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gimp/app/core/gimpdrawable-preview.c
Michael Natterer 09454fb2a4 some general cleanup. 
2005-09-03  Michael Natterer  <mitch@gimp.org>

	* app/base/pixel-region.[ch]: some general cleanup.

	(pixel_region_init_temp_buf)
	(pixel_region_init_data): new functions which initialize pixel
	regions on TempBufs and on raw contiguous arrays of pixel data.

	(pixel_region_configure): fixed a bug that has probably been there
	forever: when processing contiguous (non-tiled) data, interpret
	the original x and y coordinates of the region as offsets into
	the data. Before this fix, the initial x and y were simply ignored
	(by using them in a broken way), thus always forcing the upper
	left corner of the region being the beginning of the passed data.

	Lots of code was working around this problem by setting the
	pixel_region's data pointer to the proper starting pixel of the
	region in the middle the buffer.

	* libgimp/gimppixelrgn.c: some general cleanup.

	(gimp_pixel_rgn_configure): same fix as above. Fortunately, nobody
	seems to know that libgimp pixel regions can be used on arrays of
	data, just as core ones. Only two plug-ins were using this
	feature, and they are antique and written by spencer and federico,
	respectively. They both don't use offsets into the buffers and are
	not affected by this change. It's highly unlikely that anybody out
	there knows/uses this feature, so it can IMHO be safely changed.

	* app/base/temp-buf.c
	* app/core/gimpbuffer.c
	* app/core/gimpdrawable-combine.c
	* app/core/gimpdrawable-preview.c
	* app/core/gimpimage-preview.c
	* app/core/gimplayer.c
	* app/paint/gimpbrushcore.c
	* app/paint/gimpclone.c
	* app/paint/gimpconvolve.c
	* app/paint/gimpdodgeburn.c
	* app/paint/gimppaintcore.c
	* app/paint/gimpsmudge.c
	* app/tools/gimpiscissorstool.c
	* app/tools/gimppainttool.c: use the pixel_region_init_foo()
	functions instead of initializing regions of TempBufs and raw data
	manually. Removed lots of workarounds for the broken offset
	handling. The changed places of code are much more readable now.
2005-09-03 17:16:58 +00:00

