adg/adg-toy-text.c

   1 /* ADG - Automatic Drawing Generation
   2  * Copyright (C) 2007-2008, 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  * SECTION:toytext
  22  * @title: AdgToyText
  23  * @short_description: Simple text entity that use the cairo "toy" text API
  24  *
  25  * The #AdgToyText class is a basic class to show simple text. It internally
  26  * uses the so called cairo "toy" API and it shares the same limitations.
  27  **/
  28
  29 #include "adg-toy-text.h"
  30 #include "adg-toy-text-private.h"
  31 #include "adg-positionable.h"
  32 #include "adg-font-style.h"
  33 #include "adg-intl.h"
  34
  35 #define PARENT_CLASS ((AdgEntityClass *) adg_toy_text_parent_class)
  36
  37
  38 enum {
  39     PROP_0,
  40     PROP_ORG,
  41     PROP_LABEL
  42 };
  43
  44 static void     positionable_init       (AdgPositionableIface *iface);
  45 static AdgPoint*org                     (AdgPositionable*positionable);
  46
  47 static void     finalize                (GObject        *object);
  48 static void     get_property            (GObject        *object,
  49                                          guint           param_id,
  50                                          GValue         *value,
  51                                          GParamSpec     *pspec);
  52 static void     set_property            (GObject        *object,
  53                                          guint           param_id,
  54                                          const GValue   *value,
  55                                          GParamSpec     *pspec);
  56 static void     model_matrix_changed    (AdgEntity      *entity,
  57                                          AdgMatrix      *parent_matrix);
  58 static void     invalidate              (AdgEntity      *entity);
  59 static void     render                  (AdgEntity      *entity,
  60                                          cairo_t        *cr);
  61 static gboolean update_org_cache        (AdgToyText     *toy_text);
  62 static gboolean update_label_cache      (AdgToyText     *toy_text,
  63                                          cairo_t        *cr);
  64 static void     clear_label_cache       (AdgToyText     *toy_text);
  65 static void     move_label_cache        (AdgToyText     *toy_text,
  66                                          const AdgPair  *to);
  67
  68
  69 G_DEFINE_TYPE_WITH_CODE(AdgToyText, adg_toy_text, ADG_TYPE_ENTITY,
  70                         G_IMPLEMENT_INTERFACE(ADG_TYPE_POSITIONABLE,
  71                                               positionable_init))
  72
  73
  74 static void
  75 adg_toy_text_class_init(AdgToyTextClass *klass)
  76 {
  77     GObjectClass *gobject_class;
  78     AdgEntityClass *entity_class;
  79     GParamSpec *param;
  80
  81     gobject_class = (GObjectClass *) klass;
  82     entity_class = (AdgEntityClass *) klass;
  83
  84     g_type_class_add_private(klass, sizeof(AdgToyTextPrivate));
  85
  86     gobject_class->finalize = finalize;
  87     gobject_class->get_property = get_property;
  88     gobject_class->set_property = set_property;
  89
  90     entity_class->model_matrix_changed = model_matrix_changed;
  91     entity_class->invalidate = invalidate;
  92     entity_class->render = render;
  93
  94     g_object_class_override_property(gobject_class, PROP_ORG, "org");
  95
  96     param = g_param_spec_string("label",
  97                                 P_("Label"),
  98                                 P_("The label to display"),
  99                                 NULL, G_PARAM_READWRITE);
 100     g_object_class_install_property(gobject_class, PROP_LABEL, param);
 101 }
 102
 103 static void
 104 adg_toy_text_init(AdgToyText *toy_text)
 105 {
 106     AdgToyTextPrivate *priv = G_TYPE_INSTANCE_GET_PRIVATE(toy_text,
 107                                                           ADG_TYPE_TOY_TEXT,
 108                                                           AdgToyTextPrivate);
 109
 110     priv->label = NULL;
 111     adg_point_unset(&priv->org);
 112     priv->org_pair.x = priv->org_pair.y = 0.;
 113     priv->num_glyphs = 0;
 114     priv->glyphs = NULL;
 115
 116     toy_text->priv = priv;
 117 }
 118
 119 static void
 120 positionable_init(AdgPositionableIface *iface)
 121 {
 122     iface->org = org;
 123 }
 124
 125 static AdgPoint *
 126 org(AdgPositionable *positionable)
 127 {
 128     return & ((AdgToyText *) positionable)->priv->org;
 129 }
 130
 131 static void
 132 finalize(GObject *object)
 133 {
 134     AdgToyText *toy_text = (AdgToyText *) object;
 135
 136     g_free(toy_text->priv->label);
 137     clear_label_cache(toy_text);
 138
 139     ((GObjectClass *) PARENT_CLASS)->finalize(object);
 140 }
 141
 142 static void
 143 get_property(GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
 144 {
 145     AdgToyText *toy_text = (AdgToyText *) toy_text;
 146
 147     switch (prop_id) {
 148     case PROP_ORG:
 149         g_value_set_boxed(value, &toy_text->priv->org);
 150         break;
 151     case PROP_LABEL:
 152         g_value_set_string(value, toy_text->priv->label);
 153         break;
 154     default:
 155         G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
 156         break;
 157     }
 158 }
 159
 160 static void
 161 set_property(GObject *object, guint prop_id,
 162              const GValue *value, GParamSpec *pspec)
 163 {
 164     AdgToyText *toy_text = (AdgToyText *) object;
 165     AdgToyTextPrivate *priv = toy_text->priv;
 166
 167     switch (prop_id) {
 168     case PROP_ORG:
 169         adg_point_copy(&priv->org, (AdgPoint *) g_value_get_boxed(value));
 170         update_org_cache(toy_text);
 171         break;
 172     case PROP_LABEL:
 173         g_free(priv->label);
 174         priv->label = g_value_dup_string(value);
 175         clear_label_cache(toy_text);
 176         break;
 177     default:
 178         G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
 179         break;
 180     }
 181 }
 182
 183
 184 /**
 185  * adg_toy_text_new:
 186  * @label: the label text
 187  *
 188  * Creates a new toy text entity using @label as its text
 189  *
 190  * Return value: the new entity
 191  */
 192 AdgEntity *
 193 adg_toy_text_new(const gchar *label)
 194 {
 195     return (AdgEntity *) g_object_new(ADG_TYPE_TOY_TEXT, "label", label, NULL);
 196 }
 197
 198 /**
 199  * adg_toy_text_get_label:
 200  * @toy_text: an #AdgToyText
 201  *
 202  * Gets the label text. The string is internally owned and
 203  * must not be freed or modified.
