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gimp/libgimp/gimppixelfetcher.c

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/* LIBGIMP - The GIMP Library
* Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball
*
* gimppixelfetcher.c
*
* This library is free software: you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "gimp.h"
/**
* SECTION: gimppixelfetcher
* @title: gimppixelfetcher
* @short_description: Functions for operating on pixel regions.
*
* These functions provide neighbourhood-based algorithms which get
* dramatically slower on region boundaries, to the point where a
* special treatment for neighbourhoods which are completely inside a
* tile is called for. It hides the special treatment of tile borders,
* making plug-in code more readable and shorter.
**/
struct _GimpPixelFetcher
{
gint col, row;
gint img_width;
gint img_height;
gint sel_x1, sel_y1, sel_x2, sel_y2;
gint img_bpp;
gint tile_width, tile_height;
guchar bg_color[4];
GimpPixelFetcherEdgeMode mode;
GimpDrawable *drawable;
GimpTile *tile;
gboolean tile_dirty;
gboolean shadow;
};
/* local function prototypes */
static guchar * gimp_pixel_fetcher_provide_tile (GimpPixelFetcher *pf,
gint x,
gint y);
/* public functions */
/**
* gimp_pixel_fetcher_new:
* @drawable: the #GimpDrawable the new region will be attached to.
* @shadow: a #gboolean indicating whether the region is attached to
* the shadow tiles or the real @drawable tiles.
*
* Initialize a pixel region from the drawable.
*
* Return value: a pointer to a #GimpPixelRgn structure (or NULL).
**/
GimpPixelFetcher *
gimp_pixel_fetcher_new (GimpDrawable *drawable,
gboolean shadow)
{
GimpPixelFetcher *pf;
gint width;
gint height;
gint bpp;
g_return_val_if_fail (drawable != NULL, NULL);
width = gimp_drawable_width (drawable->drawable_id);
height = gimp_drawable_height (drawable->drawable_id);
bpp = gimp_drawable_bpp (drawable->drawable_id);
g_return_val_if_fail (width > 0 && height > 0 && bpp > 0, NULL);
pf = g_slice_new0 (GimpPixelFetcher);
gimp_drawable_mask_bounds (drawable->drawable_id,
&pf->sel_x1, &pf->sel_y1,
&pf->sel_x2, &pf->sel_y2);
pf->col = -1;
pf->row = -1;
pf->img_width = width;
pf->img_height = height;
pf->img_bpp = bpp;
pf->tile_width = gimp_tile_width ();
pf->tile_height = gimp_tile_height ();
pf->bg_color[0] = 0;
pf->bg_color[1] = 0;
pf->bg_color[2] = 0;
pf->bg_color[3] = 255;
pf->mode = GIMP_PIXEL_FETCHER_EDGE_NONE;
pf->drawable = drawable;
pf->tile = NULL;
pf->tile_dirty = FALSE;
pf->shadow = shadow;
return pf;
}
/**
* gimp_pixel_fetcher_destroy:
* @pf: a pointer to a previously initialized #GimpPixelFetcher.
*
* Close a previously initializd pixel region.
**/
void
gimp_pixel_fetcher_destroy (GimpPixelFetcher *pf)
{
g_return_if_fail (pf != NULL);
if (pf->tile)
gimp_tile_unref (pf->tile, pf->tile_dirty);
g_slice_free (GimpPixelFetcher, pf);
}
/**
* gimp_pixel_fetcher_set_edge_mode:
* @pf: a pointer to a previously initialized #GimpPixelFetcher.
* @mode: the new edge mode from #GimpPixelFetcherEdgeMode.
*
* Change the edage mode of a previously initialized pixel region.
**/
void
gimp_pixel_fetcher_set_edge_mode (GimpPixelFetcher *pf,
GimpPixelFetcherEdgeMode mode)
{
g_return_if_fail (pf != NULL);
pf->mode = mode;
}
/**
* gimp_pixel_fetcher_set_bg_color:
* @pf: a pointer to a previously initialized #GimpPixelFetcher.
* @color: the color to be used as bg color.
*
* Change the background color of a previously initialized pixel region.
