file name,
use its file extension as image type.

Optional DATA-P non-nil means FILE-OR-DATA is a string containing image data.

Optional PROPS are additional image attributes to assign to the image,
like, e.g. `:mask MASK'.  See Info node `(elisp)Image Descriptors' for
the list of supported properties; see the nodes following that node
for properties specific to certain image types.

If the property `:scale' is not given and the display has a high
resolution (more exactly, when the average width of a character
in the default font is more than 10 pixels), the image is
automatically scaled up in proportion to the default font.

Value is the image created, or nil if images of type TYPE are not supported.

Images should not be larger than specified by `max-image-size'."
  (let ((data-format
         ;; Pass the image format, if any, if this is data.
         (and data-p (or (plist-get props :format) t))))
    ;; It is `x_find_image_fd' in image.c that sets the search path.
    (setq type (ignore-error unknown-image-type
                 (image-type file-or-data type data-format)))
    ;; If we have external image conversion switched on (for exotic,
    ;; non-native image formats), then we convert the file.
    (when (eq type 'image-convert)
      (require 'image-converter)
      (setq file-or-data (image-convert file-or-data data-format)
            type (intern image-convert-to-format)
            data-p t)))
  (when (image-type-available-p type)
    (let ((image
           (append (list 'image :type type (if data-p :data :file)
                         file-or-data)
                   (and (not (plist-get props :scale))
                        ;; Add default scaling.
                        (list :scale 'default))
	           props)))
      ;; Add default smoothing.
      (unless (plist-member props :transform-smoothing)
        (let* ((func image-transform-smoothing)
               (value (or (eq func t)
                          (and func (funcall func image)))))
          (unless (eq value 'lambda)
            (setq image (nconc image
                               (list :transform-smoothing
                                     value))))))
      ;; Add original map from map.
      (when (and (plist-get props :map)
                 (not (plist-get props :original-map)))
        (setq image (nconc image (list :original-map
                                       (image--compute-original-map image)))))
      ;; Add map from original map.
      (when (and (plist-get props :original-map)
                 (not (plist-get props :map)))
        (setq image (nconc image (list :map
                                       (image--compute-map image)))))
      image)))

(defun image--default-smoothing (image)
  "Say whether IMAGE should be smoothed when transformed.
Return `lambda' if the decision should be deferred to the time IMAGE is
loaded."
  (let* ((props (nthcdr 5 image))
         (scaling (plist-get props :scale))
         (rotation (plist-get props :rotation)))
    (cond
     ;; The scale of the image won't be available until
     ;; `image_set_transform', and as such, defer to its judgment.
     ((eq scaling 'default) 'lambda)
     ;; We always smooth when scaling down and small upwards scaling.
     ((and scaling (< scaling 2))
      t)
     ;; Smooth when doing non-90-degree rotation
     ((and rotation
           (or (not (zerop (mod rotation 1)))
               (not (zerop (% (truncate rotation) 90)))))
      t)
     (t nil))))

(defun image--set-property (image property value)
  "Set PROPERTY in IMAGE to VALUE.
Internal use only."
  (if (null value)
      (while (cdr image)
        ;; IMAGE starts with the symbol `image', and the rest is a
        ;; plist.  Decouple plist entries where the key matches
        ;; the property.
        (if (eq (cadr image) property)
            (setcdr image (cdddr image))
          (setq image (cddr image))))
    ;; Just enter the new value.
    (setcdr image (plist-put (cdr image) property value)))
  value)

(defun image-property (image property)
  "Return the value of PROPERTY in IMAGE.
Properties can be set with

  (setf (image-property IMAGE PROPERTY) VALUE)
If VALUE is nil, PROPERTY is removed from IMAGE.

See Info node `(elisp)Image Descriptors' for the list of
supported properties; see the nodes following that node for
properties specific to certain image types."
  (declare (gv-setter image--set-property))
  (plist-get (cdr image) property))

(defun image-compute-scaling-factor (&optional scaling)
  "Compute the scaling factor based on SCALING.
If a number, use that.  If it's `auto', compute the factor.
If nil, use the `image-scaling-factor' variable.

This function is provided for the benefit of Lisp code that
must compute this factor; it does not affect Emacs's scaling
of images."
  (unless scaling
    (setq scaling image-scaling-factor))
  (cond
   ((numberp scaling) scaling)
   ((eq scaling 'auto)
    (let ((width (/ (float (window-width nil t)) (window-width))))
      ;; If we assume that a typical character is 10 pixels in width,
      ;; then we should scale all images according to how wide they
      ;; are.  But don't scale images down.
      (if (< width 10)
          1
        (/ (float width) 10))))
   (t
    (error "Invalid scaling factor %s" scaling))))

;;;###autoload
(defun put-image (image pos &optional string area)
  "Put image IMAGE in front of POS in the current buffer.
IMAGE must be an image created with `create-image' or `defimage'.
IMAGE is displayed by putting an overlay into the current buffer with a
`before-string' STRING that has a `display' property whose value is the
image.  STRING defaults to \"x\" if it's nil or omitted.
Upon success, this function returns the created overlay with its
`put-image' property set to t.

