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gimp/app/core/gimpgradient.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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <glib-object.h>
#include "libgimpcolor/gimpcolor.h"
#include "libgimpmath/gimpmath.h"
#include "libgimpbase/gimpbase.h"
#include "core-types.h"
#include "base/temp-buf.h"
#include "gimpimage.h"
#include "gimpgradient.h"
#include "libgimp/gimpintl.h"
#define EPSILON 1e-10
static void gimp_gradient_class_init (GimpGradientClass *klass);
static void gimp_gradient_init (GimpGradient *gradient);
static void gimp_gradient_finalize (GObject *object);
static gsize gimp_gradient_get_memsize (GimpObject *object);
static void gimp_gradient_get_preview_size (GimpViewable *viewable,
gint size,
gboolean popup,
gboolean dot_for_dot,
gint *width,
gint *height);
static gboolean gimp_gradient_get_popup_size (GimpViewable *viewable,
gint width,
gint height,
gboolean dot_for_dot,
gint *popup_width,
gint *popup_height);
static TempBuf * gimp_gradient_get_new_preview (GimpViewable *viewable,
gint width,
gint height);
static void gimp_gradient_dirty (GimpData *data);
static gboolean gimp_gradient_save (GimpData *data,
GError **error);
static gchar * gimp_gradient_get_extension (GimpData *data);
static GimpData * gimp_gradient_duplicate (GimpData *data,
gboolean stingy_memory_use);
static gdouble gimp_gradient_calc_linear_factor (gdouble middle,
gdouble pos);
static gdouble gimp_gradient_calc_curved_factor (gdouble middle,
gdouble pos);
static gdouble gimp_gradient_calc_sine_factor (gdouble middle,
gdouble pos);
static gdouble gimp_gradient_calc_sphere_increasing_factor (gdouble middle,
gdouble pos);
static gdouble gimp_gradient_calc_sphere_decreasing_factor (gdouble middle,
gdouble pos);
static GimpDataClass *parent_class = NULL;
GType
gimp_gradient_get_type (void)
{
static GType gradient_type = 0;
if (! gradient_type)
{
static const GTypeInfo gradient_info =
{
sizeof (GimpGradientClass),
(GBaseInitFunc) NULL,
(GBaseFinalizeFunc) NULL,
(GClassInitFunc) gimp_gradient_class_init,
NULL, /* class_finalize */
NULL, /* class_data */
sizeof (GimpGradient),
0, /* n_preallocs */
(GInstanceInitFunc) gimp_gradient_init,
};
gradient_type = g_type_register_static (GIMP_TYPE_DATA,
"GimpGradient",
&gradient_info, 0);
}
return gradient_type;
}
static void
gimp_gradient_class_init (GimpGradientClass *klass)
{
GObjectClass *object_class;
GimpObjectClass *gimp_object_class;
GimpViewableClass *viewable_class;
GimpDataClass *data_class;
object_class = G_OBJECT_CLASS (klass);
gimp_object_class = GIMP_OBJECT_CLASS (klass);
viewable_class = GIMP_VIEWABLE_CLASS (klass);
data_class = GIMP_DATA_CLASS (klass);
parent_class = g_type_class_peek_parent (klass);
object_class->finalize = gimp_gradient_finalize;
gimp_object_class->get_memsize = gimp_gradient_get_memsize;
viewable_class->get_preview_size = gimp_gradient_get_preview_size;
viewable_class->get_popup_size = gimp_gradient_get_popup_size;
viewable_class->get_new_preview = gimp_gradient_get_new_preview;
data_class->dirty = gimp_gradient_dirty;
data_class->save = gimp_gradient_save;
data_class->get_extension = gimp_gradient_get_extension;
data_class->duplicate = gimp_gradient_duplicate;
}
static void
gimp_gradient_init (GimpGradient *gradient)
{
gradient->segments = NULL;
gradient->last_visited = NULL;
}
static void
gimp_gradient_finalize (GObject *object)
{
GimpGradient *gradient;
