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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:
1 |
<span foreground="blue" size="x-large">Blue text</span> is <i>cool</i>! |
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
,
single-line
, double-line
or error-line
.
underline_color
:
The color of underlines; an RGB color
specification such as #00FF00
or a color name such as red
overline
:
One of none
or single
overline_color
:
The color of overlines; 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
gboolean pango_parse_markup (const char *markup_text
,int length
,gunichar accel_marker
,PangoAttrList **attr_list
,char **text
,gunichar *accel_char
,GError **error
);
Parses marked-up text (see
markup format) to createa plain-text string and an attribute list.
If accel_marker
is nonzero, the given character will mark the
character following it as an accelerator. For example, accel_marker
might be an ampersand or underscore. All characters marked
as an accelerator will receive a PANGO_UNDERLINE_LOW
attribute,
and the first character so marked will be returned in accel_char
.
Two accel_marker
characters following each other produce a single
literal accel_marker
character.
To parse a stream of pango markup incrementally, use pango_markup_parser_new()
.
If any error happens, none of the output arguments are touched except
for error
.
markup_text |
markup to parse (see markup format) |
|
length |
length of |
|
accel_marker |
character that precedes an accelerator, or 0 for none |
|
attr_list |
address of return location for a PangoAttrList, or |
[out][allow-none] |
text |
address of return location for text with tags stripped, or |
[out][allow-none] |
accel_char |
address of return location for accelerator char, or |
[out][allow-none] |
error |
address of return location for errors, or |
GMarkupParseContext *
pango_markup_parser_new (gunichar accel_marker
);
Parses marked-up text (see
markup format) to createa plain-text string and an attribute list.
If accel_marker
is nonzero, the given character will mark the
character following it as an accelerator. For example, accel_marker
might be an ampersand or underscore. All characters marked
as an accelerator will receive a PANGO_UNDERLINE_LOW
attribute,
and the first character so marked will be returned in accel_char
,
when calling finish()
. Two accel_marker
characters following each
other produce a single literal accel_marker
character.
To feed markup to the parser, use g_markup_parse_context_parse()
on the returned GMarkupParseContext. When done with feeding markup
to the parser, use pango_markup_parser_finish()
to get the data out
of it, and then use g_markup_parse_context_free()
to free it.
This function is designed for applications that read pango markup
from streams. To simply parse a string containing pango markup,
the simpler pango_parse_markup()
API is recommended instead.
a GMarkupParseContext that should be
destroyed with g_markup_parse_context_free()
.
[transfer none]
Since: 1.31.0
gboolean pango_markup_parser_finish (GMarkupParseContext *context
,PangoAttrList **attr_list
,char **text
,gunichar *accel_char
,GError **error
);
After feeding a pango markup parser some data with g_markup_parse_context_parse()
,
use this function to get the list of pango attributes and text out of the
markup. This function will not free context
, use g_markup_parse_context_free()
to do so.
context |
A valid parse context that was returned from |
|
attr_list |
address of return location for a PangoAttrList, or |
[out][allow-none] |
text |
address of return location for text with tags stripped, or |
[out][allow-none] |
accel_char |
address of return location for accelerator char, or |
[out][allow-none] |
error |
address of return location for errors, or |
Since: 1.31.0