Re: Extent boundaries inconsistent w.r.t. extent properties
On Thu, 11 Apr 2002, Michael Toomim stipulated:
The XEmacs extent behavior is inconsistent when dealing with the
boundaries of
extents. Here are some examples of the problems I have encountered:
Thanks for highlighting this; preview-latex has to work around some of
these bugs, and it is annoying.
Inconsistency 1.5:
Not only does the face from the second extent map onto the end-glyph of the
first extent, the "invisible" property of the second extent does too. The
following code makes the first extent's end-glyph disappear:
The same thing applies if the first extent is invisible and the second
has a begin-glyph (even if the second is zero-width: very
annoying). Also, the begin-glyph on an extent is made invisible if you
declare the extent invisible, but the end-glyph is not.
(Please, if possible make the begin-glyph visible if the text is
invisible, too: this lets us emulate Emacs's `display' property
sanely. If the end-glyph and begin-glyph and other glyphs at those
points were consistently made invisible when the text was invisible,
preview-latex would be unimplementable on XEmacs...)
This is documented in redisplay.c, by the way, line 2154 of 21.4.6's redisplay.c:
#### The behavior of begin and end-glyphs at the edge of an
invisible extent should be investigated further. This is
fairly low priority though. */
--
`Unless they've moved it since I last checked, travelling between
England and America does not involve crossing the equator.'
--- pir