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PangoFcFontMap

PangoFcFontMap — Base fontmap class for Fontconfig-based backends

Object Hierarchy

    GObject
    ╰── PangoFontMap
        ╰── PangoFcFontMap
            ├── PangoFT2FontMap
            ╰── PangoXftFontMap

Description

PangoFcFontMap is a base class for font map implementations using the Fontconfig and FreeType libraries. It is used in the

Xft and FreeType

backends shipped with Pango, but can also be used when creating new backends. Any backend deriving from this base class will take advantage of the wide range of shapers implemented using FreeType that come with Pango.

Functions

pango_fc_font_map_create_context ()

PangoContext *
pango_fc_font_map_create_context (PangoFcFontMap *fcfontmap);

pango_fc_font_map_create_context has been deprecated since version 1.22 and should not be used in newly-written code.

Use pango_font_map_create_context() instead.

Creates a new context for this fontmap. This function is intended only for backend implementations deriving from PangoFcFontMap; it is possible that a backend will store additional information needed for correct operation on the PangoContext after calling this function.

Parameters

fcfontmap

a PangoFcFontMap

 

Returns

a new PangoContext

Since: 1.4


PangoFcDecoderFindFunc ()

PangoFcDecoder *
(*PangoFcDecoderFindFunc) (FcPattern *pattern,
                           gpointer user_data);

Callback function passed to pango_fc_font_map_add_decoder_find_func().

Parameters

pattern

a fully resolved FcPattern specifying the font on the system

 

user_data

user data passed to pango_fc_font_map_add_decoder_find_func()

 

Returns

a new reference to a custom decoder for this pattern, or NULL if the default decoder handling should be used.


pango_fc_font_map_add_decoder_find_func ()

void
pango_fc_font_map_add_decoder_find_func
                               (PangoFcFontMap *fcfontmap,
                                PangoFcDecoderFindFunc findfunc,
                                gpointer user_data,
                                GDestroyNotify dnotify);

This function saves a callback method in the PangoFcFontMap that will be called whenever new fonts are created. If the function returns a PangoFcDecoder, that decoder will be used to determine both coverage via a FcCharSet and a one-to-one mapping of characters to glyphs. This will allow applications to have application-specific encodings for various fonts.

Parameters

fcfontmap

The PangoFcFontMap to add this method to.

 

findfunc

The PangoFcDecoderFindFunc callback function

 

user_data

User data.

 

dnotify

A GDestroyNotify callback that will be called when the fontmap is finalized and the decoder is released.

 

Since: 1.6


pango_fc_font_map_find_decoder ()

PangoFcDecoder *
pango_fc_font_map_find_decoder (PangoFcFontMap *fcfontmap,
                                FcPattern *pattern);

Finds the decoder to use for pattern . Decoders can be added to a font map using pango_fc_font_map_add_decoder_find_func().

Parameters

fcfontmap

The PangoFcFontMap to use.

 

pattern

The FcPattern to find the decoder for.

 

Returns

a newly created PangoFcDecoder object or NULL if no decoder is set for pattern .

[nullable]

Since: 1.26


pango_fc_font_map_cache_clear ()

void
pango_fc_font_map_cache_clear (PangoFcFontMap *fcfontmap);

Clear all cached information and fontsets for this font map; this should be called whenever there is a change in the output of the default_substitute() virtual function of the font map, or if fontconfig has been reinitialized to new configuration.

Parameters

fcfontmap

a PangoFcFontMap

 

Since: 1.4


pango_fc_font_map_config_changed ()

void
pango_fc_font_map_config_changed (PangoFcFontMap *fcfontmap);

Informs font map that the fontconfig configuration (ie, FcConfig object) used by this font map has changed. This currently calls pango_fc_font_map_cache_clear() which ensures that list of fonts, etc will be regenerated using the updated configuration.

Parameters

fcfontmap

a PangoFcFontMap

 

Since: 1.38


pango_fc_font_map_shutdown ()

void
pango_fc_font_map_shutdown (PangoFcFontMap *fcfontmap);

Clears all cached information for the fontmap and marks all fonts open for the fontmap as dead. (See the shutdown() virtual function of PangoFcFont.) This function might be used by a backend when the underlying windowing system for the font map exits. This function is only intended to be called only for backend implementations deriving from PangoFcFontMap.

Parameters

fcfontmap

a PangoFcFontMap

 

Since: 1.4


pango_fc_font_map_set_config ()

void
pango_fc_font_map_set_config (PangoFcFontMap *fcfontmap,
                              FcConfig *fcconfig);

Set the FcConfig for this font map to use. The default value is NULL, which causes Fontconfig to use its global "current config". You can create a new FcConfig object and use this API to attach it to a font map.

This is particularly useful for example, if you want to use application fonts with Pango. For that, you would create a fresh FcConfig, add your app fonts to it, and attach it to a new Pango font map.

