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gimp/app/core/gimpgradient.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 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 <string.h>
#include <glib-object.h>
#include "libgimpcolor/gimpcolor.h"
#include "libgimpmath/gimpmath.h"
#include "core-types.h"
#include "base/temp-buf.h"
#include "gimpcontext.h"
#include "gimpgradient.h"
#include "gimpgradient-load.h"
#include "gimpgradient-save.h"
#define EPSILON 1e-10
static void gimp_gradient_finalize (GObject *object);
static gint64 gimp_gradient_get_memsize (GimpObject *object,
gint64 *gui_size);
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,
GimpContext *context,
gint width,
gint height);
static gchar * gimp_gradient_get_extension (GimpData *data);
static GimpData * gimp_gradient_duplicate (GimpData *data);
static GimpGradientSegment *
gimp_gradient_get_segment_at_internal (GimpGradient *gradient,
GimpGradientSegment *seg,
gdouble pos);
static inline gdouble gimp_gradient_calc_linear_factor (gdouble middle,
gdouble pos);
static inline gdouble gimp_gradient_calc_curved_factor (gdouble middle,
gdouble pos);
static inline gdouble gimp_gradient_calc_sine_factor (gdouble middle,
gdouble pos);
static inline gdouble gimp_gradient_calc_sphere_increasing_factor (gdouble middle,
gdouble pos);
static inline gdouble gimp_gradient_calc_sphere_decreasing_factor (gdouble middle,
gdouble pos);
G_DEFINE_TYPE (GimpGradient, gimp_gradient, GIMP_TYPE_DATA)
#define parent_class gimp_gradient_parent_class
static void
gimp_gradient_class_init (GimpGradientClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GimpObjectClass *gimp_object_class = GIMP_OBJECT_CLASS (klass);
GimpViewableClass *viewable_class = GIMP_VIEWABLE_CLASS (klass);
GimpDataClass *data_class = GIMP_DATA_CLASS (klass);
object_class->finalize = gimp_gradient_finalize;
gimp_object_class->get_memsize = gimp_gradient_get_memsize;
viewable_class->default_stock_id = "gimp-gradient";
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->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;
}
static void
gimp_gradient_finalize (GObject *object)
{
GimpGradient *gradient = GIMP_GRADIENT (object);
if (gradient->segments)
{
gimp_gradient_segments_free (gradient->segments);
gradient->segments = NULL;
}
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static gint64
gimp_gradient_get_memsize (GimpObject *object,
gint64 *gui_size)
{
GimpGradient *gradient = GIMP_GRADIENT (object);
GimpGradientSegment *segment;
gint64 memsize = 0;
for (segment = gradient->segments; segment; segment = segment->next)
memsize += sizeof (GimpGradientSegment);
return memsize + GIMP_OBJECT_CLASS (parent_class)->get_memsize (object,
gui_size);
}
static void
gimp_gradient_get_preview_size (GimpViewable *viewable,
gint size,
gboolean popup,
gboolean dot_for_dot,
gint *width,
gint *height)
{
*width = size;
*height = 1 + 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,
GimpContext *context,
gint width,
gint height)
{
GimpGradient *gradient = GIMP_GRADIENT (viewable);
GimpGradientSegment *seg = NULL;
TempBuf *temp_buf;
guchar *buf;
guchar *p;
guchar *row;
gint x, y;
gdouble dx, cur_x;
GimpRGB color;
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++)
{
seg = gimp_gradient_get_color_at (gradient, context, seg, cur_x,
FALSE, &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)
{
GimpGradient *gradient;
GimpGradientSegment *head, *prev, *cur, *orig;
gradient = g_object_new (GIMP_TYPE_GRADIENT, NULL);
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);
}
/* public functions */
GimpData *
gimp_gradient_new (const gchar *name)
{
GimpGradient *gradient;
g_return_val_if_fail (name != NULL, NULL);
g_return_val_if_fail (*name != '\0', NULL);
gradient = g_object_new (GIMP_TYPE_GRADIENT,
"name", name,
NULL);
gradient->segments = gimp_gradient_segment_new ();
return GIMP_DATA (gradient);
}
GimpData *
gimp_gradient_get_standard (void)
{
static GimpData *standard_gradient = NULL;
if (! standard_gradient)
{
standard_gradient = gimp_gradient_new ("Standard");
standard_gradient->dirty = FALSE;
gimp_data_make_internal (standard_gradient);
g_object_ref (standard_gradient);
}
return standard_gradient;
}
static gchar *
gimp_gradient_get_extension (GimpData *data)
{
return GIMP_GRADIENT_FILE_EXTENSION;
}
/**
* gimp_gradient_get_color_at:
* @gradient: a gradient
* @context: a context
* @seg: a segment to seed the search with (or %NULL)
* @pos: position in the gradient (between 0.0 and 1.0)
* @reverse: when %TRUE, use the reversed gradient
* @color: returns the color
*
* If you are iterating over an gradient, you should pass the the
* return value from the last call for @seg.
