Re: display word wrapping

[Juanma Barranquero]

On 07 Jun 2004 15:34:18 +0200
address@hidden (Kim F. Storm) wrote:

> Add:
>   Returns non-nil if TYPE is a supported image type.

Of course!  Silly me.

> Replace by:
> 
>      if (!NILP (Fmemq (type, Vimage_types)))
>        return Qt;
> 
> [...]
> 
> > +    }
> > +
> > +  return Vimage_types;
> > +}
> 
> Replace by:
> 
>     return Fmemq (type, Vimage_types);
> 
> to redo lookup after initializing the image type.

Yes, you're right.

> Alternatively, you could let define_image_type return Qt or Qnil
> depending on whether the type was added to Vimage_types, 
> and then write the code like this:
> 
> +#if defined (HAVE_PNG) || defined (MAC_OS)
> +      IF_LIB_AVAILABLE(Qpng, init_png_functions)
> +        return define_image_type (&png_type);
> +#endif
> +

I initially argued why shouldn't be so, but after giving some thought to the
problem below, I came to think it's the best answer.

> However, one problem with the dynamic loading is that for image
> formats that fails to load, you will try to load them again every
> time you test for the availablity of that image type.

Right.

> Maybe Vimage_types should be changed to an alist
> 
>         ((png . t) (jpeg . nil) ...)
> 
> storing the results of the type lookups already performed.

That's what I've implemented.

                                                                Juanma



--- src/image.c.orig    2004-06-07 13:14:55.000000000 +0200
+++ src/image.c 2004-06-07 17:55:26.000000000 +0200
@@ -630,5 +630,5 @@
 /* Function prototypes.  */
 
-static void define_image_type P_ ((struct image_type *type));
+static int define_image_type P_ ((struct image_type *type, int loaded));
 static struct image_type *lookup_image_type P_ ((Lisp_Object symbol));
 static void image_error P_ ((char *format, Lisp_Object, Lisp_Object));
@@ -640,17 +640,24 @@
 
 /* Define a new image type from TYPE.  This adds a copy of TYPE to
-   image_types and adds the symbol *TYPE->type to Vimage_types.  */
+   image_types and adds (*TYPE->type, loaded) to Vimage_types.  */
 
-static void
-define_image_type (type)
+static int
+define_image_type (type, loaded)
      struct image_type *type;
+     int loaded;
 {
-  /* Make a copy of TYPE to avoid a bus error in a dumped Emacs.
-     The initialized data segment is read-only.  */
-  struct image_type *p = (struct image_type *) xmalloc (sizeof *p);
-  bcopy (type, p, sizeof *p);
-  p->next = image_types;
-  image_types = p;
-  Vimage_types = Fcons (*p->type, Vimage_types);
+  if (loaded)
+    {
+      /* Make a copy of TYPE to avoid a bus error in a dumped Emacs.
+         The initialized data segment is read-only.  */
+      struct image_type *p = (struct image_type *) xmalloc (sizeof *p);
+      bcopy (type, p, sizeof *p);
+      p->next = image_types;
+      image_types = p;
+    }
+
+  Vimage_types = Fcons (Fcons (*type->type, loaded ? Qt : Qnil), Vimage_types);
+
+  return loaded;
 }
 
@@ -1789,4 +1796,31 @@
   }
 
+/* Load a DLL implementing an image type.
+   The `image-library-alist' variable associates a symbol,
+   identifying  an image type, to a list of possible filenames.
+   The function returns NULL if no library could be loaded for
+   the given image type, or if the library was previously loaded;
+   else the handle of the DLL.  */
+static HMODULE
+w32_dynaload (Lisp_Object libraries, Lisp_Object library_id)
+{
+  HMODULE library = NULL;
+
+  if (CONSP (libraries) && NILP (Fassq (library_id, Vimage_types)))
+    {
+      Lisp_Object dlls = Fassq (library_id, libraries);
+
+      if (CONSP (dlls))
+        for (dlls = XCDR (dlls); CONSP (dlls); dlls = XCDR (dlls))
+          {
+            CHECK_STRING_CAR (dlls);
+            if (library = LoadLibrary (SDATA (XCAR (dlls))))
+              break;
+          }
+    }
+
+  return library;
+}
+
 #endif /* HAVE_NTGUI */
 
@@ -3489,11 +3522,10 @@
 DEF_IMGLIB_FN (XImageFree);
 
-
 static int
-init_xpm_functions (void)
+init_xpm_functions (Lisp_Object libraries)
 {
   HMODULE library;
 