**/
void
gimp_pixel_fetcher_set_bg_color (GimpPixelFetcher *pf,
const GimpRGB *color)
{
g_return_if_fail (pf != NULL);
g_return_if_fail (color != NULL);
switch (pf->img_bpp)
{
case 2: pf->bg_color[1] = 255;
case 1:
pf->bg_color[0] = gimp_rgb_luminance_uchar (color);
break;
case 4: pf->bg_color[3] = 255;
case 3:
gimp_rgb_get_uchar (color,
pf->bg_color, pf->bg_color + 1, pf->bg_color + 2);
break;
}
}
/**
* gimp_pixel_fetcher_get_pixel:
* @pf: a pointer to a previously initialized #GimpPixelFetcher.
* @x: the x coordinate of the pixel to get.
* @y: the y coordinate of the pixel to get.
* @pixel: the memory location where to return the pixel.
*
* Get a pixel from the pixel region.
**/
void
gimp_pixel_fetcher_get_pixel (GimpPixelFetcher *pf,
gint x,
gint y,
guchar *pixel)
{
guchar *p;
gint i;
g_return_if_fail (pf != NULL);
g_return_if_fail (pixel != NULL);
if (pf->mode == GIMP_PIXEL_FETCHER_EDGE_NONE &&
(x < pf->sel_x1 || x >= pf->sel_x2 ||
y < pf->sel_y1 || y >= pf->sel_y2))
{
return;
}
if (x < 0 || x >= pf->img_width ||
y < 0 || y >= pf->img_height)
{
switch (pf->mode)
{
case GIMP_PIXEL_FETCHER_EDGE_WRAP:
if (x < 0 || x >= pf->img_width)
{
x %= pf->img_width;
if (x < 0)
x += pf->img_width;
}
if (y < 0 || y >= pf->img_height)
{
y %= pf->img_height;
if (y < 0)
y += pf->img_height;
}
break;
case GIMP_PIXEL_FETCHER_EDGE_SMEAR:
x = CLAMP (x, 0, pf->img_width - 1);
y = CLAMP (y, 0, pf->img_height - 1);
break;
case GIMP_PIXEL_FETCHER_EDGE_BLACK:
for (i = 0; i < pf->img_bpp; i++)
pixel[i] = 0;
return;
case GIMP_PIXEL_FETCHER_EDGE_BACKGROUND:
for (i = 0; i < pf->img_bpp; i++)
pixel[i] = pf->bg_color[i];
return;
default:
return;
}
}
p = gimp_pixel_fetcher_provide_tile (pf, x, y);
i = pf->img_bpp;
do
{
*pixel++ = *p++;
}
while (--i);
}
/**
* gimp_pixel_fetcher_put_pixel:
* @pf: a pointer to a previously initialized #GimpPixelFetcher.
* @x: the x coordinate of the pixel to set.
* @y: the y coordinate of the pixel to set.
* @pixel: the pixel to set.
*
* Set a pixel in the pixel region.
**/
void
gimp_pixel_fetcher_put_pixel (GimpPixelFetcher *pf,
gint x,
gint y,
const guchar *pixel)
{
guchar *p;
gint i;
g_return_if_fail (pf != NULL);
g_return_if_fail (pixel != NULL);
if (x < pf->sel_x1 || x >= pf->sel_x2 ||
y < pf->sel_y1 || y >= pf->sel_y2)
{
return;
}
p = gimp_pixel_fetcher_provide_tile (pf, x, y);
i = pf->img_bpp;
do
{
*p++ = *pixel++;
}
while (--i);
pf->tile_dirty = TRUE;
}
/* private functions */
static guchar *
gimp_pixel_fetcher_provide_tile (GimpPixelFetcher *pf,
gint x,
gint y)
{
gint col, row;
gint coloff, rowoff;
col = x / pf->tile_width;
coloff = x % pf->tile_width;
row = y / pf->tile_height;
rowoff = y % pf->tile_height;
if ((col != pf->col) || (row != pf->row) || (pf->tile == NULL))
{
if (pf->tile != NULL)
gimp_tile_unref (pf->tile, pf->tile_dirty);
pf->tile = gimp_drawable_get_tile (pf->drawable, pf->shadow, row, col);
pf->tile_dirty = FALSE;
gimp_tile_ref (pf->tile);
pf->col = col;
pf->row = row;
}
return pf->tile->data + pf->img_bpp * (pf->tile->ewidth * rowoff + coloff);
}
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