adg/adg-dress.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-dress
  23  * @Section_Id:AdgDress
  24  * @title: AdgDress
  25  * @short_description: The ADG way to associate styles to entities
  26  *
  27  * The dress is a virtualization of an #AdgStyle instance. #AdgEntity
  28  * objects do not directly refer to #AdgStyle but use #AdgDress values
  29  * instead. This allows some advanced operations, such as overriding
  30  * a dress only in a specific entity branch of the hierarchy or
  31  * customize multiple entities at once.
  32  **/
  33
  34 /**
  35  * AdgDress:
  36  *
  37  * An index representing a virtual #AdgStyle.
  38  **/
  39
  40 /**
  41  * ADG_TYPE_DRESS:
  42  *
  43  * The type used to express a dress index. It is defined only for GObject
  44  * internal and should not be used directly (at least, as far as I know).
  45  **/
  46
  47 /**
  48  * ADG_VALUE_HOLDS_DRESS:
  49  * @value: a #GValue
  50  *
  51  * Checks whether a #GValue is actually holding an #AdgDress value or not.
  52  *
  53  * Returns: %TRUE is @value is holding an #AdgDress, %FALSE otherwise
  54  **/
  55
  56
  57 #include "adg-dress.h"
  58 #include "adg-dress-private.h"
  59 #include "adg-dress-builtins.h"
  60
  61
  62 static AdgDress         quark_to_dress          (GQuark          quark);
  63 static void             dress_to_string         (const GValue   *src,
  64                                                  GValue         *dst);
  65 static void             string_to_dress         (const GValue   *src,
  66                                                  GValue         *dst);
  67 static void             param_class_init        (GParamSpecClass*klass);
  68 static gboolean         value_validate          (GParamSpec     *spec,
  69                                                  GValue         *value);
  70
  71 static guint            array_append            (AdgDressPrivate*data);
  72 static AdgDressPrivate *array_lookup            (guint           n);
  73 static guint            array_len               (void);
  74
  75
  76 GType
  77 adg_dress_get_type(void)
  78 {
  79     static GType type = 0;
  80
  81     if (G_UNLIKELY(type == 0)) {
  82         const GTypeInfo info = { 0, };
  83
  84         type = g_type_register_static(G_TYPE_INT, "AdgDress", &info, 0);
  85
  86         g_value_register_transform_func(type, G_TYPE_STRING, dress_to_string);
  87         g_value_register_transform_func(G_TYPE_STRING, type, string_to_dress);
  88     }
  89
  90     return type;
  91 }
  92
  93 /**
  94  * adg_dress_new:
  95  * @name: the dress name
  96  * @fallback: the fallback style
  97  *
  98  * Creates a new dress. It is a convenient wrapper of adg_dress_new_full()
  99  * that uses as ancestor the G_TYPE_FROM_INSTANCE() of @fallback.
 100  *
 101  * After a succesfull call, a new reference is added to @fallback.
 102  *
 103  * Returns: the new #AdgDress value or #ADG_DRESS_UNDEFINED on errors
 104  **/
 105 AdgDress
 106 adg_dress_new(const gchar *name, AdgStyle *fallback)
 107 {
 108     g_return_val_if_fail(ADG_IS_STYLE(fallback), ADG_DRESS_UNDEFINED);
 109
 110     return adg_dress_new_full(name, fallback, G_TYPE_FROM_INSTANCE(fallback));
 111 }
 112
 113 /**
 114  * adg_dress_new_full:
 115  * @name: the dress name
 116  * @fallback: the fallback style
 117  * @ancestor_type: the common ancestor type
 118  *
 119  * Creates a new dress, explicitely setting the ancestor type.
 120  * If @fallback is not %NULL, @ancestor_type must be present in
 121  * its hierarchy: check out the adg_dress_style_is_compatible()
 122  * documentation to know what the ancestor type is used for.
 123  *
 124  * @fallback can be %NULL, in which case a "transparent" dress
 125  * is created. This kind of dress does not change the cairo
 126  * context because there is no style to apply. Any entity could
 127  * override it to change this behavior though.
 128  *
 129  * After a succesfull call, a new reference is added to @fallback
 130  * if needed.
