source/libs/cairo/cairo-src/src/cairo-surface-snapshot.c

   1 /* cairo - a vector graphics library with display and print output
   2  *
   3  * Copyright © 2002 University of Southern California
   4  * Copyright © 2005 Red Hat, Inc.
   5  * Copyright © 2009 Intel Corporation
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it either under the terms of the GNU Lesser General Public
   9  * License version 2.1 as published by the Free Software Foundation
  10  * (the "LGPL") or, at your option, under the terms of the Mozilla
  11  * Public License Version 1.1 (the "MPL"). If you do not alter this
  12  * notice, a recipient may use your version of this file under either
  13  * the MPL or the LGPL.
  14  *
  15  * You should have received a copy of the LGPL along with this library
  16  * in the file COPYING-LGPL-2.1; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
  18  * You should have received a copy of the MPL along with this library
  19  * in the file COPYING-MPL-1.1
  20  *
  21  * The contents of this file are subject to the Mozilla Public License
  22  * Version 1.1 (the "License"); you may not use this file except in
  23  * compliance with the License. You may obtain a copy of the License at
  24  * http://www.mozilla.org/MPL/
  25  *
  26  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
  27  * OF ANY KIND, either express or implied. See the LGPL or the MPL for
  28  * the specific language governing rights and limitations.
  29  *
  30  * The Original Code is the cairo graphics library.
  31  *
  32  * The Initial Developer of the Original Code is University of Southern
  33  * California.
  34  *
  35  * Contributor(s):
  36  *      Carl D. Worth <cworth@cworth.org>
  37  *      Chris Wilson <chris@chris-wilson.co.uk>
  38  */
  39
  40 #include "cairoint.h"
  41
  42 #include "cairo-error-private.h"
  43 #include "cairo-image-surface-private.h"
  44 #include "cairo-surface-snapshot-inline.h"
  45
  46 static cairo_status_t
  47 _cairo_surface_snapshot_finish (void *abstract_surface)
  48 {
  49     cairo_surface_snapshot_t *surface = abstract_surface;
  50     cairo_status_t status = CAIRO_STATUS_SUCCESS;
  51
  52     TRACE ((stderr, "%s\n", __FUNCTION__));
  53
  54     if (surface->clone != NULL) {
  55         cairo_surface_finish (surface->clone);
  56         status = surface->clone->status;
  57
  58         cairo_surface_destroy (surface->clone);
  59     }
  60
  61     CAIRO_MUTEX_FINI (surface->mutex);
  62
  63     return status;
  64 }
  65
  66 static cairo_status_t
  67 _cairo_surface_snapshot_flush (void *abstract_surface, unsigned flags)
  68 {
  69     cairo_surface_snapshot_t *surface = abstract_surface;
  70     cairo_surface_t *target;
  71     cairo_status_t status;
  72
  73     target = _cairo_surface_snapshot_get_target (&surface->base);
  74     status = _cairo_surface_flush (target, flags);
  75     cairo_surface_destroy (target);
  76
  77     return status;
  78 }
  79
  80 static cairo_surface_t *
  81 _cairo_surface_snapshot_source (void                    *abstract_surface,
  82                                 cairo_rectangle_int_t *extents)
  83 {
  84     cairo_surface_snapshot_t *surface = abstract_surface;
  85     return _cairo_surface_get_source (surface->target, extents); /* XXX racy */
  86 }
  87
  88 struct snapshot_extra {
  89     cairo_surface_t *target;
  90     void *extra;
  91 };
  92
  93 static cairo_status_t
  94 _cairo_surface_snapshot_acquire_source_image (void                    *abstract_surface,
  95                                               cairo_image_surface_t  **image_out,
  96                                               void                   **extra_out)
  97 {
  98     cairo_surface_snapshot_t *surface = abstract_surface;
  99     struct snapshot_extra *extra;
 100     cairo_status_t status;
 101
 102     extra = malloc (sizeof (*extra));
 103     if (unlikely (extra == NULL))
 104         return _cairo_error (CAIRO_STATUS_NO_MEMORY);
 105
 106     extra->target = _cairo_surface_snapshot_get_target (&surface->base);
 107     status =  _cairo_surface_acquire_source_image (extra->target, image_out, &extra->extra);
 108     if (unlikely (status)) {
 109         cairo_surface_destroy (extra->target);
 110         free (extra);
 111     }
 112
 113     *extra_out = extra;
 114     return status;
 115 }
 116
 117 static void
 118 _cairo_surface_snapshot_release_source_image (void                   *abstract_surface,
 119                                               cairo_image_surface_t  *image,
 120                                               void                   *_extra)
 121 {
 122     struct snapshot_extra *extra = _extra;
 123
 124     _cairo_surface_release_source_image (extra->target, image, extra->extra);
 125     cairo_surface_destroy (extra->target);
 126     free (extra);
 127 }
 128
 129 static cairo_bool_t
 130 _cairo_surface_snapshot_get_extents (void                  *abstract_surface,
 131                                      cairo_rectangle_int_t *extents)
 132 {
 133     cairo_surface_snapshot_t *surface = abstract_surface;
 134     cairo_surface_t *target;
 135     cairo_bool_t bounded;
 136
 137     target = _cairo_surface_snapshot_get_target (&surface->base);
 138     bounded = _cairo_surface_get_extents (target, extents);
 139     cairo_surface_destroy (target);
 140
 141     return bounded;
 142 }
 143
 144 static const cairo_surface_backend_t _cairo_surface_snapshot_backend = {
 145     CAIRO_INTERNAL_SURFACE_TYPE_SNAPSHOT,
 146     _cairo_surface_snapshot_finish,
 147     NULL,
 148
 149     NULL, /* create similar */
 150     NULL, /* create similar image  */
 151     NULL, /* map to image */
 152     NULL, /* unmap image  */
 153
 154     _cairo_surface_snapshot_source,
 155     _cairo_surface_snapshot_acquire_source_image,
 156     _cairo_surface_snapshot_release_source_image,
 157     NULL, /* snapshot */
 158
 159     NULL, /* copy_page */
 160     NULL, /* show_page */
 161
 162     _cairo_surface_snapshot_get_extents,
 163     NULL, /* get-font-options */
 164
 165     _cairo_surface_snapshot_flush,
 166 };
 167
 168 static void
 169 _cairo_surface_snapshot_copy_on_write (cairo_surface_t *surface)
 170 {
 171     cairo_surface_snapshot_t *snapshot = (cairo_surface_snapshot_t *) surface;
 172     cairo_image_surface_t *image;
 173     cairo_surface_t *clone;
 174     void *extra;
 175     cairo_status_t status;
 176
 177     TRACE ((stderr, "%s: target=%d\n",
 178             __FUNCTION__, snapshot->target->unique_id));
 179
 180     /* We need to make an image copy of the original surface since the
 181      * snapshot may exceed the lifetime of the original device, i.e.
