Pileus Git - ~andy/gtk/blob - gdk-pixbuf/gdk-pixbuf-loader.c

   1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
   2
   3 /* GdkPixbuf library - Main header file
   4  *
   5  * Copyright (C) 1999 The Free Software Foundation
   6  *
   7  * Authors: Mark Crichton <crichton@gimp.org>
   8  *          Miguel de Icaza <miguel@gnu.org>
   9  *          Federico Mena-Quintero <federico@gimp.org>
  10  *          Jonathan Blandford <jrb@redhat.com>
  11  *
  12  * This library is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU Library General Public
  14  * License as published by the Free Software Foundation; either
  15  * version 2 of the License, or (at your option) any later version.
  16  *
  17  * This library is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with this library; if not, write to the
  24  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  25  * Boston, MA 02111-1307, USA.
  26  */
  27
  28 #include "gdk-pixbuf/gdk-pixbuf-loader.h"
  29 #include "gdk-pixbuf/gdk-pixbuf-io.h"
  30 #include <gtk/gtksignal.h>
  31
  32 \f
  33
  34 enum {
  35         AREA_UPDATED,
  36         AREA_PREPARED,
  37         CLOSED,
  38         LAST_SIGNAL
  39 };
  40
  41 static GtkObjectClass *parent_class;
  42
  43 static void gdk_pixbuf_loader_class_init    (GdkPixbufLoaderClass   *klass);
  44 static void gdk_pixbuf_loader_init          (GdkPixbufLoader        *loader);
  45 static void gdk_pixbuf_loader_destroy       (GtkObject              *loader);
  46 static void gdk_pixbuf_loader_finalize      (GtkObject              *loader);
  47
  48 static guint pixbuf_loader_signals[LAST_SIGNAL] = { 0 };
  49
  50 \f
  51
  52 /* Internal data */
  53
  54 #define LOADER_HEADER_SIZE 128
  55
  56 typedef struct {
  57         GdkPixbuf *pixbuf;
  58         gboolean closed;
  59         gchar header_buf[LOADER_HEADER_SIZE];
  60         gint header_buf_offset;
  61         GdkPixbufModule *image_module;
  62         gpointer context;
  63 } GdkPixbufLoaderPrivate;
  64
  65 \f
  66
  67 /* our marshaller */
  68 typedef void (* GtkSignal_NONE__INT_INT_INT_INT) (GtkObject *object,
  69                                                   gint arg1, gint arg2, gint arg3, gint arg4,
  70                                                   gpointer user_data);
  71 static void
  72 gtk_marshal_NONE__INT_INT_INT_INT (GtkObject *object, GtkSignalFunc func, gpointer func_data,
  73                                    GtkArg * args)
  74 {
  75         GtkSignal_NONE__INT_INT_INT_INT rfunc;
  76
  77         rfunc = (GtkSignal_NONE__INT_INT_INT_INT) func;
  78         (*rfunc) (object,
  79                   GTK_VALUE_INT (args[0]),
  80                   GTK_VALUE_INT (args[1]),
  81                   GTK_VALUE_INT (args[2]),
  82                   GTK_VALUE_INT (args[3]),
  83                   func_data);
  84 }
  85
  86 \f
  87
  88 /**
  89  * gdk_pixbuf_loader_get_type:
  90  * @void:
  91  *
  92  * Registers the #GdkPixubfLoader class if necessary, and returns the type ID
  93  * associated to it.
  94  *
  95  * Return value: The type ID of the #GdkPixbufLoader class.
