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gimp/app/core/gimpchannel-combine.c

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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 <glib-object.h>
#include "core-types.h"
#include "paint-funcs/paint-funcs.h"
#include "base/pixel-processor.h"
#include "base/pixel-region.h"
#include "gimp-utils.h"
#include "gimpchannel.h"
#include "gimpchannel-combine.h"
void
gimp_channel_add_segment (GimpChannel *mask,
gint x,
gint y,
gint width,
gint value)
{
PixelRegion maskPR;
guchar *data;
gint val;
gint x2;
gpointer pr;
g_return_if_fail (GIMP_IS_CHANNEL (mask));
/* check horizontal extents... */
x2 = x + width;
x2 = CLAMP (x2, 0, GIMP_ITEM (mask)->width);
x = CLAMP (x, 0, GIMP_ITEM (mask)->width);
width = x2 - x;
if (!width)
return;
if (y < 0 || y > GIMP_ITEM (mask)->height)
return;
pixel_region_init (&maskPR, GIMP_DRAWABLE (mask)->tiles,
x, y, width, 1, TRUE);
for (pr = pixel_regions_register (1, &maskPR);
pr != NULL;
pr = pixel_regions_process (pr))
{
data = maskPR.data;
width = maskPR.w;
while (width--)
{
val = *data + value;
if (val > 255)
val = 255;
*data++ = val;
}
}
}
void
gimp_channel_sub_segment (GimpChannel *mask,
gint x,
gint y,
gint width,
gint value)
{
PixelRegion maskPR;
guchar *data;
gint val;
gint x2;
gpointer pr;
g_return_if_fail (GIMP_IS_CHANNEL (mask));
/* check horizontal extents... */
x2 = x + width;
x2 = CLAMP (x2, 0, GIMP_ITEM (mask)->width);
x = CLAMP (x, 0, GIMP_ITEM (mask)->width);
width = x2 - x;
if (! width)
return;
if (y < 0 || y > GIMP_ITEM (mask)->height)
return;
pixel_region_init (&maskPR, GIMP_DRAWABLE (mask)->tiles,
x, y, width, 1, TRUE);
for (pr = pixel_regions_register (1, &maskPR);
pr != NULL;
pr = pixel_regions_process (pr))
{
data = maskPR.data;
width = maskPR.w;
while (width--)
{
val = *data - value;
if (val < 0)
val = 0;
*data++ = val;
}
}
}
void
gimp_channel_combine_rect (GimpChannel *mask,
GimpChannelOps op,
gint x,
gint y,
gint w,
gint h)
{
PixelRegion maskPR;
guchar color;
g_return_if_fail (GIMP_IS_CHANNEL (mask));
if (! gimp_rectangle_intersect (x, y, w, h,
0, 0,
GIMP_ITEM (mask)->width,
GIMP_ITEM (mask)->height,
&x, &y, &w, &h))
return;
pixel_region_init (&maskPR, GIMP_DRAWABLE (mask)->tiles,
x, y, w, h, TRUE);
if (op == GIMP_CHANNEL_OP_ADD || op == GIMP_CHANNEL_OP_REPLACE)
color = OPAQUE_OPACITY;
else
color = TRANSPARENT_OPACITY;
color_region (&maskPR, &color);
/* Determine new boundary */
if (mask->bounds_known && (op == GIMP_CHANNEL_OP_ADD) && !mask->empty)
{
if (x < mask->x1)
mask->x1 = x;
if (y < mask->y1)
mask->y1 = y;
if ((x + w) > mask->x2)
mask->x2 = (x + w);
if ((y + h) > mask->y2)
mask->y2 = (y + h);
}
else if (op == GIMP_CHANNEL_OP_REPLACE || mask->empty)
{
mask->empty = FALSE;
mask->x1 = x;
mask->y1 = y;
mask->x2 = x + w;
mask->y2 = y + h;
}
else
mask->bounds_known = FALSE;
mask->x1 = CLAMP (mask->x1, 0, GIMP_ITEM (mask)->width);
mask->y1 = CLAMP (mask->y1, 0, GIMP_ITEM (mask)->height);
mask->x2 = CLAMP (mask->x2, 0, GIMP_ITEM (mask)->width);
mask->y2 = CLAMP (mask->y2, 0, GIMP_ITEM (mask)->height);
gimp_drawable_update (GIMP_DRAWABLE (mask), x, y, w, h);
}
/**
* gimp_channel_combine_ellipse:
* @mask: the channel with which to combine the ellipse
* @op: whether to replace, add to, or subtract from the current
* contents
* @x: x coordinate of upper left corner of ellipse
* @y: y coordinate of upper left corner of ellipse
* @w: width of ellipse bounding box
* @h: height of ellipse bounding box
* @antialias: if %TRUE, antialias the ellipse
*
* Mainly used for elliptical selections. If @op is
* %GIMP_CHANNEL_OP_REPLACE or %GIMP_CHANNEL_OP_ADD, sets pixels
* within the ellipse to 255. If @op is %GIMP_CHANNEL_OP_SUBTRACT,
* sets pixels within to zero. If @antialias is %TRUE, pixels that
* impinge on the edge of the ellipse are set to intermediate values,
* depending on how much they overlap.