POS may be an integer or marker.
AREA is where to display the image.  AREA nil or omitted means
display it in the text area, a value of `left-margin' means
display it in the left marginal area, a value of `right-margin'
means display it in the right marginal area."
  (unless string (setq string "x"))
  (let ((buffer (current-buffer)))
    (unless (eq (car-safe image) 'image)
      (error "Not an image: %s" image))
    (unless (or (null area) (memq area '(left-margin right-margin)))
      (error "Invalid area %s" area))
    (setq string (copy-sequence string))
    (let ((overlay (make-overlay pos pos buffer))
	  (prop (if (null area) image (list (list 'margin area) image))))
      (put-text-property 0 (length string) 'display prop string)
      (overlay-put overlay 'put-image t)
      (overlay-put overlay 'before-string string)
      (overlay-put overlay 'keymap image-map)
      (overlay-put overlay 'context-menu-functions '(image-context-menu))
      overlay)))


;;;###autoload
(defun insert-image (image &optional string area slice inhibit-isearch)
  "Insert IMAGE into current buffer at point.
IMAGE is displayed by inserting STRING into the current buffer
with a `display' property whose value is the image.

STRING defaults to a single space if you omit it, which means
that the inserted image will behave as whitespace syntactically.

AREA is where to display the image.  AREA nil or omitted means
display it in the text area, a value of `left-margin' means
display it in the left marginal area, a value of `right-margin'
means display it in the right marginal area.

SLICE specifies slice of IMAGE to insert.  SLICE nil or omitted
means insert whole image.  SLICE is a list (X Y WIDTH HEIGHT)
specifying the X and Y positions and WIDTH and HEIGHT of image area
to insert.  A float value 0.0 - 1.0 means relative to the width or
height of the image; integer values are taken as pixel values.

Normally `isearch' is able to search for STRING in the buffer
even if it's hidden behind a displayed image.  If INHIBIT-ISEARCH
is non-nil, this is inhibited."
  ;; Use a space as least likely to cause trouble when it's a hidden
  ;; character in the buffer.
  (unless string (setq string " "))
  (unless (eq (car-safe image) 'image)
    (error "Not an image: %s" image))
  (unless (or (null area) (memq area '(left-margin right-margin)))
    (error "Invalid area %s" area))
  (if area
      (setq image (list (list 'margin area) image))
    ;; Cons up a new spec equal but not eq to `image' so that
    ;; inserting it twice in a row (adjacently) displays two copies of
    ;; the image.  Don't try to avoid this by looking at the display
    ;; properties on either side so that we DTRT more often with
    ;; cut-and-paste.  (Yanking killed image text next to another copy
    ;; of it loses anyway.)
    (setq image (cons 'image (cdr image))))
  (let ((start (point)))
    (insert string)
    (add-text-properties start (point)
			 `(display ,(if slice
					(list (cons 'slice slice) image)
				      image)
                                   rear-nonsticky t
				   inhibit-isearch ,inhibit-isearch
                                   keymap ,(if slice
                                               image-slice-map
                                             image-map)
                                   context-menu-functions
                                   (image-context-menu)))))

;;;###autoload
(defun insert-sliced-image (image &optional string area rows cols)
  "Insert IMAGE into current buffer at point.
IMAGE is displayed by inserting STRING into the current buffer
with a `display' property whose value is the image.  The default
STRING is a single space.
AREA is where to display the image.  AREA nil or omitted means
display it in the text area, a value of `left-margin' means
display it in the left marginal area, a value of `right-margin'
means display it in the right marginal area.
The image is automatically split into ROWS x COLS slices."
  (unless string (setq string " "))
  (unless (eq (car-safe image) 'image)
    (error "Not an image: %s" image))
  (unless (or (null area) (memq area '(left-margin right-margin)))
    (error "Invalid area %s" area))
  (if area
      (setq image (list (list 'margin area) image))
    ;; Cons up a new spec equal but not eq to `image' so that
    ;; inserting it twice in a row (adjacently) displays two copies of
    ;; the image.  Don't try to avoid this by looking at the display
    ;; properties on either side so that we DTRT more often with
    ;; cut-and-paste.  (Yanking killed image text next to another copy
    ;; of it loses anyway.)
    (setq image (cons 'image (cdr image))))
  (let ((x 0.0) (dx (/ 1.0001 (or cols 1)))
	 (y 0.0) (dy (/ 1.0001 (or rows 1))))
    (while (< y 1.0)
      (while (< x 1.0)
	(let ((start (point)))
	  (insert string)
	  (add-text-properties start (point)
			       `(display ,(list (list 'slice x y dx dy) image)
					 rear-nonsticky (display keymap)
                                         keymap ,image-slice-map
                                         context-menu-functions
                                         (image-context-menu)))
	  (setq x (+ x dx))))
      (setq x 0.0
	    y (+ y dy))
      (insert (propertize "\n" 'line-height t)))))



;;;###autoload
(defun remove-images (start end &optional buffer)
  "Remove images between START and END in BUFFER.
Remove only images that were put in BUFFER with calls to `put-image'.
BUFFER nil or omitted means use the current buffer."
  (unless buffer
    (setq buffer (current-buffer)))
  (let ((overlays (overlays-in start end)))
    (while overlays
      (let ((overlay (car overlays)))
	(when (overlay-get overlay 'put-image)
	  (delete-overlay overlay)))
      (setq overlays (cdr overlays)))))

(defun image-search-load-path (file &optional path)
  (unless path
    (setq path image-load-path))
  (let (element found filename)
    (while (and (not found) (consp path))
      (setq element (car path))
      (cond
       ((stringp element)
	(setq found
	      (file-readable-p
	       (setq filename (expand-file-name file element)))))
       ((and (symbolp element) (boundp element))
	(setq element (symbol-value element))
	(cond
	 ((stringp element)
	  (setq found
		(file-readable-p
		 (setq filename (expand-file-name file element)))))
	 ((consp element)
	  (if (setq filename (image-search-load-path file element))
	      (setq found t))))))
      (setq path (cdr path)))
    (if found filename)))

(defvar find-image--cache (make-hash-table :test #'equal))

;;;###autoload
(defun find-image (specs &optional cache)
  "Find an image that satisfies one of a list of image specifications.

