Description
Frequently, you want to display some text to the user with attributes
applied to part of the text (for example, you might want bold or
italicized words). With the base Pango interfaces, you could create a
PangoAttrList and apply it to the text; the problem is that you'd
need to apply attributes to some numeric range of characters, for
example "characters 12-17." This is broken from an internationalization
standpoint; once the text is translated, the word you wanted to
italicize could be in a different position.
The solution is to include the text attributes in the string to be
translated. Pango provides this feature with a small markup language.
You can parse a marked-up string into the string text plus a
PangoAttrList using either of pango_parse_markup() or
pango_markup_parser_new().
A simple example of a marked-up string might be:
Pango uses GMarkup to parse this language, which means that XML
features such as numeric character entities such as &169; for
© can be used too.
The root tag of a marked-up document is <markup>, but
pango_parse_markup()allows you to omit this tag, so you will most
likely never need to use it. The most general markup tag is <span>,
then there are some convenience tags.
<span> has the following attributes:
font_desc
: A font description string, such as "Sans Italic 12".
See pango_font_description_from_string() for a description of the
format of the string representation . Note that any other span
attributes will override this description. So if you have "Sans Italic"
and also a style="normal" attribute, you will get Sans normal,
not italic.
font_family
: A font family name
font_size, size
: Font size in 1024ths of a point, or one of the absolute
sizes 'xx-small', 'x-small', 'small', 'medium', 'large',
'x-large', 'xx-large', or one of the relative sizes 'smaller'
or 'larger'. If you want to specify a absolute size, it's usually
easier to take advantage of the ability to specify a partial
font description using 'font'; you can use |font='12.5'|
rather than |size='12800'|.
font_style
: One of 'normal', 'oblique', 'italic'
font_weight
: One of 'ultralight', 'light', 'normal', 'bold',
'ultrabold', 'heavy', or a numeric weight
font_variant
: One of 'normal' or 'smallcaps'
font_stretch, stretch
: One of 'ultracondensed', 'extracondensed', 'condensed',
'semicondensed', 'normal', 'semiexpanded', 'expanded',
'extraexpanded', 'ultraexpanded'
font_features
: A comma separated list of OpenType font feature
settings, in the same syntax as accepted by CSS. E.g:
|font_features='dlig=1, -kern, afrc on'|
foreground, fgcolor
: An RGB color specification such as '00FF00' or a color
name such as 'red'. Since 1.38, an RGBA color specification such
as '00FF007F' will be interpreted as specifying both a foreground
color and foreground alpha.
background, bgcolor
: An RGB color specification such as '00FF00' or a color
name such as'red'.
Since 1.38, an RGBA color specification such as '00FF007F' will
be interpreted as specifying both a background color and
background alpha.
alpha, fgalpha
: An alpha value for the foreground color, either a plain
integer between 1 and 65536 or a percentage value like '50%'.
background_alpha, bgalpha
: An alpha value for the background color, either a plain
integer between 1 and 65536 or a percentage value like '50%'.
underline
: One of 'none', 'single', 'double', 'low', 'error'
underline_color
: The color of underlines; an RGB color
specification such as '00FF00' or a color name such as 'red'
rise
: Vertical displacement, in Pango units. Can be negative for
subscript, positive for superscript.
strikethrough
: 'true' or 'false' whether to strike through the text
strikethrough_color
: The color of strikethrough lines; an RGB
color specification such as '00FF00' or a color name such as 'red'
fallback
: 'true' or 'false' whether to enable fallback. If
disabled, then characters will only be used from the closest
matching font on the system. No fallback will be done to other
fonts on the system that might contain the characters in the text.
Fallback is enabled by default. Most applications should not
disable fallback.
allow_breaks
: 'true' or 'false' whether to allow line breaks or not. If
not allowed, the range will be kept in a single run as far
as possible. Breaks are allowed by default.
insert_hyphens
: 'true' or 'false' whether to insert hyphens when breaking
lines in the middle of a word. Hyphens are inserted by default.
show
: A value determining how invisible characters are treated.
Possible values are 'spaces', 'line-breaks', 'ignorables'
or combinations, such as 'spaces|line-breaks'.
lang
: A language code, indicating the text language
letter_spacing
: Inter-letter spacing in 1024ths of a point.
gravity
: One of 'south', 'east', 'north', 'west', 'auto'.
gravity_hint
: One of 'natural', 'strong', 'line'.
The following convenience tags are provided:
<b>
: Bold
<big>
: Makes font relatively larger, equivalent to <span size="larger">
<i>
: Italic
<s>
: Strikethrough
<sub>
: Subscript
<sup>
: Superscript
<small>
: Makes font relatively smaller, equivalent to <span size="smaller">
<tt>
: Monospace
<u>
: Underline