gradient = GIMP_GRADIENT (object);
if (gradient->segments)
{
gimp_gradient_segments_free (gradient->segments);
gradient->segments = NULL;
}
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static gsize
gimp_gradient_get_memsize (GimpObject *object)
{
GimpGradient *gradient;
GimpGradientSegment *segment;
gsize memsize = 0;
gradient = GIMP_GRADIENT (object);
for (segment = gradient->segments; segment; segment = segment->next)
{
memsize += sizeof (GimpGradientSegment);
}
return memsize + GIMP_OBJECT_CLASS (parent_class)->get_memsize (object);
}
static void
gimp_gradient_get_preview_size (GimpViewable *viewable,
gint size,
gboolean popup,
gboolean dot_for_dot,
gint *width,
gint *height)
{
*width = size;
*height = size / 2;
}
static gboolean
gimp_gradient_get_popup_size (GimpViewable *viewable,
gint width,
gint height,
gboolean dot_for_dot,
gint *popup_width,
gint *popup_height)
{
if (width < 128 || height < 32)
{
*popup_width = 128;
*popup_height = 32;
return TRUE;
}
return FALSE;
}
static TempBuf *
gimp_gradient_get_new_preview (GimpViewable *viewable,
gint width,
gint height)
{
GimpGradient *gradient;
TempBuf *temp_buf;
guchar *buf;
guchar *p;
guchar *row;
gint x, y;
gdouble dx, cur_x;
GimpRGB color;
gradient = GIMP_GRADIENT (viewable);
dx = 1.0 / (width - 1);
cur_x = 0.0;
p = row = g_malloc (width * 4);
/* Create lines to fill the image */
for (x = 0; x < width; x++)
{
gimp_gradient_get_color_at (gradient, cur_x, &color);
*p++ = color.r * 255.0;
*p++ = color.g * 255.0;
*p++ = color.b * 255.0;
*p++ = color.a * 255.0;
cur_x += dx;
}
temp_buf = temp_buf_new (width, height, 4, 0, 0, NULL);
buf = temp_buf_data (temp_buf);
for (y = 0; y < height; y++)
memcpy (buf + (width * y * 4), row, width * 4);
g_free (row);
return temp_buf;
}
static GimpData *
gimp_gradient_duplicate (GimpData *data,
gboolean stingy_memory_use)
{
GimpGradient *gradient;
GimpGradientSegment *head, *prev, *cur, *orig;
gradient = GIMP_GRADIENT (g_object_new (GIMP_TYPE_GRADIENT, NULL));
gimp_data_dirty (GIMP_DATA (gradient));
prev = NULL;
orig = GIMP_GRADIENT (data)->segments;
head = NULL;
while (orig)
{
cur = gimp_gradient_segment_new ();
*cur = *orig; /* Copy everything */
cur->prev = prev;
cur->next = NULL;
if (prev)
prev->next = cur;
else
head = cur; /* Remember head */
prev = cur;
orig = orig->next;
}
gradient->segments = head;
return GIMP_DATA (gradient);
}
GimpData *
gimp_gradient_new (const gchar *name,
gboolean stingy_memory_use)
{
GimpGradient *gradient;
g_return_val_if_fail (name != NULL, NULL);
gradient = GIMP_GRADIENT (g_object_new (GIMP_TYPE_GRADIENT, NULL));
gimp_object_set_name (GIMP_OBJECT (gradient), name);
gradient->segments = gimp_gradient_segment_new ();
return GIMP_DATA (gradient);
}
GimpData *
gimp_gradient_get_standard (void)
{
static GimpGradient *standard_gradient = NULL;
if (! standard_gradient)
{
standard_gradient = GIMP_GRADIENT (gimp_gradient_new ("Standard", FALSE));
g_object_ref (standard_gradient);
}
return GIMP_DATA (standard_gradient);
}
GimpData *
gimp_gradient_load (const gchar *filename,
gboolean stingy_memory_use,
GError **error)
{
GimpGradient *gradient;
GimpGradientSegment *seg;
GimpGradientSegment *prev;
gint num_segments;
gint i;
gint type, color;
FILE *file;
gchar line[1024];
g_return_val_if_fail (filename != NULL, NULL);
g_return_val_if_fail (error == NULL || *error == NULL, NULL);
file = fopen (filename, "rb");
if (!file)
{