SPECS is a list of image specifications.

Each image specification in SPECS is a property list.  The
contents of a specification are image type dependent; see the
info node `(elisp)Image Descriptors' for details.  All specifications
must at least contain either the property `:file FILE' or `:data DATA',
where FILE is the file from which to load the image, and DATA is a
string containing the actual image data.  If the property `:type TYPE'
is omitted or nil, try to determine the image type from its first few
bytes of image data.  If that doesn't work, and the property `:file
FILE' provide a file name, use its file extension as indication of the
image type.  If `:type TYPE' is provided, it must match the actual type
determined for FILE or DATA by `create-image'.

The function returns the image specification for the first specification
in the list whose TYPE is supported and FILE, if specified, exists.  It
returns nil if no specification in the list can be satisfied.

If CACHE is non-nil, results are cached and returned on subsequent calls.

The image is looked for in `image-load-path'.

Image files should not be larger than specified by `max-image-size'."
  (or (and cache
           (gethash specs find-image--cache))
      (let ((orig-specs specs)
            image)
        (while (and specs (null image))
          (let* ((spec (car specs))
	         (type (plist-get spec :type))
	         (data (plist-get spec :data))
	         (file (plist-get spec :file)))
	    (cond
             ((stringp file)
	      (when (setq file (image-search-load-path file))
                ;; At this point, remove the :type and :file properties.
                ;; `create-image' will set them depending on image file.
                (setq image (cons 'image (copy-sequence spec)))
                (setf (image-property image :type) nil)
                (setf (image-property image :file) nil)
                (and (setq image (ignore-errors
                                   (apply #'create-image file nil nil
                                          (cdr image))))
                     ;; Ensure, if a type has been provided, it is
                     ;; consistent with the type returned by
                     ;; `create-image'. If not, return nil.
                     (not (null type))
                     (not (eq type (image-property image :type)))
                     (setq image nil))))
	     ((not (null data))
              ;; At this point, remove the :type and :data properties.
              ;; `create-image' will set them depending on image data.
              (setq image (cons 'image (copy-sequence spec)))
              (setf (image-property image :type) nil)
              (setf (image-property image :data) nil)
	      (and (setq image (ignore-errors
                                 (apply #'create-image data nil t
                                        (cdr image))))
                   ;; Ensure, if a type has been provided, it is
                   ;; consistent with the type returned by
                   ;; `create-image'. If not, return nil.
                   (not (null type))
                   (not (eq type (image-property image :type)))
                   (setq image nil))))
	    (setq specs (cdr specs))))
        (when cache
          (setf (gethash orig-specs find-image--cache) image))
        image)))

;;;###autoload
(defmacro defimage (symbol specs &optional doc)
  "Define SYMBOL as an image, and return SYMBOL.

SPECS is a list of image specifications.  DOC is an optional
documentation string.

Each image specification in SPECS is a property list.  The contents of
a specification are image type dependent.  All specifications must at
least contain the properties `:type TYPE' and either `:file FILE' or
`:data DATA', where TYPE is a symbol specifying the image type,
e.g. `xbm', FILE is the file to load the image from, and DATA is a
string containing the actual image data.  The first image
specification whose TYPE is supported, and FILE exists, is used to
define SYMBOL.

Example:

   (defimage test-image ((:type xpm :file \"~/test1.xpm\")
                         (:type xbm :file \"~/test1.xbm\")))"
  (declare (doc-string 3) (indent defun))
  `(defvar ,symbol (find-image ',specs) ,doc))


;;; Animated image API

(defvar image-default-frame-delay 0.1
  "Default interval in seconds between frames of a multi-frame image.
Only used if the image does not specify a value.")

(defun image-multi-frame-p (image)
  "Return non-nil if IMAGE contains more than one frame.
The actual return value is a cons (NIMAGES . DELAY), where NIMAGES is
the number of frames (or sub-images) in the image and DELAY is the delay
in seconds that the image specifies between each frame.  DELAY may be nil,
in which case you might want to use `image-default-frame-delay'."
  (when (fboundp 'image-metadata)
    (let* ((metadata (image-metadata image))
	   (images (plist-get metadata 'count))
	   (delay (plist-get metadata 'delay)))
      (when (and images (> images 1))
	(and delay (or (not (numberp delay)) (< delay 0))
	     (setq delay image-default-frame-delay))
	(cons images delay)))))

(defun image-animated-p (image)
  "Like `image-multi-frame-p', but return nil if no delay is specified."
  (let ((multi (image-multi-frame-p image)))
    (and (cdr multi) multi)))

(make-obsolete 'image-animated-p 'image-multi-frame-p "24.4")

(defun image-animate (image &optional index limit position)
  "Start animating IMAGE.
Animation occurs by destructively altering the IMAGE spec list.

With optional INDEX, begin animating from that animation frame.
LIMIT specifies how long to animate the image.  If omitted or
nil, play the animation until the end.  If t, loop forever.  If a
number, play until that number of seconds has elapsed.

