adg/adg-arrow.c

   1 /* ADG - Automatic Drawing Generation
   2  * Copyright (C) 2007,2008,2009 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-arrow
  23  * @short_description: Arrow rendering related stuff
  24  *
  25  * Contains parameters on how to draw arrows, providing a way to register a
  26  * custom rendering callback.
  27  **/
  28
  29 /**
  30  * AdgArrow:
  31  *
  32  * All fields are private and should not be used directly.
  33  * Use its public methods instead.
  34  **/
  35
  36
  37 #include "adg-arrow.h"
  38 #include "adg-arrow-private.h"
  39 #include "adg-path.h"
  40 #include "adg-intl.h"
  41
  42
  43 enum {
  44     PROP_0,
  45     PROP_ANGLE
  46 };
  47
  48
  49 static void             get_property            (GObject        *object,
  50                                                  guint           prop_id,
  51                                                  GValue         *value,
  52                                                  GParamSpec     *pspec);
  53 static void             set_property            (GObject        *object,
  54                                                  guint           prop_id,
  55                                                  const GValue   *value,
  56                                                  GParamSpec     *pspec);
  57 static void             arrange                 (AdgEntity      *entity);
  58 static void             render                  (AdgEntity      *entity,
  59                                                  cairo_t        *cr);
  60 static AdgModel *       create_model            (AdgMarker      *marker);
  61 static gboolean         set_angle               (AdgArrow       *arrow,
  62                                                  gdouble         angle);
  63
  64
  65 G_DEFINE_TYPE(AdgArrow, adg_arrow, ADG_TYPE_MARKER);
  66
  67
  68 static void
  69 adg_arrow_class_init(AdgArrowClass *klass)
  70 {
  71     GObjectClass *gobject_class;
  72     AdgEntityClass *entity_class;
  73     AdgMarkerClass *marker_class;
  74     GParamSpec *param;
  75
  76     gobject_class = (GObjectClass *) klass;
  77     entity_class = (AdgEntityClass *) klass;
  78     marker_class = (AdgMarkerClass *) klass;
  79
  80     g_type_class_add_private(klass, sizeof(AdgArrowPrivate));
  81
  82     gobject_class->set_property = set_property;
  83     gobject_class->get_property = get_property;
  84
  85     entity_class->arrange = arrange;
  86     entity_class->render = render;
  87
  88     marker_class->create_model = create_model;
  89
  90     param = g_param_spec_double("angle",
  91                                 P_("Arrow Angle"),
  92                                 P_("The opening angle of the arrow"),
  93                                 0, G_PI*2, G_PI/6,
  94                                 G_PARAM_READWRITE);
  95     g_object_class_install_property(gobject_class, PROP_ANGLE, param);
  96 }
  97
  98 static void
  99 adg_arrow_init(AdgArrow *arrow)
 100 {
 101     AdgArrowPrivate *data = G_TYPE_INSTANCE_GET_PRIVATE(arrow,
 102                                                         ADG_TYPE_ARROW,
 103                                                         AdgArrowPrivate);
 104
 105     data->angle = G_PI/6;
 106
 107     arrow->data = data;
 108 }
 109
 110 static void
 111 get_property(GObject *object,
 112              guint prop_id, GValue *value, GParamSpec *pspec)
 113 {
 114     AdgArrowPrivate *data = ((AdgArrow *) object)->data;
 115
 116     switch (prop_id) {
 117     case PROP_ANGLE:
 118         g_value_set_double(value, data->angle);
 119         break;
 120     default:
 121         G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
 122         break;
 123     }
 124 }
 125
 126 static void
 127 set_property(GObject *object,
 128              guint prop_id, const GValue *value, GParamSpec *pspec)
 129 {
 130     AdgArrow *arrow = (AdgArrow *) object;
 131
 132     switch (prop_id) {
 133     case PROP_ANGLE:
 134         set_angle(arrow, g_value_get_double(value));
 135         break;
 136     default:
 137         G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
 138         break;
 139     }
 140 }
 141
 142
 143 /**
 144  * adg_arrow_get_angle:
 145  * @arrow: an #AdgArrow
 146  *
 147  * Gets the current angle of @arrow.
 148  *
 149  * Returns: the arrow angle, in radians
 150  **/
 151 gdouble
 152 adg_arrow_get_angle(AdgArrow *arrow)
 153 {
 154     AdgArrowPrivate *data;
 155
 156     g_return_val_if_fail(ADG_IS_ARROW(arrow), 0);
 157
 158     data = arrow->data;
 159
 160     return data->angle;
 161 }
 162
 163 /**
 164  * adg_arrow_set_angle:
 165  * @arrow: an #AdgArrow
 166  * @angle: the new angle
 167  *
 168  * Sets a new angle: @angle will be the new opening angle of @arrow.
 169  * Changing the arrow angle will invalidate @arrow.
 170  **/
 171 void
 172 adg_arrow_set_angle(AdgArrow *arrow, gdouble angle)
 173 {
 174     g_return_if_fail(ADG_IS_ARROW(arrow));
 175
 176     if (set_angle(arrow, angle))
 177         g_object_notify((GObject *) arrow, "angle");
 178 }
 179
 180 static void
 181 arrange(AdgEntity *entity)
 182 {
 183     /* TODO */
 184 }
 185
 186 static void
 187 render(AdgEntity *entity, cairo_t *cr)
 188 {
 189     AdgModel *model;
 190     const cairo_path_t *cairo_path;
 191
 192     model = adg_marker_model((AdgMarker *) entity);
 193     cairo_path = adg_trail_get_cairo_path((AdgTrail *) model);
 194
 195     if (cairo_path != NULL) {
 196         cairo_save(cr);
 197         cairo_set_matrix(cr, adg_entity_ctm(entity));
 198         cairo_append_path(cr, cairo_path);
 199         cairo_restore(cr);
 200
 201         cairo_fill(cr);
 202     }
 203 }
 204
 205 static AdgModel *
 206 create_model(AdgMarker *marker)
 207 {
 208     AdgArrowPrivate *data;
 209     AdgPath *path;
 210     CpmlVector vector;
 211
 212     data = ((AdgArrow *) marker)->data;
 213     path = adg_path_new();
 214     cpml_vector_from_angle(&vector, data->angle / 2);
 215
 216     adg_path_move_to(path, 0, 0);
 217     adg_path_line_to(path, vector.x, vector.y);
 218     adg_path_line_to(path, vector.x, -vector.y);
 219     adg_path_close(path);
 220
 221     return (AdgModel *) path;
 222 }
 223
 224 static gboolean
 225 set_angle(AdgArrow *arrow, gdouble angle)
 226 {
 227     AdgArrowPrivate *data = arrow->data;
 228
 229     if (angle == data->angle)
 230         return FALSE;
 231
 232     data->angle = angle;
 233     adg_entity_invalidate((AdgEntity *) arrow);
 234
 235     return TRUE;
 236 }