g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_OPEN,
_("Could not open '%s' for reading: %s"),
filename, g_strerror (errno));
return NULL;
}
fgets (line, 1024, file);
if (strcmp (line, "GIMP Gradient\n") != 0)
{
g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
_("Fatal Parse Error: '%s' is not a GIMP Gradient file"),
filename);
fclose (file);
return NULL;
}
gradient = GIMP_GRADIENT (g_object_new (GIMP_TYPE_GRADIENT, NULL));
gimp_data_set_filename (GIMP_DATA (gradient), filename);
fgets (line, 1024, file);
if (! strncmp (line, "Name: ", strlen ("Name: ")))
{
if (g_utf8_validate (line, -1, NULL))
{
gimp_object_set_name (GIMP_OBJECT (gradient),
g_strstrip (&line[strlen ("Name: ")]));
}
else
{
g_message (_("Invalid UTF-8 string in gradient file '%s'."),
filename);
gimp_object_set_name (GIMP_OBJECT (gradient), _("Unnamed"));
}
fgets (line, 1024, file);
}
else /* old gradient format */
{
gchar *basename;
basename = g_path_get_basename (filename);
gimp_object_set_name (GIMP_OBJECT (gradient), basename);
g_free (basename);
}
num_segments = atoi (line);
if (num_segments < 1)
{
g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_READ,
_("Fatal parsing error:\nGradient file '%s' is corrupt."),
filename);
g_object_unref (gradient);
fclose (file);
return NULL;
}
prev = NULL;
for (i = 0; i < num_segments; i++)
{
gchar *end;
seg = gimp_gradient_segment_new ();
seg->prev = prev;
if (prev)
prev->next = seg;
else
gradient->segments = seg;
fgets (line, 1024, file);
seg->left = g_ascii_strtod (line, &end);
if (end && errno != ERANGE)
seg->middle = g_ascii_strtod (end, &end);
if (end && errno != ERANGE)
seg->right = g_ascii_strtod (end, &end);
if (end && errno != ERANGE)
seg->left_color.r = g_ascii_strtod (end, &end);
if (end && errno != ERANGE)
seg->left_color.g = g_ascii_strtod (end, &end);
if (end && errno != ERANGE)
seg->left_color.b = g_ascii_strtod (end, &end);
if (end && errno != ERANGE)
seg->left_color.a = g_ascii_strtod (end, &end);
if (end && errno != ERANGE)
seg->right_color.r = g_ascii_strtod (end, &end);
if (end && errno != ERANGE)
seg->right_color.g = g_ascii_strtod (end, &end);
if (end && errno != ERANGE)
seg->right_color.b = g_ascii_strtod (end, &end);
if (end && errno != ERANGE)
seg->right_color.a = g_ascii_strtod (end, &end);
if (errno != ERANGE &&
sscanf (end, "%d %d", &type, &color) == 2)
{
seg->type = (GimpGradientSegmentType) type;
seg->color = (GimpGradientSegmentColor) color;
}
else
{
g_message (_("Corrupt segment %d in gradient file '%s'."),
i, filename);
}
prev = seg;
}
fclose (file);
GIMP_DATA (gradient)->dirty = FALSE;
return GIMP_DATA (gradient);
}
static void
gimp_gradient_dirty (GimpData *data)
{
GimpGradient *gradient;
gradient = GIMP_GRADIENT (data);
gradient->last_visited = NULL;
if (GIMP_DATA_CLASS (parent_class)->dirty)
GIMP_DATA_CLASS (parent_class)->dirty (data);
}
static gboolean
gimp_gradient_save (GimpData *data,
GError **error)
{
GimpGradient *gradient;
GimpGradientSegment *seg;
gint num_segments;
FILE *file;
gradient = GIMP_GRADIENT (data);
file = fopen (data->filename, "wb");
if (! file)
{
g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_OPEN,
_("Could not open '%s' for writing: %s"),
data->filename, g_strerror (errno));
return FALSE;
}
/* File format is:
*
* GIMP Gradient
* Name: name
* number_of_segments
* left middle right r0 g0 b0 a0 r1 g1 b1 a1 type coloring
* left middle right r0 g0 b0 a0 r1 g1 b1 a1 type coloring
* ...
