1 /* ADG - Automatic Drawing Generation
2 * Copyright (C) 2007,2008,2009 Nicola Fontana <ntd at entidi.it>
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.
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.
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.
23 * @short_description: A bare model built around #CpmlPath
25 * The #AdgTrail model is a really basic model built around the #CpmlPath
26 * struct: for a full fledged path model consider using #AdgPath.
28 * A trail is a path model that demands all the implementation details to
29 * the caller: this requires a deep knowledge of the ADG details but
30 * provides a great customization level. It should be used when an
31 * #AdgPath is not enough, such as when a model is subject to change
32 * dynamically and the global and local maps do not suffice to express
33 * this alteration. A typical example is the path used to draw extension
34 * lines and base line of #AdgLDim: every point is subject to different
35 * constrains not expressible with a single affine transformation.
41 * All fields are private and should not be used directly.
42 * Use its public methods instead.
47 * @trail: an #AdgTrail
48 * @user_data: the general purpose pointer set by adg_trail_new()
50 * This is the callback used to generate the #CpmlPath and it is
51 * called directly by adg_trail_get_cpml_path(). The caller owns
52 * the returned path, that is the finalization of the returned
53 * #CpmlPath should be made by the caller when appropriate.
55 * Returns: the #CpmlPath of this trail model
59 #include "adg-trail.h"
60 #include "adg-trail-private.h"
62 #define PARENT_OBJECT_CLASS ((GObjectClass *) adg_trail_parent_class)
63 #define PARENT_MODEL_CLASS ((AdgModelClass *) adg_trail_parent_class)
66 static void finalize (GObject
*object
);
67 static void clear (AdgModel
*model
);
68 static CpmlPath
* get_cpml_path (AdgTrail
*trail
);
69 static GArray
* arc_to_curves (GArray
*array
,
70 const cairo_path_data_t
74 G_DEFINE_TYPE(AdgTrail
, adg_trail
, ADG_TYPE_MODEL
);
78 adg_trail_class_init(AdgTrailClass
*klass
)
80 GObjectClass
*gobject_class
;
81 AdgModelClass
*model_class
;
83 gobject_class
= (GObjectClass
*) klass
;
84 model_class
= (AdgModelClass
*) klass
;
86 g_type_class_add_private(klass
, sizeof(AdgTrailPrivate
));
88 gobject_class
->finalize
= finalize
;
90 model_class
->clear
= clear
;
92 klass
->get_cpml_path
= get_cpml_path
;
96 adg_trail_init(AdgTrail
*trail
)
98 AdgTrailPrivate
*data
= G_TYPE_INSTANCE_GET_PRIVATE(trail
, ADG_TYPE_TRAIL
,
101 data
->cairo_path
.status
= CAIRO_STATUS_INVALID_PATH_DATA
;
102 data
->cairo_path
.data
= NULL
;
103 data
->cairo_path
.num_data
= 0;
105 data
->callback
= NULL
;
106 data
->user_data
= NULL
;
112 finalize(GObject
*object
)
114 clear((AdgModel
*) object
);
116 if (PARENT_OBJECT_CLASS
->finalize
!= NULL
)
117 PARENT_OBJECT_CLASS
->finalize(object
);
123 * @callback: the #CpmlPath constructor function
124 * @user_data: generic pointer to pass to the callback
126 * Creates a new trail model. The #CpmlPath must be constructed by the
127 * @callback function: #AdgTrail will not cache anything, so you should
128 * implement any caching mechanism in the callback, if needed.
130 * Returns: a new trail model
133 adg_trail_new(AdgTrailCallback callback
, gpointer user_data
)
136 AdgTrailPrivate
*data
;
138 trail
= g_object_new(ADG_TYPE_TRAIL
, NULL
);
141 data
->callback
= callback
;
142 data
->user_data
= user_data
;
149 * adg_trail_get_cairo_path:
150 * @trail: an #AdgTrail
152 * Gets a pointer to the cairo path of @trail. The return path is
153 * owned by @trail and must be considered read-only.