  96  **/
  97 GtkType
  98 gdk_pixbuf_loader_get_type (void)
  99 {
 100         static GtkType loader_type = 0;
 101
 102         if (!loader_type) {
 103                 static const GtkTypeInfo loader_info = {
 104                         "GdkPixbufLoader",
 105                         sizeof (GdkPixbufLoader),
 106                         sizeof (GdkPixbufLoaderClass),
 107                         (GtkClassInitFunc) gdk_pixbuf_loader_class_init,
 108                         (GtkObjectInitFunc) gdk_pixbuf_loader_init,
 109                         /* reserved_1 */ NULL,
 110                         /* reserved_2 */ NULL,
 111                         (GtkClassInitFunc) NULL,
 112                 };
 113
 114                 loader_type = gtk_type_unique (GTK_TYPE_OBJECT, &loader_info);
 115         }
 116
 117         return loader_type;
 118 }
 119
 120 static void
 121 gdk_pixbuf_loader_class_init (GdkPixbufLoaderClass *class)
 122 {
 123         GtkObjectClass *object_class;
 124
 125         object_class = (GtkObjectClass *) class;
 126
 127         parent_class = gtk_type_class (gtk_object_get_type ());
 128
 129         pixbuf_loader_signals[AREA_PREPARED] =
 130                 gtk_signal_new ("area_prepared",
 131                                 GTK_RUN_LAST,
 132                                 parent_class->type,
 133                                 GTK_SIGNAL_OFFSET (GdkPixbufLoaderClass, area_prepared),
 134                                 gtk_marshal_NONE__NONE,
 135                                 GTK_TYPE_NONE, 0);
 136
 137         pixbuf_loader_signals[AREA_UPDATED] =
 138                 gtk_signal_new ("area_updated",
 139                                 GTK_RUN_LAST,
 140                                 parent_class->type,
 141                                 GTK_SIGNAL_OFFSET (GdkPixbufLoaderClass, area_updated),
 142                                 gtk_marshal_NONE__INT_INT_INT_INT,
 143                                 GTK_TYPE_NONE, 4,
 144                                 GTK_TYPE_INT,
 145                                 GTK_TYPE_INT,
 146                                 GTK_TYPE_INT,
 147                                 GTK_TYPE_INT);
 148
 149         pixbuf_loader_signals[CLOSED] =
 150                 gtk_signal_new ("closed",
 151                                 GTK_RUN_LAST,
 152                                 parent_class->type,
 153                                 GTK_SIGNAL_OFFSET (GdkPixbufLoaderClass, closed),
 154                                 gtk_marshal_NONE__NONE,
 155                                 GTK_TYPE_NONE, 0);
 156
 157         gtk_object_class_add_signals (object_class, pixbuf_loader_signals, LAST_SIGNAL);
 158
 159         object_class->destroy = gdk_pixbuf_loader_destroy;
 160         object_class->finalize = gdk_pixbuf_loader_finalize;
 161 }
 162
 163 static void
 164 gdk_pixbuf_loader_init (GdkPixbufLoader *loader)
 165 {
 166         GdkPixbufLoaderPrivate *priv;
 167
 168         priv = g_new0 (GdkPixbufLoaderPrivate, 1);
 169         loader->private = priv;
 170 }
 171
 172 static void
 173 gdk_pixbuf_loader_destroy (GtkObject *object)
 174 {
 175         GdkPixbufLoader *loader;
 176         GdkPixbufLoaderPrivate *priv = NULL;
 177
 178         g_return_if_fail (object != NULL);
 179         g_return_if_fail (GDK_IS_PIXBUF_LOADER (object));
 180
 181         loader = GDK_PIXBUF_LOADER (object);
 182         priv = loader->private;
 183
 184         if (!priv->closed)
 185                 gdk_pixbuf_loader_close (loader);
 186
 187         if (priv->pixbuf)
 188                 gdk_pixbuf_unref (priv->pixbuf);
 189
 190         if (GTK_OBJECT_CLASS (parent_class)->destroy)
 191                 (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
 192 }
 193
 194 static void
 195 gdk_pixbuf_loader_finalize (GtkObject *object)
 196 {
 197         GdkPixbufLoader *loader;
 198         GdkPixbufLoaderPrivate *priv = NULL;
 199
