Clarify documentation of 'raise' and 'height' display specs

* doc/lispref/display.texi (Other Display Specs): Clarify the
effect of 'height' display spec on the following 'raise'.
(Bug#25824)
This commit is contained in:
Eli Zaretskii 2017-03-04 17:58:03 +02:00
parent f366f6e670
commit a314c1ff05

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@ -4666,16 +4666,21 @@ a form. Emacs evaluates it to get the new height, with the symbol
@item (raise @var{factor})
This kind of display specification raises or lowers the text
it applies to, relative to the baseline of the line.
it applies to, relative to the baseline of the line. It is mainly
meant to support display of subscripts and superscripts.
@var{factor} must be a number, which is interpreted as a multiple of the
height of the affected text. If it is positive, that means to display
the characters raised. If it is negative, that means to display them
lower down.
The @var{factor} must be a number, which is interpreted as a multiple
of the height of the affected text. If it is positive, that means to
display the characters raised. If it is negative, that means to
display them lower down.
If the text also has a @code{height} display specification, that does
not affect the amount of raising or lowering, which is based on the
faces used for the text.
Note that if the text also has a @code{height} display specification,
which was specified before (i.e.@: to the left of) @code{raise}, the
latter will affect the amount of raising or lowering in pixels,
because that is based on the height of the text being raised.
Therefore, if you want to display a sub- or superscript that is
smaller than the normal text height, consider specifying @code{raise}
before @code{height}.
@end table
@c We put all the '@code{(when ...)}' on one line to encourage