*/
fprintf (file, "GIMP Gradient\n");
fprintf (file, "Name: %s\n", GIMP_OBJECT (gradient)->name);
/* Count number of segments */
num_segments = 0;
seg = gradient->segments;
while (seg)
{
num_segments++;
seg = seg->next;
}
/* Write rest of file */
fprintf (file, "%d\n", num_segments);
for (seg = gradient->segments; seg; seg = seg->next)
{
gchar buf[11][G_ASCII_DTOSTR_BUF_SIZE];
g_ascii_formatd (buf[0], G_ASCII_DTOSTR_BUF_SIZE, "%f", seg->left);
g_ascii_formatd (buf[1], G_ASCII_DTOSTR_BUF_SIZE, "%f", seg->middle);
g_ascii_formatd (buf[2], G_ASCII_DTOSTR_BUF_SIZE, "%f", seg->right);
g_ascii_formatd (buf[3], G_ASCII_DTOSTR_BUF_SIZE, "%f", seg->left_color.r);
g_ascii_formatd (buf[4], G_ASCII_DTOSTR_BUF_SIZE, "%f", seg->left_color.g);
g_ascii_formatd (buf[5], G_ASCII_DTOSTR_BUF_SIZE, "%f", seg->left_color.b);
g_ascii_formatd (buf[6], G_ASCII_DTOSTR_BUF_SIZE, "%f", seg->left_color.a);
g_ascii_formatd (buf[7], G_ASCII_DTOSTR_BUF_SIZE, "%f", seg->right_color.r);
g_ascii_formatd (buf[8], G_ASCII_DTOSTR_BUF_SIZE, "%f", seg->right_color.g);
g_ascii_formatd (buf[9], G_ASCII_DTOSTR_BUF_SIZE, "%f", seg->right_color.b);
g_ascii_formatd (buf[10], G_ASCII_DTOSTR_BUF_SIZE, "%f", seg->right_color.a);
fprintf (file, "%s %s %s %s %s %s %s %s %s %s %s %d %d\n",
buf[0], buf[1], buf[2], buf[3], buf[4],
buf[5], buf[6], buf[7], buf[8], buf[9], buf[10],
(gint) seg->type,
(gint) seg->color);
}
fclose (file);
return TRUE;
}
static gchar *
gimp_gradient_get_extension (GimpData *data)
{
return GIMP_GRADIENT_FILE_EXTENSION;
}
gboolean
gimp_gradient_save_as_pov (GimpGradient *gradient,
const gchar *filename,
GError **error)
{
FILE *file;
GimpGradientSegment *seg;
gchar buf[G_ASCII_DTOSTR_BUF_SIZE];
gchar color_buf[4][G_ASCII_DTOSTR_BUF_SIZE];
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), FALSE);
g_return_val_if_fail (filename != NULL, FALSE);
g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
file = fopen (filename, "wb");
if (! file)
{
g_set_error (error, GIMP_DATA_ERROR, GIMP_DATA_ERROR_OPEN,
_("Could not open '%s' for writing: %s"),
filename, g_strerror (errno));
return FALSE;
}
else
{
fprintf (file, "/* color_map file created by the GIMP */\n");
fprintf (file, "/* http://www.gimp.org/ */\n");
fprintf (file, "color_map {\n");
for (seg = gradient->segments; seg; seg = seg->next)
{
/* Left */
g_ascii_formatd (buf, G_ASCII_DTOSTR_BUF_SIZE, "%f",
seg->left);
g_ascii_formatd (color_buf[0], G_ASCII_DTOSTR_BUF_SIZE, "%f",
seg->left_color.r);
g_ascii_formatd (color_buf[1], G_ASCII_DTOSTR_BUF_SIZE, "%f",
seg->left_color.g);
g_ascii_formatd (color_buf[2], G_ASCII_DTOSTR_BUF_SIZE, "%f",
seg->left_color.b);
g_ascii_formatd (color_buf[3], G_ASCII_DTOSTR_BUF_SIZE, "%f",
1.0 - seg->left_color.a);
fprintf (file, "\t[%s color rgbt <%s, %s, %s, %s>]\n",
buf,
color_buf[0], color_buf[1], color_buf[2], color_buf[3]);
