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Gimp/app/core/gimpbrush-transform.c
Ell 1c25a2f0bf app: remove double identity check from raster brush transform funcs 
The identity parameter checks added to the raster brush
transformation functions in the previous commit are unnecessary,
since we're already testing for the identity matrix.  Remove them.
2017-06-14 15:47:29 -04:00

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/* GIMP - The GNU Image Manipulation Program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* gimpbrush-transform.c
*
* 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 <gdk-pixbuf/gdk-pixbuf.h>
#include <gegl.h>
#include "libgimpmath/gimpmath.h"
#include "core-types.h"
#include "gegl/gimp-gegl-loops.h"
#include "gimpbrush.h"
#include "gimpbrush-transform.h"
#include "gimptempbuf.h"
/* local function prototypes */
static void gimp_brush_transform_bounding_box (GimpBrush *brush,
const GimpMatrix3 *matrix,
gint *x,
gint *y,
gint *width,
gint *height);
static void gimp_brush_transform_blur (GimpTempBuf *buf,
gint r);
static gint gimp_brush_transform_blur_radius (gint height,
gint width,
gdouble hardness);
static void gimp_brush_transform_adjust_hardness_matrix (gdouble width,
gdouble height,
gdouble blur_radius,
GimpMatrix3 *matrix);
/* public functions */
void
gimp_brush_real_transform_size (GimpBrush *brush,
gdouble scale,
gdouble aspect_ratio,
gdouble angle,
gint *width,
gint *height)
{
GimpMatrix3 matrix;
gint x, y;
gimp_brush_transform_matrix (gimp_brush_get_width (brush),
gimp_brush_get_height (brush),
scale, aspect_ratio, angle, &matrix);
gimp_brush_transform_bounding_box (brush, &matrix, &x, &y, width, height);
}
/*
* Transforms the brush mask with bilinear interpolation.
*
* Rather than calculating the inverse transform for each point in the
* transformed image, this algorithm uses the inverse transformed
* corner points of the destination image to work out the starting
* position in the source image and the U and V deltas in the source
* image space. It then uses a scan-line approach, looping through
* rows and colummns in the transformed (destination) image while
* walking along the corresponding rows and columns (named U and V) in
* the source image.
*
* The horizontal in destination space (transform result) is reverse
* transformed into source image space to get U. The vertical in
* destination space (transform result) is reverse transformed into
* source image space to get V.
*
* The strength of this particular algorithm is that calculation work
* should depend more upon the final transformed brush size rather
* than the input brush size.
*
* There are no floating point calculations in the inner loop for speed.
*
* Some variables end with the suffix _i to indicate they have been
* premultiplied by int_multiple
*/
GimpTempBuf *
gimp_brush_real_transform_mask (GimpBrush *brush,
gdouble scale,
gdouble aspect_ratio,
gdouble angle,
gdouble hardness)
{
GimpTempBuf *result;
GimpTempBuf *source;
guchar *dest;
const guchar *src;
GimpMatrix3 matrix;
gint src_width;
gint src_height;
gint src_width_minus_one;
gint src_height_minus_one;
gint dest_width;
gint dest_height;
gint blur_radius;
gint x, y;
gdouble blx, brx, tlx, trx;
gdouble bly, bry, tly, try;
gdouble src_tl_to_tr_delta_x;
gdouble src_tl_to_tr_delta_y;
gdouble src_tl_to_bl_delta_x;
gdouble src_tl_to_bl_delta_y;
gint src_walk_ux_i;
gint src_walk_uy_i;
gint src_walk_vx_i;
gint src_walk_vy_i;
gint src_space_cur_pos_x;
gint src_space_cur_pos_y;
gint src_space_cur_pos_x_i;
gint src_space_cur_pos_y_i;
gint src_space_row_start_x_i;
gint src_space_row_start_y_i;
const guchar *src_walker;
const guchar *pixel_next;
const guchar *pixel_below;
const guchar *pixel_below_next;
gint opposite_x, distance_from_true_x;
gint opposite_y, distance_from_true_y;
/*
* tl, tr etc are used because it is easier to visualize top left,
* top right etc corners of the forward transformed source image
* rectangle.
