src/adg/adg-arrow.c

   1 /* ADG - Automatic Drawing Generation
   2  * Copyright (C) 2007-2019  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  * <note><para>
  29  * By default, the #AdgEntity:local-mix property is set to #ADG_MIX_PARENT
  30  * on #AdgArrow entities.
  31  * </para></note>
  32  *
  33  * Since: 1.0
  34  **/
  35
  36 /**
  37  * AdgArrow:
  38  *
  39  * All fields are private and should not be used directly.
  40  * Use its public methods instead.
  41  *
  42  * Since: 1.0
  43  **/
  44
  45
  46 #include "adg-internal.h"
  47 #include "adg-model.h"
  48 #include "adg-trail.h"
  49 #include "adg-path.h"
  50 #include "adg-marker.h"
  51
  52 #include "adg-arrow.h"
  53 #include "adg-arrow-private.h"
  54
  55
  56 G_DEFINE_TYPE(AdgArrow, adg_arrow, ADG_TYPE_MARKER)
  57
  58 enum {
  59     PROP_0,
  60     PROP_ANGLE
  61 };
  62
  63
  64 static void             _adg_get_property       (GObject        *object,
  65                                                  guint           prop_id,
  66                                                  GValue         *value,
  67                                                  GParamSpec     *pspec);
  68 static void             _adg_set_property       (GObject        *object,
  69                                                  guint           prop_id,
  70                                                  const GValue   *value,
  71                                                  GParamSpec     *pspec);
  72 static void             _adg_arrange            (AdgEntity      *entity);
  73 static void             _adg_render             (AdgEntity      *entity,
  74                                                  cairo_t        *cr);
  75 static AdgModel *       _adg_create_model       (AdgMarker      *marker);
  76
  77
  78 static void
  79 adg_arrow_class_init(AdgArrowClass *klass)
  80 {
  81     GObjectClass *gobject_class;
  82     AdgEntityClass *entity_class;
  83     AdgMarkerClass *marker_class;
  84     GParamSpec *param;
  85
  86     gobject_class = (GObjectClass *) klass;
  87     entity_class = (AdgEntityClass *) klass;
  88     marker_class = (AdgMarkerClass *) klass;
  89
  90     g_type_class_add_private(klass, sizeof(AdgArrowPrivate));
  91
  92     gobject_class->set_property = _adg_set_property;
  93     gobject_class->get_property = _adg_get_property;
  94
  95     entity_class->arrange = _adg_arrange;
  96     entity_class->render = _adg_render;
  97
  98     marker_class->create_model = _adg_create_model;
  99
 100     param = g_param_spec_double("angle",
 101                                 P_("Arrow Angle"),
 102                                 P_("The opening angle of the arrow"),
 103                                 -G_PI, G_PI, G_PI / 6,
 104                                 G_PARAM_READWRITE);
 105     g_object_class_install_property(gobject_class, PROP_ANGLE, param);
 106 }
 107
 108 static void
 109 adg_arrow_init(AdgArrow *arrow)
 110 {
 111     AdgArrowPrivate *data = G_TYPE_INSTANCE_GET_PRIVATE(arrow,
 112                                                         ADG_TYPE_ARROW,
 113                                                         AdgArrowPrivate);
 114
 115     data->angle = G_PI/6;
 116
 117     arrow->data = data;
 118
 119     adg_entity_set_local_mix((AdgEntity *) arrow, ADG_MIX_PARENT);
 120 }
 121
 122 static void
 123 _adg_get_property(GObject *object, guint prop_id,
 124                   GValue *value, GParamSpec *pspec)
 125 {
 126     AdgArrowPrivate *data = ((AdgArrow *) object)->data;
 127
 128     switch (prop_id) {
 129     case PROP_ANGLE:
 130         g_value_set_double(value, data->angle);
 131         break;
 132     default:
 133         G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
 134         break;
 135     }
 136 }
 137
 138 static void
 139 _adg_set_property(GObject *object, guint prop_id,
 140                   const GValue *value, GParamSpec *pspec)
 141 {
 142     AdgArrowPrivate *data = ((AdgArrow *) object)->data;
 143
 144     switch (prop_id) {
 145     case PROP_ANGLE:
 146         data->angle = cpml_angle(g_value_get_double(value));
 147         break;
 148     default:
 149         G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
 150         break;
 151     }
 152 }
 153
 154
 155 /**
 156  * adg_arrow_new:
 157  *
 158  * Creates a new undefined arrow entity. The position must be defined
 159  * by setting the #AdgMarker:trail and #AdgMarker:pos properties.