-  if (!(library = LoadLibrary ("libXpm.dll")))
+  if (!(library = w32_dynaload (libraries, Qxpm)))
     return 0;
 
@@ -5589,19 +5621,10 @@
 
 static int
-init_png_functions (void)
+init_png_functions (Lisp_Object libraries)
 {
   HMODULE library;
 
-  /* Ensure zlib is loaded.  Try debug version first.  */
-  if (!LoadLibrary ("zlibd.dll")
-      && !LoadLibrary ("zlib.dll"))
-    return 0;
-
   /* Try loading libpng under probable names.  */
-  if (!(library = LoadLibrary ("libpng13d.dll"))
-      && !(library = LoadLibrary ("libpng13.dll"))
-      && !(library = LoadLibrary ("libpng12d.dll"))
-      && !(library = LoadLibrary ("libpng12.dll"))
-      && !(library = LoadLibrary ("libpng.dll")))
+  if (!(library = w32_dynaload (libraries, Qpng)))
     return 0;
 
@@ -6247,11 +6270,9 @@
 
 static int
-init_jpeg_functions (void)
+init_jpeg_functions (Lisp_Object libraries)
 {
   HMODULE library;
 
-  if (!(library = LoadLibrary ("libjpeg.dll"))
-      && !(library = LoadLibrary ("jpeg-62.dll"))
-      && !(library = LoadLibrary ("jpeg.dll")))
+  if (!(library = w32_dynaload (libraries, Qjpeg)))
     return 0;
 
@@ -6684,9 +6705,9 @@
 
 static int
-init_tiff_functions (void)
+init_tiff_functions (Lisp_Object libraries)
 {
   HMODULE library;
 
-  if (!(library = LoadLibrary ("libtiff.dll")))
+  if (!(library = w32_dynaload (libraries, Qtiff)))
     return 0;
 
@@ -7104,9 +7125,9 @@
 
 static int
-init_gif_functions (void)
+init_gif_functions (Lisp_Object libraries)
 {
   HMODULE library;
 
-  if (!(library = LoadLibrary ("libungif.dll")))
+  if (!(library = w32_dynaload (libraries, Qgif)))
     return 0;
 
@@ -7881,4 +7902,63 @@
  ***********************************************************************/
 
+#ifdef HAVE_NTGUI
+/* Image types that rely on external libraries are loaded dynamically
+   if the library is available.  */
+#define CHECK_LIB_AVAILABLE(image_type, init_lib_fn) \
+  define_image_type (image_type, init_lib_fn (libraries))
+#else
+#define CHECK_LIB_AVAILABLE(image_type, init_lib_fn) \
+  define_image_type (image_type, TRUE)
+#endif /* HAVE_NTGUI */
+
+DEFUN ("init-image-library", Finit_image_library, Sinit_image_library, 2, 2, 0,
+       doc: /* Initialize image library implementing image type TYPE.
+Return non-nil if TYPE is a supported image type.
+
+Image types pbm and xbm are prebuilt; other types are loaded here.
+Libraries to load are specified in alist LIBRARIES (usually, the value
+of `image-library-alist', which see.  */)
+  (type, libraries)
+{
+  Lisp_Object tested;
+
+  /* Don't try to reload the library.  */
+  tested = Fassq (type, Vimage_types);
+  if (CONSP (tested))
+    return XCDR (tested);
+
+#if defined (HAVE_XPM) || defined (MAC_OS)
+  if (EQ (type, Qxpm))
+    return CHECK_LIB_AVAILABLE(&xpm_type, init_xpm_functions);
+#endif
+
+#if defined (HAVE_JPEG) || defined (MAC_OS)
+  if (EQ (type, Qjpeg))
+    return CHECK_LIB_AVAILABLE(&jpeg_type, init_jpeg_functions);
+#endif
+
+#if defined (HAVE_TIFF) || defined (MAC_OS)
+  if (EQ (type, Qtiff))
+    return CHECK_LIB_AVAILABLE(&tiff_type, init_tiff_functions);
+#endif
+
+#if defined (HAVE_GIF) || defined (MAC_OS)
+  if (EQ (type, Qgif))
+    return CHECK_LIB_AVAILABLE(&gif_type, init_gif_functions);
+#endif
+
+#if defined (HAVE_PNG) || defined (MAC_OS)
+  if (EQ (type, Qpng))
+    return CHECK_LIB_AVAILABLE(&png_type, init_png_functions);
+#endif
+
+#ifdef HAVE_GHOSTSCRIPT
+  if (EQ (type, Qpostscript))
+    return CHECK_LIB_AVAILABLE(&gs_type, init_gs_functions);
+#endif
+
+  return Qnil;
+}
+
 void
 syms_of_image ()
@@ -7958,4 +8038,5 @@
 #endif
 
