Adding upstream version 2.10.36.upstream/2.10.36

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 766 insertions, 0 deletions

diff --git a/app/gegl/gimptilehandlervalidate.c b/app/gegl/gimptilehandlervalidate.c
new file mode 100644
index 0000000..01915d5
--- /dev/null
+++ b/app/gegl/gimptilehandlervalidate.c
@@ -0,0 +1,766 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <cairo.h>
+#include <gegl.h>
+
+#include "gimp-gegl-types.h"
+
+#include "core/gimpchunkiterator.h"
+#include "core/gimpmarshal.h"
+
+#include "gimp-gegl-loops.h"
+#include "gimp-gegl-utils.h"
+#include "gimptilehandlervalidate.h"
+
+
+enum
+{
+  INVALIDATED,
+  LAST_SIGNAL
+};
+
+enum
+{
+  PROP_0,
+  PROP_FORMAT,
+  PROP_TILE_WIDTH,
+  PROP_TILE_HEIGHT,
+  PROP_WHOLE_TILE
+};
+
+
+static void     gimp_tile_handler_validate_finalize             (GObject         *object);
+static void     gimp_tile_handler_validate_set_property         (GObject         *object,
+                                                                 guint            property_id,
+                                                                 const GValue    *value,
+                                                                 GParamSpec      *pspec);
+static void     gimp_tile_handler_validate_get_property         (GObject         *object,
+                                                                 guint            property_id,
+                                                                 GValue          *value,
+                                                                 GParamSpec      *pspec);
+
+static void     gimp_tile_handler_validate_real_begin_validate  (GimpTileHandlerValidate *validate);
+static void     gimp_tile_handler_validate_real_end_validate    (GimpTileHandlerValidate *validate);
+static void     gimp_tile_handler_validate_real_validate        (GimpTileHandlerValidate *validate,
+                                                                 const GeglRectangle     *rect,
+                                                                 const Babl              *format,
+                                                                 gpointer                 dest_buf,
+                                                                 gint                     dest_stride);
+static void     gimp_tile_handler_validate_real_validate_buffer (GimpTileHandlerValidate *validate,
+                                                                 const GeglRectangle     *rect,
+                                                                 GeglBuffer              *buffer);
+
+static gpointer gimp_tile_handler_validate_command              (GeglTileSource  *source,
+                                                                 GeglTileCommand  command,
+                                                                 gint             x,
+                                                                 gint             y,
+                                                                 gint             z,
+                                                                 gpointer         data);
+
+
+G_DEFINE_TYPE (GimpTileHandlerValidate, gimp_tile_handler_validate,
+               GEGL_TYPE_TILE_HANDLER)
+
+#define parent_class gimp_tile_handler_validate_parent_class
+
+static guint gimp_tile_handler_validate_signals[LAST_SIGNAL];
+
+
+static void
+gimp_tile_handler_validate_class_init (GimpTileHandlerValidateClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  gimp_tile_handler_validate_signals[INVALIDATED] =
+    g_signal_new ("invalidated",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_FIRST,
+                  G_STRUCT_OFFSET (GimpTileHandlerValidateClass, invalidated),
+                  NULL, NULL,
+                  g_cclosure_marshal_VOID__BOXED,
+                  G_TYPE_NONE, 1,
+                  GEGL_TYPE_RECTANGLE);
+
+  object_class->finalize     = gimp_tile_handler_validate_finalize;
+  object_class->set_property = gimp_tile_handler_validate_set_property;
+  object_class->get_property = gimp_tile_handler_validate_get_property;
+
+  klass->begin_validate      = gimp_tile_handler_validate_real_begin_validate;
+  klass->end_validate        = gimp_tile_handler_validate_real_end_validate;
+  klass->validate            = gimp_tile_handler_validate_real_validate;
