Say there is no maintainer.

[bpt/emacs.git] / lisp / gs.el

diff --git a/lisp/gs.el b/lisp/gs.el
index 1399e42..d3bec85 100644 (file)
--- a/lisp/gs.el
+++ b/lisp/gs.el
@@ -1,6 +1,6 @@
 ;;; gs.el --- interface to Ghostscript
 
-;; Copyright (C) 1998 Free Software Foundation, Inc.
+;; Copyright (C) 1998, 2001 Free Software Foundation, Inc.
 
 ;; Maintainer: FSF
 ;; Keywords: internal
@@ -115,10 +115,10 @@ SPEC is a GS image specification.  IMG-WIDTH is the width of the
 requested image, and IMG-HEIGHT is the height of the requested
 image in pixels."
   (let* ((box (plist-get (cdr spec) :bounding-box))
-        (llx (nth 0 box))
-        (lly (nth 1 box))
-        (urx (nth 2 box))
-        (ury (nth 3 box))
+        (llx (elt box 0))
+        (lly (elt box 1))
+        (urx (elt box 2))
+        (ury (elt box 3))
         (rotation (or (plist-get (cdr spec) :rotate) 0))
         ;; The pixel width IMG-WIDTH of the pixmap gives the
         ;; dots, URX - LLX give the inch.
@@ -138,7 +138,8 @@ image in pixels."
                    ((x-display-grayscale-p frame) "Grayscale")
                    (t "Monochrome"))))
     (x-change-window-property "GHOSTVIEW_COLORS"
-                             (format "%s %s" mode pixel-colors))))
+                             (format "%s %s" mode pixel-colors)
+                             frame)))
 
 
 ;
@@ -151,7 +152,45 @@ and height of the image in pixels.  WINDOW-AND-PIXMAP-ID is a string of
 the form \"WINDOW-ID PIXMAP-ID\".  Value is non-nil if successful."
   (unwind-protect
       (let ((file (plist-get (cdr spec) :file))
-           gs)
+           gs
+           (timeout 40))
+       ;; Wait while property gets freed from a previous ghostscript process
+       ;; sit-for returns nil as soon as input starts being
+       ;; available, so if we want to give GhostScript a reasonable
+       ;; chance of starting up, we better use sleep-for.  We let
+       ;; sleep-for wait only half the time because if input is
+       ;; available, it is more likely that we don't care that much
+       ;; about garbled redisplay and are in a hurry.
+       (while (and
+               ;; Wait while the property is not yet available
+               (not (zerop (length (x-window-property "GHOSTVIEW"
+                                                      frame))))
+               ;; The following was an alternative condition: wait
+               ;; while there is still a process running.  The idea
+               ;; was to avoid contention between processes.  Turned
+               ;; out even more sluggish.
+               ;; (get-buffer-process "*GS*")
+               (not (zerop timeout)))
+         (unless (sit-for 0 100 t)
+           (sleep-for 0 50))
+         (setq timeout (1- timeout)))
+
+       ;; No use waiting longer.  We might want to try killing off
+       ;; stuck processes, but there is no point in doing so: either
+       ;; they are stuck for good, in which case the user would
+       ;; probably be responsible for that, and killing them off will
+       ;; make debugging harder, or they are not.  In that case, they
+       ;; will cause incomplete displays.  But the same will happen
+       ;; if they are killed, anyway. The whole is rather
+       ;; disconcerting, and fast scrolling through a dozen images
+       ;; will make Emacs freeze for a while.  The alternatives are a)
+       ;; proper implementation not waiting at all but creating
+       ;; appropriate queues, or b) permanently bad display due to
+       ;; bad cached images.  So remember that this
+       ;; is just a hack and if people don't like the behaviour, they
+       ;; will most likely like the easy alternatives even less.
+       ;; And at least the image cache will make the delay apparent
+       ;; just once.
        (gs-set-ghostview-window-prop frame spec img-width img-height)
        (gs-set-ghostview-colors-window-prop frame pixel-colors)
        (setenv "GHOSTVIEW" window-and-pixmap-id)