*/
const gint fraction_bits = 12;
const gint int_multiple = pow (2, fraction_bits);
/* In inner loop's bilinear calculation, two numbers that were each
* previously multiplied by int_multiple are multiplied together.
* To get back the right result, the multiplication result must be
* divided *twice* by 2^fraction_bits, equivalent to bit shift right
* by 2 * fraction_bits
*/
const gint recovery_bits = 2 * fraction_bits;
/*
* example: suppose fraction_bits = 9
* a 9-bit mask looks like this: 0001 1111 1111
* and is given by: 2^fraction_bits - 1
* demonstration:
* 2^0 = 0000 0000 0001
* 2^1 = 0000 0000 0010
* :
* 2^8 = 0001 0000 0000
* 2^9 = 0010 0000 0000
* 2^9 - 1 = 0001 1111 1111
*/
const guint fraction_bitmask = pow(2, fraction_bits) - 1 ;
source = gimp_brush_get_mask (brush);
src_width = gimp_brush_get_width (brush);
src_height = gimp_brush_get_height (brush);
gimp_brush_transform_matrix (src_width, src_height,
scale, aspect_ratio, angle, &matrix);
if (gimp_matrix3_is_identity (&matrix) && hardness == 1.0)
return gimp_temp_buf_copy (source);
src_width_minus_one = src_width - 1;
src_height_minus_one = src_height - 1;
gimp_brush_transform_bounding_box (brush, &matrix,
&x, &y, &dest_width, &dest_height);
blur_radius = 0;
if (hardness < 1.0)
{
GimpMatrix3 unrotated_matrix;
gint unrotated_x;
gint unrotated_y;
gint unrotated_dest_width;
gint unrotated_dest_height;
gimp_brush_transform_matrix (src_width, src_height,
scale, aspect_ratio, 1.0, &unrotated_matrix);
gimp_brush_transform_bounding_box (brush, &unrotated_matrix,
&unrotated_x, &unrotated_y,
&unrotated_dest_width,
&unrotated_dest_height);
blur_radius = gimp_brush_transform_blur_radius (unrotated_dest_width,
unrotated_dest_height,
hardness);
gimp_brush_transform_adjust_hardness_matrix (dest_width, dest_height,
blur_radius, &matrix);
}
gimp_matrix3_translate (&matrix, -x, -y);
gimp_matrix3_invert (&matrix);
result = gimp_temp_buf_new (dest_width, dest_height,
gimp_temp_buf_get_format (source));
dest = gimp_temp_buf_get_data (result);
src = gimp_temp_buf_get_data (source);
/* prevent disappearance of 1x1 pixel brush at some rotations when
scaling < 1 */
/*
if (src_width == 1 && src_height == 1 && scale_x < 1 && scale_y < 1 )
{
*dest = src[0];
return result;
}*/
gimp_matrix3_transform_point (&matrix, 0, 0, &tlx, &tly);
gimp_matrix3_transform_point (&matrix, dest_width, 0, &trx, &try);
gimp_matrix3_transform_point (&matrix, 0, dest_height, &blx, &bly);
gimp_matrix3_transform_point (&matrix, dest_width, dest_height, &brx, &bry);
/* in image space, calc U (what was horizontal originally)
* note: double precision
*/
src_tl_to_tr_delta_x = trx - tlx;
src_tl_to_tr_delta_y = try - tly;
/* in image space, calc V (what was vertical originally)
* note: double precision
*/
src_tl_to_bl_delta_x = blx - tlx;
src_tl_to_bl_delta_y = bly - tly;
/* speed optimized, note conversion to int precision */
src_walk_ux_i = (gint) ((src_tl_to_tr_delta_x / dest_width) * int_multiple);
src_walk_uy_i = (gint) ((src_tl_to_tr_delta_y / dest_width) * int_multiple);
src_walk_vx_i = (gint) ((src_tl_to_bl_delta_x / dest_height) * int_multiple);
src_walk_vy_i = (gint) ((src_tl_to_bl_delta_y / dest_height) * int_multiple);
/* initialize current position in source space to the start position (tl)
* speed optimized, note conversion to int precision
*/
src_space_cur_pos_x_i = (gint) (tlx* int_multiple);
src_space_cur_pos_y_i = (gint) (tly* int_multiple);
src_space_cur_pos_x = (gint) (src_space_cur_pos_x_i >> fraction_bits);
src_space_cur_pos_y = (gint) (src_space_cur_pos_y_i >> fraction_bits);
src_space_row_start_x_i = (gint) (tlx* int_multiple);
src_space_row_start_y_i = (gint) (tly* int_multiple);
