To display a space of specified width and/or height, use a display
specification of the form
(space . props), where
props is a property list (a list of alternating properties and
values). You can put this property on one or more consecutive
characters; a space of the specified height and width is displayed in
place of all of those characters. These are the properties you
can use in props to specify the weight of the space:
If width is a number, it specifies that the space width should be width times the normal character width. width can also be a pixel width specification (see Pixel Specification for Spaces).
Specifies that the width of the stretch should be computed from the
first character in the group of consecutive characters that have the
display property. The space width is the pixel width of
that character, multiplied by factor. (On text-mode terminals,
the “pixel width” of a character is usually 1, but it could be more
for TABs and double-width CJK characters.)
Specifies that the space should be wide enough to reach hpos. If hpos is a number, it is measured in units of the normal character width. hpos can also be a pixel width specification (see Pixel Specification for Spaces).
You should use one and only one of the above properties. You can also specify the height of the space, with these properties:
Specifies the height of the space. If height is a number, it specifies that the space height should be height times the normal character height. The height may also be a pixel height specification (see Pixel Specification for Spaces).
Specifies the height of the space, multiplying the ordinary height of the text having this display specification by factor.
If the value of ascent is a non-negative number no greater than 100, it specifies that ascent percent of the height of the space should be considered as the ascent of the space—that is, the part above the baseline. The ascent may also be specified in pixel units with a pixel ascent specification (see Pixel Specification for Spaces).
Don’t use both
:align-to properties are supported on
non-graphic terminals, but the other space properties in this section
Note that space properties are treated as paragraph separators for the purposes of reordering bidirectional text for display. See Bidirectional Display, for the details.