 200         loader = GDK_PIXBUF_LOADER (object);
 201         priv = loader->private;
 202
 203         g_free (priv);
 204
 205         if (GTK_OBJECT_CLASS (parent_class)->finalize)
 206                 (* GTK_OBJECT_CLASS (parent_class)->finalize) (object);
 207 }
 208
 209 static void
 210 gdk_pixbuf_loader_prepare (GdkPixbuf *pixbuf, gpointer loader)
 211 {
 212         GdkPixbufLoaderPrivate *priv = NULL;
 213
 214         priv = GDK_PIXBUF_LOADER (loader)->private;
 215         gdk_pixbuf_ref (pixbuf);
 216         g_assert (priv->pixbuf == NULL);
 217
 218         priv->pixbuf = pixbuf;
 219         gtk_signal_emit (GTK_OBJECT (loader), pixbuf_loader_signals[AREA_PREPARED]);
 220 }
 221
 222 static void
 223 gdk_pixbuf_loader_update (GdkPixbuf *pixbuf, gpointer loader, guint x, guint y, guint width, guint height)
 224 {
 225         GdkPixbufLoaderPrivate *priv = NULL;
 226
 227         priv = GDK_PIXBUF_LOADER (loader)->private;
 228
 229         gtk_signal_emit (GTK_OBJECT (loader),
 230                          pixbuf_loader_signals[AREA_UPDATED],
 231                          x, y,
 232                          /* sanity check in here.  Defend against an errant loader */
 233                          MIN (width, gdk_pixbuf_get_width (priv->pixbuf)),
 234                          MIN (height, gdk_pixbuf_get_height (priv->pixbuf)));
 235 }
 236
 237 \f
 238
 239 /**
 240  * gdk_pixbuf_loader_new:
 241  * @void:
 242  *
 243  * Creates a new pixbuf loader object.
 244  *
 245  * Return value: A newly-created pixbuf loader.
 246  **/
 247 GdkPixbufLoader *
 248 gdk_pixbuf_loader_new (void)
 249 {
 250         return gtk_type_new (gdk_pixbuf_loader_get_type ());
 251 }
 252
 253 static int
 254 gdk_pixbuf_loader_load_module(GdkPixbufLoader *loader)
 255 {
 256         GdkPixbufLoaderPrivate *priv = loader->private;
 257
 258         priv->image_module = gdk_pixbuf_get_module (priv->header_buf, priv->header_buf_offset);
 259
 260         if (priv->image_module == NULL)
 261                 return 0;
 262
 263         if (priv->image_module->module == NULL)
 264                 gdk_pixbuf_load_module (priv->image_module);
 265
 266         if (priv->image_module->module == NULL)
 267                 return 0;
 268
 269         if ((priv->image_module->begin_load == NULL) ||
 270             (priv->image_module->stop_load == NULL) ||
 271             (priv->image_module->load_increment == NULL)) {
 272                 g_warning ("module %s does not support incremental loading.\n",
 273                            priv->image_module->module_name);
 274                 return 0;
 275         }
 276
 277         priv->context = (*priv->image_module->begin_load) (gdk_pixbuf_loader_prepare, gdk_pixbuf_loader_update, loader);
 278
 279         if (priv->context == NULL) {
 280                 g_warning("Failed to begin progressive load");
 281                 return 0;
 282         }
 283
 284         if( (* priv->image_module->load_increment) (priv->context, priv->header_buf, priv->header_buf_offset) )
 285                 return priv->header_buf_offset;
 286
 287         return 0;
 288 }
 289
 290 static int
 291 gdk_pixbuf_loader_eat_header_write (GdkPixbufLoader *loader, const gchar *buf, size_t count)
 292 {
 293         int nbytes;
 294         GdkPixbufLoaderPrivate *priv = loader->private;
 295
 296         nbytes = MIN(LOADER_HEADER_SIZE - priv->header_buf_offset, count);
 297         memcpy (priv->header_buf + priv->header_buf_offset, buf, nbytes);
 298
 299         priv->header_buf_offset += nbytes;
 300
 301         if(priv->header_buf_offset >= LOADER_HEADER_SIZE)
 302                 gdk_pixbuf_loader_load_module(loader);
 303
 304         return nbytes;
 305 }
 306
 307 /**
 308  * gdk_pixbuf_loader_write:
 309  * @loader: A pixbuf loader.
 310  * @buf: Pointer to image data.
 311  * @count: Length of the @buf buffer in bytes.
 312  *
 313  * This will cause a pixbuf loader to parse the next @count bytes of an image.