If POSITION (which should be buffer position where the image is
displayed), stop the animation if the image is no longer
displayed."
  (let ((animation (image-multi-frame-p image))
	timer)
    (when animation
      (if (setq timer (image-animate-timer image))
	  (cancel-timer timer))
      (plist-put (cdr image) :animate-buffer (current-buffer))
      (plist-put (cdr image) :animate-tardiness 0)
      (when position
        (plist-put (cdr image) :animate-position
                   (set-marker (make-marker) position (current-buffer))))
      ;; Stash the data about the animation here so that we don't
      ;; trigger image recomputation unnecessarily later.
      (plist-put (cdr image) :animate-multi-frame-data animation)
      (run-with-timer 0.2 nil #'image-animate-timeout
		      image (or index 0) (car animation)
		      0 limit (+ (float-time) 0.2)))))

(defun image-animate-timer (image)
  "Return the animation timer for image IMAGE."
  ;; See cancel-function-timers
  (let ((tail timer-list) timer)
    (while tail
      (setq timer (car tail)
	    tail (cdr tail))
      (if (and (eq (timer--function timer) #'image-animate-timeout)
	       (eq (car-safe (timer--args timer)) image))
	  (setq tail nil)
	(setq timer nil)))
    timer))

(defconst image-minimum-frame-delay 0.01
  "Minimum interval in seconds between frames of an animated image.")

(defun image-current-frame (image)
  "The current frame number of IMAGE, indexed from 0."
  (or (plist-get (cdr image) :index) 0))

(defun image-show-frame (image n &optional nocheck)
  "Show frame N of IMAGE.
Frames are indexed from 0.  Optional argument NOCHECK non-nil means
do not check N is within the range of frames present in the image."
  (unless nocheck
    (if (< n 0) (setq n 0)
      (setq n (min n (1- (car (or (plist-get (cdr image)
                                             :animate-multi-frame-data)
                                  (image-multi-frame-p image))))))))
  (plist-put (cdr image) :index n)
  (force-window-update (plist-get (cdr image) :animate-buffer)))

(defun image-animate-get-speed (image)
  "Return the speed factor for animating IMAGE."
  (or (plist-get (cdr image) :speed) 1))

(defun image-animate-set-speed (image value &optional multiply)
  "Set the speed factor for animating IMAGE to VALUE.
With optional argument MULTIPLY non-nil, treat VALUE as a
multiplication factor for the current value."
  (plist-put (cdr image) :speed
	     (if multiply
		 (* value (image-animate-get-speed image))
	       value)))

;; FIXME? The delay may not be the same for different sub-images,
;; hence we need to call image-multi-frame-p to return it.
;; But it also returns count, so why do we bother passing that as an
;; argument?
(defun image-animate-timeout (image n count time-elapsed limit target-time)
  "Display animation frame N of IMAGE.
N=0 refers to the initial animation frame.
COUNT is the total number of frames in the animation.
TIME-ELAPSED is the total time that has elapsed since
`image-animate' was called.
LIMIT determines when to stop.  If t, loop forever.  If nil, stop
 after displaying the last animation frame.  Otherwise, stop
 after LIMIT seconds have elapsed.
The minimum delay between successive frames is `image-minimum-frame-delay'.

If the image has a non-nil :speed property, it acts as a multiplier
for the animation speed.  A negative value means to animate in reverse."
  ;; We keep track of "how late" image frames arrive.  We decay the
  ;; previous cumulative value by 10% and then add the current delay.
  (plist-put (cdr image) :animate-tardiness
             (+ (* (plist-get (cdr image) :animate-tardiness) 0.9)
                (float-time (time-since target-time))))
  (let* ((buffer (plist-get (cdr image) :animate-buffer))
         (position (plist-get (cdr image) :animate-position))
         (continue-animation
          (and (buffer-live-p buffer)
               ;; If we have a :animate-position setting, the caller
               ;; has requested that the animation be stopped if the
               ;; image is no longer displayed in the buffer.
               (or (null position)
                   (with-current-buffer buffer
                     (let ((disp (get-text-property position 'display)))
                       (and (consp disp)
                            (eq (car disp) 'image)
                            ;; We can't check `eq'-ness of the image
                            ;; itself, since that may change.
                            (eq position
                                (plist-get (cdr disp) :animate-position))))))
               ;; Cumulatively delayed two seconds more than expected.
               (or (< (plist-get (cdr image) :animate-tardiness) 2)
		   (progn
		     (message "Stopping animation; animation possibly too big")
		     nil)))))
    (if (not continue-animation)
        ;; Eject from the animation cache since we've decided not to
        ;; keep updating it.  This helps stop unbounded RAM usage when
        ;; doing, for instance, `g' in an eww buffer with animated
        ;; images.
        (clear-image-cache nil image)
      (let* ((time (prog1 (current-time)
		     (image-show-frame image n t)))
	     (speed (image-animate-get-speed image))
	     (time-to-load-image (time-since time))
	     (stated-delay-time
              (/ (or (cdr (plist-get (cdr image) :animate-multi-frame-data))
		     image-default-frame-delay)
	         (float (abs speed))))
	     ;; Subtract off the time we took to load the image from the
	     ;; stated delay time.
	     (delay (max (float-time (time-subtract stated-delay-time
						    time-to-load-image))
		         image-minimum-frame-delay))
	     done)
        (setq n (if (< speed 0)
		    (1- n)
		  (1+ n)))
        (if limit
	    (cond ((>= n count) (setq n 0))
		  ((< n 0) (setq n (1- count))))
	  (and (or (>= n count) (< n 0)) (setq done t)))
        (setq time-elapsed (+ delay time-elapsed))
        (if (numberp limit)
	    (setq done (>= time-elapsed limit)))
        (unless done
	  (run-with-timer delay nil #'image-animate-timeout
			  image n count time-elapsed limit
                          (+ (float-time) delay)))))))