**/
void
gimp_channel_combine_ellipse (GimpChannel *mask,
GimpChannelOps op,
gint x,
gint y,
gint w,
gint h,
gboolean antialias)
{
gint i, j;
gfloat a, b;
gfloat a_sqr, b_sqr, aob_sqr;
gfloat cx, cy;
g_return_if_fail (GIMP_IS_CHANNEL (mask));
if (! gimp_rectangle_intersect (x, y, w, h,
0, 0,
GIMP_ITEM (mask)->width,
GIMP_ITEM (mask)->height,
NULL, NULL, NULL, NULL))
return;
a = w / 2.0;
b = h / 2.0;
a_sqr = SQR (a);
b_sqr = SQR (b);
aob_sqr = a_sqr / b_sqr;
cx = x + a;
cy = y + b;
for (i = y; i < (y + h); i++)
{
if (i >= 0 && i < GIMP_ITEM (mask)->height)
{
if (!antialias)
{
gfloat y_sqr = (i + 0.5 - cy) * (i + 0.5 - cy);
gfloat rad = sqrt (a_sqr - a_sqr * y_sqr / (gdouble) b_sqr);
gint x1 = ROUND (cx - rad);
gint x2 = ROUND (cx + rad);
switch (op)
{
case GIMP_CHANNEL_OP_ADD:
case GIMP_CHANNEL_OP_REPLACE:
gimp_channel_add_segment (mask, x1, i, (x2 - x1), 255);
break;
case GIMP_CHANNEL_OP_SUBTRACT:
gimp_channel_sub_segment (mask, x1, i, (x2 - x1), 255);
break;
default:
g_return_if_reached ();
break;
}
}
else /* antialiasing */
{
/* algorithm changed 7-18-04, because the previous one did not
* work well for eccentric ellipses. The new algorithm
* measures the distance to the ellipse in the X and Y directions,
* and uses trigonometry to approximate the distance to the
* ellipse as the distance to the hypotenuse of a right triangle
* whose legs are the X and Y distances. (WES)
*/
gint val, last;
gint x0;
gfloat xj, yi;
gfloat xdist, ydist;
gfloat r;
gfloat dist;
x0 = x;
yi = ABS (i + 0.5 - cy);
last = 0;
for (j = x; j < (x + w); j++)
{
xj = ABS (j + 0.5 - cx);
if (yi < b)
xdist = xj - a * sqrt (1 - yi * yi / b_sqr);
else
xdist = 100.0; /* anything large will work */
if (xj < a)
ydist = yi - b * sqrt (1 - xj * xj / a_sqr);
else
ydist = 100.0; /* anything large will work */
r = hypot (xdist, ydist);
if (r < 0.001)
dist = 0.;
else
dist = xdist * ydist / r; /* trig formula for distance
* to hypotenuse
*/
if (xdist < 0.0)
dist *= -1;
if (dist < -0.5)
val = 255;
else if (dist < 0.5)
val = (gint) (255 * (1 - (dist + 0.5)));
else
val = 0;
if (last != val && last)
{
switch (op)
{
case GIMP_CHANNEL_OP_ADD:
case GIMP_CHANNEL_OP_REPLACE:
gimp_channel_add_segment (mask, x0, i, j - x0, last);
break;
case GIMP_CHANNEL_OP_SUBTRACT:
gimp_channel_sub_segment (mask, x0, i, j - x0, last);
break;
default:
g_return_if_reached ();
break;
}
}
if (last != val)
{
x0 = j;
last = val;
/* because we are symetric accross the y axis we can
* skip ahead a bit if we are inside the ellipse
*/
if (val == 255 && j < cx)
j = cx + (cx - j) - 1;
}
}
if (last)
{
switch (op)
{
case GIMP_CHANNEL_OP_ADD:
case GIMP_CHANNEL_OP_REPLACE:
gimp_channel_add_segment (mask, x0, i, j - x0, last);
break;
case GIMP_CHANNEL_OP_SUBTRACT:
gimp_channel_sub_segment (mask, x0, i, j - x0, last);
break;
default:
g_return_if_reached ();
break;
}
}
}
}
}
/* determine new boundary */
if (mask->bounds_known && (op == GIMP_CHANNEL_OP_ADD) && !mask->empty)
{
if (x < mask->x1)
mask->x1 = x;
if (y < mask->y1)
