lisp/obsolete/gs.el

   1 ;;; gs.el --- interface to Ghostscript
   2
   3 ;; Copyright (C) 1998, 2001-2017 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: emacs-devel@gnu.org
   6 ;; Keywords: internal
   7 ;; Obsolete-since: 26.1
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; This code is experimental.  Don't use it.  Try imagemagick images instead.
  27 ;; When this file is removed from Emacs, associated code in image.c
  28 ;; can be removed too (HAVE_GHOSTSCRIPT).
  29
  30 ;;; Code:
  31
  32 (defvar gs-program "gs"
  33   "The name of the Ghostscript interpreter.")
  34
  35
  36 (defvar gs-device "x11"
  37   "The Ghostscript device to use to produce images.")
  38
  39
  40 (defvar gs-options
  41   '("-q"
  42     ;"-dNOPAUSE"
  43     "-dSAFER"
  44     "-dBATCH"
  45     "-sDEVICE=<device>"
  46     "<file>")
  47   "List of command line arguments to pass to Ghostscript.
  48 Arguments may contain place-holders `<file>' for the name of the
  49 input file, and `<device>' for the device to use.")
  50 (put 'gs-options 'risky-local-variable t)
  51
  52 (defun gs-options (device file)
  53   "Return a list of command line options with place-holders replaced.
  54 DEVICE is the value to substitute for the place-holder `<device>',
  55 FILE is the value to substitute for the place-holder `<file>'."
  56   (mapcar #'(lambda (option)
  57               (setq option (replace-regexp-in-string "<device>" device option)
  58                     option (replace-regexp-in-string "<file>" file option)))
  59           gs-options))
  60
  61 ;; The GHOSTVIEW property (taken from gv 3.5.8).
  62 ;;
  63 ;; Type:
  64 ;;
  65 ;; STRING
  66 ;;
  67 ;; Parameters:
  68 ;;
  69 ;; BPIXMAP ORIENT LLX LLY URX URY XDPI YDPI [LEFT BOTTOM TOP RIGHT]
  70 ;;
  71 ;; Scanf format: "%d %d %d %d %d %d %f %f %d %d %d %d"
  72 ;;
  73 ;; Explanation of parameters:
  74 ;;
  75 ;; BPIXMAP: pixmap id of the backing pixmap for the window.  If no
  76 ;; pixmap is to be used, this parameter should be zero.  This
  77 ;; parameter must be zero when drawing on a pixmap.
  78 ;;
  79 ;; ORIENT: orientation of the page.  The number represents clockwise
  80 ;; rotation of the paper in degrees.  Permitted values are 0, 90, 180,
  81 ;; 270.
  82 ;;
  83 ;; LLX, LLY, URX, URY: Bounding box of the drawable.  The bounding box
  84 ;; is specified in PostScript points in default user coordinates.
  85 ;;
  86 ;; XDPI, YDPI: Resolution of window.  (This can be derived from the
  87 ;; other parameters, but not without roundoff error.  These values are
  88 ;; included to avoid this error.)
  89 ;;
  90 ;; LEFT, BOTTOM, TOP, RIGHT: (optional) Margins around the window.
  91 ;; The margins extend the imageable area beyond the boundaries of the
  92 ;; window.  This is primarily used for popup zoom windows.  I have
  93 ;; encountered several instances of PostScript programs that position
  94 ;; themselves with respect to the imageable area.  The margins are
  95 ;; specified in PostScript points.  If omitted, the margins are
  96 ;; assumed to be 0.
  97
  98 (declare-function x-display-mm-width "xfns.c" (&optional terminal))
  99 (declare-function x-display-pixel-width "xfns.c" (&optional terminal))
 100
 101 (defun gs-width-in-pt (frame pixel-width)
 102   "Return, on FRAME, pixel width PIXEL-WIDTH translated to pt."
 103   (let ((mm (* (float pixel-width)
 104                (/ (float (x-display-mm-width frame))
 105                   (float (x-display-pixel-width frame))))))
 106     (/ (* 25.4 mm) 72.0)))
 107
 108 (declare-function x-display-mm-height "xfns.c" (&optional terminal))
 109 (declare-function x-display-pixel-height "xfns.c" (&optional terminal))
 110
 111 (defun gs-height-in-pt (frame pixel-height)
 112   "Return, on FRAME, pixel height PIXEL-HEIGHT translated to pt."
 113   (let ((mm (* (float pixel-height)
 114                (/ (float (x-display-mm-height frame))
 115                   (float (x-display-pixel-height frame))))))
 116     (/ (* 25.4 mm) 72.0)))
 117
 118 (declare-function x-change-window-property "xfns.c"
 119                   (prop value &optional frame type format outer-p))
 120
 121 (defun gs-set-ghostview-window-prop (frame spec img-width img-height)
 122   "Set the `GHOSTVIEW' window property of FRAME.
 123 SPEC is a GS image specification.  IMG-WIDTH is the width of the
 124 requested image, and IMG-HEIGHT is the height of the requested
 125 image in pixels."