(defvar imagemagick-types-inhibit)
(defvar imagemagick-enabled-types)

(defun imagemagick-filter-types ()
  "Return a list of the ImageMagick types to be treated as images, or nil.
This is the result of `imagemagick-types', including only elements
that match `imagemagick-enabled-types' and do not match
`imagemagick-types-inhibit'."
  (when (fboundp 'imagemagick-types)
    (cond ((null imagemagick-enabled-types) nil)
	  ((eq imagemagick-types-inhibit t) nil)
	  (t
	   (delq nil
		 (mapcar
		  (lambda (type)
		    (unless (memq type imagemagick-types-inhibit)
		      (if (eq imagemagick-enabled-types t) type
			(catch 'found
			  (dolist (enable imagemagick-enabled-types nil)
			    (if (cond ((symbolp enable) (eq enable type))
				      ((stringp enable)
				       (string-match enable
						     (symbol-name type))))
				(throw 'found type)))))))
		  (imagemagick-types)))))))

(defvar imagemagick--file-regexp nil
  "File extension regexp for ImageMagick files, if any.
This is the extension installed into `auto-mode-alist' and
`image-type-file-name-regexps' by `imagemagick-register-types'.")

;;;###autoload
(defun imagemagick-register-types ()
  "Register file types that can be handled by ImageMagick.
This function is called at startup, after loading the init file.
It registers the ImageMagick types returned by `imagemagick-filter-types'.

Registered image types are added to `auto-mode-alist', so that
Emacs visits them in Image mode.  They are also added to
`image-type-file-name-regexps', so that the `image-type' function
recognizes these files as having image type `imagemagick'.

If Emacs is compiled without ImageMagick support, this does nothing."
  (when (fboundp 'imagemagick-types)
    (let* ((types (mapcar (lambda (type) (downcase (symbol-name type)))
			  (imagemagick-filter-types)))
	   (re (if types (concat "\\." (regexp-opt types) "\\'")))
	   (ama-elt (car (member (cons imagemagick--file-regexp 'image-mode)
				 auto-mode-alist)))
	   (itfnr-elt (car (member (cons imagemagick--file-regexp 'imagemagick)
				   image-type-file-name-regexps))))
      (if (not re)
	  (setq auto-mode-alist (delete ama-elt auto-mode-alist)
		image-type-file-name-regexps
		(delete itfnr-elt image-type-file-name-regexps))
	(if ama-elt
	    (setcar ama-elt re)
	  (push (cons re 'image-mode) auto-mode-alist))
	(if itfnr-elt
	    (setcar itfnr-elt re)
	  ;; Append to `image-type-file-name-regexps', so that we
	  ;; preferentially use specialized image libraries.
	  (add-to-list 'image-type-file-name-regexps
	  	       (cons re 'imagemagick) t)))
      (setq imagemagick--file-regexp re))))

(defcustom imagemagick-types-inhibit
  '(C HTML HTM INFO M TXT PDF)
  "List of ImageMagick types that should never be treated as images.
This should be a list of symbols, each of which should be one of
the ImageMagick types listed by `imagemagick-types'.  The listed
image types are not registered by `imagemagick-register-types'.

If the value is t, inhibit the use of ImageMagick for images.

If you change this without using customize, you must call
`imagemagick-register-types' afterwards.

If Emacs is compiled without ImageMagick support, this variable
has no effect."
  :type '(choice (const :tag "Support all ImageMagick types" nil)
		 (const :tag "Disable all ImageMagick types" t)
		 (repeat symbol))
  :initialize #'custom-initialize-default
  :set (lambda (symbol value)
	 (set-default symbol value)
	 (imagemagick-register-types))
  :version "24.3")

(defcustom imagemagick-enabled-types
  '(3FR ARW AVS BMP BMP2 BMP3 CAL CALS CMYK CMYKA CR2 CRW
    CUR CUT DCM DCR DCX DDS DJVU DNG DPX EXR FAX FITS GBR GIF
    GIF87 GRB HRZ ICB ICO ICON J2C JNG JP2 JPC JPEG JPG JPX K25
    KDC MIFF MNG MRW MSL MSVG MTV NEF ORF OTB PBM PCD PCDS PCL
    PCT PCX PDB PEF PGM PICT PIX PJPEG PNG PNG24 PNG32 PNG8 PNM
    PPM PSD PTIF PWP RAF RAS RBG RGB RGBA RGBO RLA RLE SCR SCT
    SFW SGI SR2 SRF SUN SVG SVGZ TGA TIFF TIFF64 TILE TIM TTF
    UYVY VDA VICAR VID VIFF VST WBMP WPG X3F XBM XC XCF XPM XV
    XWD YCbCr YCbCrA YUV)
  "List of ImageMagick types to treat as images.
Each list element should be a string or symbol, representing one
of the image types returned by `imagemagick-types'.  If the
element is a string, it is handled as a regexp that enables all
matching types.

The value of `imagemagick-enabled-types' may also be t, meaning
to enable all types that ImageMagick supports.

The variable `imagemagick-types-inhibit' overrides this variable.

If you change this without using customize, you must call
`imagemagick-register-types' afterwards.

