[css2] Adapted text to changed example, and made it clear that there is a

difference between rendering HTML tables and other tables.

--HG--
extra : convert_revision : svn%3A73dc7c4b-06e6-40f3-b4f7-9ed1dbc14bfc/trunk%401636

Author: bert-github

css2/images/longdesc/table-overlap-desc.html

@@ -11,27 +11,36 @@
       <h1>Long description for example showing how structurally
       overlapping cells are rendered</h1>
 
-<P>This diagram shows how the CSS table model causes structurally
-overlapping cells to be rendered visually without overlap.
-<strong>Note.</strong> The HTML table in this example is illegal since
-HTML 4.0 states that tables cannot have overlapping cells.
-
-<P>The diagram depicts two renderings of the table specified in the
-HTML example preceding the image. While some user agents may produce
-the left rendering, CSS user agents may only produce the right
-rendering. In both tables, cells have gray backgrounds and a black
-border. Each contains a single integer label. Cells are separated from
-each other by cell spacing.
-
-<P>The left table has a top row of four cells. The second cell spans
-rows one and two. The second row of the table contains one cell that
-spans columns one and two. Thus, two cells overlap at the cell in the
-second row, second column. The overlap is depicted by a darker gray
-background.
-
-<P>The right table has a top row of four cells. The second cell spans
-rows one and two. The second row of the table contains one cell that
-spans columns three and four. Thus, no cells overlap visually.
+<P>This example shows a difference between CSS's table model for HTML
+and for other document formats. The first, HTML, example is defined by
+HTML to be illegal, as it would lead to overlapping cells if HTML's
+rules for layout are followed. The CSS rules apply to other formats
+than HTML, and don't have this problem.
+
+<P>The diagram depicts how the two examples, the HTML one and the
+almost identical non-HTML one, might be rendered. The rendering of the
+HTML example is undefined, and one possible rendering is shown here,
+in the left half of the figure: it has two cells that overlap. The
+rendering of the non-HTML example is on the right, it follows the CSS
+rules and thus has no overlapping cells.
+
+<p>In both tables, cells have gray backgrounds and a black
+border. Each contains a single digit as label. Cells are separated
+from each other by cell spacing.
+
+<P>The left table has a top row of four cells, containing, resp. the
+digits "1", "2", "3", and "4". The second of these cells, the one with
+the digit "2" in it, extends into the row below. The second row of the
+table contains one cell, which contains the digit "5", and it spans
+columns one and two. Thus, the cell labeled "2" and the cell labeled
+"5" overlap in the second row, second column. The overlap is depicted
+by a darker gray background.
+
+<P>The right table has the same top row of four cells, labeled "1",
+"2", "3", and "4". The second cell again spans rows one and two. The
+second row of the table contains one cell, containing the digit "5",
+that spans columns three and four. Thus, no cells overlap, but the
+first cell of the second row is left empty.
 
 <P><a href="../../tables.html#img-table-overlap">Return to image.</a>