shr.el (shr-render-td): Allow blank/missing <TD>s.

shr.el: Document the table-rendering algorithm.

2 files changed, 39 insertions, 9 deletions

diff --git a/lisp/gnus/ChangeLog b/lisp/gnus/ChangeLog
index 1217f548a6a..ed6c541c4f0 100644
--- a/lisp/gnus/ChangeLog
+++ b/lisp/gnus/ChangeLog
@@ -1,5 +1,9 @@
 2010-10-05  Lars Magne Ingebrigtsen  <larsi@gnus.org>
 
+        * shr.el (shr-render-td): Allow blank/missing <TD>s.
+
+        * shr.el: Document the table-rendering algorithm.
+
         * gnus-html.el (gnus-html-schedule-image-fetching): Protect against
         invalid URLs.
 
diff --git a/lisp/gnus/shr.el b/lisp/gnus/shr.el
index 2d5d4d623fb..c7f94ebc6b3 100644
--- a/lisp/gnus/shr.el
+++ b/lisp/gnus/shr.el
@@ -427,16 +427,33 @@ Return a string with image data."
   (apply #'shr-fontize-cont cont types)
   (shr-ensure-paragraph))
 
+;; Table rendering is the only complicated thing here.  We do this by
+;; first counting how many TDs there are in each TR, and registering
+;; how wide they think they should be ("width=45%", etc).  Then we
+;; render each TD separately (this is done in temporary buffers, so
+;; that we can use all the rendering machinery as if we were in the
+;; main buffer).  Now we know how much space each TD really takes, so
+;; we then render everything again with the new widths, and finally
+;; insert all these boxes into the main buffer.
 (defun shr-tag-table (cont)
   (shr-ensure-paragraph)
   (setq cont (or (cdr (assq 'tbody cont))
                  cont))
   (let* ((shr-inhibit-images t)
+         ;; Find all suggested widths.
          (columns (shr-column-specs cont))
+         ;; Compute how many characters wide each TD should be.
          (suggested-widths (shr-pro-rate-columns columns))
+         ;; Do a "test rendering" to see how big each TD is (this can
+         ;; be smaller (if there's little text) or bigger (if there's
+         ;; unbreakable text).
          (sketch (shr-make-table cont suggested-widths))
          (sketch-widths (shr-table-widths sketch (length suggested-widths))))
+    ;; Then render the table again with these new "hard" widths.
     (shr-insert-table (shr-make-table cont sketch-widths t) sketch-widths))
+  ;; Finally, insert all the images after the table.  The Emacs buffer
+  ;; model isn't strong enough to allow us to put the images actually
+  ;; into the tables.
   (dolist (elem (shr-find-elements cont 'img))
     (shr-tag-img (cdr elem))))
 
@@ -506,10 +523,14 @@ Return a string with image data."
   (let ((trs nil))
     (dolist (row cont)
       (when (eq (car row) 'tr)
-        (let ((i 0)
-              (tds nil))
-          (dolist (column (cdr row))
-            (when (memq (car column) '(td th))
+        (let ((tds nil)
+              (columns (cdr row))
+              (i 0)
+              column)
+          (while (< i (length widths))
+            (setq column (pop columns))
+            (when (or (memq (car column) '(td th))
+                      (null column))
               (push (shr-render-td (cdr column) (aref widths i) fill)
                     tds)
               (setq i (1+ i))))
@@ -531,11 +552,16 @@ Return a string with image data."
         (forward-line 1))
       (when fill
         (goto-char (point-min))
-        (while (not (eobp))
-          (end-of-line)
-          (when (> (- width (current-column)) 0)
-            (insert (make-string (- width (current-column)) ? )))
-          (forward-line 1)))
+        ;; If the buffer is totally empty, then put a single blank
+        ;; line here.
+        (if (zerop (buffer-size))
+            (insert (make-string width ? ))
+          ;; Otherwise, fill the buffer.
+          (while (not (eobp))
+            (end-of-line)
+            (when (> (- width (current-column)) 0)
+              (insert (make-string (- width (current-column)) ? )))
+            (forward-line 1))))
       (list max
             (count-lines (point-min) (point-max))
             (buffer-string)