glib/gobject/gbinding.h
Dan Winship 8e17040c15 Fix overloading of "source" and "target" terminology in GBinding
GBindingTransformFunc called its arguments "source_value" and
"target_value", but in the transform_from function of a bidirectional
binding, "source_value" comes from the target object, and
"target_value" comes from the source object, which quickly gets
confusing if you need to use g_binding_get_source(), etc, in the
function.

Of course developers can call their transform function arguments
whatever they want, but many will copy from the headers/docs to start
out, so use less confusing names here ("from_value" and "to_value").

Also, fix the documentation to describe the bidirectional case
correctly.

https://bugzilla.gnome.org/show_bug.cgi?id=709440
2013-10-06 14:24:43 -04:00

152 lines
6.3 KiB
C

/* gbinding.h: Binding for object properties
*
* Copyright (C) 2010 Intel Corp.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
* Author: Emmanuele Bassi <ebassi@linux.intel.com>
*/
#ifndef __G_BINDING_H__
#define __G_BINDING_H__
#if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION)
#error "Only <glib-object.h> can be included directly."
#endif
#include <glib.h>
#include <gobject/gobject.h>
G_BEGIN_DECLS
#define G_TYPE_BINDING_FLAGS (g_binding_flags_get_type ())
#define G_TYPE_BINDING (g_binding_get_type ())
#define G_BINDING(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), G_TYPE_BINDING, GBinding))
#define G_IS_BINDING(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), G_TYPE_BINDING))
/**
* GBinding:
*
* <structname>GBinding</structname> is an opaque structure whose members
* cannot be accessed directly.
*
* Since: 2.26
*/
typedef struct _GBinding GBinding;
/**
* GBindingTransformFunc:
* @binding: a #GBinding
* @from_value: the #GValue containing the value to transform
* @to_value: the #GValue in which to store the transformed value
* @user_data: data passed to the transform function
*
* A function to be called to transform @from_value to @to_value. If
* this is the @transform_to function of a binding, then @from_value
* is the @source_property on the @source object, and @to_value is the
* @target_property on the @target object. If this is the
* @transform_from function of a %G_BINDING_BIDIRECTIONAL binding,
* then those roles are reversed.
*
* Return value: %TRUE if the transformation was successful, and %FALSE
* otherwise
*
* Since: 2.26
*/
typedef gboolean (* GBindingTransformFunc) (GBinding *binding,
const GValue *from_value,
GValue *to_value,
gpointer user_data);
/**
* GBindingFlags:
* @G_BINDING_DEFAULT: The default binding; if the source property
* changes, the target property is updated with its value.
* @G_BINDING_BIDIRECTIONAL: Bidirectional binding; if either the
* property of the source or the property of the target changes,
* the other is updated.
* @G_BINDING_SYNC_CREATE: Synchronize the values of the source and
* target properties when creating the binding; the direction of
* the synchronization is always from the source to the target.
* @G_BINDING_INVERT_BOOLEAN: If the two properties being bound are
* booleans, setting one to %TRUE will result in the other being
* set to %FALSE and vice versa. This flag will only work for
* boolean properties, and cannot be used when passing custom
* transformation functions to g_object_bind_property_full().
*
* Flags to be passed to g_object_bind_property() or
* g_object_bind_property_full().
*
* This enumeration can be extended at later date.
*
* Since: 2.26
*/
typedef enum { /*< prefix=G_BINDING >*/
G_BINDING_DEFAULT = 0,
G_BINDING_BIDIRECTIONAL = 1 << 0,
G_BINDING_SYNC_CREATE = 1 << 1,
G_BINDING_INVERT_BOOLEAN = 1 << 2
} GBindingFlags;
GLIB_AVAILABLE_IN_ALL
GType g_binding_flags_get_type (void) G_GNUC_CONST;
GLIB_AVAILABLE_IN_ALL
GType g_binding_get_type (void) G_GNUC_CONST;
GLIB_AVAILABLE_IN_ALL
GBindingFlags g_binding_get_flags (GBinding *binding);
GLIB_AVAILABLE_IN_ALL
GObject * g_binding_get_source (GBinding *binding);
GLIB_AVAILABLE_IN_ALL
GObject * g_binding_get_target (GBinding *binding);
GLIB_AVAILABLE_IN_ALL
const gchar * g_binding_get_source_property (GBinding *binding);
GLIB_AVAILABLE_IN_ALL
const gchar * g_binding_get_target_property (GBinding *binding);
GLIB_AVAILABLE_IN_2_38
void g_binding_unbind (GBinding *binding);
GLIB_AVAILABLE_IN_ALL
GBinding *g_object_bind_property (gpointer source,
const gchar *source_property,
gpointer target,
const gchar *target_property,
GBindingFlags flags);
GLIB_AVAILABLE_IN_ALL
GBinding *g_object_bind_property_full (gpointer source,
const gchar *source_property,
gpointer target,
const gchar *target_property,
GBindingFlags flags,
GBindingTransformFunc transform_to,
GBindingTransformFunc transform_from,
gpointer user_data,
GDestroyNotify notify);
GLIB_AVAILABLE_IN_ALL
GBinding *g_object_bind_property_with_closures (gpointer source,
const gchar *source_property,
gpointer target,
const gchar *target_property,
GBindingFlags flags,
GClosure *transform_to,
GClosure *transform_from);
G_END_DECLS
#endif /* __G_BINDING_H__ */