*
* Return value: the gradient segment the color is from
**/
GimpGradientSegment *
gimp_gradient_get_color_at (GimpGradient *gradient,
GimpContext *context,
GimpGradientSegment *seg,
gdouble pos,
gboolean reverse,
GimpRGB *color)
{
gdouble factor = 0.0;
gdouble seg_len;
gdouble middle;
GimpRGB left_color;
GimpRGB right_color;
GimpRGB rgb;
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), NULL);
g_return_val_if_fail (GIMP_IS_CONTEXT (context), NULL);
g_return_val_if_fail (color != NULL, NULL);
pos = CLAMP (pos, 0.0, 1.0);
if (reverse)
pos = 1.0 - pos;
seg = gimp_gradient_get_segment_at_internal (gradient, seg, 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_GRADIENT_SEGMENT_LINEAR:
factor = gimp_gradient_calc_linear_factor (middle, pos);
break;
case GIMP_GRADIENT_SEGMENT_CURVED:
factor = gimp_gradient_calc_curved_factor (middle, pos);
break;
case GIMP_GRADIENT_SEGMENT_SINE:
factor = gimp_gradient_calc_sine_factor (middle, pos);
break;
case GIMP_GRADIENT_SEGMENT_SPHERE_INCREASING:
factor = gimp_gradient_calc_sphere_increasing_factor (middle, pos);
break;
case GIMP_GRADIENT_SEGMENT_SPHERE_DECREASING:
factor = gimp_gradient_calc_sphere_decreasing_factor (middle, pos);
break;
default:
g_warning ("%s: Unknown gradient type %d.", G_STRFUNC, seg->type);
break;
}
/* Get left/right colors */
switch (seg->left_color_type)
{
case GIMP_GRADIENT_COLOR_FIXED:
left_color = seg->left_color;
break;
case GIMP_GRADIENT_COLOR_FOREGROUND:
case GIMP_GRADIENT_COLOR_FOREGROUND_TRANSPARENT:
gimp_context_get_foreground (context, &left_color);
if (seg->left_color_type == GIMP_GRADIENT_COLOR_FOREGROUND_TRANSPARENT)
gimp_rgb_set_alpha (&left_color, 0.0);
break;
case GIMP_GRADIENT_COLOR_BACKGROUND:
case GIMP_GRADIENT_COLOR_BACKGROUND_TRANSPARENT:
gimp_context_get_background (context, &left_color);
if (seg->left_color_type == GIMP_GRADIENT_COLOR_BACKGROUND_TRANSPARENT)
gimp_rgb_set_alpha (&left_color, 0.0);
break;
}
switch (seg->right_color_type)
{
case GIMP_GRADIENT_COLOR_FIXED:
right_color = seg->right_color;
break;
case GIMP_GRADIENT_COLOR_FOREGROUND:
case GIMP_GRADIENT_COLOR_FOREGROUND_TRANSPARENT:
gimp_context_get_foreground (context, &right_color);
if (seg->right_color_type == GIMP_GRADIENT_COLOR_FOREGROUND_TRANSPARENT)
gimp_rgb_set_alpha (&right_color, 0.0);
break;
case GIMP_GRADIENT_COLOR_BACKGROUND:
case GIMP_GRADIENT_COLOR_BACKGROUND_TRANSPARENT:
gimp_context_get_background (context, &right_color);
if (seg->right_color_type == GIMP_GRADIENT_COLOR_BACKGROUND_TRANSPARENT)
gimp_rgb_set_alpha (&right_color, 0.0);
break;
}
/* Calculate color components */
if (seg->color == GIMP_GRADIENT_SEGMENT_RGB)
{
rgb.r = left_color.r + (right_color.r - left_color.r) * factor;
rgb.g = left_color.g + (right_color.g - left_color.g) * factor;
rgb.b = left_color.b + (right_color.b - left_color.b) * factor;
}
else
{
GimpHSV left_hsv;
GimpHSV right_hsv;
gimp_rgb_to_hsv (&left_color, &left_hsv);
gimp_rgb_to_hsv (&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_GRADIENT_SEGMENT_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_GRADIENT_SEGMENT_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_STRFUNC, (gint) seg->color);
break;
}
gimp_hsv_to_rgb (&left_hsv, &rgb);
}
/* Calculate alpha */
rgb.a = left_color.a + (right_color.a - left_color.a) * factor;