If Emacs is compiled without ImageMagick support, this variable
has no effect."
  :type '(choice (const :tag "Support all ImageMagick types" t)
		 (const :tag "Disable all ImageMagick types" nil)
		 (repeat :tag "List of types"
			 (choice (symbol :tag "type")
				 (regexp :tag "regexp"))))
  :initialize #'custom-initialize-default
  :set (lambda (symbol value)
	 (set-default symbol value)
	 (imagemagick-register-types))
  :version "26.2")                      ; remove ART (bug#22289)

(imagemagick-register-types)

(defvar-keymap image--repeat-map
  "+" #'image-increase-size
  "-" #'image-decrease-size
  "r" #'image-rotate)

(defun image-increase-size (&optional n position)
  "Increase the image size at POSITION by a factor specified by N.
If N is 3, then the image size will be increased by 30%.  More
generally, the image size is multiplied by 1 plus N divided by 10.
N defaults to 2, which increases the image size by 20%.
POSITION can be a buffer position or a marker, and defaults to point.

When user option `image-recompute-map-p' is non-nil, the image's `:map'
is recomputed to fit the newly transformed image."
  (interactive "P")
  (image--delayed-change-size (if n
                                  (1+ (/ (prefix-numeric-value n) 10.0))
                                1.2)
                              position)
  (set-transient-map image--repeat-map nil nil
                     "Use %k for further adjustments"))

(defun image--delayed-change-size (size position)
  ;; Wait for a bit of idle-time before actually performing the change,
  ;; so as to batch together sequences of closely consecutive size changes.
  ;; `image--change-size' just changes two values in a plist.  The actual
  ;; image resizing happens later during redisplay.  So if those
  ;; consecutive calls happen without any redisplay between them,
  ;; the costly operation of image resizing should happen only once.
  (run-with-idle-timer 0.3 nil #'image--change-size size position))

(defun image-decrease-size (&optional n position)
  "Decrease the image size at POSITION by a factor specified by N.
If N is 3, then the image size will be decreased by 30%.  More
generally, the image size is multiplied by 1 minus N divided by 10.
N defaults to 2, which decreases the image size by 20%.
POSITION can be a buffer position or a marker, and defaults to point.

When user option `image-recompute-map-p' is non-nil, the image's `:map'
is recomputed to fit the newly transformed image."
  (interactive "P")
  (image--delayed-change-size (if n
                                  (- 1 (/ (prefix-numeric-value n) 10.0))
                                0.8)
                              position)
  (set-transient-map image--repeat-map nil nil
                     "Use %k for further adjustments"))

(defun image-mouse-increase-size (&optional event)
  "Increase the image size using the mouse-gesture EVENT.
This increases the size of the image at the position specified by
EVENT, if any, by the default factor used by `image-increase-size'.

When user option `image-recompute-map-p' is non-nil, the image's `:map'
is recomputed to fit the newly transformed image."
  (interactive "e")
  (when (listp event)
    (save-window-excursion
      (posn-set-point (event-start event))
      (image-increase-size nil (point-marker)))))

(defun image-mouse-decrease-size (&optional event)
  "Decrease the image size using the mouse-gesture EVENT.
This decreases the size of the image at the position specified by
EVENT, if any, by the default factor used by `image-decrease-size'.

When user option `image-recompute-map-p' is non-nil, the image's `:map'
is recomputed to fit the newly transformed image."
  (interactive "e")
  (when (listp event)
    (save-window-excursion
      (posn-set-point (event-start event))
      (image-decrease-size nil (point-marker)))))

(defun image--get-image (&optional position)
  "Return the image at POSITION.
POSITION can be a buffer position or a marker, and defaults to point."
  (let* ((image (get-char-property (or position (point)) 'display
                                   (when (markerp position)
                                     (marker-buffer position))))
         (image-car (car-safe image))
         (image
          (cond ((eq image-car 'image)
                 image)
                ;; The value of the display property could be a sliced
                ;; image of the form ((slice ...) (image ...)).
                ;; FIXME: can we have more than 2 members in the list,
                ;; so that the (image ...) part is NOT the cadr?
                ((and (listp image) (consp image-car))
                 (cadr image))
                (t nil))))
    (unless (eq (car-safe image) 'image)
      (error "No recognizable image under point"))
    image))

;;;###autoload
(defun image-at-point-p ()
  "Return non-nil if there is an image at point."
  (condition-case nil
      (prog1 t (image--get-image))
    (error nil)))

(defun image--get-imagemagick-and-warn (&optional position)
  (declare-function image-transforms-p "image.c" (&optional frame))
  (unless (or (fboundp 'imagemagick-types) (image-transforms-p))
    (error "Cannot rescale images on this terminal"))
  (let ((image (image--get-image position)))
    (image-flush image)
    (when (and (fboundp 'imagemagick-types)
               (not (image-transforms-p)))
      (plist-put (cdr image) :type 'imagemagick))
    image))

(defun image--change-size (factor &optional position)
  (let* ((image (image--get-imagemagick-and-warn position))
         (new-image (image--image-without-parameters image))
         (scale (image--current-scaling image new-image)))
    (setcdr image (cdr new-image))
    (plist-put (cdr image) :scale (* scale factor))
    (when (and (image-property image :original-map) image-recompute-map-p)
      (setf (image-property image :map) (image--compute-map image)))))

(defun image--image-without-parameters (image)
  (cons (pop image)
        (let ((new nil))
          (while image
            (let ((key (pop image))
                  (val (pop image)))
              (unless (memq key '(:scale :width :height :max-width :max-height))
              (setq new (nconc new (list key val))))))
          new)))

(declare-function image-size "image.c" (spec &optional pixels frame))

(defun image--current-scaling (image new-image)
  ;; The image may be scaled due to many reasons (:scale, :max-width,
  ;; etc), so find out what the current scaling is based on the
  ;; original image size and the displayed size.
  (let ((image-width (car (image-size new-image t)))
        (display-width (car (image-size image t))))
    (/ (float display-width) image-width)))

(defun image-rotate (&optional angle)
  "Rotate the image under point by ANGLE degrees clockwise.
If nil, ANGLE defaults to 90.  Interactively, rotate the image 90
degrees clockwise with no prefix argument, and counter-clockwise
with a prefix argument.  Note that most image types support
rotations by only multiples of 90 degrees.