/* Middle */
g_ascii_formatd (buf, G_ASCII_DTOSTR_BUF_SIZE, "%f",
seg->middle);
g_ascii_formatd (color_buf[0], G_ASCII_DTOSTR_BUF_SIZE, "%f",
(seg->left_color.r + seg->right_color.r) / 2.0);
g_ascii_formatd (color_buf[1], G_ASCII_DTOSTR_BUF_SIZE, "%f",
(seg->left_color.g + seg->right_color.g) / 2.0);
g_ascii_formatd (color_buf[2], G_ASCII_DTOSTR_BUF_SIZE, "%f",
(seg->left_color.b + seg->right_color.b) / 2.0);
g_ascii_formatd (color_buf[3], G_ASCII_DTOSTR_BUF_SIZE, "%f",
1.0 - (seg->left_color.a + seg->right_color.a) / 2.0);
fprintf (file, "\t[%s color rgbt <%s, %s, %s, %s>]\n",
buf,
color_buf[0], color_buf[1], color_buf[2], color_buf[3]);
/* Right */
g_ascii_formatd (buf, G_ASCII_DTOSTR_BUF_SIZE, "%f",
seg->right);
g_ascii_formatd (color_buf[0], G_ASCII_DTOSTR_BUF_SIZE, "%f",
seg->right_color.r);
g_ascii_formatd (color_buf[1], G_ASCII_DTOSTR_BUF_SIZE, "%f",
seg->right_color.g);
g_ascii_formatd (color_buf[2], G_ASCII_DTOSTR_BUF_SIZE, "%f",
seg->right_color.b);
g_ascii_formatd (color_buf[3], G_ASCII_DTOSTR_BUF_SIZE, "%f",
1.0 - seg->right_color.a);
fprintf (file, "\t[%s color rgbt <%s, %s, %s, %s>]\n",
buf,
color_buf[0], color_buf[1], color_buf[2], color_buf[3]);
}
fprintf (file, "} /* color_map */\n");
fclose (file);
}
return TRUE;
}
void
gimp_gradient_get_color_at (GimpGradient *gradient,
gdouble pos,
GimpRGB *color)
{
gdouble factor = 0.0;
GimpGradientSegment *seg;
gdouble seg_len;
gdouble middle;
GimpRGB rgb;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (color != NULL);
/* if there is no gradient return a totally transparent black */
if (gradient == NULL)
{
gimp_rgba_set (color, 0.0, 0.0, 0.0, 0.0);
return;
}
if (pos < 0.0)
pos = 0.0;
else if (pos > 1.0)
pos = 1.0;
seg = gimp_gradient_get_segment_at (gradient, pos);
seg_len = seg->right - seg->left;
if (seg_len < EPSILON)
{
middle = 0.5;
pos = 0.5;
}
else
{
middle = (seg->middle - seg->left) / seg_len;
pos = (pos - seg->left) / seg_len;
}
switch (seg->type)
{
case GIMP_GRAD_LINEAR:
factor = gimp_gradient_calc_linear_factor (middle, pos);
break;
case GIMP_GRAD_CURVED:
factor = gimp_gradient_calc_curved_factor (middle, pos);
break;
case GIMP_GRAD_SINE:
factor = gimp_gradient_calc_sine_factor (middle, pos);
break;
case GIMP_GRAD_SPHERE_INCREASING:
factor = gimp_gradient_calc_sphere_increasing_factor (middle, pos);
break;
case GIMP_GRAD_SPHERE_DECREASING:
factor = gimp_gradient_calc_sphere_decreasing_factor (middle, pos);
break;
default:
g_warning ("%s: Unknown gradient type %d.",
G_GNUC_PRETTY_FUNCTION, seg->type);
break;
}
/* Calculate color components */
rgb.a =
seg->left_color.a + (seg->right_color.a - seg->left_color.a) * factor;
if (seg->color == GIMP_GRAD_RGB)
{
rgb.r =
seg->left_color.r + (seg->right_color.r - seg->left_color.r) * factor;
rgb.g =
seg->left_color.g + (seg->right_color.g - seg->left_color.g) * factor;