*color = rgb;
return seg;
}
GimpGradientSegment *
gimp_gradient_get_segment_at (GimpGradient *gradient,
gdouble pos)
{
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), NULL);
return gimp_gradient_get_segment_at_internal (gradient, NULL, pos);
}
gboolean
gimp_gradient_has_fg_bg_segments (GimpGradient *gradient)
{
GimpGradientSegment *segment;
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), FALSE);
for (segment = gradient->segments; segment; segment = segment->next)
if (segment->left_color_type != GIMP_GRADIENT_COLOR_FIXED ||
segment->right_color_type != GIMP_GRADIENT_COLOR_FIXED)
return TRUE;
return FALSE;
}
GimpGradient *
gimp_gradient_flatten (GimpGradient *gradient,
GimpContext *context)
{
GimpGradient *flat;
GimpGradientSegment *seg;
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), NULL);
g_return_val_if_fail (GIMP_IS_CONTEXT (context), NULL);
flat = GIMP_GRADIENT (gimp_data_duplicate (GIMP_DATA (gradient)));
for (seg = flat->segments; seg; seg = seg->next)
{
switch (seg->left_color_type)
{
case GIMP_GRADIENT_COLOR_FIXED:
break;
case GIMP_GRADIENT_COLOR_FOREGROUND:
case GIMP_GRADIENT_COLOR_FOREGROUND_TRANSPARENT:
gimp_context_get_foreground (context, &seg->left_color);
if (seg->left_color_type == GIMP_GRADIENT_COLOR_FOREGROUND_TRANSPARENT)
gimp_rgb_set_alpha (&seg->left_color, 0.0);
break;
case GIMP_GRADIENT_COLOR_BACKGROUND:
case GIMP_GRADIENT_COLOR_BACKGROUND_TRANSPARENT:
gimp_context_get_background (context, &seg->left_color);
if (seg->left_color_type == GIMP_GRADIENT_COLOR_BACKGROUND_TRANSPARENT)
gimp_rgb_set_alpha (&seg->left_color, 0.0);
break;
}
seg->left_color_type = GIMP_GRADIENT_COLOR_FIXED;
switch (seg->right_color_type)
{
case GIMP_GRADIENT_COLOR_FIXED:
break;
case GIMP_GRADIENT_COLOR_FOREGROUND:
case GIMP_GRADIENT_COLOR_FOREGROUND_TRANSPARENT:
gimp_context_get_foreground (context, &seg->right_color);
if (seg->right_color_type == GIMP_GRADIENT_COLOR_FOREGROUND_TRANSPARENT)
gimp_rgb_set_alpha (&seg->right_color, 0.0);
break;
case GIMP_GRADIENT_COLOR_BACKGROUND:
case GIMP_GRADIENT_COLOR_BACKGROUND_TRANSPARENT:
gimp_context_get_background (context, &seg->right_color);
if (seg->right_color_type == GIMP_GRADIENT_COLOR_BACKGROUND_TRANSPARENT)
gimp_rgb_set_alpha (&seg->right_color, 0.0);
break;
}
seg->right_color_type = GIMP_GRADIENT_COLOR_FIXED;
}
return flat;
}
/* gradient segment functions */
GimpGradientSegment *
gimp_gradient_segment_new (void)
{
GimpGradientSegment *seg;
seg = g_slice_new (GimpGradientSegment);
seg->left = 0.0;
seg->middle = 0.5;
seg->right = 1.0;
seg->left_color_type = GIMP_GRADIENT_COLOR_FIXED;
gimp_rgba_set (&seg->left_color, 0.0, 0.0, 0.0, 1.0);
seg->right_color_type = GIMP_GRADIENT_COLOR_FIXED;
gimp_rgba_set (&seg->right_color, 1.0, 1.0, 1.0, 1.0);
seg->type = GIMP_GRADIENT_SEGMENT_LINEAR;
seg->color = GIMP_GRADIENT_SEGMENT_RGB;
seg->prev = seg->next = NULL;
return seg;
}
void
gimp_gradient_segment_free (GimpGradientSegment *seg)
{
g_return_if_fail (seg != NULL);
g_slice_free (GimpGradientSegment, seg);
}
void
gimp_gradient_segments_free (GimpGradientSegment *seg)
{
g_return_if_fail (seg != NULL);
g_slice_free_chain (GimpGradientSegment, seg, next);
}
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;
}
GimpGradientSegment *