 131  *
 132  * Returns: the new #AdgDress value or #ADG_DRESS_UNDEFINED on errors
 133  **/
 134 AdgDress
 135 adg_dress_new_full(const gchar *name, AdgStyle *fallback, GType ancestor_type)
 136 {
 137     GQuark quark;
 138     AdgDress dress;
 139     AdgDressPrivate data;
 140
 141     g_return_val_if_fail(name != NULL, ADG_DRESS_UNDEFINED);
 142     g_return_val_if_fail(g_type_is_a(ancestor_type, ADG_TYPE_STYLE),
 143                          ADG_DRESS_UNDEFINED);
 144     g_return_val_if_fail(fallback == NULL ||
 145                          G_TYPE_CHECK_INSTANCE_TYPE(fallback, ancestor_type),
 146                          ADG_DRESS_UNDEFINED);
 147
 148     quark = g_quark_from_string(name);
 149     dress = quark_to_dress(quark);
 150
 151     if (dress > 0) {
 152         g_warning("%s: `%s' name yet used by the `%d' dress",
 153                   G_STRLOC, name, dress);
 154         return ADG_DRESS_UNDEFINED;
 155     }
 156
 157     data.quark = quark;
 158     data.fallback = fallback;
 159     data.ancestor_type = ancestor_type;
 160
 161     if (fallback != NULL)
 162         g_object_ref(fallback);
 163
 164     return array_append(&data) - 1;
 165 }
 166
 167 /**
 168  * adg_dress_are_related:
 169  * @dress1: an #AdgDress
 170  * @dress2: another #AdgDress
 171  *
 172  * Checks whether @dress1 and @dress2 are related, that is
 173  * if they have the same ancestor type as returned by
 174  * adg_dress_get_ancestor_type().
 175  *
 176  * Returns: %TRUE if the dresses are related, %FALSE otherwise
 177  **/
 178 gboolean
 179 adg_dress_are_related(AdgDress dress1, AdgDress dress2)
 180 {
 181     GType ancestor_type1, ancestor_type2;
 182
 183     ancestor_type1 = adg_dress_get_ancestor_type(dress1);
 184     if (ancestor_type1 <= 0)
 185         return FALSE;
 186
 187     ancestor_type2 = adg_dress_get_ancestor_type(dress2);
 188     if (ancestor_type2 <= 0)
 189         return FALSE;
 190
 191     return ancestor_type1 == ancestor_type2;
 192 }
 193
 194 /**
 195  * adg_dress_set:
 196  * @dress: a pointer to an #AdgDress
 197  * @src: the source dress
 198  *
 199  * Copies @src in @dress. This operation can be succesful only if
 200  * @dress is #ADG_DRESS_UNDEFINED or if it contains a dress related
 201  * to @src, that is adg_dress_are_related() returns %TRUE.
 202  *
 203  * Returns: %TRUE on copy done, %FALSE on copy failed or not needed
 204  **/
 205 gboolean
 206 adg_dress_set(AdgDress *dress, AdgDress src)
 207 {
 208     if (*dress == src)
 209         return FALSE;
 210
 211     if (*dress != ADG_DRESS_UNDEFINED &&
 212         !adg_dress_are_related(*dress, src)) {
 213         const gchar *dress_name;
 214         const gchar *src_name;
 215
 216         dress_name = adg_dress_name(*dress);
 217         if (dress_name == NULL)
 218             dress_name = "UNDEFINED";
 219
 220         src_name = adg_dress_name(src);
 221         if (src_name == NULL)
 222             src_name = "UNDEFINED";
 223
 224         g_warning("%s: `%d' (%s) and `%d' (%s) dresses are not related",
 225                   G_STRLOC, *dress, dress_name, src, src_name);
 226
 227         return FALSE;
 228     }
 229
 230     *dress = src;
 231
 232     return TRUE;
 233 }
 234
 235 /**
 236  * adg_dress_name:
 237  * @dress: an #AdgDress
 238  *
 239  * Gets the name associated to @dress. No warnings are raised if
 240  * @dress is not found.
 241  *
 242  * Returns: the requested name or %NULL if not found
 243  **/
 244 const gchar *
 245 adg_dress_name(AdgDress dress)
 246 {
 247     if (dress <= 0 || dress >= array_len())
 248         return NULL;
 249
 250     return g_quark_to_string(array_lookup(dress)->quark);
 251 }
 252
 253 /**
 254  * adg_dress_from_name:
 255  * @name: the name of a dress
 256  *
 257  * Gets the dress bound to a @name string. No warnings are raised
 258  * if the dress is not found.