+  klass->validate_buffer     = gimp_tile_handler_validate_real_validate_buffer;
+
+  g_object_class_install_property (object_class, PROP_FORMAT,
+                                   g_param_spec_pointer ("format", NULL, NULL,
+                                                         GIMP_PARAM_READWRITE));
+
+  g_object_class_install_property (object_class, PROP_TILE_WIDTH,
+                                   g_param_spec_int ("tile-width", NULL, NULL,
+                                                     1, G_MAXINT, 1,
+                                                     GIMP_PARAM_READWRITE |
+                                                     G_PARAM_CONSTRUCT));
+
+  g_object_class_install_property (object_class, PROP_TILE_HEIGHT,
+                                   g_param_spec_int ("tile-height", NULL, NULL,
+                                                     1, G_MAXINT, 1,
+                                                     GIMP_PARAM_READWRITE |
+                                                     G_PARAM_CONSTRUCT));
+
+  g_object_class_install_property (object_class, PROP_WHOLE_TILE,
+                                   g_param_spec_boolean ("whole-tile", NULL, NULL,
+                                                         FALSE,
+                                                         GIMP_PARAM_READWRITE |
+                                                         G_PARAM_CONSTRUCT));
+}
+
+static void
+gimp_tile_handler_validate_init (GimpTileHandlerValidate *validate)
+{
+  GeglTileSource *source = GEGL_TILE_SOURCE (validate);
+
+  source->command = gimp_tile_handler_validate_command;
+
+  validate->dirty_region = cairo_region_create ();
+}
+
+static void
+gimp_tile_handler_validate_finalize (GObject *object)
+{
+  GimpTileHandlerValidate *validate = GIMP_TILE_HANDLER_VALIDATE (object);
+
+  g_clear_object (&validate->graph);
+  g_clear_pointer (&validate->dirty_region, cairo_region_destroy);
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gimp_tile_handler_validate_set_property (GObject      *object,
+                                         guint         property_id,
+                                         const GValue *value,
+                                         GParamSpec   *pspec)
+{
+  GimpTileHandlerValidate *validate = GIMP_TILE_HANDLER_VALIDATE (object);
+
+  switch (property_id)
+    {
+    case PROP_FORMAT:
+      validate->format = g_value_get_pointer (value);
+      break;
+    case PROP_TILE_WIDTH:
+      validate->tile_width = g_value_get_int (value);
+      break;
+    case PROP_TILE_HEIGHT:
+      validate->tile_height = g_value_get_int (value);
+      break;
+    case PROP_WHOLE_TILE:
+      validate->whole_tile = g_value_get_boolean (value);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+    }
+}
+
+static void
+gimp_tile_handler_validate_get_property (GObject    *object,
+                                         guint       property_id,
+                                         GValue     *value,
+                                         GParamSpec *pspec)
+{
+  GimpTileHandlerValidate *validate = GIMP_TILE_HANDLER_VALIDATE (object);
+
+  switch (property_id)
+    {
+    case PROP_FORMAT:
+      g_value_set_pointer (value, (gpointer) validate->format);
+      break;
+    case PROP_TILE_WIDTH:
+      g_value_set_int (value, validate->tile_width);
+      break;
+    case PROP_TILE_HEIGHT:
+      g_value_set_int (value, validate->tile_height);
+      break;
+    case PROP_WHOLE_TILE:
+      g_value_set_boolean (value, validate->whole_tile);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+    }
+}
+
+static void
+gimp_tile_handler_validate_real_begin_validate (GimpTileHandlerValidate *validate)
+{
+  validate->suspend_validate++;
+}
+
+static void
+gimp_tile_handler_validate_real_end_validate (GimpTileHandlerValidate *validate)
+{
+  validate->suspend_validate--;
+}
+
+static void
+gimp_tile_handler_validate_real_validate (GimpTileHandlerValidate *validate,
+                                          const GeglRectangle     *rect,
+                                          const Babl              *format,
+                                          gpointer                 dest_buf,
+                                          gint                     dest_stride)
+{
