PangoEngineLang — Rendering-system independent script engines


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

Object Hierarchy



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().



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.


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

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.


#define PANGO_ENGINE_TYPE_LANG "PangoEngineLang"

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


#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:

 PangoEngine *engine = g_object_new (prefix_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