460 lines
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/* The GIMP -- an 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 "paint-funcs/paint-funcs.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 void gimp_drawable_preview_scale (GimpImageType type,
const guchar *cmap,
PixelRegion *srcPR,
PixelRegion *destPR,
gint subsample);
/* public functions */
TempBuf *
gimp_drawable_get_preview (GimpViewable *viewable,
gint width,
gint height)
{
GimpDrawable *drawable;
GimpImage *gimage;
drawable = GIMP_DRAWABLE (viewable);
gimage = gimp_item_get_image (GIMP_ITEM (drawable));
if (! gimage->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 &&
gimage &&
gimage->width > PREVIEW_CACHE_PRIME_WIDTH &&
gimage->height > 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 *gimage;
TempBuf *preview_buf;
PixelRegion srcPR;
PixelRegion destPR;
gint bytes;
gint subsample;
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);
gimage = gimp_item_get_image (item);
if (! gimage->gimp->config->layer_previews)
return NULL;
bytes = gimp_drawable_preview_bytes (drawable);
/* calculate 'acceptable' subsample */
subsample = 1;
while ((dest_width * (subsample + 1) * 2 < src_width) &&
(dest_height * (subsample + 1) * 2 < src_width))
subsample += 1;
pixel_region_init (&srcPR, gimp_drawable_data (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);
if (GIMP_IS_LAYER (drawable))
{
gimp_drawable_preview_scale (gimp_drawable_type (drawable),
gimp_image_get_colormap (gimage),
&srcPR, &destPR,
subsample);
}
else if (GIMP_IS_CHANNEL (drawable))
{
subsample_region (&srcPR, &destPR, subsample);
}
return preview_buf;
}
/* 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 void
gimp_drawable_preview_scale (GimpImageType type,
const guchar *cmap,
PixelRegion *srcPR,
PixelRegion *destPR,
gint subsample)
{
#define EPSILON 0.000001
guchar *src, *s;
guchar *dest, *d;
gdouble *row, *r;
gint destwidth;
gint src_row, src_col;
gint bytes, b;
gint width, height;
gint orig_width, orig_height;
gdouble x_rat, y_rat;
gdouble x_cum, y_cum;
gdouble x_last, y_last;
gdouble *x_frac, y_frac, tot_frac;
gint i, j;
gint frac;
gboolean advance_dest;
gboolean has_alpha;
g_return_if_fail (! GIMP_IMAGE_TYPE_IS_INDEXED (type) || cmap != NULL);
orig_width = srcPR->w / subsample;
orig_height = srcPR->h / subsample;
width = destPR->w;
height = destPR->h;
/* Some calculations... */
bytes = destPR->bytes;
destwidth = destPR->rowstride;
has_alpha = GIMP_IMAGE_TYPE_HAS_ALPHA (type);
/* the data pointers... */
src = g_new (guchar, orig_width * bytes);
dest = destPR->data;
/* find the ratios of old x to new x and old y to new y */
x_rat = (gdouble) orig_width / (gdouble) width;
y_rat = (gdouble) orig_height / (gdouble) height;
/* allocate an array to help with the calculations */
row = g_new0 (gdouble, width * bytes);
x_frac = g_new (gdouble, width + orig_width);
/* initialize the pre-calculated pixel fraction array */
src_col = 0;
x_cum = (gdouble) src_col;
x_last = x_cum;
for (i = 0; i < width + orig_width; i++)
{
if (x_cum + x_rat <= (src_col + 1 + EPSILON))
{
x_cum += x_rat;
x_frac[i] = x_cum - x_last;
}
else
{
src_col++;
x_frac[i] = src_col - x_last;
}
x_last += x_frac[i];
}
/* counters... */
src_row = 0;
y_cum = (gdouble) src_row;
y_last = y_cum;
pixel_region_get_row (srcPR,
srcPR->x,
srcPR->y + src_row * subsample,
orig_width * subsample,
src,
subsample);
/* Scale the selected region */
for (i = 0; i < height; )
{
src_col = 0;
x_cum = (gdouble) src_col;
/* determine the fraction of the src pixel we are using for y */
if (y_cum + y_rat <= (src_row + 1 + EPSILON))
{
y_cum += y_rat;
y_frac = y_cum - y_last;
advance_dest = TRUE;
}
else
{
src_row++;
y_frac = src_row - y_last;
advance_dest = FALSE;
}
y_last += y_frac;
s = src;
r = row;
frac = 0;
j = width;
while (j)
{
tot_frac = x_frac[frac++] * y_frac;
/* If indexed, transform the color to RGB */
if (GIMP_IMAGE_TYPE_IS_INDEXED (type))
{
gint index = *s * 3;
if (has_alpha)
{
if (s[ALPHA_I_PIX] & 0x80)
{
r[RED_PIX] += cmap[index++] * tot_frac;
r[GREEN_PIX] += cmap[index++] * tot_frac;
r[BLUE_PIX] += cmap[index++] * tot_frac;
r[ALPHA_PIX] += tot_frac;
}
/* else the pixel contributes nothing and needs
* not to be added
*/
}
else
{
r[RED_PIX] += cmap[index++] * tot_frac;
r[GREEN_PIX] += cmap[index++] * tot_frac;
r[BLUE_PIX] += cmap[index++] * tot_frac;
}
}
else
{
if (has_alpha)
{
/* premultiply */
gdouble local_frac = tot_frac * (gdouble) s[bytes - 1] / 255.0;
for (b = 0; b < (bytes - 1); b++)
r[b] += s[b] * local_frac;
r[bytes - 1] += local_frac;
}
else
{
for (b = 0; b < bytes; b++)
r[b] += s[b] * tot_frac;
}
}
/* increment the destination */
if (x_cum + x_rat <= (src_col + 1 + EPSILON))
{
r += bytes;
x_cum += x_rat;
j--;
}
/* increment the source */
else
{
s += srcPR->bytes;
src_col++;
}
}
if (advance_dest)
{
tot_frac = 1.0 / (x_rat * y_rat);
/* copy "row" to "dest" */
d = dest;
r = row;
j = width;
while (j--)
{
if (has_alpha)
{
/* unpremultiply */
gdouble alpha = r[bytes - 1];
if (alpha > EPSILON)
{
for (b = 0; b < (bytes - 1); b++)
d[b] = (guchar) ((r[b] / alpha) + 0.5);
d[bytes - 1] = (guchar) ((alpha * tot_frac * 255.0) + 0.5);
}
else
{
for (b = 0; b < bytes; b++)
d[b] = 0;
}
}
else
{
for (b = 0; b < bytes; b++)
d[b] = (guchar) ((r[b] * tot_frac) + 0.5);
}
r += bytes;
d += bytes;
}
dest += destwidth;
/* clear the "row" array */
memset (row, 0, sizeof (gdouble) * destwidth);
i++;
}
else
{
pixel_region_get_row (srcPR,
srcPR->x,
srcPR->y + src_row * subsample,
orig_width * subsample,
src,
subsample);
}
}
/* free up temporary arrays */
g_free (row);
g_free (x_frac);
g_free (src);
}
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