+#if 0
+  g_printerr ("validating at %d %d %d %d\n",
+              rect.x,
+              rect.y,
+              rect.width,
+              rect.height);
+#endif
+
+  gegl_node_blit (validate->graph, 1.0, rect, format,
+                  dest_buf, dest_stride,
+                  GEGL_BLIT_DEFAULT);
+}
+
+static void
+gimp_tile_handler_validate_real_validate_buffer (GimpTileHandlerValidate *validate,
+                                                 const GeglRectangle     *rect,
+                                                 GeglBuffer              *buffer)
+{
+  GimpTileHandlerValidateClass *klass;
+
+  klass = GIMP_TILE_HANDLER_VALIDATE_GET_CLASS (validate);
+
+  if (klass->validate == gimp_tile_handler_validate_real_validate)
+    {
+      gegl_node_blit_buffer (validate->graph, buffer, rect, 0,
+                             GEGL_ABYSS_NONE);
+    }
+  else
+    {
+      const Babl *format = gegl_buffer_get_format (buffer);
+      gpointer    data;
+      gint        stride;
+
+      data = gegl_buffer_linear_open (buffer, rect, &stride, format);
+
+      klass->validate (validate, rect, format, data, stride);
+
+      gegl_buffer_linear_close (buffer, data);
+    }
+}
+
+static GeglTile *
+gimp_tile_handler_validate_validate_tile (GeglTileSource *source,
+                                          gint            x,
+                                          gint            y)
+{
+  GimpTileHandlerValidate *validate = GIMP_TILE_HANDLER_VALIDATE (source);
+  GeglTile                *tile;
+  cairo_rectangle_int_t    tile_rect;
+  cairo_region_overlap_t   overlap;
+
+  if (validate->suspend_validate ||
+      cairo_region_is_empty (validate->dirty_region))
+    {
+      return gegl_tile_handler_source_command (source,
+                                               GEGL_TILE_GET, x, y, 0, NULL);
+    }
+
+  tile_rect.x      = x * validate->tile_width;
+  tile_rect.y      = y * validate->tile_height;
+  tile_rect.width  = validate->tile_width;
+  tile_rect.height = validate->tile_height;
+
+  overlap = cairo_region_contains_rectangle (validate->dirty_region,
+                                             &tile_rect);
+
+  if (overlap == CAIRO_REGION_OVERLAP_OUT)
+    {
+      return gegl_tile_handler_source_command (source,
+                                               GEGL_TILE_GET, x, y, 0, NULL);
+    }
+
+  if (overlap == CAIRO_REGION_OVERLAP_IN || validate->whole_tile)
+    {
+      gint tile_bpp;
+      gint tile_stride;
+
+      cairo_region_subtract_rectangle (validate->dirty_region, &tile_rect);
+
+      tile_bpp    = babl_format_get_bytes_per_pixel (validate->format);
+      tile_stride = tile_bpp * validate->tile_width;
+
+      tile = gegl_tile_handler_get_source_tile (GEGL_TILE_HANDLER (source),
+                                                x, y, 0, FALSE);
+
+      gimp_tile_handler_validate_begin_validate (validate);
+
+      gegl_tile_lock (tile);
+
+      GIMP_TILE_HANDLER_VALIDATE_GET_CLASS (validate)->validate
+        (validate,
+         GEGL_RECTANGLE (tile_rect.x,
+                         tile_rect.y,
+                         tile_rect.width,
+                         tile_rect.height),
+         validate->format,
+         gegl_tile_get_data (tile),
+         tile_stride);
+
+      gegl_tile_unlock (tile);
+
+      gimp_tile_handler_validate_end_validate (validate);
+    }
+  else
+    {
+      cairo_region_t *tile_region;
+      gint            tile_bpp;
+      gint            tile_stride;
+      gint            n_rects;
+      gint            i;
+
+      tile_region = cairo_region_copy (validate->dirty_region);
+      cairo_region_intersect_rectangle (tile_region, &tile_rect);
+
+      cairo_region_subtract_rectangle (validate->dirty_region, &tile_rect);
+
+      tile_bpp    = babl_format_get_bytes_per_pixel (validate->format);
+      tile_stride = tile_bpp * validate->tile_width;
+
+      tile = gegl_tile_handler_source_command (source,
+                                               GEGL_TILE_GET, x, y, 0, NULL);
+
+      if (! tile)
+        {
+          tile = gegl_tile_handler_create_tile (GEGL_TILE_HANDLER (source),
+                                                x, y, 0);
+
+          memset (gegl_tile_get_data (tile),
+                  0, tile_stride * validate->tile_height);
+        }
+
