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The Gtk interface module can be used with
(use-modules (gtk-2.0 gtk))
Calls to gtk_init and gtk_set_locale are made automatically, an
application doesn't need to make them itself. Standard Gtk command line
options are taken from the program command line (eg. ‘--gtk-module’),
and removed from there, leaving other options and the rest of the command line
for the application. see Runtime Environment.
The following rules apply to the various Gtk types.
GtkAdjustmentThese only set the respective fields, it's up to an application to emit the standard
changedsignal when ready (eg. usinggtk-adjustment-changed).Note that
gtk-adjustment-set-valueis instead the corresponding standard Gtk function. It sets the value field and emits thevalue_changedsignal.
GtkCListGtkResponseTypeGtkResponseType are represented just as integers, and in
particular are passed that way in the GtkDialog response signal.
The following variables hold pre-defined values.
GtkStyleReturn
GdkColorobjects.
Return
GdkGCobjects.
"clicked" or "map_event".
Signal handler procedures are passed the same parameters as the C code functions, except the object and client-data are omitted. The return value is used when the signal expects a return value.
For instance the clicked signal from a GtkButton passes no
parameters,
(define (my-click-handler)
(display "hello\n"))
(gtk-signal-connect button "clicked" my-click-handler)
Or an expose_event passes just a GdkEvent, and expects a return
value.
(define (my-expose-handler)
(do-some-drawing)
#f) ;; propagate event to other handlers
(gtk-signal-connect drawarea "expose_event" my-expose-handler)
The object and client data parameters in the C level calls are deliberately omitted. Such things can be handled in a more Scheme-like and flexible way with a closure, ie. captured variables with desired values (see The Concept of Closure).
Signal handler calls are made via a trampoline to facilitate error handling, see Gtk Extras.
The following standard Gtk functions have particular notes for the Guile Gtk interface.
expand and fill default to
#f, padding defaults to 0.
Return a
GdkColorobject with red, green and blue fields set to the current colour from colorsel. The colour is not allocated in any colormap and the pixel field is zero.Note that unfortunately this is not the same as the C function
gtk_color_selection_get_color, but instead like the Gtk 2gtk_color_selection_get_current_color.
Set the current colour in colorsel to the red, green and blue fields of the given
GdkColorobject. The opacity is set to 1.0, when in use.Note that unfortunately this is not the same as the C function
gtk_color_selection_set_color, but instead like the Gtk 2gtk_color_selection_set_current_color.
As per the signal handlers, there's no “data” parameter to the idle callbacks. proc is simply called
(proc)and should return non-#fto continue being called, or#fto stop.Currently there's no destroy notify callback procedure for
gtk-idle-add-full, perhaps this will change in the future.
Register proc to be called when inputconds is satisfied on port, and return the input source ID.
As per the signal handlers, there's no “data” parameter to the input handler, it's called as
(procfdes conds).This function doesn't offer the destroy notify callback available from
gtk_input_add_full, perhaps this will change in the future.
In a signal handler or other callback, an application cannot use an exception or new continuation to escape from
gtk-mainand friends, since Gtk has no understanding of such things. There are no restrictions on control flow within a callback, just on escaping out of it.One possibility for applications wanting such things is to have an explicit loop calling
gtk-main-iterationand hold a list of pending actions to be taken outside that function. This is done in the sample program continuations.scm (see Example Programs). The callback trampoline feature might be able to help with this (see Gtk Extras).
There's no position function accepted, instead
NULLis used, which means put the menu under the current mouse position. Perhaps this will change in the future.
Get an object property. The prop property name can be either a keyword or symbol. The property value is returned, or
#fif there's no such property or it cannot be read.
gtk-object-getonly gets one property value, unlike the C functiongtk_object_getwhich can get multiple property values in one call.
The prop property names are taken as either keywords or symbols, followed by suitable values. This is in contrast to the C functions, where strings are used for property names. For example,
(gtk-widget-new 'GtkButton #:label "some words" #:relief 'half)The values set are type checked and converted in the usual way, they must correspond to the property type.
These are set from the corresponding Gtk library variables
gtk_major_versionetc, rather than the compile-time constantsGTK_MAJOR_VERIONetc. This means the values seen in Scheme code are the library actually used at run time, not merely the one Guile Gtk was compiled against.
bitmap defaults to
#f, meaning no mask.
hadjustment and vadjustment default to
#f, meaning create new adjustment objects.
gtk-set-localeis called automatically when the(gtk gtk)module is loaded, so applications don't need to do so explicitly.
objectsignal has no purpose and should always be
#f, which is its default. after defaults to#f, meaning func is called before object runs the default handler for this signal.It will be noted that
gtk-signal-connecthas the objectsignal and after parameters likegtk_signal_connect_full, but currently there's no access to the destroy notify callback.
xopts and yopts each default to
(expand fill), xpad and ypad default to 0.
The default length is -1, meaning the whole string.
The following standard Gtk functions are not provided.