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gimp/app/core/gimpdrawable-preview.c

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/* 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 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "config.h"
#include <string.h>
#include <glib-object.h>
#include "libgimpmath/gimpmath.h"
#include "core-types.h"
#include "base/pixel-region.h"
#include "base/temp-buf.h"
#include "base/tile-manager-preview.h"
#include "paint-funcs/subsample-region.h"
#include "config/gimpcoreconfig.h"
#include "gimp.h"
#include "gimpchannel.h"
#include "gimpimage.h"
#include "gimpimage-colormap.h"
#include "gimpdrawable-preview.h"
#include "gimplayer.h"
#include "gimppreviewcache.h"
/* local function prototypes */
static TempBuf * gimp_drawable_preview_private (GimpDrawable *drawable,
gint width,
gint height);
static TempBuf * gimp_drawable_indexed_preview (GimpDrawable *drawable,
const guchar *cmap,
gint src_x,
gint src_y,
gint src_width,
gint src_height,
gint dest_width,
gint dest_height);
/* public functions */
TempBuf *
gimp_drawable_get_preview (GimpViewable *viewable,
GimpContext *context,
gint width,
gint height)
{
GimpDrawable *drawable;
GimpImage *image;
drawable = GIMP_DRAWABLE (viewable);
image = gimp_item_get_image (GIMP_ITEM (drawable));
if (! image->gimp->config->layer_previews)
return NULL;
/* Ok prime the cache with a large preview if the cache is invalid */
if (! drawable->preview_valid &&
width <= PREVIEW_CACHE_PRIME_WIDTH &&
height <= PREVIEW_CACHE_PRIME_HEIGHT &&
image &&
gimp_image_get_width (image) > PREVIEW_CACHE_PRIME_WIDTH &&
gimp_image_get_height (image) > PREVIEW_CACHE_PRIME_HEIGHT)
{
TempBuf *tb = gimp_drawable_preview_private (drawable,
PREVIEW_CACHE_PRIME_WIDTH,
PREVIEW_CACHE_PRIME_HEIGHT);
/* Save the 2nd call */
if (width == PREVIEW_CACHE_PRIME_WIDTH &&
height == PREVIEW_CACHE_PRIME_HEIGHT)
return tb;
}
/* Second call - should NOT visit the tile cache...*/
return gimp_drawable_preview_private (drawable, width, height);
}
gint
gimp_drawable_preview_bytes (GimpDrawable *drawable)
{
GimpImageBaseType base_type;
gint bytes = 0;
g_return_val_if_fail (GIMP_IS_DRAWABLE (drawable), 0);
base_type = GIMP_IMAGE_TYPE_BASE_TYPE (gimp_drawable_type (drawable));
switch (base_type)
{
case GIMP_RGB:
case GIMP_GRAY:
bytes = gimp_drawable_bytes (drawable);
break;
case GIMP_INDEXED:
bytes = gimp_drawable_has_alpha (drawable) ? 4 : 3;
break;
}
return bytes;
}
TempBuf *
gimp_drawable_get_sub_preview (GimpDrawable *drawable,
gint src_x,
gint src_y,
gint src_width,
gint src_height,
gint dest_width,
gint dest_height)
{
GimpItem *item;
GimpImage *image;
g_return_val_if_fail (GIMP_IS_DRAWABLE (drawable), NULL);
g_return_val_if_fail (src_x >= 0, NULL);
g_return_val_if_fail (src_y >= 0, NULL);
g_return_val_if_fail (src_width > 0, NULL);
g_return_val_if_fail (src_height > 0, NULL);
g_return_val_if_fail (dest_width > 0, NULL);
g_return_val_if_fail (dest_height > 0, NULL);
item = GIMP_ITEM (drawable);
g_return_val_if_fail ((src_x + src_width) <= gimp_item_width (item), NULL);
g_return_val_if_fail ((src_y + src_height) <= gimp_item_height (item), NULL);
image = gimp_item_get_image (item);
if (! image->gimp->config->layer_previews)
return NULL;
if (GIMP_IMAGE_TYPE_BASE_TYPE (gimp_drawable_type (drawable)) == GIMP_INDEXED)
return gimp_drawable_indexed_preview (drawable,
gimp_image_get_colormap (image),
src_x, src_y, src_width, src_height,
dest_width, dest_height);
return tile_manager_get_sub_preview (gimp_drawable_get_tiles (drawable),
src_x, src_y, src_width, src_height,
dest_width, dest_height);
}
/* private functions */
static TempBuf *
gimp_drawable_preview_private (GimpDrawable *drawable,
gint width,
gint height)
{
TempBuf *ret_buf;
if (! drawable->preview_valid ||
! (ret_buf = gimp_preview_cache_get (&drawable->preview_cache,
width, height)))
{
GimpItem *item = GIMP_ITEM (drawable);
ret_buf = gimp_drawable_get_sub_preview (drawable,
0, 0,
gimp_item_width (item),
gimp_item_height (item),
width,
height);
if (! drawable->preview_valid)
gimp_preview_cache_invalidate (&drawable->preview_cache);
drawable->preview_valid = TRUE;
gimp_preview_cache_add (&drawable->preview_cache, ret_buf);
}
return ret_buf;
}
static TempBuf *
gimp_drawable_indexed_preview (GimpDrawable *drawable,
const guchar *cmap,
gint src_x,
gint src_y,
gint src_width,
gint src_height,
gint dest_width,
gint dest_height)
{
TempBuf *preview_buf;
PixelRegion srcPR;
PixelRegion destPR;
gint bytes = gimp_drawable_preview_bytes (drawable);
gint subsample = 1;
/* calculate 'acceptable' subsample */
while ((dest_width * (subsample + 1) * 2 < src_width) &&
(dest_height * (subsample + 1) * 2 < src_width))
subsample += 1;
pixel_region_init (&srcPR, gimp_drawable_get_tiles (drawable),
src_x, src_y, src_width, src_height,
FALSE);
preview_buf = temp_buf_new (dest_width, dest_height, bytes, 0, 0, NULL);
pixel_region_init_temp_buf (&destPR, preview_buf,
0, 0, dest_width, dest_height);
subsample_indexed_region (&srcPR, &destPR, cmap, subsample);
return preview_buf;
}
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