for (y = 0; y < dest_height; y++)
{
for (x = 0; x < dest_width; x++)
{
if (src_space_cur_pos_x > src_width_minus_one ||
src_space_cur_pos_x < 0 ||
src_space_cur_pos_y > src_height_minus_one ||
src_space_cur_pos_y < 0)
/* no corresponding pixel in source space */
{
*dest = 0;
}
else /* reverse transformed point hits source pixel */
{
src_walker = src
+ src_space_cur_pos_y * src_width
+ src_space_cur_pos_x;
/* bottom right corner
* no pixel below, reuse current pixel instead
* no next pixel to the right so reuse current pixel instead
*/
if (src_space_cur_pos_y == src_height_minus_one &&
src_space_cur_pos_x == src_width_minus_one )
{
pixel_next = src_walker;
pixel_below = src_walker;
pixel_below_next = src_walker;
}
/* bottom edge pixel row, except rightmost corner
* no pixel below, reuse current pixel instead */
else if (src_space_cur_pos_y == src_height_minus_one)
{
pixel_next = src_walker + 1;
pixel_below = src_walker;
pixel_below_next = src_walker + 1;
}
/* right edge pixel column, except bottom corner
* no next pixel to the right so reuse current pixel instead */
else if (src_space_cur_pos_x == src_width_minus_one)
{
pixel_next = src_walker;
pixel_below = src_walker + src_width;
pixel_below_next = pixel_below;
}
/* neither on bottom edge nor on right edge */
else
{
pixel_next = src_walker + 1;
pixel_below = src_walker + src_width;
pixel_below_next = pixel_below + 1;
}
distance_from_true_x = src_space_cur_pos_x_i & fraction_bitmask;
distance_from_true_y = src_space_cur_pos_y_i & fraction_bitmask;
opposite_x = int_multiple - distance_from_true_x;
opposite_y = int_multiple - distance_from_true_y;
*dest = ((src_walker[0] * opposite_x +
pixel_next[0] * distance_from_true_x) * opposite_y +
(pixel_below[0] * opposite_x +
pixel_below_next[0] *distance_from_true_x) * distance_from_true_y
) >> recovery_bits;
}
src_space_cur_pos_x_i+=src_walk_ux_i;
src_space_cur_pos_y_i+=src_walk_uy_i;
src_space_cur_pos_x = src_space_cur_pos_x_i >> fraction_bits;
src_space_cur_pos_y = src_space_cur_pos_y_i >> fraction_bits;
dest ++;
} /* end for x */
src_space_row_start_x_i +=src_walk_vx_i;
src_space_row_start_y_i +=src_walk_vy_i;
src_space_cur_pos_x_i = src_space_row_start_x_i;
src_space_cur_pos_y_i = src_space_row_start_y_i;
src_space_cur_pos_x = src_space_cur_pos_x_i >> fraction_bits;
src_space_cur_pos_y = src_space_cur_pos_y_i >> fraction_bits;
} /* end for y */
gimp_brush_transform_blur (result, blur_radius);
return result;
}
/*
* Transforms the brush pixmap with bilinear interpolation.
*
* The algorithm used is exactly the same as for the brush mask
* (gimp_brush_real_transform_mask) except it accounts for 3 color channels
* instead of 1 grayscale channel.
*
* Rather than calculating the inverse transform for each point in the
* transformed image, this algorithm uses the inverse transformed
* corner points of the destination image to work out the starting
* position in the source image and the U and V deltas in the source
* image space. It then uses a scan-line approach, looping through
* rows and colummns in the transformed (destination) image while
* walking along the corresponding rows and columns (named U and V) in
* the source image.
*
* The horizontal in destination space (transform result) is reverse
* transformed into source image space to get U. The vertical in
* destination space (transform result) is reverse transformed into
* source image space to get V.
*
* The strength of this particular algorithm is that calculation work
* should depend more upon the final transformed brush size rather
* than the input brush size.
*
* There are no floating point calculations in the inner loop for speed.