+  defsubr (&Sinit_image_library);
   defsubr (&Sclear_image_cache);
   defsubr (&Simage_size);
@@ -7985,13 +8066,4 @@
 }
 
-
-#ifdef HAVE_NTGUI
-/* Image types that rely on external libraries are loaded dynamically
-   if the library is available.  */
-#define IF_LIB_AVAILABLE(init_lib_fn)  if (init_lib_fn())
-#else
-#define IF_LIB_AVAILABLE(init_func)    /* Load unconditionally */
-#endif /* HAVE_NTGUI */
-
 void
 init_image ()
@@ -8000,35 +8072,6 @@
   Vimage_types = Qnil;
 
-  define_image_type (&xbm_type);
-  define_image_type (&pbm_type);
-
-#if defined (HAVE_XPM) || defined (MAC_OS)
-  IF_LIB_AVAILABLE(init_xpm_functions)
-    define_image_type (&xpm_type);
-#endif
-
-#if defined (HAVE_JPEG) || defined (MAC_OS)
-  IF_LIB_AVAILABLE(init_jpeg_functions)
-    define_image_type (&jpeg_type);
-#endif
-
-#if defined (HAVE_TIFF) || defined (MAC_OS)
-  IF_LIB_AVAILABLE(init_tiff_functions)
-    define_image_type (&tiff_type);
-#endif
-
-#if defined (HAVE_GIF) || defined (MAC_OS)
-  IF_LIB_AVAILABLE(init_gif_functions)
-    define_image_type (&gif_type);
-#endif
-
-#if defined (HAVE_PNG) || defined (MAC_OS)
-  IF_LIB_AVAILABLE(init_png_functions)
-    define_image_type (&png_type);
-#endif
-
-#ifdef HAVE_GHOSTSCRIPT
-  define_image_type (&gs_type);
-#endif
+  define_image_type (&xbm_type, TRUE);
+  define_image_type (&pbm_type, TRUE);
 
 #ifdef MAC_OS
--- lisp/image.el.orig  2004-06-07 13:13:55.000000000 +0200
+++ lisp/image.el       2004-06-07 17:34:51.000000000 +0200
@@ -49,4 +49,15 @@
 a non-nil value, TYPE is the image's type.")
 
+;;;###autoload
+(defvar image-library-alist nil
+  "Alist of image types vs external libraries needed to display them.
+
+Each element is a list (IMAGE-TYPE LIBRARY...), where the car is a symbol
+representing a supported image type, and the rest are strings giving
+alternate filenames for the corresponding external libraries to load.
+They are tried in the order they appear on the list; if none of them can
+be loaded, the running session of Emacs won't display the image type.
+No entries are needed for pbm and xbm images; they're always supported.")
+;;;###autoload (put 'image-library-alist 'risky-local-variable t)
 
 (defun image-jpeg-p (data)
@@ -112,6 +123,6 @@
   "Value is non-nil if image type TYPE is available.
 Image types are symbols like `xbm' or `jpeg'."
-  (and (boundp 'image-types) (not (null (memq type image-types)))))
-
+  (and (fboundp 'init-image-library)
+       (init-image-library type image-library-alist)))
 
 ;;;###autoload
--- lisp/term/w32-win.el.orig   2004-06-07 13:16:33.000000000 +0200
+++ lisp/term/w32-win.el        2004-06-04 02:15:48.000000000 +0200
@@ -1262,4 +1262,12 @@
            (error "Font not found")))))
 
+;;; Set default known names for image libraries
+(setq image-library-alist
+      '((xpm "libXpm-nox4.dll" "libxpm.dll")
+        (png "libpng13d.dll" "libpng13.dll" "libpng12d.dll" "libpng12.dll" 
"libpng.dll")
+        (jpeg "jpeg62.dll" "libjpeg.dll" "jpeg-62.dll" "jpeg.dll")
+        (tiff "libtiff3.dll" "libtiff.dll")
+        (gif "libungif.dll")))
+
 ;;; arch-tag: 69fb1701-28c2-4890-b351-3d1fe4b4f166
 ;;; w32-win.el ends here