PangoEngineLang

PangoEngineLang — Rendering-system independent script engines

Stability Level

Unstable, unless otherwise indicated

Synopsis

                    PangoEngineLang;
struct              PangoEngineLangClass;
#define             PANGO_ENGINE_TYPE_LANG
#define             PANGO_ENGINE_LANG_DEFINE_TYPE       (name,
                                                         prefix,
                                                         class_init,
                                                         instance_init)

Object Hierarchy

  GObject
   +----PangoEngine
         +----PangoEngineLang

Description

The language engines are rendering-system independent engines that determine line, word, and character breaks for character strings. These engines are used in pango_break().

Details

PangoEngineLang

typedef struct _PangoEngineLang PangoEngineLang;

The PangoEngineLang class is implemented by engines that customize the rendering-system independent part of the Pango pipeline for a particular script or language. For instance, a custom PangoEngineLang could be provided for Thai to implement the dictionary-based word boundary lookups needed for that language.

struct PangoEngineLangClass

struct PangoEngineLangClass {
  void (*script_break) (PangoEngineLang *engine,
			const char    *text,
			int            len,
			PangoAnalysis *analysis,
			PangoLogAttr  *attrs,
			int            attrs_len);
};

Class structure for PangoEngineLang

script_break ()

Provides a custom implementation of pango_break(). If NULL, pango_default_break() is used instead. If not NULL, for Pango versions before 1.16 (module interface version before 1.6.0), this was called instead of pango_default_break(), but in newer versions, pango_default_break() is always called and this is called after that to allow tailoring the breaking results.

PANGO_ENGINE_TYPE_LANG

#define PANGO_ENGINE_TYPE_LANG "PangoEngineLang"

A string constant defining the engine type for language engines. These engines derive from PangoEngineLang.

PANGO_ENGINE_LANG_DEFINE_TYPE()

#define             PANGO_ENGINE_LANG_DEFINE_TYPE(name, prefix, class_init, instance_init)

Outputs the necessary code for GObject type registration for a PangoEngineLang class defined in a module. Two static symbols are defined.

 static GType prefix_type;
 static void prefix_register_type (GTypeModule module);

The prefix, _register_type() function should be called in your script_engine_init() function for each type that your module implements, and then your script_engine_create() function can create instances of the object as follows:

1	PangoEngine *engine = g_object_new (<em class="replaceable"><code>prefix</code></em>_type, NULL);

`name` :	Name of the the type to register (for example:, `ArabicEngineFc`
`prefix` :	Prefix for symbols that will be defined (for example:, `arabic_engine_fc`
`class_init` :	Class initialization function for the new type, or `NULL`
`instance_init` :	Instance initialization function for the new type, or `NULL`