 182      * when we later need to use the snapshot the data may have already
 183      * been lost.
 184      */
 185
 186     CAIRO_MUTEX_LOCK (snapshot->mutex);
 187
 188     if (snapshot->target->backend->snapshot != NULL) {
 189         clone = snapshot->target->backend->snapshot (snapshot->target);
 190         if (clone != NULL) {
 191             assert (clone->status || ! _cairo_surface_is_snapshot (clone));
 192             goto done;
 193         }
 194     }
 195
 196     /* XXX copy to a similar surface, leave acquisition till later?
 197      * We should probably leave such decisions to the backend in case we
 198      * rely upon devices/connections like Xlib.
 199     */
 200     status = _cairo_surface_acquire_source_image (snapshot->target, &image, &extra);
 201     if (unlikely (status)) {
 202         snapshot->target = _cairo_surface_create_in_error (status);
 203         status = _cairo_surface_set_error (surface, status);
 204         goto unlock;
 205     }
 206     clone = image->base.backend->snapshot (&image->base);
 207     _cairo_surface_release_source_image (snapshot->target, image, extra);
 208
 209 done:
 210     status = _cairo_surface_set_error (surface, clone->status);
 211     snapshot->target = snapshot->clone = clone;
 212     snapshot->base.type = clone->type;
 213 unlock:
 214     CAIRO_MUTEX_UNLOCK (snapshot->mutex);
 215 }
 216
 217 /**
 218  * _cairo_surface_snapshot:
 219  * @surface: a #cairo_surface_t
 220  *
 221  * Make an immutable reference to @surface. It is an error to call a
 222  * surface-modifying function on the result of this function. The
 223  * resulting 'snapshot' is a lazily copied-on-write surface i.e. it
 224  * remains a reference to the original surface until that surface is
 225  * written to again, at which time a copy is made of the original surface
 226  * and the snapshot then points to that instead. Multiple snapshots of the
 227  * same unmodified surface point to the same copy.
 228  *
 229  * The caller owns the return value and should call
 230  * cairo_surface_destroy() when finished with it. This function will not
 231  * return %NULL, but will return a nil surface instead.
 232  *
 233  * Return value: The snapshot surface. Note that the return surface
 234  * may not necessarily be of the same type as @surface.
 235  **/
 236 cairo_surface_t *
 237 _cairo_surface_snapshot (cairo_surface_t *surface)
 238 {
 239     cairo_surface_snapshot_t *snapshot;
 240     cairo_status_t status;
 241
 242     TRACE ((stderr, "%s: target=%d\n", __FUNCTION__, surface->unique_id));
 243
 244     if (unlikely (surface->status))
 245         return _cairo_surface_create_in_error (surface->status);
 246
 247     if (unlikely (surface->finished))
 248         return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_SURFACE_FINISHED));
 249
 250     if (surface->snapshot_of != NULL)
 251         return cairo_surface_reference (surface);
 252
 253     if (_cairo_surface_is_snapshot (surface))
 254         return cairo_surface_reference (surface);
 255
 256     snapshot = (cairo_surface_snapshot_t *)
 257         _cairo_surface_has_snapshot (surface, &_cairo_surface_snapshot_backend);
 258     if (snapshot != NULL)
 259         return cairo_surface_reference (&snapshot->base);
 260
 261     snapshot = malloc (sizeof (cairo_surface_snapshot_t));
 262     if (unlikely (snapshot == NULL))
 263         return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_SURFACE_FINISHED));
 264
 265     _cairo_surface_init (&snapshot->base,
 266                          &_cairo_surface_snapshot_backend,
 267                          NULL, /* device */
 268                          surface->content);
 269     snapshot->base.type = surface->type;
 270
 271     CAIRO_MUTEX_INIT (snapshot->mutex);
 272     snapshot->target = surface;
 273     snapshot->clone = NULL;
 274
 275     status = _cairo_surface_copy_mime_data (&snapshot->base, surface);
 276     if (unlikely (status)) {
 277         cairo_surface_destroy (&snapshot->base);
 278         return _cairo_surface_create_in_error (status);
 279     }
 280
 281     snapshot->base.device_transform = surface->device_transform;
 282     snapshot->base.device_transform_inverse = surface->device_transform_inverse;
 283
 284     _cairo_surface_attach_snapshot (surface,
 285                                     &snapshot->base,
 286                                     _cairo_surface_snapshot_copy_on_write);
 287
 288     return &snapshot->base;
 289 }