155 * This function gets the #CpmlPath of @trail by calling
156 * adg_trail_get_cpml_path() and converts its %CAIRO_PATH_ARC_TO
157 * primitives, not recognized by cairo, into approximated Bézier
158 * curves primitives (%CAIRO_PATH_CURVE_TO). The conversion is
159 * cached, so any furter request is O(1). This cache is cleared
160 * only by the adg_model_clear() method.
163 * <title>TODO</title>
165 * <listitem>Actually, the arcs are approximated to Bézier using the
166 * hardcoded max angle of PI/2. This should be customizable
167 * by adding, for instance, a property to the #AdgTrail class
168 * with a default value of PI/2.</listitem>
172 * Returns: a pointer to the internal cairo path or %NULL on errors
175 adg_trail_get_cairo_path(AdgTrail
*trail
)
177 AdgTrailPrivate
*data
;
178 cairo_path_t
*cairo_path
;
181 const cairo_path_data_t
*p_src
;
184 g_return_val_if_fail(ADG_IS_TRAIL(trail
), NULL
);
187 cairo_path
= &data
->cairo_path
;
189 /* Check for cached result */
190 if (cairo_path
->data
!= NULL
)
193 src
= adg_trail_get_cpml_path(trail
);
194 dst
= g_array_sized_new(FALSE
, FALSE
,
195 sizeof(cairo_path_data_t
), src
->num_data
);
197 /* Cycle the CpmlPath and convert arcs to Bézier curves */
198 for (i
= 0; i
< src
->num_data
; i
+= p_src
->header
.length
) {
199 p_src
= (const cairo_path_data_t
*) src
->data
+ i
;
201 if (p_src
->header
.type
== CAIRO_PATH_ARC_TO
)
202 dst
= arc_to_curves(dst
, p_src
);
204 dst
= g_array_append_vals(dst
, p_src
, p_src
->header
.length
);
207 cairo_path
->status
= CAIRO_STATUS_SUCCESS
;
208 cairo_path
->num_data
= dst
->len
;
209 cairo_path
->data
= (cairo_path_data_t
*) g_array_free(dst
, FALSE
);
215 * adg_trail_get_cpml_path:
216 * @trail: an #AdgTrail
218 * Gets the CPML path structure defined by @trail. The returned
219 * value is managed by the #AdgTrail implementation, that is this
220 * method simply calls the #AdgTrailClass::get_cpml_path() virtual
221 * function that any trail instance must implement.
223 * Whenever used internally by the ADG project, the returned path
224 * is (by convention) owned by @trail and so it should not be freed.
225 * Anyway, it is allowed to modify it as long as its size is
226 * retained and its data contains a valid path: this is needed to
227 * let the #AdgMarker infrastructure work properly (the markers
228 * should be able to modify the trail where they are applied).
230 * Any further call to this method will probably make the pointer
231 * previously returned useless because the #CpmlPath could be
232 * relocated and the old #CpmlPath will likely contain rubbish.
234 * Returns: a pointer to the #CpmlPath or %NULL on errors
237 adg_trail_get_cpml_path(AdgTrail
*trail
)
239 g_return_val_if_fail(ADG_IS_TRAIL(trail
), NULL
);
241 return ADG_TRAIL_GET_CLASS(trail
)->get_cpml_path(trail
);
245 * adg_trail_get_segment:
246 * @trail: an #AdgTrail
247 * @segment: the destination #AdgSegment
248 * @n: the segment number to retrieve, where %1 is the first segment
250 * Convenient function to get a segment from @trail. The segment is
251 * got from the CPML path: check out adg_trail_get_cpml_path() for
252 * further information.