rgb.b =
seg->left_color.b + (seg->right_color.b - seg->left_color.b) * factor;
}
else
{
GimpHSV left_hsv;
GimpHSV right_hsv;
gimp_rgb_to_hsv (&seg->left_color, &left_hsv);
gimp_rgb_to_hsv (&seg->right_color, &right_hsv);
left_hsv.s = left_hsv.s + (right_hsv.s - left_hsv.s) * factor;
left_hsv.v = left_hsv.v + (right_hsv.v - left_hsv.v) * factor;
switch (seg->color)
{
case GIMP_GRAD_HSV_CCW:
if (left_hsv.h < right_hsv.h)
{
left_hsv.h += (right_hsv.h - left_hsv.h) * factor;
}
else
{
left_hsv.h += (1.0 - (left_hsv.h - right_hsv.h)) * factor;
if (left_hsv.h > 1.0)
left_hsv.h -= 1.0;
}
break;
case GIMP_GRAD_HSV_CW:
if (right_hsv.h < left_hsv.h)
{
left_hsv.h -= (left_hsv.h - right_hsv.h) * factor;
}
else
{
left_hsv.h -= (1.0 - (right_hsv.h - left_hsv.h)) * factor;
if (left_hsv.h < 0.0)
left_hsv.h += 1.0;
}
break;
default:
g_warning ("%s(): Unknown coloring mode %d",
G_GNUC_PRETTY_FUNCTION, (gint) seg->color);
break;
}
gimp_hsv_to_rgb (&left_hsv, &rgb);
}
*color = rgb;
}
GimpGradientSegment *
gimp_gradient_get_segment_at (GimpGradient *gradient,
gdouble pos)
{
GimpGradientSegment *seg;
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), NULL);
/* handle FP imprecision at the edges of the gradient */
pos = CLAMP (pos, 0.0, 1.0);
if (gradient->last_visited)
seg = gradient->last_visited;
else
seg = gradient->segments;
while (seg)
{
if (pos >= seg->left)
{
if (pos <= seg->right)
{
gradient->last_visited = seg; /* for speed */
return seg;
}
else
{
seg = seg->next;
}
}
else
{
seg = seg->prev;
}
}
/* Oops: we should have found a segment, but we didn't */
g_warning ("%s(): no matching segment for position %0.15f",
G_GNUC_PRETTY_FUNCTION, pos);
return NULL;
}
static gdouble
gimp_gradient_calc_linear_factor (gdouble middle,
gdouble pos)
{
if (pos <= middle)
{
if (middle < EPSILON)
return 0.0;
else
return 0.5 * pos / middle;
}
else
{
pos -= middle;
middle = 1.0 - middle;
if (middle < EPSILON)
return 1.0;
else
return 0.5 + 0.5 * pos / middle;
}
}
static gdouble
gimp_gradient_calc_curved_factor (gdouble middle,
gdouble pos)
{
if (middle < EPSILON)
middle = EPSILON;
return pow(pos, log (0.5) / log (middle));
}
static gdouble
gimp_gradient_calc_sine_factor (gdouble middle,
gdouble pos)
{
pos = gimp_gradient_calc_linear_factor (middle, pos);
return (sin ((-G_PI / 2.0) + G_PI * pos) + 1.0) / 2.0;
}
static gdouble
gimp_gradient_calc_sphere_increasing_factor (gdouble middle,
gdouble pos)
{
pos = gimp_gradient_calc_linear_factor (middle, pos) - 1.0;
return sqrt (1.0 - pos * pos); /* Works for convex increasing and concave decreasing */
}
static gdouble
gimp_gradient_calc_sphere_decreasing_factor (gdouble middle,
gdouble pos)
{
pos = gimp_gradient_calc_linear_factor (middle, pos);
return 1.0 - sqrt(1.0 - pos * pos); /* Works for convex decreasing and concave increasing */
}
