gi-gtk-3.0.11: Gtk bindings

CopyrightWill Thompson, Iñaki García Etxebarria and Jonas Platte
LicenseLGPL-2.1
MaintainerIñaki García Etxebarria (garetxe@gmail.com)
Safe HaskellNone
LanguageHaskell2010

GI.Gtk.Objects.IMContext

Contents

Description

IMContext defines the interface for GTK+ input methods. An input method is used by GTK+ text input widgets like Entry to map from key events to Unicode character strings.

The default input method can be set programmatically via the Settings:gtk-im-module GtkSettings property. Alternatively, you may set the GTK_IM_MODULE environment variable as documented in [Running GTK+ Applications][gtk-running].

The Entry Entry:im-module and TextView TextView:im-module properties may also be used to set input methods for specific widget instances. For instance, a certain entry widget might be expected to contain certain characters which would be easier to input with a certain input method.

An input method may consume multiple key events in sequence and finally output the composed result. This is called preediting, and an input method may provide feedback about this process by displaying the intermediate composition states as preedit text. For instance, the default GTK+ input method implements the input of arbitrary Unicode code points by holding down the Control and Shift keys and then typing “U” followed by the hexadecimal digits of the code point. When releasing the Control and Shift keys, preediting ends and the character is inserted as text. Ctrl+Shift+u20AC for example results in the € sign.

Additional input methods can be made available for use by GTK+ widgets as loadable modules. An input method module is a small shared library which implements a subclass of IMContext or IMContextSimple and exports these four functions:

C code

void im_module_init(GTypeModule *module);

This function should register the GType of the IMContext subclass which implements the input method by means of typeModuleRegisterType. Note that typeRegisterStatic cannot be used as the type needs to be registered dynamically.

C code

void im_module_exit(void);

Here goes any cleanup code your input method might require on module unload.

C code

void im_module_list(const GtkIMContextInfo ***contexts, int *n_contexts)
{
  *contexts = info_list;
  *n_contexts = G_N_ELEMENTS (info_list);
}

This function returns the list of input methods provided by the module. The example implementation above shows a common solution and simply returns a pointer to statically defined array of IMContextInfo items for each provided input method.

C code

GtkIMContext * im_module_create(const gchar *context_id);

This function should return a pointer to a newly created instance of the IMContext subclass identified by contextId. The context ID is the same as specified in the IMContextInfo array returned by im_module_list().

After a new loadable input method module has been installed on the system, the configuration file gtk.immodules needs to be regenerated by [gtk-query-immodules-3.0][gtk-query-immodules-3.0], in order for the new input method to become available to GTK+ applications.

Synopsis

Exported types

Methods

deleteSurrounding

iMContextDeleteSurrounding Source #

Arguments

:: (HasCallStack, MonadIO m, IsIMContext a) 
=> a

context: a IMContext

-> Int32

offset: offset from cursor position in chars; a negative value means start before the cursor.

-> Int32

nChars: number of characters to delete.

-> m Bool

Returns: True if the signal was handled.

Asks the widget that the input context is attached to to delete characters around the cursor position by emitting the GtkIMContext::delete_surrounding signal. Note that offset and nChars are in characters not in bytes which differs from the usage other places in IMContext.

In order to use this function, you should first call iMContextGetSurrounding to get the current context, and call this function immediately afterwards to make sure that you know what you are deleting. You should also account for the fact that even if the signal was handled, the input context might not have deleted all the characters that were requested to be deleted.

This function is used by an input method that wants to make subsitutions in the existing text in response to new input. It is not useful for applications.

filterKeypress

iMContextFilterKeypress Source #

Arguments

:: (HasCallStack, MonadIO m, IsIMContext a) 
=> a

context: a IMContext

-> EventKey

event: the key event

-> m Bool

Returns: True if the input method handled the key event.

Allow an input method to internally handle key press and release events. If this function returns True, then no further processing should be done for this key event.

focusIn

data IMContextFocusInMethodInfo Source #

Instances

((~) * signature (m ()), MonadIO m, IsIMContext a) => MethodInfo * IMContextFocusInMethodInfo a signature Source # 

iMContextFocusIn Source #

Arguments

:: (HasCallStack, MonadIO m, IsIMContext a) 
=> a

context: a IMContext

-> m () 

Notify the input method that the widget to which this input context corresponds has gained focus. The input method may, for example, change the displayed feedback to reflect this change.

focusOut

data IMContextFocusOutMethodInfo Source #

Instances

((~) * signature (m ()), MonadIO m, IsIMContext a) => MethodInfo * IMContextFocusOutMethodInfo a signature Source # 

iMContextFocusOut Source #

Arguments

:: (HasCallStack, MonadIO m, IsIMContext a) 
=> a

context: a IMContext

-> m () 