+      gimp_tile_handler_validate_begin_validate (validate);
+
+      gegl_tile_lock (tile);
+
+      n_rects = cairo_region_num_rectangles (tile_region);
+
+#if 0
+      g_printerr ("%d chunks\n", n_rects);
+#endif
+
+      for (i = 0; i < n_rects; i++)
+        {
+          cairo_rectangle_int_t blit_rect;
+          gint                  tile_x;
+          gint                  tile_y;
+
+          cairo_region_get_rectangle (tile_region, i, &blit_rect);
+
+          tile_x = blit_rect.x % validate->tile_width;
+          if (tile_x < 0) tile_x += validate->tile_width;
+
+          tile_y = blit_rect.y % validate->tile_height;
+          if (tile_y < 0) tile_y += validate->tile_height;
+
+          GIMP_TILE_HANDLER_VALIDATE_GET_CLASS (validate)->validate
+            (validate,
+             GEGL_RECTANGLE (blit_rect.x,
+                             blit_rect.y,
+                             blit_rect.width,
+                             blit_rect.height),
+             validate->format,
+             gegl_tile_get_data (tile) +
+             tile_y * tile_stride      +
+             tile_x * tile_bpp,
+             tile_stride);
+        }
+
+      gegl_tile_unlock (tile);
+
+      gimp_tile_handler_validate_end_validate (validate);
+
+      cairo_region_destroy (tile_region);
+    }
+
+  return tile;
+}
+
+static gpointer
+gimp_tile_handler_validate_command (GeglTileSource  *source,
+                                    GeglTileCommand  command,
+                                    gint             x,
+                                    gint             y,
+                                    gint             z,
+                                    gpointer         data)
+{
+  if (command == GEGL_TILE_GET && z == 0)
+    return gimp_tile_handler_validate_validate_tile (source, x, y);
+
+  return gegl_tile_handler_source_command (source, command, x, y, z, data);
+}
+
+
+/*  public functions  */
+
+GeglTileHandler *
+gimp_tile_handler_validate_new (GeglNode *graph)
+{
+  GimpTileHandlerValidate *validate;
+
+  g_return_val_if_fail (GEGL_IS_NODE (graph), NULL);
+
+  validate = g_object_new (GIMP_TYPE_TILE_HANDLER_VALIDATE, NULL);
+
+  validate->graph = g_object_ref (graph);
+
+  return GEGL_TILE_HANDLER (validate);
+}
+
+void
+gimp_tile_handler_validate_assign (GimpTileHandlerValidate *validate,
+                                   GeglBuffer              *buffer)
+{
+  g_return_if_fail (GIMP_IS_TILE_HANDLER_VALIDATE (validate));
+  g_return_if_fail (GEGL_IS_BUFFER (buffer));
+  g_return_if_fail (gimp_tile_handler_validate_get_assigned (buffer) == NULL);
+
+  gegl_buffer_add_handler (buffer, validate);
+
+  g_object_get (buffer,
+                "format",      &validate->format,
+                "tile-width",  &validate->tile_width,
+                "tile-height", &validate->tile_height,
+                NULL);
+
+  g_object_set_data (G_OBJECT (buffer),
+                     "gimp-tile-handler-validate", validate);
+}
+
+void
+gimp_tile_handler_validate_unassign (GimpTileHandlerValidate *validate,
+                                     GeglBuffer              *buffer)
+{
+  g_return_if_fail (GIMP_IS_TILE_HANDLER_VALIDATE (validate));
+  g_return_if_fail (GEGL_IS_BUFFER (buffer));
+  g_return_if_fail (gimp_tile_handler_validate_get_assigned (buffer) == validate);
+
+  g_object_set_data (G_OBJECT (buffer),
+                     "gimp-tile-handler-validate", NULL);
+
+  gegl_buffer_remove_handler (buffer, validate);
+}
+
+GimpTileHandlerValidate *
+gimp_tile_handler_validate_get_assigned (GeglBuffer *buffer)
+{
+  g_return_val_if_fail (GEGL_IS_BUFFER (buffer), NULL);
+
+  return g_object_get_data (G_OBJECT (buffer),
+                            "gimp-tile-handler-validate");
+}
+
+void
+gimp_tile_handler_validate_invalidate (GimpTileHandlerValidate *validate,
+                                       const GeglRectangle     *rect)
+{
+  g_return_if_fail (GIMP_IS_TILE_HANDLER_VALIDATE (validate));
+  g_return_if_fail (rect != NULL);
+
+  cairo_region_union_rectangle (validate->dirty_region,
+                                (cairo_rectangle_int_t *) rect);
+
+  gegl_tile_handler_damage_rect (GEGL_TILE_HANDLER (validate), rect);
+
+  g_signal_emit (validate, gimp_tile_handler_validate_signals[INVALIDATED],
+                 0, rect, NULL);
+}
+
+void