*
* Some variables end with the suffix _i to indicate they have been
* premultiplied by int_multiple
*/
GimpTempBuf *
gimp_brush_real_transform_pixmap (GimpBrush *brush,
gdouble scale,
gdouble aspect_ratio,
gdouble angle,
gdouble hardness)
{
GimpTempBuf *result;
GimpTempBuf *source;
guchar *dest;
const guchar *src;
GimpMatrix3 matrix;
gint src_width;
gint src_height;
gint src_width_minus_one;
gint src_height_minus_one;
gint dest_width;
gint dest_height;
gint blur_radius;
gint x, y;
gdouble blx, brx, tlx, trx;
gdouble bly, bry, tly, try;
gdouble src_tl_to_tr_delta_x;
gdouble src_tl_to_tr_delta_y;
gdouble src_tl_to_bl_delta_x;
gdouble src_tl_to_bl_delta_y;
gint src_walk_ux_i;
gint src_walk_uy_i;
gint src_walk_vx_i;
gint src_walk_vy_i;
gint src_space_cur_pos_x;
gint src_space_cur_pos_y;
gint src_space_cur_pos_x_i;
gint src_space_cur_pos_y_i;
gint src_space_row_start_x_i;
gint src_space_row_start_y_i;
const guchar *src_walker;
const guchar *pixel_next;
const guchar *pixel_below;
const guchar *pixel_below_next;
gint opposite_x, distance_from_true_x;
gint opposite_y, distance_from_true_y;
/*
* tl, tr etc are used because it is easier to visualize top left,
* top right etc corners of the forward transformed source image
* rectangle.
*/
const gint fraction_bits = 12;
const gint int_multiple = pow(2,fraction_bits);
/* In inner loop's bilinear calculation, two numbers that were each
* previously multiplied by int_multiple are multiplied together.
* To get back the right result, the multiplication result must be
* divided *twice* by 2^fraction_bits, equivalent to bit shift right
* by 2 * fraction_bits
*/
const gint recovery_bits = 2 * fraction_bits;
/*
* example: suppose fraction_bits = 9
* a 9-bit mask looks like this: 0001 1111 1111
* and is given by: 2^fraction_bits - 1
* demonstration:
* 2^0 = 0000 0000 0001
* 2^1 = 0000 0000 0010
* :
* 2^8 = 0001 0000 0000
* 2^9 = 0010 0000 0000
* 2^9 - 1 = 0001 1111 1111
*/
const guint fraction_bitmask = pow(2, fraction_bits)- 1 ;
source = gimp_brush_get_pixmap (brush);
src_width = gimp_brush_get_width (brush);
src_height = gimp_brush_get_height (brush);
gimp_brush_transform_matrix (src_width, src_height,
scale, aspect_ratio, angle, &matrix);
if (gimp_matrix3_is_identity (&matrix) && hardness == 1.0)
return gimp_temp_buf_copy (source);
src_width_minus_one = src_width - 1;
src_height_minus_one = src_height - 1;
gimp_brush_transform_bounding_box (brush, &matrix,
&x, &y, &dest_width, &dest_height);
blur_radius = 0;
if (hardness < 1.0)
{
GimpMatrix3 unrotated_matrix;
gint unrotated_x;
gint unrotated_y;
gint unrotated_dest_width;
gint unrotated_dest_height;
gimp_brush_transform_matrix (src_width, src_height,
scale, aspect_ratio, 1.0, &unrotated_matrix);
gimp_brush_transform_bounding_box (brush, &unrotated_matrix,
&unrotated_x, &unrotated_y,
&unrotated_dest_width,
&unrotated_dest_height);
blur_radius = gimp_brush_transform_blur_radius (unrotated_dest_width,
unrotated_dest_height,
hardness);
gimp_brush_transform_adjust_hardness_matrix (dest_width, dest_height,
blur_radius, &matrix);
}
gimp_matrix3_translate (&matrix, -x, -y);
gimp_matrix3_invert (&matrix);
result = gimp_temp_buf_new (dest_width, dest_height,
gimp_temp_buf_get_format (source));
