Synopsis#include <gdk/gdk.h> GdkFont; enum GdkFontType; GdkFont* gdk_font_load (const gchar *font_name); GdkFont* gdk_font_load_for_display (GdkDisplay *display, const gchar *font_name); GdkFont* gdk_fontset_load (const gchar *fontset_name); GdkFont* gdk_fontset_load_for_display (GdkDisplay *display, const gchar *fontset_name); GdkFont* gdk_font_from_description (PangoFontDescription *font_desc); GdkFont* gdk_font_from_description_for_display (GdkDisplay *display, PangoFontDescription *font_desc); GdkDisplay* gdk_font_get_display (GdkFont *font); GdkFont* gdk_font_ref (GdkFont *font); void gdk_font_unref (GdkFont *font); gint gdk_font_id (const GdkFont *font); gboolean gdk_font_equal (const GdkFont *fonta, const GdkFont *fontb); void gdk_string_extents (GdkFont *font, const gchar *string, gint *lbearing, gint *rbearing, gint *width, gint *ascent, gint *descent); void gdk_text_extents (GdkFont *font, const gchar *text, gint text_length, gint *lbearing, gint *rbearing, gint *width, gint *ascent, gint *descent); void gdk_text_extents_wc (GdkFont *font, const GdkWChar *text, gint text_length, gint *lbearing, gint *rbearing, gint *width, gint *ascent, gint *descent); gint gdk_string_width (GdkFont *font, const gchar *string); gint gdk_text_width (GdkFont *font, const gchar *text, gint text_length); gint gdk_text_width_wc (GdkFont *font, const GdkWChar *text, gint text_length); gint gdk_char_width (GdkFont *font, gchar character); gint gdk_char_width_wc (GdkFont *font, GdkWChar character); gint gdk_string_measure (GdkFont *font, const gchar *string); gint gdk_text_measure (GdkFont *font, const gchar *text, gint text_length); gint gdk_char_measure (GdkFont *font, gchar character); gint gdk_string_height (GdkFont *font, const gchar *string); gint gdk_text_height (GdkFont *font, const gchar *text, gint text_length); gint gdk_char_height (GdkFont *font, gchar character); typedef GdkWChar; gchar* gdk_wcstombs (const GdkWChar *src); gint gdk_mbstowcs (GdkWChar *dest, const gchar *src, gint dest_max); DescriptionThe GdkFont data type represents a font for drawing on the screen. These functions provide support for loading fonts, and also for determining the dimensions of characters and strings when drawn with a particular font. Fonts in X are specified by a X Logical Font Description. The following description is considerably simplified. For definitive information about XLFD's see the X reference documentation. A X Logical Font Description (XLFD) consists of a sequence of fields separated (and surrounded by) '-' characters. For example, Adobe Helvetica Bold 12 pt, has the full description: "-adobe-helvetica-bold-r-normal--12-120-75-75-p-70-iso8859-1"
The fields in the XLFD are:
When specifying a font via a X logical Font Description, '*' can be used as a wildcard to match any portion of the XLFD. For instance, the above example could also be specified as "-*-helvetica-bold-r-normal--*-120-*-*-*-*-iso8859-1" It is generally a good idea to use wildcards for any portion of the XLFD that your program does not care about specifically, since that will improve the chances of finding a matching font. A fontset is a list of fonts that is used for drawing international text that may contain characters from a number of different character sets. It is represented by a list of XLFD's. The font for a given character set is determined by going through the list of XLFD's in order. For each one, if the registry and and encoding fields match the desired character set, then that font is used, otherwise if the XLFD contains wild-cards for the registry and encoding fields, the registry and encoding for the desired character set are substituted in and a lookup is done. If a match is found that font is used. Otherwise, processing continues on to the next font in the list. The functions for determining the metrics of a string come in several varieties that can take a number of forms of string input:
GDK provides functions to determine a number of different measurements (metrics) for a given string. (Need diagram here).
DetailsGdkFonttypedef struct { GdkFontType type; gint ascent; gint descent; } GdkFont; Warning
The GdkFont structure represents a font or fontset. It
contains the following public fields. A new GdkFont
structure is returned by
enum GdkFontTypetypedef enum { GDK_FONT_FONT, GDK_FONT_FONTSET } GdkFontType; Warning
Indicates the type of a font. The possible values are currently: gdk_font_load ()GdkFont* gdk_font_load (const gchar *font_name); Warning
Loads a font. The font may be newly loaded or looked up the font in a cache. You should make no assumptions about the initial reference count.
gdk_font_load_for_display ()GdkFont* gdk_font_load_for_display (GdkDisplay *display, const gchar *font_name); Warning
Loads a font for use on The font may be newly loaded or looked up the font in a cache. You should make no assumptions about the initial reference count.
Since 2.2 gdk_fontset_load ()GdkFont* gdk_fontset_load (const gchar *fontset_name); Warning
Loads a fontset. The fontset may be newly loaded or looked up in a cache. You should make no assumptions about the initial reference count.
gdk_fontset_load_for_display ()GdkFont* gdk_fontset_load_for_display (GdkDisplay *display, const gchar *fontset_name); Warning
Loads a fontset for use on The fontset may be newly loaded or looked up in a cache. You should make no assumptions about the initial reference count.