/* gradient segment functions */
GimpGradientSegment *
gimp_gradient_segment_new (void)
{
GimpGradientSegment *seg;
seg = g_new (GimpGradientSegment, 1);
seg->left = 0.0;
seg->middle = 0.5;
seg->right = 1.0;
gimp_rgba_set (&seg->left_color, 0.0, 0.0, 0.0, 1.0);
gimp_rgba_set (&seg->right_color, 1.0, 1.0, 1.0, 1.0);
seg->type = GIMP_GRAD_LINEAR;
seg->color = GIMP_GRAD_RGB;
seg->prev = seg->next = NULL;
return seg;
}
void
gimp_gradient_segment_free (GimpGradientSegment *seg)
{
g_return_if_fail (seg != NULL);
g_free (seg);
}
void
gimp_gradient_segments_free (GimpGradientSegment *seg)
{
GimpGradientSegment *tmp;
g_return_if_fail (seg != NULL);
while (seg)
{
tmp = seg->next;
gimp_gradient_segment_free (seg);
seg = tmp;
}
}
GimpGradientSegment *
gimp_gradient_segment_get_last (GimpGradientSegment *seg)
{
if (!seg)
return NULL;
while (seg->next)
seg = seg->next;
return seg;
}
GimpGradientSegment *
gimp_gradient_segment_get_first (GimpGradientSegment *seg)
{
if (!seg)
return NULL;
while (seg->prev)
seg = seg->prev;
return seg;
}
void
gimp_gradient_segment_split_midpoint (GimpGradient *gradient,
GimpGradientSegment *lseg,
GimpGradientSegment **newl,
GimpGradientSegment **newr)
{
GimpRGB color;
GimpGradientSegment *newseg;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (lseg != NULL);
g_return_if_fail (newl != NULL);
g_return_if_fail (newr != NULL);
/* Get color at original segment's midpoint */
gimp_gradient_get_color_at (gradient, lseg->middle, &color);
/* Create a new segment and insert it in the list */
newseg = gimp_gradient_segment_new ();
newseg->prev = lseg;
newseg->next = lseg->next;
lseg->next = newseg;
if (newseg->next)
newseg->next->prev = newseg;
/* Set coordinates of new segment */
newseg->left = lseg->middle;
newseg->right = lseg->right;
newseg->middle = (newseg->left + newseg->right) / 2.0;
/* Set coordinates of original segment */
lseg->right = newseg->left;
lseg->middle = (lseg->left + lseg->right) / 2.0;
/* Set colors of both segments */
newseg->right_color = lseg->right_color;
lseg->right_color.r = newseg->left_color.r = color.r;
lseg->right_color.g = newseg->left_color.g = color.g;
lseg->right_color.b = newseg->left_color.b = color.b;
lseg->right_color.a = newseg->left_color.a = color.a;
/* Set parameters of new segment */
newseg->type = lseg->type;
newseg->color = lseg->color;
/* Done */
*newl = lseg;
*newr = newseg;
}
void
gimp_gradient_segment_split_uniform (GimpGradient *gradient,
GimpGradientSegment *lseg,
gint parts,
GimpGradientSegment **newl,
GimpGradientSegment **newr)
{
GimpGradientSegment *seg, *prev, *tmp;
gdouble seg_len;
gint i;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (lseg != NULL);
g_return_if_fail (newl != NULL);
g_return_if_fail (newr != NULL);
seg_len = (lseg->right - lseg->left) / parts; /* Length of divisions */
seg = NULL;
prev = NULL;
