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gimp/app/core/gimpchannel-combine.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 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 <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <string.h>
#include <gegl.h>
#include "libgimpbase/gimpbase.h"
#include "libgimpmath/gimpmath.h"
#include "core-types.h"
#include "paint-funcs/paint-funcs.h"
#include "base/pixel-processor.h"
#include "base/pixel-region.h"
#include "gimpchannel.h"
#include "gimpchannel-combine.h"
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_get_width (GIMP_ITEM (mask)),
gimp_item_get_height (GIMP_ITEM (mask)),
&x, &y, &w, &h))
return;
pixel_region_init (&maskPR, gimp_drawable_get_tiles (GIMP_DRAWABLE (mask)),
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_get_width (GIMP_ITEM (mask)));
mask->y1 = CLAMP (mask->y1, 0, gimp_item_get_height (GIMP_ITEM (mask)));
mask->x2 = CLAMP (mask->x2, 0, gimp_item_get_width (GIMP_ITEM (mask)));
mask->y2 = CLAMP (mask->y2, 0, gimp_item_get_height (GIMP_ITEM (mask)));
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)
{
gimp_channel_combine_ellipse_rect (mask, op, x, y, w, h,
w / 2.0, h / 2.0, antialias);
}
static void
gimp_channel_combine_span (guchar *data,
GimpChannelOps op,
gint x1,
gint x2,
gint value)
{
if (x2 <= x1)
return;
switch (op)
{
case GIMP_CHANNEL_OP_ADD:
case GIMP_CHANNEL_OP_REPLACE:
if (value == 255)
{
memset (data + x1, 255, x2 - x1);
}
else
{
while (x1 < x2)
{
const guint val = data[x1] + value;
data[x1++] = val > 255 ? 255 : val;
}
}
break;
case GIMP_CHANNEL_OP_SUBTRACT:
if (value == 255)
{
memset (data + x1, 0, x2 - x1);
}
else
{
while (x1 < x2)
{
const gint val = data[x1] - value;
data[x1++] = val > 0 ? val : 0;
}
}
break;
case GIMP_CHANNEL_OP_INTERSECT:
/* Should not happen */
break;
}
}
/**
* gimp_channel_combine_ellipse_rect:
* @mask: the channel with which to combine the elliptic rect
* @op: whether to replace, add to, or subtract from the current
* contents
* @x: x coordinate of upper left corner of bounding rect
* @y: y coordinate of upper left corner of bounding rect
* @w: width of bounding rect
* @h: height of bounding rect
* @a: elliptic a-constant applied to corners
* @b: elliptic b-constant applied to corners
* @antialias: if %TRUE, antialias the elliptic corners
*
* Used for rounded cornered rectangles and ellipses. 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_rect (GimpChannel *mask,
GimpChannelOps op,
gint x,
gint y,
gint w,
gint h,
gdouble a,
gdouble b,
gboolean antialias)
{
PixelRegion maskPR;
gdouble a_sqr;
gdouble b_sqr;
gdouble ellipse_center_x;
gint x0, y0;
gint width, height;
gpointer pr;
g_return_if_fail (GIMP_IS_CHANNEL (mask));
g_return_if_fail (a >= 0.0 && b >= 0.0);
g_return_if_fail (op != GIMP_CHANNEL_OP_INTERSECT);
/* Make sure the elliptic corners fit into the rect */
a = MIN (a, w / 2.0);
b = MIN (b, h / 2.0);
a_sqr = SQR (a);
b_sqr = SQR (b);
if (! gimp_rectangle_intersect (x, y, w, h,
0, 0,
gimp_item_get_width (GIMP_ITEM (mask)),
gimp_item_get_height (GIMP_ITEM (mask)),
&x0, &y0, &width, &height))
return;
ellipse_center_x = x + a;
pixel_region_init (&maskPR, gimp_drawable_get_tiles (GIMP_DRAWABLE (mask)),
x0, y0, width, height, TRUE);
for (pr = pixel_regions_register (1, &maskPR);
pr != NULL;
pr = pixel_regions_process (pr))
{
guchar *data = maskPR.data;
gint py;
for (py = maskPR.y;
py < maskPR.y + maskPR.h;
py++, data += maskPR.rowstride)
{
const gint px = maskPR.x;
gdouble ellipse_center_y;
if (py >= y + b && py < y + h - b)
{
/* we are on a row without rounded corners */
gimp_channel_combine_span (data, op, 0, maskPR.w, 255);
continue;
}
/* Match the ellipse center y with our current y */
if (py < y + b)
{
ellipse_center_y = y + b;
}
else
{
ellipse_center_y = y + h - b;
}
/* For a non-antialiased ellipse, use the normal equation
* for an ellipse with an arbitrary center
* (ellipse_center_x, ellipse_center_y).