dest = gimp_temp_buf_get_data (result);
src = gimp_temp_buf_get_data (source);
gimp_matrix3_transform_point (&matrix, 0, 0, &tlx, &tly);
gimp_matrix3_transform_point (&matrix, dest_width, 0, &trx, &try);
gimp_matrix3_transform_point (&matrix, 0, dest_height, &blx, &bly);
gimp_matrix3_transform_point (&matrix, dest_width, dest_height, &brx, &bry);
/* in image space, calc U (what was horizontal originally)
* note: double precision
*/
src_tl_to_tr_delta_x = trx - tlx;
src_tl_to_tr_delta_y = try - tly;
/* in image space, calc V (what was vertical originally)
* note: double precision
*/
src_tl_to_bl_delta_x = blx - tlx;
src_tl_to_bl_delta_y = bly - tly;
/* speed optimized, note conversion to int precision */
src_walk_ux_i = (gint) ((src_tl_to_tr_delta_x / dest_width)* int_multiple);
src_walk_uy_i = (gint) ((src_tl_to_tr_delta_y / dest_width)* int_multiple);
src_walk_vx_i = (gint) ((src_tl_to_bl_delta_x / dest_height)* int_multiple);
src_walk_vy_i = (gint) ((src_tl_to_bl_delta_y / dest_height)* int_multiple);
/* initialize current position in source space to the start position (tl)
* speed optimized, note conversion to int precision
*/
src_space_cur_pos_x_i = (gint) (tlx* int_multiple);
src_space_cur_pos_y_i = (gint) (tly* int_multiple);
src_space_cur_pos_x = (gint) (src_space_cur_pos_x_i >> fraction_bits);
src_space_cur_pos_y = (gint) (src_space_cur_pos_y_i >> fraction_bits);
src_space_row_start_x_i = (gint) (tlx* int_multiple);
src_space_row_start_y_i = (gint) (tly* int_multiple);
for (y = 0; y < dest_height; y++)
{
for (x = 0; x < dest_width; x++)
{
if (src_space_cur_pos_x > src_width_minus_one ||
src_space_cur_pos_x < 0 ||
src_space_cur_pos_y > src_height_minus_one ||
src_space_cur_pos_y < 0)
/* no corresponding pixel in source space */
{
dest[0] = 0;
dest[1] = 0;
dest[2] = 0;
}
else /* reverse transformed point hits source pixel */
{
src_walker = src
+ 3 * (
src_space_cur_pos_y * src_width
+ src_space_cur_pos_x);
/* bottom right corner
* no pixel below, reuse current pixel instead
* no next pixel to the right so reuse current pixel instead
*/
if (src_space_cur_pos_y == src_height_minus_one &&
src_space_cur_pos_x == src_width_minus_one )
{
pixel_next = src_walker;
pixel_below = src_walker;
pixel_below_next = src_walker;
}
/* bottom edge pixel row, except rightmost corner
* no pixel below, reuse current pixel instead */
else if (src_space_cur_pos_y == src_height_minus_one)
{
pixel_next = src_walker + 3;
pixel_below = src_walker;
pixel_below_next = src_walker + 3;
}
/* right edge pixel column, except bottom corner
* no next pixel to the right so reuse current pixel instead */
else if (src_space_cur_pos_x == src_width_minus_one)
{
pixel_next = src_walker;
pixel_below = src_walker + src_width * 3;
pixel_below_next = pixel_below;
}
/* neither on bottom edge nor on right edge */
else
{
pixel_next = src_walker + 3;
pixel_below = src_walker + src_width * 3;
pixel_below_next = pixel_below + 3;
}
distance_from_true_x = src_space_cur_pos_x_i & fraction_bitmask;
distance_from_true_y = src_space_cur_pos_y_i & fraction_bitmask;
opposite_x = int_multiple - distance_from_true_x;
opposite_y = int_multiple - distance_from_true_y;
dest[0] = ((src_walker[0] * opposite_x +