 204  *
 205  * Return value: the label text
 206  **/
 207 const gchar *
 208 adg_toy_text_get_label(AdgToyText *toy_text)
 209 {
 210     g_return_val_if_fail(ADG_IS_TOY_TEXT(toy_text), NULL);
 211
 212     return toy_text->priv->label;
 213 }
 214
 215 /**
 216  * adg_toy_text_set_label:
 217  * @toy_text: an #AdgToyText
 218  * @label: the label text
 219  *
 220  * Explicitely sets the text to use as label.
 221  **/
 222 void
 223 adg_toy_text_set_label(AdgToyText *toy_text, const gchar *label)
 224 {
 225     g_return_if_fail(ADG_IS_TOY_TEXT(label));
 226
 227     g_free(toy_text->priv->label);
 228     toy_text->priv->label = g_strdup(label);
 229     g_object_notify((GObject *) toy_text, "label");
 230
 231     clear_label_cache(toy_text);
 232 }
 233
 234
 235 static void
 236 render(AdgEntity *entity, cairo_t *cr)
 237 {
 238     AdgToyText *toy_text = (AdgToyText *) entity;
 239     AdgToyTextPrivate *priv = toy_text->priv;
 240
 241     if (priv->label) {
 242         AdgStyle *font_style = adg_entity_get_style(entity, ADG_SLOT_FONT_STYLE);
 243         cairo_set_matrix(cr, adg_entity_get_paper_matrix(entity));
 244         adg_style_apply(font_style, cr);
 245
 246         if (!priv->glyphs) {
 247             update_label_cache(toy_text, cr);
 248             update_org_cache(toy_text);
 249         }
 250
 251         cairo_show_glyphs(cr, priv->glyphs, priv->num_glyphs);
 252     }
 253
 254     PARENT_CLASS->render(entity, cr);
 255 }
 256
 257 static void
 258 model_matrix_changed(AdgEntity *entity, AdgMatrix *parent_matrix)
 259 {
 260     update_org_cache((AdgToyText *) entity);
 261     PARENT_CLASS->model_matrix_changed(entity, parent_matrix);
 262 }
 263
 264 static void
 265 invalidate(AdgEntity *entity)
 266 {
 267     clear_label_cache((AdgToyText *) entity);
 268     PARENT_CLASS->invalidate(entity);
 269 }
 270
 271 static gboolean
 272 update_org_cache(AdgToyText *toy_text)
 273 {
 274     AdgToyTextPrivate *priv = toy_text->priv;
 275     AdgPoint *org = &toy_text->priv->org;
 276     AdgPair *org_pair = &toy_text->priv->org_pair;
 277     cairo_glyph_t *glyph;
 278     double x, y;
 279     int cnt;
 280
 281     org = &priv->org;
 282     org_pair = &priv->org_pair;
 283     glyph = priv->glyphs;
 284     cnt = priv->num_glyphs;
 285
 286     if (glyph == NULL || cnt <= 0) {
 287         /* No label cache to update: return */
 288         return TRUE;
 289     }
 290
 291     adg_entity_point_to_paper_pair((AdgEntity *) toy_text, org, org_pair);
 292     if (org_pair->x == glyph->x && org_pair->y == glyph->y) {
 293         /* The label is yet properly positioned */
 294         return TRUE;
 295     }
 296
 297     x = org_pair->x - glyph->x;
 298     y = org_pair->y - glyph->y;
 299
 300     while (cnt --) {
 301         glyph->x += x;
 302         glyph->y += y;
 303         ++ glyph;
 304     }
 305 }
 306
 307 static gboolean
 308 update_label_cache(AdgToyText *toy_text, cairo_t *cr)
 309 {
 310     AdgToyTextPrivate *priv = toy_text->priv;
 311     cairo_status_t status;
 312
 313     status = cairo_scaled_font_text_to_glyphs(cairo_get_scaled_font(cr),
 314                                               0., 0., priv->label, -1,
 315                                               &priv->glyphs,
 316                                               &priv->num_glyphs,
 317                                               NULL, NULL, NULL);
 318
 319     if (status != CAIRO_STATUS_SUCCESS) {
 320         g_error("Unable to build glyphs (cairo message: %s)",
 321                 cairo_status_to_string(status));
 322         return FALSE;
 323     }
 324
 325     cairo_glyph_extents(cr, priv->glyphs, priv->num_glyphs, &priv->extents);
 326
 327     return TRUE;
 328 }
 329
 330 static void
 331 clear_label_cache(AdgToyText *toy_text)
 332 {
 333     AdgToyTextPrivate *priv = toy_text->priv;
 334
 335     if (priv->glyphs) {
 336         cairo_glyph_free(priv->glyphs);
 337         priv->glyphs = NULL;
 338     }
 339     priv->num_glyphs = 0;
 340     memset(&priv->extents, 0, sizeof(priv->extents));
 341 }