gimp_gradient_segment_get_nth (GimpGradientSegment *seg,
gint index)
{
gint i = 0;
g_return_val_if_fail (index >= 0, NULL);
if (! seg)
return NULL;
while (seg && (i < index))
{
seg = seg->next;
i++;
}
if (i == index)
return seg;
return NULL;
}
void
gimp_gradient_segment_split_midpoint (GimpGradient *gradient,
GimpContext *context,
GimpGradientSegment *lseg,
GimpGradientSegment **newl,
GimpGradientSegment **newr)
{
GimpRGB color;
GimpGradientSegment *newseg;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (GIMP_IS_CONTEXT (context));
g_return_if_fail (lseg != NULL);
g_return_if_fail (newl != NULL);
g_return_if_fail (newr != NULL);
gimp_data_freeze (GIMP_DATA (gradient));
/* Get color at original segment's midpoint */
gimp_gradient_get_color_at (gradient, context, lseg, lseg->middle,
FALSE, &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_type = lseg->right_color_type;
newseg->right_color = lseg->right_color;
lseg->right_color_type = newseg->left_color_type = GIMP_GRADIENT_COLOR_FIXED;
lseg->right_color = newseg->left_color = color;
/* Set parameters of new segment */
newseg->type = lseg->type;
newseg->color = lseg->color;
/* Done */
*newl = lseg;
*newr = newseg;
gimp_data_thaw (GIMP_DATA (gradient));
}
void
gimp_gradient_segment_split_uniform (GimpGradient *gradient,
GimpContext *context,
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 (GIMP_IS_CONTEXT (context));
g_return_if_fail (lseg != NULL);
g_return_if_fail (newl != NULL);
g_return_if_fail (newr != NULL);
gimp_data_freeze (GIMP_DATA (gradient));
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;
seg->left_color_type = GIMP_GRADIENT_COLOR_FIXED;
seg->right_color_type = GIMP_GRADIENT_COLOR_FIXED;
gimp_gradient_get_color_at (gradient, context, lseg,
seg->left, FALSE, &seg->left_color);
gimp_gradient_get_color_at (gradient, context, lseg,
seg->right, FALSE, &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_type = lseg->left_color_type;
tmp->left_color = lseg->left_color;
seg->right_color_type = lseg->right_color_type;
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;
/* Done */
*newl = tmp;
*newr = seg;
/* Delete old segment */
gimp_gradient_segment_free (lseg);
gimp_data_thaw (GIMP_DATA (gradient));
}
void
gimp_gradient_segment_get_left_color (GimpGradient *gradient,
GimpGradientSegment *seg,
GimpRGB *color)
{
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (seg != NULL);
g_return_if_fail (color != NULL);
*color = seg->left_color;
}
void
gimp_gradient_segment_set_left_color (GimpGradient *gradient,
GimpGradientSegment *seg,
const GimpRGB *color)
{
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (seg != NULL);
g_return_if_fail (color != NULL);
gimp_data_freeze (GIMP_DATA (gradient));
gimp_gradient_segment_range_blend (gradient, seg, seg,
color, &seg->right_color,
TRUE, TRUE);
gimp_data_thaw (GIMP_DATA (gradient));
}
void
gimp_gradient_segment_get_right_color (GimpGradient *gradient,
GimpGradientSegment *seg,
GimpRGB *color)
{
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (seg != NULL);
g_return_if_fail (color != NULL);
*color = seg->right_color;
}
void
gimp_gradient_segment_set_right_color (GimpGradient *gradient,
GimpGradientSegment *seg,
const GimpRGB *color)
{
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (seg != NULL);
