src/adg/adg-style.c

   1 /* ADG - Automatic Drawing Generation
   2  * Copyright (C) 2007,2008,2009,2010,2011  Nicola Fontana <ntd at entidi.it>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA  02110-1301, USA.
  18  */
  19
  20
  21 /**
  22  * SECTION:adg-style
  23  * @short_description: The base class of all styling objects
  24  *
  25  * This is the fundamental abstract class for styles.
  26  **/
  27
  28 /**
  29  * AdgStyle:
  30  *
  31  * All fields are private and should not be used directly.
  32  * Use its public methods instead.
  33  **/
  34
  35
  36 #include "adg-internal.h"
  37
  38 #include "adg-style.h"
  39
  40
  41 #define _ADG_OLD_OBJECT_CLASS  ((GObjectClass *) adg_style_parent_class)
  42
  43
  44 G_DEFINE_ABSTRACT_TYPE(AdgStyle, adg_style, G_TYPE_OBJECT)
  45
  46 enum {
  47     INVALIDATE,
  48     APPLY,
  49     LAST_SIGNAL
  50 };
  51
  52
  53 static void             _adg_dispose            (GObject        *object);
  54 static void             _adg_apply              (AdgStyle       *style,
  55                                                  AdgEntity      *entity,
  56                                                  cairo_t        *cr);
  57 static guint            _adg_signals[LAST_SIGNAL] = { 0 };
  58
  59
  60 static void
  61 adg_style_class_init(AdgStyleClass *klass)
  62 {
  63     GObjectClass *gobject_class;
  64
  65     gobject_class = (GObjectClass *) klass;
  66
  67     gobject_class->dispose = _adg_dispose;
  68
  69     klass->invalidate = NULL;
  70     klass->apply = _adg_apply;
  71
  72     /**
  73      * AdgStyle::invalidate:
  74      * @style: an #AdgStyle
  75      *
  76      * Invalidates the @style, that is resets all the cache, if any,
  77      * retained by the internal implementation.
  78      *
  79      * This signal is emitted while disposing @style, so be sure it
  80      * can be called more than once without harms. Furthermore it
  81      * will be emitted from property setter code of new implementations
  82      * to force the recomputation of the cache.
  83      **/
  84     _adg_signals[INVALIDATE] =
  85         g_signal_new("invalidate",
  86                      G_OBJECT_CLASS_TYPE(klass),
  87                      G_SIGNAL_RUN_LAST,
  88                      G_STRUCT_OFFSET(AdgStyleClass, invalidate),
  89                      NULL, NULL,
  90                      adg_marshal_VOID__VOID,
  91                      G_TYPE_NONE, 0);
  92
  93     /**
  94      * AdgStyle::apply:
  95      * @style: an #AdgStyle
  96      * @entity: the caller #AdgEntity
  97      * @cr: the #cairo_t context
  98      *
  99      * Applies @style to @cr so the next rendering operations will be
 100      * done accordling to this style directives. The @entity parameter
 101      * is used to resolve the internal dresses of @style, if any.
 102      **/
 103     _adg_signals[APPLY] =
 104         g_signal_new("apply",
 105                      G_OBJECT_CLASS_TYPE(klass),
 106                      G_SIGNAL_RUN_LAST,
 107                      G_STRUCT_OFFSET(AdgStyleClass, apply),
 108                      NULL, NULL,
 109                      adg_marshal_VOID__OBJECT_POINTER,
 110                      G_TYPE_NONE, 2, ADG_TYPE_ENTITY, G_TYPE_POINTER);
 111 }
 112
 113 static void
 114 adg_style_init(AdgStyle *style)
 115 {
 116 }
 117
 118 static void
 119 _adg_dispose(GObject *object)
 120 {
 121     g_signal_emit(object, _adg_signals[INVALIDATE], 0);
 122
 123     if (_ADG_OLD_OBJECT_CLASS->dispose != NULL)
 124         _ADG_OLD_OBJECT_CLASS->dispose(object);
 125 }
 126
 127
 128 /**
 129  * adg_style_invalidate:
 130  * @style: an #AdgStyle derived style
 131  *
 132  * Emits the #AdgStyle::invalidate signal on @style. This signal
 133  * is always emitted while disposing @style, so be sure it
 134  * can be called more than once without harms.
 135  *
 136  * <note><para>
 137  * This function is only useful in new style implementations.
 138  * </para></note>
 139  **/
 140 void
 141 adg_style_invalidate(AdgStyle *style)
 142 {
 143     g_return_if_fail(ADG_IS_STYLE(style));
 144
 145     g_signal_emit(style, _adg_signals[INVALIDATE], 0);
 146 }
 147
 148 /**
 149  * adg_style_apply:
 150  * @style: an #AdgStyle derived style
 151  * @entity: the caller #AdgEntity
 152  * @cr: the subject cairo context
 153  *
 154  * Emits the #AdgStyle::apply signal on @style, passing @entity and
 155  * @cr as parameters to the signal.
 156  **/
 157 void
 158 adg_style_apply(AdgStyle *style, AdgEntity *entity, cairo_t *cr)
 159 {
 160     g_return_if_fail(ADG_IS_STYLE(style));
 161     g_return_if_fail(ADG_IS_ENTITY(entity));
 162     g_return_if_fail(cr != NULL);
 163
 164     g_signal_emit(style, _adg_signals[APPLY], 0, entity, cr);
 165 }
 166
 167
 168 static void
 169 _adg_apply(AdgStyle *style, AdgEntity *entity, cairo_t *cr)
 170 {
 171     /* The apply method must be defined */
 172     g_warning(_("%s: `apply' method not implemented for type `%s'"),
 173               G_STRLOC, g_type_name(G_OBJECT_TYPE(style)));
 174 }