mask->y1 = y;
if ((x + w) > mask->x2)
mask->x2 = (x + w);
if ((y + h) > mask->y2)
mask->y2 = (y + h);
}
else if (op == GIMP_CHANNEL_OP_REPLACE || mask->empty)
{
mask->empty = FALSE;
mask->x1 = x;
mask->y1 = y;
mask->x2 = x + w;
mask->y2 = y + h;
}
else
{
mask->bounds_known = FALSE;
}
mask->x1 = CLAMP (mask->x1, 0, GIMP_ITEM (mask)->width);
mask->y1 = CLAMP (mask->y1, 0, GIMP_ITEM (mask)->height);
mask->x2 = CLAMP (mask->x2, 0, GIMP_ITEM (mask)->width);
mask->y2 = CLAMP (mask->y2, 0, GIMP_ITEM (mask)->height);
gimp_drawable_update (GIMP_DRAWABLE (mask), x, y, w, h);
}
static void
gimp_channel_combine_sub_region_add (gpointer unused,
PixelRegion *srcPR,
PixelRegion *destPR)
{
guchar *src, *dest;
gint x, y, val;
src = srcPR->data;
dest = destPR->data;
for (y = 0; y < srcPR->h; y++)
{
for (x = 0; x < srcPR->w; x++)
{
val = dest[x] + src[x];
if (val > 255)
dest[x] = 255;
else
dest[x] = val;
}
src += srcPR->rowstride;
dest += destPR->rowstride;
}
}
static void
gimp_channel_combine_sub_region_sub (gpointer unused,
PixelRegion *srcPR,
PixelRegion *destPR)
{
guchar *src, *dest;
gint x, y;
src = srcPR->data;
dest = destPR->data;
for (y = 0; y < srcPR->h; y++)
{
for (x = 0; x < srcPR->w; x++)
{
if (src[x] > dest[x])
dest[x] = 0;
else
dest[x]-= src[x];
}
src += srcPR->rowstride;
dest += destPR->rowstride;
}
}
static void
gimp_channel_combine_sub_region_intersect (gpointer unused,
PixelRegion *srcPR,
PixelRegion *destPR)
{
guchar *src, *dest;
gint x, y;
src = srcPR->data;
dest = destPR->data;
for (y = 0; y < srcPR->h; y++)
{
for (x = 0; x < srcPR->w; x++)
{
dest[x] = MIN (dest[x], src[x]);
}
src += srcPR->rowstride;
dest += destPR->rowstride;
}
}
void
gimp_channel_combine_mask (GimpChannel *mask,
GimpChannel *add_on,
GimpChannelOps op,
gint off_x,
gint off_y)
{
PixelRegion srcPR, destPR;
gint x, y, w, h;
g_return_if_fail (GIMP_IS_CHANNEL (mask));
g_return_if_fail (GIMP_IS_CHANNEL (add_on));
if (! gimp_rectangle_intersect (off_x, off_y,
GIMP_ITEM (add_on)->width,
GIMP_ITEM (add_on)->height,
0, 0,
GIMP_ITEM (mask)->width,
GIMP_ITEM (mask)->height,
&x, &y, &w, &h))
return;
pixel_region_init (&srcPR, GIMP_DRAWABLE (add_on)->tiles,
x - off_x, y - off_y, w, h, FALSE);
pixel_region_init (&destPR, GIMP_DRAWABLE (mask)->tiles,
x, y, w, h, TRUE);
switch (op)
{
case GIMP_CHANNEL_OP_ADD:
case GIMP_CHANNEL_OP_REPLACE:
pixel_regions_process_parallel ((PixelProcessorFunc)
gimp_channel_combine_sub_region_add,
NULL, 2, &srcPR, &destPR);
break;
case GIMP_CHANNEL_OP_SUBTRACT:
pixel_regions_process_parallel ((PixelProcessorFunc)
gimp_channel_combine_sub_region_sub,
NULL, 2, &srcPR, &destPR);
break;
case GIMP_CHANNEL_OP_INTERSECT:
pixel_regions_process_parallel ((PixelProcessorFunc)
gimp_channel_combine_sub_region_intersect,
NULL, 2, &srcPR, &destPR);
break;
default:
g_warning ("%s: unknown operation type", G_STRFUNC);
break;
}
mask->bounds_known = FALSE;
gimp_drawable_update (GIMP_DRAWABLE (mask), x, y, w, h);
}
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