src/adg/adg-style.c

   1 /* ADG - Automatic Drawing Generation
   2  * Copyright (C) 2007,2008,2009,2010  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 #include "adg-style.h"
  38
  39
  40 static void             apply           (AdgStyle       *style,
  41                                          AdgEntity      *entity,
  42                                          cairo_t        *cr);
  43
  44
  45 G_DEFINE_ABSTRACT_TYPE(AdgStyle, adg_style, G_TYPE_OBJECT);
  46
  47
  48 static void
  49 adg_style_class_init(AdgStyleClass *klass)
  50 {
  51     klass->apply = apply;
  52 }
  53
  54 static void
  55 adg_style_init(AdgStyle *style)
  56 {
  57 }
  58
  59
  60 /**
  61  * adg_style_apply:
  62  * @style: an #AdgStyle derived style
  63  * @entity: the caller #AdgEntity
  64  * @cr: the subject cairo context
  65  *
  66  * Applies @style to @cr so the next rendering operations will be
  67  * done accordling to this style directives. The @entity parameter
  68  * is used to resolve the internal dresses of @style, if any.
  69  **/
  70 void
  71 adg_style_apply(AdgStyle *style, AdgEntity *entity, cairo_t *cr)
  72 {
  73     AdgStyleClass *klass;
  74
  75     g_return_if_fail(ADG_IS_STYLE(style));
  76     g_return_if_fail(ADG_IS_ENTITY(entity));
  77     g_return_if_fail(cr != NULL);
  78
  79     klass = ADG_STYLE_GET_CLASS(style);
  80
  81     if (klass->apply)
  82         klass->apply(style, entity, cr);
  83 }
  84
  85
  86 static void
  87 apply(AdgStyle *style, AdgEntity *entity, cairo_t *cr)
  88 {
  89     /* The apply method must be defined */
  90     g_warning("%s: `apply' method not implemented for type `%s'",
  91               G_STRLOC, g_type_name(G_OBJECT_TYPE(style)));
  92 }