g_return_if_fail (color != NULL);
gimp_data_freeze (GIMP_DATA (gradient));
gimp_gradient_segment_range_blend (gradient, seg, seg,
&seg->left_color, color,
TRUE, TRUE);
gimp_data_thaw (GIMP_DATA (gradient));
}
GimpGradientColor
gimp_gradient_segment_get_left_color_type (GimpGradient *gradient,
GimpGradientSegment *seg)
{
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), 0);
g_return_val_if_fail (seg != NULL, 0);
return seg->left_color_type;
}
void
gimp_gradient_segment_set_left_color_type (GimpGradient *gradient,
GimpGradientSegment *seg,
GimpGradientColor color_type)
{
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (seg != NULL);
gimp_data_freeze (GIMP_DATA (gradient));
seg->left_color_type = color_type;
gimp_data_thaw (GIMP_DATA (gradient));
}
GimpGradientColor
gimp_gradient_segment_get_right_color_type (GimpGradient *gradient,
GimpGradientSegment *seg)
{
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), 0);
g_return_val_if_fail (seg != NULL, 0);
return seg->right_color_type;
}
void
gimp_gradient_segment_set_right_color_type (GimpGradient *gradient,
GimpGradientSegment *seg,
GimpGradientColor color_type)
{
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (seg != NULL);
gimp_data_freeze (GIMP_DATA (gradient));
seg->right_color_type = color_type;
gimp_data_thaw (GIMP_DATA (gradient));
}
gdouble
gimp_gradient_segment_get_left_pos (GimpGradient *gradient,
GimpGradientSegment *seg)
{
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), 0.0);
g_return_val_if_fail (seg != NULL, 0.0);
return seg->left;
}
gdouble
gimp_gradient_segment_set_left_pos (GimpGradient *gradient,
GimpGradientSegment *seg,
gdouble pos)
{
gdouble final_pos;
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), 0.0);
g_return_val_if_fail (seg != NULL, 0.0);
if (seg->prev == NULL)
{
final_pos = 0;
}
else
{
gimp_data_freeze (GIMP_DATA (gradient));
final_pos = seg->prev->right = seg->left =
CLAMP (pos,
seg->prev->middle + EPSILON,
seg->middle - EPSILON);
gimp_data_thaw (GIMP_DATA (gradient));
}
return final_pos;
}
gdouble
gimp_gradient_segment_get_right_pos (GimpGradient *gradient,
GimpGradientSegment *seg)
{
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), 0.0);
g_return_val_if_fail (seg != NULL, 0.0);
return seg->right;
}
gdouble
gimp_gradient_segment_set_right_pos (GimpGradient *gradient,
GimpGradientSegment *seg,
gdouble pos)
{
gdouble final_pos;
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), 0.0);
g_return_val_if_fail (seg != NULL, 0.0);
if (seg->next == NULL)
{
final_pos = 1.0;
}
else
{
gimp_data_freeze (GIMP_DATA (gradient));
final_pos = seg->next->left = seg->right =
CLAMP (pos,
seg->middle + EPSILON,
seg->next->middle - EPSILON);
gimp_data_thaw (GIMP_DATA (gradient));
}
return final_pos;
}
gdouble
gimp_gradient_segment_get_middle_pos (GimpGradient *gradient,
GimpGradientSegment *seg)
{
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), 0.0);
g_return_val_if_fail (seg != NULL, 0.0);
return seg->middle;
}
gdouble
gimp_gradient_segment_set_middle_pos (GimpGradient *gradient,
GimpGradientSegment *seg,
gdouble pos)
{
gdouble final_pos;
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), 0.0);
g_return_val_if_fail (seg != NULL, 0.0);
gimp_data_freeze (GIMP_DATA (gradient));
final_pos = seg->middle =