+gimp_tile_handler_validate_undo_invalidate (GimpTileHandlerValidate *validate,
+                                            const GeglRectangle     *rect)
+{
+  g_return_if_fail (GIMP_IS_TILE_HANDLER_VALIDATE (validate));
+  g_return_if_fail (rect != NULL);
+
+  cairo_region_subtract_rectangle (validate->dirty_region,
+                                   (cairo_rectangle_int_t *) rect);
+}
+
+void
+gimp_tile_handler_validate_begin_validate (GimpTileHandlerValidate *validate)
+{
+  g_return_if_fail (GIMP_IS_TILE_HANDLER_VALIDATE (validate));
+
+  if (validate->validating++ == 0)
+    GIMP_TILE_HANDLER_VALIDATE_GET_CLASS (validate)->begin_validate (validate);
+}
+
+void
+gimp_tile_handler_validate_end_validate (GimpTileHandlerValidate *validate)
+{
+  g_return_if_fail (GIMP_IS_TILE_HANDLER_VALIDATE (validate));
+  g_return_if_fail (validate->validating > 0);
+
+  if (--validate->validating == 0)
+    GIMP_TILE_HANDLER_VALIDATE_GET_CLASS (validate)->end_validate (validate);
+}
+
+void
+gimp_tile_handler_validate_validate (GimpTileHandlerValidate *validate,
+                                     GeglBuffer              *buffer,
+                                     const GeglRectangle     *rect,
+                                     gboolean                 intersect,
+                                     gboolean                 chunked)
+{
+  GimpTileHandlerValidateClass *klass;
+  cairo_region_t               *region = NULL;
+
+  g_return_if_fail (GIMP_IS_TILE_HANDLER_VALIDATE (validate));
+  g_return_if_fail (gimp_tile_handler_validate_get_assigned (buffer) ==
+                    validate);
+
+  klass = GIMP_TILE_HANDLER_VALIDATE_GET_CLASS (validate);
+
+  if (! rect)
+    rect = gegl_buffer_get_extent (buffer);
+
+  if (intersect)
+    {
+      region = cairo_region_copy (validate->dirty_region);
+
+      cairo_region_intersect_rectangle (region,
+                                        (const cairo_rectangle_int_t *) rect);
+    }
+  else if (chunked)
+    {
+      region = cairo_region_create_rectangle (
+        (const cairo_rectangle_int_t *) rect);
+    }
+
+  if (region)
+    {
+      if (! cairo_region_is_empty (region))
+        {
+          gimp_tile_handler_validate_begin_validate (validate);
+
+          if (chunked)
+            {
+              GimpChunkIterator *iter;
+
+              iter   = gimp_chunk_iterator_new (region);
+              region = NULL;
+
+              while (gimp_chunk_iterator_next (iter))
+                {
+                  GeglRectangle blit_rect;
+
+                  while (gimp_chunk_iterator_get_rect (iter, &blit_rect))
+                    klass->validate_buffer (validate, &blit_rect, buffer);
+                }
+            }
+          else
+            {
+              gint n_rects;
+              gint i;
+
+              n_rects = cairo_region_num_rectangles (region);
+
+              for (i = 0; i < n_rects; i++)
+                {
+                  cairo_rectangle_int_t blit_rect;
+
+                  cairo_region_get_rectangle (region, i, &blit_rect);
+
+                  klass->validate_buffer (validate,
+                                          (const GeglRectangle *) &blit_rect,
+                                          buffer);
+                }
+              }
+
+          gimp_tile_handler_validate_end_validate (validate);
+
+          cairo_region_subtract_rectangle (
+            validate->dirty_region,
+            (const cairo_rectangle_int_t *) rect);
+        }
+
+      g_clear_pointer (&region, cairo_region_destroy);
+    }
+  else
+    {
+      gimp_tile_handler_validate_begin_validate (validate);
+
+      klass->validate_buffer (validate, rect, buffer);
+
+      gimp_tile_handler_validate_end_validate (validate);
+
+      cairo_region_subtract_rectangle (
+            validate->dirty_region,
+            (const cairo_rectangle_int_t *) rect);
+    }
+}
+
+gboolean
+gimp_tile_handler_validate_buffer_set_extent (GeglBuffer          *buffer,
+                                              const GeglRectangle *extent)
+{
+  GimpTileHandlerValidate *validate;
+
+  g_return_val_if_fail (GEGL_IS_BUFFER (buffer), FALSE);
+  g_return_val_if_fail (extent != NULL, FALSE);
+
+  validate = gimp_tile_handler_validate_get_assigned (buffer);
+
+  g_return_val_if_fail (validate != NULL, FALSE);
+