Since 2.2 gdk_font_from_description ()GdkFont* gdk_font_from_description (PangoFontDescription *font_desc); Warning
Load a GdkFont based on a Pango font description. This font will only be an approximation of the Pango font, and internationalization will not be handled correctly. This function should only be used for legacy code that cannot be easily converted to use Pango. Using Pango directly will produce better results.
gdk_font_from_description_for_display ()GdkFont* gdk_font_from_description_for_display (GdkDisplay *display, PangoFontDescription *font_desc); Warning
Loads a GdkFont based on a Pango font description for use on
Since 2.2 gdk_font_get_display ()GdkDisplay* gdk_font_get_display (GdkFont *font); Warning
Returns the GdkDisplay for
Since 2.2 gdk_font_ref ()GdkFont* gdk_font_ref (GdkFont *font); Warning
Increases the reference count of a font by one.
gdk_font_unref ()void gdk_font_unref (GdkFont *font); Warning
Decreases the reference count of a font by one. If the result is zero, destroys the font.
gdk_font_id ()gint gdk_font_id (const GdkFont *font); Warning
Returns the X Font ID for the given font.
gdk_font_equal ()gboolean gdk_font_equal (const GdkFont *fonta, const GdkFont *fontb); Warning
Compares two fonts for equality. Single fonts compare equal if they have the same X font ID. This operation does not currently work correctly for fontsets.
gdk_string_extents ()void gdk_string_extents (GdkFont *font, const gchar *string, gint *lbearing, gint *rbearing, gint *width, gint *ascent, gint *descent); Warning
Gets the metrics of a nul-terminated string.
gdk_text_extents ()void gdk_text_extents (GdkFont *font, const gchar *text, gint text_length, gint *lbearing, gint *rbearing, gint *width, gint *ascent, gint *descent); Warning
Gets the metrics of a string.
gdk_text_extents_wc ()void gdk_text_extents_wc (GdkFont *font, const GdkWChar *text, gint text_length, gint *lbearing, gint *rbearing, gint *width, gint *ascent, gint *descent); Warning
Gets the metrics of a string of wide characters.
gdk_string_width ()gint gdk_string_width (GdkFont *font, const gchar *string); Warning
Determines the width of a nul-terminated string. (The distance from the origin of the string to the point where the next string in a sequence of strings should be drawn)
gdk_text_width ()gint gdk_text_width (GdkFont *font, const gchar *text, gint text_length); Warning
Determines the width of a given string.
gdk_text_width_wc ()gint gdk_text_width_wc (GdkFont *font, const GdkWChar *text, gint text_length); Warning
Determines the width of a given wide-character string.
gdk_char_width ()gint gdk_char_width (GdkFont *font, gchar character); Warning
Determines the width of a given character.
gdk_char_width_wc ()gint gdk_char_width_wc (GdkFont *font, GdkWChar character); Warning
Determines the width of a given wide character. (Encoded in the wide-character encoding of the current locale).
gdk_string_measure ()gint gdk_string_measure (GdkFont *font, const gchar *string); Warning
Determines the distance from the origin to the rightmost
portion of a nul-terminated string when drawn. This is not the
correct value for determining the origin of the next
portion when drawing text in multiple pieces.
See
gdk_text_measure ()gint gdk_text_measure (GdkFont *font, const gchar *text, gint text_length); Warning
Determines the distance from the origin to the rightmost
portion of a string when drawn. This is not the
correct value for determining the origin of the next
portion when drawing text in multiple pieces.
See
gdk_char_measure ()gint gdk_char_measure (GdkFont *font, gchar character); Warning
Determines the distance from the origin to the rightmost portion of a character when drawn. This is not the correct value for determining the origin of the next portion when drawing text in multiple pieces.
gdk_string_height ()gint gdk_string_height (GdkFont *font, const gchar *string); Warning
Determines the total height of a given nul-terminated
string. This value is not generally useful, because you
cannot determine how this total height will be drawn in
relation to the baseline. See
gdk_text_height ()gint gdk_text_height (GdkFont *font, const gchar *text, gint text_length); Warning
Determines the total height of a given string.
This value is not generally useful, because you cannot
determine how this total height will be drawn in
relation to the baseline. See
gdk_char_height ()gint gdk_char_height (GdkFont *font, gchar character); Warning
Determines the total height of a given character.
This value is not generally useful, because you cannot
determine how this total height will be drawn in
relation to the baseline. See
GdkWChartypedef guint32 GdkWChar; Specifies a wide character type, used to represent character codes. This is needed since some native languages have character sets which have more than 256 characters (Japanese and Chinese, for example). Wide character values between 0 and 127 are always identical in meaning to the ASCII character codes. The wide character value 0 is often used to terminate strings of wide characters in a similar way to normal strings using the char type. An alternative to wide characters is multi-byte characters, which extend normal char strings to cope with larger character sets. As the name suggests, multi-byte characters use a different number of bytes to store different character codes. For example codes 0-127 (i.e. the ASCII codes) often use just one byte of memory, while other codes may use 2, 3 or even 4 bytes. Multi-byte characters have the advantage that they can often be used in an application with little change, since strings are still represented as arrays of char values. However multi-byte strings are much easier to manipulate since the character are all of the same size.
Applications typically use wide characters to represent character codes
internally, and multi-byte strings when saving the characters to a file.
The See the 'Extended Characters' section of the GNU C Library Reference Manual for more detailed information on wide and multi-byte characters. gdk_wcstombs ()gchar* gdk_wcstombs (const GdkWChar *src); Warning
Converts a wide character string to a multi-byte string. (The function name comes from an acronym of 'Wide Character String TO Multi-Byte String').
gdk_mbstowcs ()gint gdk_mbstowcs (GdkWChar *dest, const gchar *src, gint dest_max); Warning
Converts a multi-byte string to a wide character string. (The function name comes from an acronym of 'Multi-Byte String TO Wide Character String').
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