src/adg/adg-arrow.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-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-internal.h"
  38 #include "adg-arrow.h"
  39 #include "adg-arrow-private.h"
  40 #include "adg-path.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                                 -G_PI, G_PI, 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_new:
 145  * @trail: the #AdgTrail to arrow
 146  *
 147  * Creates a new undefined arrow entity. The position must be defined
 148  * by setting the #AdgMarker:trail and #AdgMarker:pos properties.
 149  * By default, an arrow as #AdgEntity:local-method set to #ADG_MIX_PARENT.
 150  *
 151  * Returns: the newly created arrow entity
 152  **/
 153 AdgArrow *
 154 adg_arrow_new(void)
 155 {
 156     return g_object_new(ADG_TYPE_ARROW,
 157                         "local-method", ADG_MIX_PARENT,
 158                         NULL);
 159 }
 160
 161 /**
 162  * adg_arrow_new_with_trail:
 163  * @trail: the #AdgTrail where the arrow should be added
 164  * @pos: the position ratio on @trail
 165  *
 166  * Creates a new arrow on the first segment on @trail at position
 167  * @pos, where @pos is a ratio of the @trail length (being %0 the
 168  * start point, %1 the end point, %0.5 the middle point and so on).
 169  * By default, an arrow as #AdgEntity:local-method set to #ADG_MIX_PARENT.
 170  *
 171  * Returns: the newly created arrow entity
 172  **/
 173 AdgArrow *
 174 adg_arrow_new_with_trail(AdgTrail *trail, gdouble pos)
 175 {
 176     return g_object_new(ADG_TYPE_ARROW,
 177                         "local-method", ADG_MIX_PARENT,
 178                         "trail", trail,
 179                         "n-segment", 1,
 180                         "pos", pos,
 181                         NULL);
 182 }
 183
 184 /**
 185  * adg_arrow_set_angle:
 186  * @arrow: an #AdgArrow
 187  * @angle: the new angle
 188  *
 189  * Sets a new angle: @angle will be the new opening angle of @arrow.
 190  * Changing the arrow angle will invalidate @arrow.
 191  **/
 192 void
 193 adg_arrow_set_angle(AdgArrow *arrow, gdouble angle)
 194 {
 195     g_return_if_fail(ADG_IS_ARROW(arrow));
 196
 197     if (set_angle(arrow, angle))
 198         g_object_notify((GObject *) arrow, "angle");
 199 }
 200
 201 /**
 202  * adg_arrow_get_angle:
 203  * @arrow: an #AdgArrow
 204  *
 205  * Gets the current angle of @arrow.
 206  *
 207  * Returns: the arrow angle, in radians
 208  **/
 209 gdouble
 210 adg_arrow_get_angle(AdgArrow *arrow)
 211 {
 212     AdgArrowPrivate *data;
 213
 214     g_return_val_if_fail(ADG_IS_ARROW(arrow), 0);
 215
 216     data = arrow->data;
 217
 218     return data->angle;
 219 }
 220
 221
 222 static void
 223 arrange(AdgEntity *entity)
 224 {
 225     /* TODO */
 226 }
 227
 228 static void
 229 render(AdgEntity *entity, cairo_t *cr)
 230 {
 231     AdgModel *model;
 232     const cairo_path_t *cairo_path;
 233
 234     model = adg_marker_model((AdgMarker *) entity);
 235     cairo_path = adg_trail_get_cairo_path((AdgTrail *) model);
 236
 237     if (cairo_path != NULL) {
 238         cairo_save(cr);
 239         cairo_transform(cr, adg_entity_get_local_matrix(entity));
 240         cairo_append_path(cr, cairo_path);
 241         cairo_restore(cr);
 242
 243         cairo_fill(cr);
 244     }
 245 }
 246
 247 static AdgModel *
 248 create_model(AdgMarker *marker)
 249 {
 250     AdgArrowPrivate *data;
 251     AdgPath *path;
 252     CpmlPair p1, p2;
 253
 254     data = ((AdgArrow *) marker)->data;
 255     path = adg_path_new();
 256     cpml_vector_from_angle(&p1, data->angle / 2);
 257     p2.x = p1.x;
 258     p2.y = -p1.y;
 259
 260     adg_path_move_to_explicit(path, 0, 0);
 261     adg_path_line_to(path, &p1);
 262     adg_path_line_to(path, &p2);
 263     adg_path_close(path);
 264
 265     return (AdgModel *) path;
 266 }
 267
 268 static gboolean
 269 set_angle(AdgArrow *arrow, gdouble angle)
 270 {
 271     AdgArrowPrivate *data = arrow->data;
 272
 273     angle = cpml_angle(angle);
 274
 275     if (angle == data->angle)
 276         return FALSE;
 277
 278     data->angle = angle;
 279     adg_entity_invalidate((AdgEntity *) arrow);
 280
 281     return TRUE;
 282 }