pixel_next[0] * distance_from_true_x) * opposite_y +
(pixel_below[0] * opposite_x +
pixel_below_next[0] *distance_from_true_x) * distance_from_true_y
) >> recovery_bits;
dest[1] = ((src_walker[1] * opposite_x +
pixel_next[1] * distance_from_true_x) * opposite_y +
(pixel_below[1] * opposite_x +
pixel_below_next[1] *distance_from_true_x) * distance_from_true_y
) >> recovery_bits;
dest[2] = ((src_walker[2] * opposite_x +
pixel_next[2] * distance_from_true_x) * opposite_y +
(pixel_below[2] * opposite_x +
pixel_below_next[2] *distance_from_true_x) * distance_from_true_y
) >> recovery_bits;
}
src_space_cur_pos_x_i += src_walk_ux_i;
src_space_cur_pos_y_i += src_walk_uy_i;
src_space_cur_pos_x = src_space_cur_pos_x_i >> fraction_bits;
src_space_cur_pos_y = src_space_cur_pos_y_i >> fraction_bits;
dest += 3;
} /* end for x */
src_space_row_start_x_i +=src_walk_vx_i;
src_space_row_start_y_i +=src_walk_vy_i;
src_space_cur_pos_x_i = src_space_row_start_x_i;
src_space_cur_pos_y_i = src_space_row_start_y_i;
src_space_cur_pos_x = src_space_cur_pos_x_i >> fraction_bits;
src_space_cur_pos_y = src_space_cur_pos_y_i >> fraction_bits;
} /* end for y */
gimp_brush_transform_blur (result, blur_radius);
return result;
}
void
gimp_brush_transform_matrix (gdouble width,
gdouble height,
gdouble scale,
gdouble aspect_ratio,
gdouble angle,
GimpMatrix3 *matrix)
{
const gdouble center_x = width / 2;
const gdouble center_y = height / 2;
gdouble scale_x = scale;
gdouble scale_y = scale;
if (aspect_ratio < 0.0)
{
scale_x = scale * (1.0 - (fabs (aspect_ratio) / 20.0));
scale_y = scale;
}
else if (aspect_ratio > 0.0)
{
scale_x = scale;
scale_y = scale * (1.0 - (aspect_ratio / 20.0));
}
gimp_matrix3_identity (matrix);
gimp_matrix3_scale (matrix, scale_x, scale_y);
gimp_matrix3_translate (matrix, - center_x * scale_x, - center_y * scale_y);
gimp_matrix3_rotate (matrix, -2 * G_PI * angle);
gimp_matrix3_translate (matrix, center_x * scale_x, center_y * scale_y);
}
/* private functions */
static void
gimp_brush_transform_bounding_box (GimpBrush *brush,
const GimpMatrix3 *matrix,
gint *x,
gint *y,
gint *width,
gint *height)
{
const gdouble w = gimp_brush_get_width (brush);
const gdouble h = gimp_brush_get_height (brush);
gdouble x1, x2, x3, x4;
gdouble y1, y2, y3, y4;
gdouble temp_x;
gdouble temp_y;
gimp_matrix3_transform_point (matrix, 0, 0, &x1, &y1);
gimp_matrix3_transform_point (matrix, w, 0, &x2, &y2);
gimp_matrix3_transform_point (matrix, 0, h, &x3, &y3);
gimp_matrix3_transform_point (matrix, w, h, &x4, &y4);
temp_x = MIN (MIN (x1, x2), MIN (x3, x4));
temp_y = MIN (MIN (y1, y2), MIN (y3, y4));
*width = (gint) ceil (MAX (MAX (x1, x2), MAX (x3, x4)) - temp_x);
*height = (gint) ceil (MAX (MAX (y1, y2), MAX (y3, y4)) - temp_y);
*x = floor (temp_x);
*y = floor (temp_y);
/* Transform size can not be less than 1 px */
*width = MAX (1, *width);
*height = MAX (1, *height);
}
/* Blurs the brush mask/pixmap, in place, using a convolution of the form:
*
* 12 11 10 9 8
* 7 6 5 4 3
* 2 1 0 1 2
* 3 4 5 6 7
* 8 9 10 11 12
*
* (i.e., an array, wrapped into a matrix, whose i-th element is
* `abs (i - a / 2)`, where `a` is the length of the array.) `r` specifies the
* convolution kernel's radius.