If fcconfig is different from the previous config attached to the font map, pango_fc_font_map_config_changed() is called.

This function acquires a reference to the FcConfig object; the caller does NOT need to retain a reference.

Parameters

fcfontmap

a PangoFcFontMap

 

fcconfig

(nullable) a FcConfig, or NULL

 

Since: 1.38


pango_fc_font_map_get_config ()

FcConfig *
pango_fc_font_map_get_config (PangoFcFontMap *fcfontmap);

Fetches FcConfig attached to a font map. See pango_fc_font_map_set_config().

Parameters

fcfontmap

a PangoFcFontMap

 

Returns

the FcConfig object attached to fcfontmap , which might be NULL.

[nullable]

Since: 1.38


pango_fc_font_description_from_pattern ()

PangoFontDescription *
pango_fc_font_description_from_pattern
                               (FcPattern *pattern,
                                gboolean include_size);

Creates a PangoFontDescription that matches the specified Fontconfig pattern as closely as possible. Many possible Fontconfig pattern values, such as FC_RASTERIZER or FC_DPI, don't make sense in the context of PangoFontDescription, so will be ignored.

Parameters

pattern

a FcPattern

 

include_size

if TRUE, the pattern will include the size from the pattern ; otherwise the resulting pattern will be unsized. (only FC_SIZE is examined, not FC_PIXEL_SIZE)

 

Since: 1.4


pango_fc_fontset_key_get_context_key ()

gpointer
pango_fc_fontset_key_get_context_key (const PangoFcFontsetKey *key);

Gets the context key member of key .

Parameters

key

the font key

 

Returns

the context key, which is owned by key and should not be modified.

Since: 1.24


pango_fc_fontset_key_get_description ()

const PangoFontDescription *
pango_fc_fontset_key_get_description (const PangoFcFontsetKey *key);

Gets the font description of key .

Parameters

key

the fontset key

 

Returns

the font description, which is owned by key and should not be modified.

Since: 1.24


pango_fc_fontset_key_get_language ()

PangoLanguage *
pango_fc_fontset_key_get_language (const PangoFcFontsetKey *key);

Gets the language member of key .

Parameters

key

the fontset key

 

Returns

the language

Since: 1.24


pango_fc_fontset_key_get_matrix ()

const PangoMatrix *
pango_fc_fontset_key_get_matrix (const PangoFcFontsetKey *key);

Gets the matrix member of key .

Parameters

key

the fontset key

 

Returns

the matrix, which is owned by key and should not be modified.

Since: 1.24


pango_fc_fontset_key_get_absolute_size ()

double
pango_fc_fontset_key_get_absolute_size
                               (const PangoFcFontsetKey *key);

Gets the absolute font size of key in Pango units. This is adjusted for both resolution and transformation matrix.

Parameters

key

the fontset key

 

Returns

the pixel size of key .

Since: 1.24


pango_fc_fontset_key_get_resolution ()

double
pango_fc_fontset_key_get_resolution (const PangoFcFontsetKey *key);

Gets the resolution of key

Parameters

key

the fontset key

 

Returns

the resolution of key

Since: 1.24


pango_fc_font_key_get_context_key ()

gpointer
pango_fc_font_key_get_context_key (const PangoFcFontKey *key);

Gets the context key member of key .

Parameters

key

the font key

 

Returns

the context key, which is owned by key and should not be modified.

Since: 1.24


pango_fc_font_key_get_matrix ()

const PangoMatrix *
pango_fc_font_key_get_matrix (const PangoFcFontKey *key);

Gets the matrix member of key .

Parameters

key

the font key

 

Returns

the matrix, which is owned by key and should not be modified.

Since: 1.24


pango_fc_font_key_get_pattern ()

const FcPattern *
pango_fc_font_key_get_pattern (const PangoFcFontKey *key);

Gets the fontconfig pattern member of key .

Parameters

key

the font key

 

Returns

the pattern, which is owned by key and should not be modified.

Since: 1.24

Types and Values

struct PangoFcFontMap

struct PangoFcFontMap;

PangoFcFontMap is a base class for font map implementations using the Fontconfig and FreeType libraries. To create a new backend using Fontconfig and FreeType, you derive from this class and implement a new_font() virtual function that creates an instance deriving from PangoFcFont.