 259  *
 260  * Returns: the #AdgDress code or #ADG_DRESS_UNDEFINED if not found
 261  **/
 262 AdgDress
 263 adg_dress_from_name(const gchar *name)
 264 {
 265     return quark_to_dress(g_quark_try_string(name));
 266 }
 267
 268 /**
 269  * adg_dress_get_ancestor_type:
 270  * @dress: an #AdgDress
 271  *
 272  * Gets the base type that should be present in every #AdgStyle
 273  * acceptable by @dress.
 274  *
 275  * Returns: the ancestor type
 276  **/
 277 GType
 278 adg_dress_get_ancestor_type(AdgDress dress)
 279 {
 280     AdgDressPrivate *data;
 281
 282     if (dress <= 0 || dress >= array_len())
 283         return 0;
 284
 285     data = array_lookup(dress);
 286
 287     return data->ancestor_type;
 288 }
 289
 290 /**
 291  * adg_dress_get_fallback:
 292  * @dress: an #AdgDress
 293  *
 294  * Gets the fallback style associated to @dress. No warnings
 295  * are raised if the dress is not found.
 296  *
 297  * Returns: the requested #AdgStyle derived instance or %NULL if not set
 298  **/
 299 AdgStyle *
 300 adg_dress_get_fallback(AdgDress dress)
 301 {
 302     AdgDressPrivate *data;
 303
 304     if (dress <= 0 || dress >= array_len())
 305         return NULL;
 306
 307     data = array_lookup(dress);
 308
 309     return data->fallback;
 310 }
 311
 312 /**
 313  * adg_dress_set_fallback:
 314  * @dress: an #AdgDress
 315  * @fallback: the new fallback style
 316  *
 317  * Associates a new @fallback style to @dress. If the dress does
 318  * not exist (it was not previously created by adg_dress_new()),
 319  * a warning message is raised and the function fails.
 320  *
 321  * @fallback is checked for compatibily with @dress. Any dress holds
 322  * an ancestor type: if this type is not found in the @fallback
 323  * hierarchy, a warning message is raised and the function fails.
 324  *
 325  * After a succesfull call, the reference to the previous fallback
 326  * (if any) is dropped while a new reference to @fallback is added.
 327  **/
 328 void
 329 adg_dress_set_fallback(AdgDress dress, AdgStyle *fallback)
 330 {
 331     AdgDressPrivate *data;
 332
 333     if (dress <= 0 || dress >= array_len()) {
 334         g_warning("%s: `%d' dress undefined", G_STRLOC, dress);
 335         return;
 336     }
 337
 338     data = array_lookup(dress);
 339
 340     if (data->fallback == fallback)
 341         return;
 342
 343     /* Check if the new fallback style is compatible with this dress */
 344     if (fallback != NULL && !adg_dress_style_is_compatible(dress, fallback)) {
 345         g_warning("%s: `%s' is not compatible with `%s' for `%s' dress",
 346                   G_STRLOC, g_type_name(G_TYPE_FROM_INSTANCE(fallback)),
 347                   g_type_name(data->ancestor_type), adg_dress_name(dress));
 348         return;
 349     }
 350
 351     if (data->fallback != NULL)
 352         g_object_unref(data->fallback);
 353
 354     data->fallback = fallback;
 355
 356     if (data->fallback != NULL)
 357         g_object_ref(data->fallback);
 358 }
 359
 360 /**
 361  * adg_dress_style_is_compatible:
 362  * @dress: an #AdgDress
 363  * @style: the #AdgStyle to check
 364  *
 365  * Checks whether @style is compatible with @dress, that is if
 366  * @style has the ancestor style type (as returned by
 367  * adg_dress_get_ancestor_type()) in its hierarchy.