 314  * It will return TRUE if the data was loaded successfully, and FALSE if an
 315  * error occurred.  In the latter case, the loader will be closed, and will not
 316  * accept further writes.
 317  *
 318  * Return value: #TRUE if the write was successful, or #FALSE if the loader
 319  * cannot parse the buffer.
 320  **/
 321 gboolean
 322 gdk_pixbuf_loader_write (GdkPixbufLoader *loader, const gchar *buf, size_t count)
 323 {
 324         GdkPixbufLoaderPrivate *priv;
 325
 326         g_return_val_if_fail (loader != NULL, FALSE);
 327         g_return_val_if_fail (GDK_IS_PIXBUF_LOADER (loader), FALSE);
 328
 329         g_return_val_if_fail (buf != NULL, FALSE);
 330         g_return_val_if_fail (count >= 0, FALSE);
 331
 332         priv = loader->private;
 333
 334         /* we expect it's not to be closed */
 335         g_return_val_if_fail (priv->closed == FALSE, FALSE);
 336
 337         if (priv->image_module == NULL) {
 338                 int eaten;
 339
 340                 eaten = gdk_pixbuf_loader_eat_header_write(loader, buf, count);
 341                 if (eaten <= 0)
 342                         return FALSE;
 343
 344                 count -= eaten;
 345                 buf += eaten;
 346         }
 347
 348         if (count > 0 && priv->image_module->load_increment)
 349                 return (* priv->image_module->load_increment) (priv->context, buf, count);
 350
 351         return TRUE;
 352 }
 353
 354 /**
 355  * gdk_pixbuf_loader_get_pixbuf:
 356  * @loader: A pixbuf loader.
 357  *
 358  * Queries the GdkPixbuf that a pixbuf loader is currently creating.  In general
 359  * it only makes sense to call this function afer the "area_prepared" signal has
 360  * been emitted by the loader; this means that enough data has been read to know
 361  * the size of the image that will be allocated.  If the loader has not received
 362  * enough data via gdk_pixbuf_loader_write(), then this function returns NULL.
 363  * The returned pixbuf will be the same in all future calls to the loader, so
 364  * simply calling gdk_pixbuf_ref() should be sufficient to continue using it.
 365  *
 366  * Return value: The GdkPixbuf that the loader is creating, or NULL if not
 367  * enough data has been read to determine how to create the image buffer.
 368  **/
 369 GdkPixbuf *
 370 gdk_pixbuf_loader_get_pixbuf (GdkPixbufLoader *loader)
 371 {
 372         GdkPixbufLoaderPrivate *priv;
 373
 374         g_return_val_if_fail (loader != NULL, NULL);
 375         g_return_val_if_fail (GDK_IS_PIXBUF_LOADER (loader), NULL);
 376
 377         priv = loader->private;
 378
 379         return priv->pixbuf;
 380 }
 381
 382 /**
 383  * gdk_pixbuf_loader_close:
 384  * @loader: A pixbuf loader.
 385  *
 386  * Informs a pixbuf loader that no further writes with gdk_pixbuf_load_write()
 387  * will occur, so that it can free its internal loading structures.
 388  **/
 389 void
 390 gdk_pixbuf_loader_close (GdkPixbufLoader *loader)
 391 {
 392         GdkPixbufLoaderPrivate *priv;
 393
 394         g_return_if_fail (loader != NULL);
 395         g_return_if_fail (GDK_IS_PIXBUF_LOADER (loader));
 396
 397         priv = loader->private;
 398
 399         /* we expect it's not closed */
 400         g_return_if_fail (priv->closed == FALSE);
 401
 402         /* We have less the 128 bytes in the image.  Flush it, and keep going. */
 403         if (priv->image_module == NULL)
 404                 gdk_pixbuf_loader_load_module (loader);
 405
 406         if (priv->image_module && priv->image_module->stop_load)
 407                 (* priv->image_module->stop_load) (priv->context);
 408
 409         priv->closed = TRUE;
 410
 411         gtk_signal_emit (GTK_OBJECT (loader),
 412                          pixbuf_loader_signals[CLOSED]);
 413 }