struct PangoFcFontMapClass

struct PangoFcFontMapClass {
  /* Deprecated in favor of fontset_key_substitute */
  void         (*default_substitute) (PangoFcFontMap   *fontmap,
				      FcPattern        *pattern);
  /* Deprecated in favor of create_font */
  PangoFcFont  *(*new_font)          (PangoFcFontMap  *fontmap,
				      FcPattern       *pattern);

  double       (*get_resolution)     (PangoFcFontMap             *fcfontmap,
				      PangoContext               *context);

  gconstpointer (*context_key_get)   (PangoFcFontMap             *fcfontmap,
				      PangoContext               *context);
  gpointer     (*context_key_copy)   (PangoFcFontMap             *fcfontmap,
				      gconstpointer               key);
  void         (*context_key_free)   (PangoFcFontMap             *fcfontmap,
				      gpointer                    key);
  guint32      (*context_key_hash)   (PangoFcFontMap             *fcfontmap,
				      gconstpointer               key);
  gboolean     (*context_key_equal)  (PangoFcFontMap             *fcfontmap,
				      gconstpointer               key_a,
				      gconstpointer               key_b);
  void         (*fontset_key_substitute)(PangoFcFontMap             *fontmap,

				      PangoFcFontsetKey          *fontsetkey,
				      FcPattern                  *pattern);
  PangoFcFont  *(*create_font)       (PangoFcFontMap             *fontmap,
				      PangoFcFontKey             *fontkey);
};

Class structure for PangoFcFontMap.

Members

default_substitute ()

Substitutes in default values for unspecified fields in a FcPattern. This will be called prior to creating a font for the pattern. May be NULL. Deprecated in favor of font_key_substitute() .

[nullable]

new_font ()

Creates a new PangoFcFont for the specified pattern of the appropriate type for this font map. The pattern argument must be passed to the "pattern" property of PangoFcFont when you call g_object_new(). Deprecated in favor of create_font() .

 

get_resolution ()

Gets the resolution (the scale factor between logical and absolute font sizes) that the backend will use for a particular fontmap and context. context may be null.

 

context_key_get ()

Gets an opaque key holding backend specific options for the context that will affect fonts created by create_font() . The result must point to persistant storage owned by the fontmap. This key is used to index hash tables used to look up fontsets and fonts.

 

context_key_copy ()

Copies a context key. Pango uses this to make a persistant copy of the value returned from context_key_get .

 

context_key_free ()

Frees a context key copied with context_key_copy .

 

context_key_hash ()

Gets a hash value for a context key

 

context_key_equal ()

Compares two context keys for equality.

 

fontset_key_substitute ()

Substitutes in default values for unspecified fields in a FcPattern. This will be called prior to creating a font for the pattern. May be NULL. (Since: 1.24).

[nullable]

create_font ()

Creates a new PangoFcFont for the specified pattern of the appropriate type for this font map using information from the font key that is passed in. The pattern member of font_key can be retrieved using pango_fc_font_key_get_pattern() and must be passed to the "pattern" property of PangoFcFont when you call g_object_new(). If NULL, new_font() is used. (Since: 1.24).

[nullable]

PANGO_FC_FONT_FEATURES

#define PANGO_FC_FONT_FEATURES "fontfeatures"

String representing a fontconfig property name that Pango reads from font patterns to populate list of OpenType features to be enabled for the font by default.

The property will have a number of string elements, each of which is the OpenType feature tag of one feature to enable.

This is equivalent to FC_FONT_FEATURES in versions of fontconfig that have that.

Since: 1.34


PANGO_FC_GRAVITY

#define PANGO_FC_GRAVITY "pangogravity"

String representing a fontconfig property name that Pango sets on any fontconfig pattern it passes to fontconfig if a PangoGravity other than PANGO_GRAVITY_SOUTH is desired.

The property will have a PangoGravity value as a string, like "east". This can be used to write fontconfig configuration rules to choose different fonts for horizontal and vertical writing directions.

Since: 1.20


PANGO_FC_VERSION

#define PANGO_FC_VERSION "pangoversion"

String representing a fontconfig property name that Pango sets on any fontconfig pattern it passes to fontconfig.

The property will have an integer value equal to what pango_version() returns. This can be used to write fontconfig configuration rules that only affect certain pango versions (or only pango-using applications, or only non-pango-using applications).

Since: 1.20


PANGO_FC_PRGNAME

#define PANGO_FC_PRGNAME "prgname"

String representing a fontconfig property name that Pango sets on any fontconfig pattern it passes to fontconfig.

The property will have a string equal to what g_get_prgname() returns. This can be used to write fontconfig configuration rules that only affect certain applications.

This is equivalent to FC_PRGNAME in versions of fontconfig that have that.

Since: 1.24


PangoFcFontsetKey

typedef struct _PangoFcFontsetKey PangoFcFontsetKey;

An opaque structure containing all the information needed for loading a fontset with the PangoFc fontmap.

Since: 1.24


PangoFcFontKey

typedef struct _PangoFcFontKey PangoFcFontKey;

An opaque structure containing all the information needed for loading a font with the PangoFc fontmap.

Since: 1.24

See Also

PangoFcFont

The base class for fonts; creating a new Fontconfig-based backend involves deriving from both PangoFcFontMap and PangoFcFont.
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