254 * Returns: %TRUE on success or %FALSE on errors
257 adg_trail_get_segment(AdgTrail
*trail
, AdgSegment
*segment
, guint n
)
262 g_return_val_if_fail(ADG_IS_TRAIL(trail
), FALSE
);
263 g_return_val_if_fail(segment
!= NULL
, FALSE
);
266 g_warning("%s: requested undefined segment for type `%s'",
267 G_STRLOC
, g_type_name(G_OBJECT_TYPE(trail
)));
271 cpml_path
= adg_trail_get_cpml_path(trail
);
273 cpml_segment_from_cairo(segment
, cpml_path
);
274 for (cnt
= 1; cnt
< n
; ++cnt
)
275 if (!cpml_segment_next(segment
)) {
276 g_warning("%s: segment `%u' out of range for type `%s'",
277 G_STRLOC
, n
, g_type_name(G_OBJECT_TYPE(trail
)));
286 * @trail: an #AdgTrail
288 * Gets the extents of @trail. The returned pointer is owned by
289 * @trail and should not be freed nor modified.
291 * Returns: the requested extents or %NULL on errors
294 adg_trail_extents(AdgTrail
*trail
)
296 AdgTrailPrivate
*data
;
298 g_return_val_if_fail(ADG_IS_TRAIL(trail
), NULL
);
302 if (!data
->extents
.is_defined
) {
307 cpml_path
= adg_trail_get_cpml_path(trail
);
309 if (cpml_segment_from_cairo(&segment
, cpml_path
))
311 cpml_segment_extents(&segment
, &extents
);
312 cpml_extents_add(&data
->extents
, &extents
);
313 } while (cpml_segment_next(&segment
));
316 return &data
->extents
;
321 * @trail: an #AdgTrail
323 * Dumps the data content of @trail to stdout in a human readable format.
326 adg_trail_dump(AdgTrail
*trail
)
329 cairo_path_t
*cairo_path
;
331 g_return_if_fail(ADG_IS_TRAIL(trail
));
333 cairo_path
= (cairo_path_t
*) adg_trail_get_cairo_path(trail
);
335 g_return_if_fail(cairo_path
!= NULL
);
337 if (!cpml_segment_from_cairo(&segment
, cairo_path
)) {
338 g_warning("Invalid path data to dump!\n");
341 cpml_segment_dump(&segment
);
342 } while (cpml_segment_next(&segment
));
348 clear(AdgModel
*model
)
350 AdgTrailPrivate
*data
= ((AdgTrail
*) model
)->data
;
352 g_free(data
->cairo_path
.data
);
354 data
->cairo_path
.status
= CAIRO_STATUS_INVALID_PATH_DATA
;
355 data
->cairo_path
.data
= NULL
;
356 data
->cairo_path
.num_data
= 0;
358 if (PARENT_MODEL_CLASS
->clear
!= NULL
)
359 PARENT_MODEL_CLASS
->clear(model
);
363 get_cpml_path(AdgTrail
*trail
)
365 AdgTrailPrivate
*data
= trail
->data
;
367 if (data
->callback
== NULL
) {
368 g_warning("%s: callback not defined for instance of type `%s'",
369 G_STRLOC
, g_type_name(G_OBJECT_TYPE(trail
)));
373 return data
->callback(trail
, data
->user_data
);
377 arc_to_curves(GArray
*array
, const cairo_path_data_t
*src
)
382 /* Build the arc primitive: the arc origin is supposed to be the previous
383 * point (src-1): this means a primitive must exist before the arc */
385 arc
.org
= (cairo_path_data_t
*) (src
-1);
386 arc
.data
= (cairo_path_data_t
*) src
;
388 if (cpml_arc_info(&arc
, NULL
, NULL
, &start
, &end
)) {
391 cairo_path_data_t
*curves
;
393 n_curves
= ceil(fabs(end
-start
) / M_PI_2
);
394 curves
= g_new(cairo_path_data_t
, n_curves
* 4);
395 segment
.data
= curves
;
396 cpml_arc_to_curves(&arc
, &segment
, n_curves
);
398 array
= g_array_append_vals(array
, curves
, n_curves
* 4);