When user option `image-recompute-map-p' is non-nil, the image's `:map'
is recomputed to fit the newly transformed image."
  (interactive (and current-prefix-arg '(-90)))
  (let ((image (image--get-imagemagick-and-warn)))
    (setf (image-property image :rotation)
          (float (mod (+ (or (image-property image :rotation) 0)
                         (or angle 90))
                      ;; We don't want to exceed 360 degrees rotation,
                      ;; because it's not seen as valid in Exif data.
                      360)))
    (when (and (image-property image :original-map) image-recompute-map-p)
      (setf (image-property image :map) (image--compute-map image))))
  (set-transient-map image--repeat-map nil nil
                     "Use %k for further adjustments"))

(defun image-save ()
  "Save the image under point.
This writes the original image data to a file.  Rotating or
changing the displayed image size does not affect the saved image."
  (interactive)
  (let ((image (image--get-image)))
    (with-temp-buffer
      (let ((file (plist-get (cdr image) :file)))
        (if file
            (if (not (file-exists-p file))
                (error "File %s no longer exists" file)
              (insert-file-contents-literally file))
          (insert (plist-get (cdr image) :data))))
      (write-region (point-min) (point-max)
                    (read-file-name "Write image to file: ")))))

(defun image-flip-horizontally ()
  "Horizontally flip the image under point.

When user option `image-recompute-map-p' is non-nil, the image's `:map'
is recomputed to fit the newly transformed image."
  (interactive)
  (let ((image (image--get-image)))
    (image-flush image)
    (setf (image-property image :flip)
          (not (image-property image :flip)))
    (when (and (image-property image :original-map) image-recompute-map-p)
      (setf (image-property image :map) (image--compute-map image)))))

(defun image-flip-vertically ()
  "Vertically flip the image under point.

When user option `image-recompute-map-p' is non-nil, the image's `:map'
is recomputed to fit the newly transformed image."
  (interactive)
  (let ((image (image--get-image)))
    (image-rotate 180)
    (setf (image-property image :flip)
          (not (image-property image :flip)))
    (when (and (image-property image :original-map) image-recompute-map-p)
      (setf (image-property image :map) (image--compute-map image)))))

(define-obsolete-function-alias 'image-refresh #'image-flush "29.1")

;;; Map transformation

(defcustom image-recompute-map-p t
  "Recompute image map when scaling, rotating, or flipping an image."
  :type 'boolean
  :version "30.1")

(defsubst image--compute-rotation (image)
  "Return the current rotation of IMAGE, or 0 if no rotation.
Also return nil if rotation is not a multiples of 90 degrees (0, 90,
180[-180] and 270[-90])."
  (let ((degrees (or (image-property image :rotation) 0)))
    (and (= 0 (mod degrees 1))
         (car (memql (truncate (mod degrees 360)) '(0 90 180 270))))))

(defun image--compute-map (image)
  "Compute map for IMAGE suitable to be used as its :map property.
Return a copy of :original-map transformed based on IMAGE's :scale,
:rotation, and :flip.  When IMAGE's :original-map is nil, return nil.
When :rotation is not a multiple of 90, return copy of :original-map."
  (when-let* ((map (image-property image :original-map)))
    (setq map (copy-tree map t))
    (let* ((size (image-size image t))
           ;; The image can be scaled for many reasons (:scale,
           ;; :max-width, etc), so using `image--current-scaling' to
           ;; calculate the current scaling is the correct method.  But,
           ;; since each call to `image_size' is expensive, the code is
           ;; duplicated here to save the a call to `image-size'.
           (scale (/ (float (car size))
                     (car (image-size
                           (image--image-without-parameters image) t))))
           (rotation (image--compute-rotation image))
           ;; Image is flipped only if rotation is a multiple of 90,
           ;; including 0.
           (flip (and rotation (image-property image :flip))))
      ;; SIZE fits MAP after transformations.  Scale MAP before flip and
      ;; rotate operations, since both need MAP to fit SIZE.
      (unless (= scale 1)
        (image--scale-map map scale))
      ;; In rendered images, rotation is always applied before flip.
      (when (memql rotation '(90 180 270))
        (image--rotate-map
         map rotation (if (= rotation 180)
                          size
                        ;; If rotated ±90°, swap width and height.
                        (cons (cdr size) (car size)))))
      ;; After rotation, there's no need to swap width and height.
      (when flip
        (image--flip-map map size)))
    map))