tmp = NULL;
for (i = 0; i < parts; i++)
{
seg = gimp_gradient_segment_new ();
if (i == 0)
tmp = seg; /* Remember first segment */
seg->left = lseg->left + i * seg_len;
seg->right = lseg->left + (i + 1) * seg_len;
seg->middle = (seg->left + seg->right) / 2.0;
gimp_gradient_get_color_at (gradient, seg->left, &seg->left_color);
gimp_gradient_get_color_at (gradient, seg->right, &seg->right_color);
seg->type = lseg->type;
seg->color = lseg->color;
seg->prev = prev;
seg->next = NULL;
if (prev)
prev->next = seg;
prev = seg;
}
/* Fix edges */
tmp->left_color = lseg->left_color;
seg->right_color = lseg->right_color;
tmp->left = lseg->left;
seg->right = lseg->right; /* To squish accumulative error */
/* Link in list */
tmp->prev = lseg->prev;
seg->next = lseg->next;
if (lseg->prev)
lseg->prev->next = tmp;
else
gradient->segments = tmp; /* We are on leftmost segment */
if (lseg->next)
lseg->next->prev = seg;
gradient->last_visited = NULL; /* Force re-search */
/* Done */
*newl = tmp;
*newr = seg;
/* Delete old segment */
gimp_gradient_segment_free (lseg);
}
void
gimp_gradient_segments_compress_range (GimpGradientSegment *range_l,
GimpGradientSegment *range_r,
gdouble new_l,
gdouble new_r)
{
gdouble orig_l, orig_r;
gdouble scale;
GimpGradientSegment *seg, *aseg;
g_return_if_fail (range_l != NULL);
g_return_if_fail (range_r != NULL);
orig_l = range_l->left;
orig_r = range_r->right;
scale = (new_r - new_l) / (orig_r - orig_l);
seg = range_l;
do
{
seg->left = new_l + (seg->left - orig_l) * scale;
seg->middle = new_l + (seg->middle - orig_l) * scale;
seg->right = new_l + (seg->right - orig_l) * scale;
/* Next */
aseg = seg;
seg = seg->next;
}
while (aseg != range_r);
}
void
gimp_gradient_segments_blend_endpoints (GimpGradientSegment *lseg,
GimpGradientSegment *rseg,
GimpRGB *rgb1,
GimpRGB *rgb2,
gboolean blend_colors,
gboolean blend_opacity)
{
GimpRGB d;
gdouble left, len;
GimpGradientSegment *seg;
GimpGradientSegment *aseg;
g_return_if_fail (lseg != NULL);
g_return_if_fail (rseg != NULL);
d.r = rgb2->r - rgb1->r;
d.g = rgb2->g - rgb1->g;
d.b = rgb2->b - rgb1->b;
d.a = rgb2->a - rgb1->a;
left = lseg->left;
len = rseg->right - left;
seg = lseg;
do
{
if (blend_colors)
{
seg->left_color.r = rgb1->r + (seg->left - left) / len * d.r;
seg->left_color.g = rgb1->g + (seg->left - left) / len * d.g;
seg->left_color.b = rgb1->b + (seg->left - left) / len * d.b;
seg->right_color.r = rgb1->r + (seg->right - left) / len * d.r;
seg->right_color.g = rgb1->g + (seg->right - left) / len * d.g;
seg->right_color.b = rgb1->b + (seg->right - left) / len * d.b;
}
if (blend_opacity)
{
seg->left_color.a = rgb1->a + (seg->left - left) / len * d.a;
seg->right_color.a = rgb1->a + (seg->right - left) / len * d.a;
}
aseg = seg;
seg = seg->next;
}
while (aseg != rseg);
}
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