Notify the input method that the widget to which this input context corresponds has lost focus. The input method may, for example, change the displayed feedback or reset the contexts state to reflect this change.

getPreeditString

iMContextGetPreeditString Source #

Arguments

:: (HasCallStack, MonadIO m, IsIMContext a) 
=> a

context: a IMContext

-> m (Text, AttrList, Int32) 

Retrieve the current preedit string for the input context, and a list of attributes to apply to the string. This string should be displayed inserted at the insertion point.

getSurrounding

iMContextGetSurrounding Source #

Arguments

:: (HasCallStack, MonadIO m, IsIMContext a) 
=> a

context: a IMContext

-> m (Bool, Text, Int32)

Returns: True if surrounding text was provided; in this case you must free the result stored in *text.

Retrieves context around the insertion point. Input methods typically want context in order to constrain input text based on existing text; this is important for languages such as Thai where only some sequences of characters are allowed.

This function is implemented by emitting the GtkIMContext::retrieve_surrounding signal on the input method; in response to this signal, a widget should provide as much context as is available, up to an entire paragraph, by calling iMContextSetSurrounding. Note that there is no obligation for a widget to respond to the ::retrieve_surrounding signal, so input methods must be prepared to function without context.

reset

data IMContextResetMethodInfo Source #

Instances

((~) * signature (m ()), MonadIO m, IsIMContext a) => MethodInfo * IMContextResetMethodInfo a signature Source # 

iMContextReset Source #

Arguments

:: (HasCallStack, MonadIO m, IsIMContext a) 
=> a

context: a IMContext

-> m () 

Notify the input method that a change such as a change in cursor position has been made. This will typically cause the input method to clear the preedit state.

setClientWindow

iMContextSetClientWindow Source #

Arguments

:: (HasCallStack, MonadIO m, IsIMContext a, IsWindow b) 
=> a

context: a IMContext

-> Maybe b

window: the client window. This may be Nothing to indicate that the previous client window no longer exists.

-> m () 

Set the client window for the input context; this is the Window in which the input appears. This window is used in order to correctly position status windows, and may also be used for purposes internal to the input method.

setCursorLocation

iMContextSetCursorLocation Source #

Arguments

:: (HasCallStack, MonadIO m, IsIMContext a) 
=> a

context: a IMContext

-> Rectangle

area: new location

-> m () 

Notify the input method that a change in cursor position has been made. The location is relative to the client window.

setSurrounding

iMContextSetSurrounding Source #

Arguments

:: (HasCallStack, MonadIO m, IsIMContext a) 
=> a

context: a IMContext

-> Text

text: text surrounding the insertion point, as UTF-8. the preedit string should not be included within text.

-> Int32

len: the length of text, or -1 if text is nul-terminated

-> Int32

cursorIndex: the byte index of the insertion cursor within text.

-> m () 

Sets surrounding context around the insertion point and preedit string. This function is expected to be called in response to the GtkIMContext::retrieve_surrounding signal, and will likely have no effect if called at other times.

setUsePreedit

iMContextSetUsePreedit Source #

Arguments

:: (HasCallStack, MonadIO m, IsIMContext a) 
=> a

context: a IMContext

-> Bool

usePreedit: whether the IM context should use the preedit string.

-> m () 

Sets whether the IM context should use the preedit string to display feedback. If usePreedit is FALSE (default is TRUE), then the IM context may use some other method to display feedback, such as displaying it in a child of the root window.

Properties

inputHints

data IMContextInputHintsPropertyInfo Source #

Instances

AttrInfo IMContextInputHintsPropertyInfo Source # 
type AttrOrigin IMContextInputHintsPropertyInfo Source # 
type AttrLabel IMContextInputHintsPropertyInfo Source # 
type AttrGetType IMContextInputHintsPropertyInfo Source # 
type AttrBaseTypeConstraint IMContextInputHintsPropertyInfo Source # 
type AttrSetTypeConstraint IMContextInputHintsPropertyInfo Source # 
type AttrAllowedOps IMContextInputHintsPropertyInfo Source # 

inputPurpose

data IMContextInputPurposePropertyInfo Source #

Instances

AttrInfo IMContextInputPurposePropertyInfo Source # 
type AttrOrigin IMContextInputPurposePropertyInfo Source # 
type AttrLabel IMContextInputPurposePropertyInfo Source # 
type AttrGetType IMContextInputPurposePropertyInfo Source # 
type AttrBaseTypeConstraint IMContextInputPurposePropertyInfo Source # 
type AttrSetTypeConstraint IMContextInputPurposePropertyInfo Source # 
type AttrAllowedOps IMContextInputPurposePropertyInfo Source # 

Signals

commit

deleteSurrounding

preeditChanged

preeditEnd

preeditStart

retrieveSurrounding