*/
static void
gimp_brush_transform_blur (GimpTempBuf *buf,
gint r)
{
typedef struct
{
gint sum;
gint weighted_sum;
gint middle_sum;
} Sums;
const Babl *format = gimp_temp_buf_get_format (buf);
gint components = babl_format_get_n_components (format);
gint components_r = components * r;
gint width = gimp_temp_buf_get_width (buf);
gint height = gimp_temp_buf_get_height (buf);
gint stride = components * width;
gint stride_r = stride * r;
guchar *data = gimp_temp_buf_get_data (buf);
gint rw = MIN (r, width - 1);
gint rh = MIN (r, height - 1);
gfloat n = 2 * r + 1;
gfloat n_r = n * r;
gfloat weight = floor (n * n / 2) * (floor (n * n / 2) + 1);
gfloat weight_inv = 1 / weight;
gint x;
gint y;
gint c;
Sums *sums;
guchar *d;
Sums *s;
if (rw <= 0 || rh <= 0)
return;
sums = g_new (Sums, width * height * components);
d = data;
s = sums;
for (y = 0; y < height; y++)
{
const guchar *p;
struct
{
gint sum;
gint weighted_sum;
gint leading_sum;
gint leading_weighted_sum;
} acc[components];
memset (acc, 0, sizeof (acc));
p = d;
for (x = 0; x <= rw; x++)
{
for (c = 0; c < components; c++)
{
acc[c].sum += *p;
acc[c].weighted_sum += -x * *p;
p++;
}
}
for (x = 0; x < width; x++)
{
for (c = 0; c < components; c++)
{
if (x > 0)
{
acc[c].weighted_sum += acc[c].sum;
acc[c].leading_weighted_sum += acc[c].leading_sum;
if (x < width - r)
{
acc[c].sum += d[components_r];
acc[c].weighted_sum += -r * d[components_r];
}
}
acc[c].leading_sum += d[0];
s->sum = acc[c].sum;
s->weighted_sum = acc[c].weighted_sum;
s->middle_sum = 2 * acc[c].leading_weighted_sum -
acc[c].weighted_sum;
if (x >= r)
{
acc[c].sum -= d[-components_r];
acc[c].weighted_sum -= r * d[-components_r];
acc[c].leading_sum -= d[-components_r];
acc[c].leading_weighted_sum -= r * d[-components_r];
}
d++;
s++;
}
}
}
for (x = 0; x < width; x++)
{
const Sums *p;
gfloat n_y;
struct
{
gfloat weighted_sum;
gint leading_sum;
gint trailing_sum;
} acc[components];
memset (acc, 0, sizeof (acc));
d = data + components * x;
s = sums + components * x;
p = s + stride;
for (y = 1, n_y = n; y <= rh; y++, n_y += n)
{
for (c = 0; c < components; c++)
{
acc[c].weighted_sum += n_y * p->sum - p->weighted_sum;
acc[c].trailing_sum += p->sum;
p++;
}
p += stride - components;
}
for (y = 0; y < height; y++)
{
for (c = 0; c < components; c++)
{
if (y > 0)
{
acc[c].weighted_sum += s->weighted_sum +
n * (acc[c].leading_sum -
acc[c].trailing_sum);
acc[c].trailing_sum -= s->sum;
if (y < height - r)
{
acc[c].weighted_sum += n_r * s[stride_r].sum -
s[stride_r].weighted_sum;
acc[c].trailing_sum += s[stride_r].sum;
}
}
acc[c].leading_sum += s->sum;
*d = (acc[c].weighted_sum + s->middle_sum) * weight_inv + 0.5f;
acc[c].weighted_sum += s->weighted_sum;
if (y >= r)
{
acc[c].weighted_sum -= n_r * s[-stride_r].sum +
s[-stride_r].weighted_sum;
acc[c].leading_sum -= s[-stride_r].sum;
}
d++;
s++;
}
d += stride - components;
s += stride - components;
}
}
g_free (sums);
}
static gint
gimp_brush_transform_blur_radius (gint height,
gint width,
gdouble hardness)
{
return floor ((1.0 - hardness) * (sqrt (0.5) - 0.5) * MIN (width, height));
}
static void
gimp_brush_transform_adjust_hardness_matrix (gdouble width,
gdouble height,
gdouble blur_radius,
GimpMatrix3 *matrix)
{
gdouble scale;
if (blur_radius == 0.0)
return;
scale = (MIN (width, height) - 2.0 * blur_radius) / MIN (width, height);
gimp_matrix3_scale (matrix, scale, scale);
gimp_matrix3_translate (matrix,
(1.0 - scale) * width / 2.0,
(1.0 - scale) * height / 2.0);
}
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