 160  *
 161  * Returns: the newly created arrow entity
 162  *
 163  * Since: 1.0
 164  **/
 165 AdgArrow *
 166 adg_arrow_new(void)
 167 {
 168     return g_object_new(ADG_TYPE_ARROW, NULL);
 169 }
 170
 171 /**
 172  * adg_arrow_new_with_trail:
 173  * @trail: the #AdgTrail where the arrow should be added
 174  * @pos: the position ratio on @trail
 175  *
 176  * Creates a new arrow on the first segment on @trail at position
 177  * @pos, where @pos is a ratio of the @trail length (being 0 the
 178  * start point, 1 the end point, 0.5 the middle point and so on).
 179  * By default, an arrow as #AdgEntity:local-mix set to #ADG_MIX_PARENT.
 180  *
 181  * Returns: the newly created arrow entity
 182  *
 183  * Since: 1.0
 184  **/
 185 AdgArrow *
 186 adg_arrow_new_with_trail(AdgTrail *trail, gdouble pos)
 187 {
 188     return g_object_new(ADG_TYPE_ARROW,
 189                         "local-mix", ADG_MIX_PARENT,
 190                         "trail", trail,
 191                         "n-segment", 1,
 192                         "pos", pos,
 193                         NULL);
 194 }
 195
 196 /**
 197  * adg_arrow_set_angle:
 198  * @arrow: an #AdgArrow
 199  * @angle: the new angle
 200  *
 201  * Sets a new angle: @angle will be the new opening angle of @arrow.
 202  * Changing the arrow angle will invalidate @arrow.
 203  *
 204  * Since: 1.0
 205  **/
 206 void
 207 adg_arrow_set_angle(AdgArrow *arrow, gdouble angle)
 208 {
 209     g_return_if_fail(ADG_IS_ARROW(arrow));
 210     g_object_set(arrow, "angle", angle, NULL);
 211 }
 212
 213 /**
 214  * adg_arrow_get_angle:
 215  * @arrow: an #AdgArrow
 216  *
 217  * Gets the current angle of @arrow.
 218  *
 219  * Returns: the arrow angle, in radians
 220  *
 221  * Since: 1.0
 222  **/
 223 gdouble
 224 adg_arrow_get_angle(AdgArrow *arrow)
 225 {
 226     AdgArrowPrivate *data;
 227
 228     g_return_val_if_fail(ADG_IS_ARROW(arrow), 0);
 229
 230     data = arrow->data;
 231
 232     return data->angle;
 233 }
 234
 235
 236 static void
 237 _adg_arrange(AdgEntity *entity)
 238 {
 239     AdgModel *model;
 240     const CpmlExtents *extents;
 241     CpmlExtents new_extents;
 242
 243     model = adg_marker_model((AdgMarker *) entity);
 244     if (model == NULL)
 245         return;
 246
 247     extents = adg_trail_get_extents((AdgTrail *) model);
 248     if (extents == NULL)
 249         return;
 250
 251     cpml_extents_copy(&new_extents, extents);
 252     cpml_extents_transform(&new_extents, adg_entity_get_local_matrix(entity));
 253     adg_entity_set_extents(entity, &new_extents);
 254 }
 255
 256 static void
 257 _adg_render(AdgEntity *entity, cairo_t *cr)
 258 {
 259     AdgModel *model;
 260     const cairo_path_t *cairo_path;
 261
 262     model = adg_marker_model((AdgMarker *) entity);
 263     if (model == NULL)
 264         return;
 265
 266     cairo_path = adg_trail_get_cairo_path((AdgTrail *) model);
 267
 268     if (cairo_path != NULL) {
 269         cairo_save(cr);
 270         cairo_transform(cr, adg_entity_get_global_matrix(entity));
 271         cairo_transform(cr, adg_entity_get_local_matrix(entity));
 272         cairo_append_path(cr, cairo_path);
 273         cairo_restore(cr);
 274
 275         cairo_fill(cr);
 276     }
 277 }
 278
 279 static AdgModel *
 280 _adg_create_model(AdgMarker *marker)
 281 {
 282     AdgArrowPrivate *data;
 283     AdgPath *path;
 284     CpmlPair p1, p2;
 285
 286     data = ((AdgArrow *) marker)->data;
 287     path = adg_path_new();
 288     cpml_vector_from_angle(&p1, data->angle / 2);
 289     p2.x = p1.x;
 290     p2.y = -p1.y;
 291
 292     adg_path_move_to_explicit(path, 0, 0);
 293     adg_path_line_to(path, &p1);
 294     adg_path_line_to(path, &p2);
 295     adg_path_close(path);
 296
 297     return (AdgModel *) path;
 298 }