+  validate->suspend_validate++;
+
+  if (gimp_gegl_buffer_set_extent (buffer, extent))
+    {
+      validate->suspend_validate--;
+
+      cairo_region_intersect_rectangle (validate->dirty_region,
+                                        (const cairo_rectangle_int_t *) extent);
+
+      return TRUE;
+    }
+
+  validate->suspend_validate--;
+
+  return FALSE;
+}
+
+void
+gimp_tile_handler_validate_buffer_copy (GeglBuffer          *src_buffer,
+                                        const GeglRectangle *src_rect,
+                                        GeglBuffer          *dst_buffer,
+                                        const GeglRectangle *dst_rect)
+{
+  GimpTileHandlerValidate *src_validate;
+  GimpTileHandlerValidate *dst_validate;
+  GeglRectangle            real_src_rect;
+  GeglRectangle            real_dst_rect;
+
+  g_return_if_fail (GEGL_IS_BUFFER (src_buffer));
+  g_return_if_fail (GEGL_IS_BUFFER (dst_buffer));
+  g_return_if_fail (src_rect != dst_rect);
+
+  src_validate = gimp_tile_handler_validate_get_assigned (src_buffer);
+  dst_validate = gimp_tile_handler_validate_get_assigned (dst_buffer);
+
+  g_return_if_fail (dst_validate != NULL);
+
+  if (! src_rect)
+    src_rect = gegl_buffer_get_extent (src_buffer);
+
+  if (! dst_rect)
+    dst_rect = src_rect;
+
+  real_src_rect = *src_rect;
+
+  gegl_rectangle_intersect (&real_dst_rect,
+                            dst_rect, gegl_buffer_get_extent (dst_buffer));
+
+  real_src_rect.x      += real_dst_rect.x - dst_rect->x;
+  real_src_rect.y      += real_dst_rect.y - dst_rect->y;
+  real_src_rect.width  -= real_dst_rect.x - dst_rect->x;
+  real_src_rect.height -= real_dst_rect.y - dst_rect->y;
+
+  real_src_rect.width  = CLAMP (real_src_rect.width,  0, real_dst_rect.width);
+  real_src_rect.height = CLAMP (real_src_rect.height, 0, real_dst_rect.height);
+
+  /* temporarily remove the source buffer's validate handler, so that
+   * gegl_buffer_copy() can use fast tile copying, using the TILE_COPY command.
+   * currently, gegl only uses TILE_COPY when the source buffer has no user-
+   * provided tile handlers.
+   */
+  if (src_validate)
+    {
+      g_object_ref (src_validate);
+
+      gimp_tile_handler_validate_unassign (src_validate, src_buffer);
+    }
+
+  dst_validate->suspend_validate++;
+
+  gimp_gegl_buffer_copy (src_buffer, &real_src_rect, GEGL_ABYSS_NONE,
+                         dst_buffer, &real_dst_rect);
+
+  dst_validate->suspend_validate--;
+
+  if (src_validate)
+    {
+      gimp_tile_handler_validate_assign (src_validate, src_buffer);
+
+      g_object_unref (src_validate);
+    }
+
+  cairo_region_subtract_rectangle (dst_validate->dirty_region,
+                                   (cairo_rectangle_int_t *) &real_dst_rect);
+
+  if (src_validate)
+    {
+      if (real_src_rect.x == real_dst_rect.x &&
+          real_src_rect.y == real_dst_rect.y &&
+          gegl_rectangle_equal (&real_src_rect,
+                                gegl_buffer_get_extent (src_buffer)))
+        {
+          cairo_region_union (dst_validate->dirty_region,
+                              src_validate->dirty_region);
+        }
+      else if (cairo_region_contains_rectangle (
+                 src_validate->dirty_region,
+                 (cairo_rectangle_int_t *) &real_src_rect) !=
+               CAIRO_REGION_OVERLAP_OUT)
+        {
+          cairo_region_t *region;
+
+          region = cairo_region_copy (src_validate->dirty_region);
+
+          if (! gegl_rectangle_equal (&real_src_rect,
+                                      gegl_buffer_get_extent (src_buffer)))
+            {
+              cairo_region_intersect_rectangle (
+                region, (cairo_rectangle_int_t *) &real_src_rect);
+            }
+
+          cairo_region_translate (region,
+                                  real_dst_rect.x - real_src_rect.x,
+                                  real_dst_rect.y - real_src_rect.y);
+
+          if (cairo_region_is_empty (dst_validate->dirty_region))
+            {
+              cairo_region_destroy (dst_validate->dirty_region);
+
+              dst_validate->dirty_region = region;
+            }
+          else
+            {
+              cairo_region_union (dst_validate->dirty_region, region);
+
+              cairo_region_destroy (region);
+            }
+        }
+    }
+}