(defun image--compute-original-map (image)
  "Return original map for IMAGE.
If IMAGE lacks :map property, return nil.
When there is no transformation, return copy of :map."
  (when-let* ((original-map (image-property image :map)))
    (setq original-map (copy-tree original-map t))
    (let* ((size (image-size image t))
           ;; The image can be scaled for many reasons (:scale,
           ;; :max-width, etc), so using `image--current-scaling' to
           ;; calculate the current scaling is the correct method.  But,
           ;; since each call to `image_size' is expensive, the code is
           ;; duplicated here to save the a call to `image-size'.
           (scale (/ (float (car size))
                     (car (image-size
                           (image--image-without-parameters image) t))))
           (rotation (image--compute-rotation image))
           ;; Image is flipped only if rotation is a multiple of 90
           ;; including 0.
           (flip (and rotation (image-property image :flip))))
      ;; In rendered images, rotation is always applied before flip.
      ;; To undo the transformation, flip before rotating.  SIZE fits
      ;; ORIGINAL-MAP before transformations are applied.  Therefore,
      ;; scale ORIGINAL-MAP after flip and rotate operations, since
      ;; both need ORIGINAL-MAP to fit SIZE.
      ;; In rendered images, rotation is always applied before flip.
      (when flip
        (image--flip-map original-map size))
      (when (memql rotation '(90 180 270))
        (image--rotate-map original-map (- rotation) size))
      (unless (= scale 1)
        (image--scale-map original-map (/ 1.0 scale))))
    original-map))

(defun image--scale-map (map scale)
  "Scale MAP according to SCALE.
Destructively modifies and returns MAP."
  (pcase-dolist (`(,`(,type . ,coords) ,_id ,_plist) map)
    (pcase-exhaustive type
      ('rect
       (setf (caar coords) (round (* (caar coords) scale)))
       (setf (cdar coords) (round (* (cdar coords) scale)))
       (setf (cadr coords) (round (* (cadr coords) scale)))
       (setf (cddr coords) (round (* (cddr coords) scale))))
      ('circle
       (setf (caar coords) (round (* (caar coords) scale)))
       (setf (cdar coords) (round (* (cdar coords) scale)))
       (setcdr coords (round (* (cdr coords) scale))))
      ('poly
       (dotimes (i (length coords))
         (aset coords i
               (round (* (aref coords i) scale)))))))
  map)

(defun image--rotate-map (map rotation size)
  "Rotate MAP according to ROTATION and SIZE.
ROTATION must be a non-zero multiple of 90.
Destructively modifies and returns MAP."
  (setq rotation (mod rotation 360))
  (pcase-dolist (`(,`(,type . ,coords) ,_id ,_plist) map)
    (pcase-exhaustive type
      ('rect
       (let ( x0 y0  ; New upper left corner
              x1 y1) ; New bottom right corner
         (pcase rotation ; Set new corners to...
           (90 ; ...old bottom left and upper right
            (setq x0 (caar coords) y0 (cddr coords)
                  x1 (cadr coords) y1 (cdar coords)))
           (180 ; ...old bottom right and upper left
            (setq x0 (cadr coords) y0 (cddr coords)
                  x1 (caar coords) y1 (cdar coords)))
           (270 ; ...old upper right and bottom left
            (setq x0 (cadr coords) y0 (cdar coords)
                  x1 (caar coords) y1 (cddr coords))))
         (setcar coords (image--rotate-coord x0 y0 rotation size))
         (setcdr coords (image--rotate-coord x1 y1 rotation size))))
      ('circle
       (setcar coords (image--rotate-coord
                       (caar coords) (cdar coords) rotation size)))
      ('poly
       (dotimes (i (length coords))
         (when (= 0 (% i 2))
           (pcase-let ((`(,x . ,y)
                        (image--rotate-coord
                         (aref coords i) (aref coords (1+ i)) rotation size)))
             (aset coords i x)
             (aset coords (1+ i) y)))))))
  map)

(defun image--rotate-coord (x y angle size)
  "Rotate coordinates X and Y by ANGLE in image of SIZE.
ANGLE must be a multiple of 90 in [90 180 270].  Returns a cons cell of
rounded coordinates (X1 Y1)."
  (pcase-let* ((radian (* (/ angle 180.0) float-pi))
               (`(,width . ,height) size)
               ;; y is positive, but we are in the bottom-right quadrant
               (y (- y))
               ;; Rotate clockwise
               (x1 (+ (* (sin radian) y) (* (cos radian) x)))
               (y1 (- (* (cos radian) y) (* (sin radian) x)))
               ;; Translate image back into bottom-right quadrant
               (`(,x1 . ,y1)
                (pcase (truncate (mod angle 360))
                  (90 ; Translate right by height
                   (cons (+ x1 height) y1))
                  (180 ; Translate right by width and down by height
                   (cons (+ x1 width) (- y1 height)))
                  (270 ; Translate down by width
                   (cons x1 (- y1 width)))))
               ;; Invert y1 to make both x1 and y1 positive
               (y1 (- y1)))
    (cons (round x1) (round y1))))

(defun image--flip-map (map size)
  "Horizontally flip MAP according to SIZE.
Destructively modifies and returns MAP."
  (pcase-dolist (`(,`(,type . ,coords) ,_id ,_plist) map)
    (pcase-exhaustive type
      ('rect
       (let ((x0 (- (car size) (cadr coords)))
             (y0 (cdar coords))
             (x1 (- (car size) (caar coords)))
             (y1 (cddr coords)))
         (setcar coords (cons x0 y0))
         (setcdr coords (cons x1 y1))))
      ('circle
       (setf (caar coords) (- (car size) (caar coords))))
      ('poly
       (dotimes (i (length coords))
         (when (= 0 (% i 2))
           (aset coords i (- (car size) (aref coords i))))))))
  map)

(provide 'image)

;;; image.el ends here