 368  *
 369  * Returns: %TRUE if @dress can accept @style, %FALSE otherwise
 370  **/
 371 gboolean
 372 adg_dress_style_is_compatible(AdgDress dress, AdgStyle *style)
 373 {
 374     GType ancestor_type = adg_dress_get_ancestor_type(dress);
 375
 376     g_return_val_if_fail(ancestor_type > 0, FALSE);
 377     g_return_val_if_fail(ADG_IS_STYLE(style), FALSE);
 378
 379     return G_TYPE_CHECK_INSTANCE_TYPE(style, ancestor_type);
 380 }
 381
 382
 383 static AdgDress
 384 quark_to_dress(GQuark quark)
 385 {
 386     AdgDress dress;
 387     AdgDressPrivate *data;
 388
 389     for (dress = 0; dress < array_len(); ++dress) {
 390         data = array_lookup(dress);
 391
 392         if (data->quark == quark)
 393             return dress;
 394     }
 395
 396     return ADG_DRESS_UNDEFINED;
 397 }
 398
 399 static void
 400 dress_to_string(const GValue *src, GValue *dst)
 401 {
 402     g_value_set_string(dst, adg_dress_name(g_value_get_int(src)));
 403 }
 404
 405 static void
 406 string_to_dress(const GValue *src, GValue *dst)
 407 {
 408     g_value_set_int(dst, adg_dress_from_name(g_value_get_string(src)));
 409 }
 410
 411
 412 typedef struct _AdgParamSpecDress AdgParamSpecDress;
 413
 414 struct _AdgParamSpecDress {
 415     GParamSpecInt parent;
 416     AdgDress     source_dress;
 417 };
 418
 419
 420 GType
 421 _adg_param_spec_dress_get_type(void)
 422 {
 423     static GType type = 0;
 424
 425     if (G_UNLIKELY(type == 0)) {
 426         const GTypeInfo info = {
 427             sizeof(GParamSpecClass),
 428             NULL,
 429             NULL,
 430             (GClassInitFunc) param_class_init,
 431             NULL,
 432             NULL,
 433             sizeof(AdgParamSpecDress),
 434             0,
 435         };
 436
 437         type = g_type_register_static(G_TYPE_PARAM_INT,
 438                                       "AdgParamSpecDress", &info, 0);
 439     }
 440
 441     return type;
 442 }
 443
 444 static void
 445 param_class_init(GParamSpecClass *klass)
 446 {
 447     klass->value_type = ADG_TYPE_DRESS;
 448     klass->value_validate = value_validate;
 449 }
 450
 451 static gboolean
 452 value_validate(GParamSpec *spec, GValue *value)
 453 {
 454     AdgParamSpecDress *fspec;
 455     AdgDress dress, new_dress;
 456
 457     fspec = (AdgParamSpecDress *) spec;
 458     dress = value->data[0].v_int;
 459     new_dress = ADG_DRESS_UNDEFINED;
 460
 461     adg_dress_set(&new_dress, dress);
 462     value->data[0].v_int = new_dress;
 463
 464     return dress != new_dress;
 465 }
 466
 467
 468 /**
 469  * adg_param_spec_dress:
 470  * @name: canonical name
 471  * @nick: nickname of the param
 472  * @blurb: brief desciption
 473  * @dress: the #AdgDress dress
 474  * @flags: a combination of #GParamFlags
 475  *
 476  * Creates a param spec to hold a dress value.
 477  *
 478  * Returns: the newly allocated #GParamSpec
 479  **/
 480 GParamSpec *
 481 adg_param_spec_dress(const gchar *name, const gchar *nick, const gchar *blurb,
 482                      AdgDress dress, GParamFlags flags)
 483 {
 484     AdgParamSpecDress *fspec;
 485
 486     if (dress <= 0 || dress >= array_len()) {
 487         g_warning("%s: `%d' dress undefined", G_STRLOC, dress);
 488         return NULL;
 489     }
 490
 491     fspec = g_param_spec_internal(ADG_TYPE_PARAM_SPEC_DRESS,
 492                                   name, nick, blurb, flags);
 493     fspec->source_dress = dress;
 494
 495     return (GParamSpec *) fspec;
 496 }
 497
 498
 499 static GArray * array_singleton         (void) G_GNUC_CONST;
 500
 501 static GArray *
 502 array_singleton(void)
 503 {
 504     static GArray *array = NULL;
 505
 506     if (array == NULL) {
 507         const AdgDressPrivate data = { 0, };
 508
 509         array = g_array_new(FALSE, FALSE, sizeof(AdgDressPrivate));
 510
 511         /* Reserve the first item for the undefined dress */
 512         g_array_append_val(array, data);
 513     }
 514
 515     return array;
 516 }
 517
 518 static guint
 519 array_append(AdgDressPrivate *data)
 520 {
 521     return g_array_append_val(array_singleton(), *data)->len;
 522 }
 523
 524 static AdgDressPrivate *
 525 array_lookup(guint n)
 526 {
 527     return &g_array_index(array_singleton(), AdgDressPrivate, n);
 528 }
 529
 530 static guint
 531 array_len(void)
 532 {
 533     return array_singleton()->len;
 534 }