 126   (let* ((box (plist-get (cdr spec) :bounding-box))
 127          (llx (elt box 0))
 128          (lly (elt box 1))
 129          (urx (elt box 2))
 130          (ury (elt box 3))
 131          (rotation (or (plist-get (cdr spec) :rotate) 0))
 132          ;; The pixel width IMG-WIDTH of the pixmap gives the
 133          ;; dots, URX - LLX give the inch.
 134          (in-width (/ (- urx llx) 72.0))
 135          (in-height (/ (- ury lly) 72.0))
 136          (xdpi (/ img-width in-width))
 137          (ydpi (/ img-height in-height)))
 138     (x-change-window-property "GHOSTVIEW"
 139                               (format "0 %d %d %d %d %d %g %g"
 140                                       rotation llx lly urx ury xdpi ydpi)
 141                               frame)))
 142
 143 (declare-function x-display-grayscale-p "xfns.c" (&optional terminal))
 144
 145 (defun gs-set-ghostview-colors-window-prop (frame pixel-colors)
 146   "Set the `GHOSTVIEW_COLORS' environment variable depending on FRAME."
 147   (let ((mode (cond ((x-display-color-p frame) "Color")
 148                     ((x-display-grayscale-p frame) "Grayscale")
 149                     (t "Monochrome"))))
 150     (x-change-window-property "GHOSTVIEW_COLORS"
 151                               (format "%s %s" mode pixel-colors)
 152                               frame)))
 153
 154 (declare-function x-window-property "xfns.c"
 155                   (prop &optional frame type source delete-p vector-ret-p))
 156
 157 ;;;###autoload
 158 (defun gs-load-image (frame spec img-width img-height window-and-pixmap-id
 159                             pixel-colors)
 160   "Load a PS image for display on FRAME.
 161 SPEC is an image specification, IMG-HEIGHT and IMG-WIDTH are width
 162 and height of the image in pixels.  WINDOW-AND-PIXMAP-ID is a string of
 163 the form \"WINDOW-ID PIXMAP-ID\".  Value is non-nil if successful."
 164   (unwind-protect
 165       (let ((file (plist-get (cdr spec) :file))
 166             gs
 167             (timeout 40))
 168         ;; Wait while property gets freed from a previous ghostscript process
 169         ;; sit-for returns nil as soon as input starts being
 170         ;; available, so if we want to give GhostScript a reasonable
 171         ;; chance of starting up, we better use sleep-for.  We let
 172         ;; sleep-for wait only half the time because if input is
 173         ;; available, it is more likely that we don't care that much
 174         ;; about garbled redisplay and are in a hurry.
 175         (while (and
 176                 ;; Wait while the property is not yet available
 177                 (not (zerop (length (x-window-property "GHOSTVIEW"
 178                                                        frame))))
 179                 ;; The following was an alternative condition: wait
 180                 ;; while there is still a process running.  The idea
 181                 ;; was to avoid contention between processes.  Turned
 182                 ;; out even more sluggish.
 183                 ;; (get-buffer-process "*GS*")
 184                 (not (zerop timeout)))
 185           (unless (sit-for 0.1 t)
 186             (sleep-for 0.05))
 187           (setq timeout (1- timeout)))
 188
 189         ;; No use waiting longer.  We might want to try killing off
 190         ;; stuck processes, but there is no point in doing so: either
 191         ;; they are stuck for good, in which case the user would
 192         ;; probably be responsible for that, and killing them off will
 193         ;; make debugging harder, or they are not.  In that case, they
 194         ;; will cause incomplete displays.  But the same will happen
 195         ;; if they are killed, anyway. The whole is rather
 196         ;; disconcerting, and fast scrolling through a dozen images
 197         ;; will make Emacs freeze for a while.  The alternatives are a)
 198         ;; proper implementation not waiting at all but creating
 199         ;; appropriate queues, or b) permanently bad display due to
 200         ;; bad cached images.  So remember that this
 201         ;; is just a hack and if people don't like the behavior, they
 202         ;; will most likely like the easy alternatives even less.
 203         ;; And at least the image cache will make the delay apparent
 204         ;; just once.
 205         (gs-set-ghostview-window-prop frame spec img-width img-height)
 206         (gs-set-ghostview-colors-window-prop frame pixel-colors)
 207         (setenv "GHOSTVIEW" window-and-pixmap-id)
 208         (setq gs (apply 'start-process "gs" "*GS*" gs-program
 209                         (gs-options gs-device file)))
 210         (set-process-query-on-exit-flag gs nil)
 211         gs)
 212     nil))
 213
 214
 215 ;(defun gs-put-tiger ()
 216 ;  (let* ((ps-file "/usr/local/share/ghostscript/5.10/examples/tiger.ps")
 217 ;         (spec `(image :type postscript
 218 ;                       :pt-width 200 :pt-height 200
 219 ;                       :bounding-box (22 171 567 738)
 220 ;                       :file ,ps-file)))
 221 ;    (put-text-property 1 2 'display spec)))
 222 ;
 223
 224 (provide 'gs)
 225
 226 ;;; gs.el ends here