From 53a6b03ad51ed4e05053a220872c2de72f2d254c Mon Sep 17 00:00:00 2001
From: Manuel Giraud <manuel.giraud@univ-nantes.fr>
Date: Wed, 20 Apr 2011 16:04:17 +0200
Subject: [PATCH 2/2] * org-html.el (org-html-handle-links): use fragment part of an image
   description as the alt

---
 doc/org.texi     |    4 ++-
 lisp/org-html.el |   92 +++++++++++++++++++++++++++---------------------------
 2 files changed, 49 insertions(+), 47 deletions(-)

diff --git a/doc/org.texi b/doc/org.texi
index 8ca4426..3ff862e 100644
--- a/doc/org.texi
+++ b/doc/org.texi
@@ -9771,9 +9771,11 @@ image will activate the link.  For example, to include a thumbnail that
 will link to a high resolution version of the image, you could use:
 
 @example
-[[file:highres.jpg][file:thumb.jpg]]
+[[file:highres.jpg][file:thumb.jpg::my cat hunting a mosquito]]
 @end example
 
+The part after the double colon is used to make the @code{alt} attribute.
+
 If you need to add attributes to an inlined image, use a @code{#+ATTR_HTML}.
 In the example below we specify the @code{alt} and @code{title} attributes to
 support text viewers and accessibility, and align it to the right.
diff --git a/lisp/org-html.el b/lisp/org-html.el
index 7a4564d..4a53f77 100644
--- a/lisp/org-html.el
+++ b/lisp/org-html.el
@@ -854,6 +854,14 @@ MAY-INLINE-P allows inlining it as an image."
 	       (org-export-html-format-desc desc)
 	       "</a>")))))
 
+(defun org-html-split-path-fragment (fullpath)
+  "Return a cons with car as the path and cdr as the fragment."
+  (save-match-data
+    (if (string-match "::\\(.*\\)" fullpath)
+	(cons (replace-match "" t nil fullpath)
+	      (match-string 1 fullpath))
+      (cons fullpath nil))))
+
 (defun org-html-handle-links (line opt-plist)
   "Return LINE with markup of Org mode links.
 OPT-PLIST is the export options list."
@@ -882,15 +890,17 @@ OPT-PLIST is the export options list."
 	    descp (and desc1 (not (equal desc1 desc2)))
 	    desc (or desc1 desc2))
       ;; Make an image out of the description if that is so wanted
-      (when (and descp (org-file-image-p
-			desc org-export-html-inline-image-extensions))
-	(save-match-data
-	  (if (string-match "^file:" desc)
-	      (setq desc (substring desc (match-end 0)))))
-	(setq desc (org-add-props
-		       (concat "<img src=\"" desc "\" alt=\"" 
-			       (file-name-nondirectory desc) "\"/>")
-		       '(org-protected t))))
+      (let* ((components (org-html-split-path-fragment desc))
+	     (src (car components))
+	     (alt (cdr components)))
+	(when (and descp 
+		   (org-file-image-p src org-export-html-inline-image-extensions))
+	  (save-match-data
+	    (if (string-match "^file:" src)
+		(setq src (substring src (match-end 0)))))
+	  (setq desc (org-add-props
+		      (concat "<img src=\"" src "\" alt=\"" alt "\"/>")
+		      '(org-protected t)))))
       (cond
        ((equal type "internal")
 	(let
@@ -965,44 +975,34 @@ OPT-PLIST is the export options list."
        ((string= type "file")
 	;; FILE link
 	(save-match-data
-	  (let*
-	      ((components
-		(if
-		    (string-match "::\\(.*\\)" path)
-		    (list
-		     (replace-match "" t nil path)
-		     (match-string 1 path))
-		  (list path nil)))
-
-	       ;;The proper path, without a fragment
-	       (path-1
-		(first components))
-
-	       ;;The raw fragment
-	       (fragment-0
-		(second components))
-
-	       ;;Check the fragment.  If it can't be used as
-	       ;;target fragment we'll pass nil instead.
-	       (fragment-1
-		(if
-		    (and fragment-0
-			 (not (string-match "^[0-9]*$" fragment-0))
-			 (not (string-match "^\\*" fragment-0))
-			 (not (string-match "^/.*/$" fragment-0)))
-		    (org-solidify-link-text
-		     (org-link-unescape fragment-0))
-		  nil))
-	       (desc-2
-		;;Description minus "file:" and ".org"
-		(if (string-match "^file:" desc)
-		    (let
-			((desc-1 (replace-match "" t t desc)))
-		      (if (string-match "\\.org$" desc-1)
-			  (replace-match "" t t desc-1)
-			desc-1))
-		  desc)))
+	  (let* ((components (org-html-split-path-fragment path))
 
+		 ;;The proper path, without a fragment
+		 (path-1 (car components))
+
+		 ;;The raw fragment
+		 (fragment-0 (cdr components))
+
+		 ;;Check the fragment.  If it can't be used as
+		 ;;target fragment we'll pass nil instead.
+		 (fragment-1
+		  (if
+		      (and fragment-0
+			   (not (string-match "^[0-9]*$" fragment-0))
+			   (not (string-match "^\\*" fragment-0))
+			   (not (string-match "^/.*/$" fragment-0)))
+		      (org-solidify-link-text
+		       (org-link-unescape fragment-0))
+		    nil))
+		 (desc-2
+		  ;;Description minus "file:" and ".org"
+		  (if (string-match "^file:" desc)
+		      (let
+			  ((desc-1 (replace-match "" t t desc)))
+			(if (string-match "\\.org$" desc-1)
+			    (replace-match "" t t desc-1)
+			  desc-1))
+		    desc)))
 	    (setq rpl
 		  (if
 		      (and
-- 
1.7.3.5