*/
if (! antialias)
{
gdouble half_ellipse_width_at_y;
gint x_start;
gint x_end;
half_ellipse_width_at_y =
sqrt (a_sqr -
a_sqr * SQR (py + 0.5f - ellipse_center_y) / b_sqr);
x_start = ROUND (ellipse_center_x - half_ellipse_width_at_y);
x_end = ROUND (ellipse_center_x + w - 2 * a +
half_ellipse_width_at_y);
gimp_channel_combine_span (data, op,
MAX (x_start - px, 0),
MIN (x_end - px, maskPR.w), 255);
}
else /* use 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)
*/
const gfloat yi = ABS (py + 0.5 - ellipse_center_y);
gint last_val = 0;
gint x_start = px;
gint cur_x;
for (cur_x = px; cur_x < (px + maskPR.w); cur_x++)
{
gfloat xj;
gfloat xdist;
gfloat ydist;
gfloat r;
gfloat dist;
gint val;
if (cur_x < x + w / 2)
{
ellipse_center_x = x + a;
}
else
{
ellipse_center_x = x + w - a;
}
xj = ABS (cur_x + 0.5 - ellipse_center_x);
if (yi < b)
xdist = xj - a * sqrt (1 - SQR (yi) / b_sqr);
else
xdist = 1000.0; /* anything large will work */
if (xj < a)
ydist = yi - b * sqrt (1 - SQR (xj) / a_sqr);
else
ydist = 1000.0; /* 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;
gimp_channel_combine_span (data, op,
MAX (x_start - px, 0),
MIN (cur_x - px, maskPR.w),
last_val);
if (last_val != val)
{
x_start = cur_x;
last_val = val;
}
/* skip ahead if we are on the straight segment
* between rounded corners
*/
if (cur_x >= x + a && cur_x < x + w - a)
{
x_start = cur_x;
cur_x = x + w - a;
last_val = val = 255;
}
/* Time to change center? */
if (cur_x >= x + w / 2)
{
ellipse_center_x = x + w - a;
}
}
gimp_channel_combine_span (data, op,
MAX (x_start - px, 0),
MIN (cur_x - px, maskPR.w),
last_val);
}
}
}
/* use the intersected values for the boundary calculation */
x = x0;
y = y0;
w = width;
h = height;
/* 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;
}
gimp_drawable_update (GIMP_DRAWABLE (mask), x, y, w, h);
}
static void
gimp_channel_combine_sub_region_add (gpointer unused,
PixelRegion *srcPR,
PixelRegion *destPR)
{
const guchar *src = srcPR->data;
guchar *dest = destPR->data;
gint x, y;
for (y = 0; y < srcPR->h; y++)
{
for (x = 0; x < srcPR->w; x++)
{
const guint val = dest[x] + src[x];
dest[x] = val > 255 ? 255 : val;
}
src += srcPR->rowstride;
dest += destPR->rowstride;
}
}
static void
gimp_channel_combine_sub_region_sub (gpointer unused,
PixelRegion *srcPR,
PixelRegion *destPR)
{
const guchar *src = srcPR->data;
guchar *dest = destPR->data;
gint x, y;
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)
{
const guchar *src = srcPR->data;
guchar *dest = destPR->data;
gint x, y;
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_get_width (GIMP_ITEM (add_on)),
gimp_item_get_height (GIMP_ITEM (add_on)),
0, 0,
gimp_item_get_width (GIMP_ITEM (mask)),
gimp_item_get_height (GIMP_ITEM (mask)),
&x, &y, &w, &h))
return;
pixel_region_init (&srcPR, gimp_drawable_get_tiles (GIMP_DRAWABLE (add_on)),
x - off_x, y - off_y, w, h, FALSE);
pixel_region_init (&destPR, gimp_drawable_get_tiles (GIMP_DRAWABLE (mask)),
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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