CLAMP (pos,
seg->left + EPSILON,
seg->right - EPSILON);
gimp_data_thaw (GIMP_DATA (gradient));
return final_pos;
}
GimpGradientSegmentType
gimp_gradient_segment_get_blending_function (GimpGradient *gradient,
GimpGradientSegment *seg)
{
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), 0);
return seg->type;
}
GimpGradientSegmentColor
gimp_gradient_segment_get_coloring_type (GimpGradient *gradient,
GimpGradientSegment *seg)
{
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), 0);
return seg->color;
}
void
gimp_gradient_segment_range_compress (GimpGradient *gradient,
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 (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (range_l != NULL);
gimp_data_freeze (GIMP_DATA (gradient));
if (! range_r)
range_r = gimp_gradient_segment_get_last (range_l);
orig_l = range_l->left;
orig_r = range_r->right;
scale = (new_r - new_l) / (orig_r - orig_l);
seg = range_l;
do
{
if (seg->prev)
seg->left = new_l + (seg->left - orig_l) * scale;
seg->middle = new_l + (seg->middle - orig_l) * scale;
if (seg->next)
seg->right = new_l + (seg->right - orig_l) * scale;
/* Next */
aseg = seg;
seg = seg->next;
}
while (aseg != range_r);
gimp_data_thaw (GIMP_DATA (gradient));
}
void
gimp_gradient_segment_range_blend (GimpGradient *gradient,
GimpGradientSegment *lseg,
GimpGradientSegment *rseg,
const GimpRGB *rgb1,
const GimpRGB *rgb2,
gboolean blend_colors,
gboolean blend_opacity)
{
GimpRGB d;
gdouble left, len;
GimpGradientSegment *seg;
GimpGradientSegment *aseg;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (lseg != NULL);
gimp_data_freeze (GIMP_DATA (gradient));
if (! rseg)
rseg = gimp_gradient_segment_get_last (lseg);
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);
gimp_data_thaw (GIMP_DATA (gradient));
}
void
gimp_gradient_segment_range_set_blending_function (GimpGradient *gradient,
GimpGradientSegment *start_seg,
GimpGradientSegment *end_seg,
GimpGradientSegmentType new_type)
{
GimpGradientSegment *seg;
gboolean reached_last_segment = FALSE;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
gimp_data_freeze (GIMP_DATA (gradient));
seg = start_seg;
while (seg && ! reached_last_segment)
{
if (seg == end_seg)
reached_last_segment = TRUE;
seg->type = new_type;
seg = seg->next;
}
gimp_data_thaw (GIMP_DATA (gradient));
}
void
gimp_gradient_segment_range_set_coloring_type (GimpGradient *gradient,
GimpGradientSegment *start_seg,
GimpGradientSegment *end_seg,
GimpGradientSegmentColor new_color)
{
GimpGradientSegment *seg;
gboolean reached_last_segment = FALSE;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
gimp_data_freeze (GIMP_DATA (gradient));
seg = start_seg;
while (seg && ! reached_last_segment)
{
if (seg == end_seg)
reached_last_segment = TRUE;
seg->color = new_color;
seg = seg->next;
}
gimp_data_thaw (GIMP_DATA (gradient));
}
void
gimp_gradient_segment_range_flip (GimpGradient *gradient,
GimpGradientSegment *start_seg,
GimpGradientSegment *end_seg,
GimpGradientSegment **final_start_seg,
GimpGradientSegment **final_end_seg)
{
GimpGradientSegment *oseg, *oaseg;
GimpGradientSegment *seg, *prev, *tmp;
GimpGradientSegment *lseg, *rseg;
gdouble left, right;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
gimp_data_freeze (GIMP_DATA (gradient));
if (! end_seg)
end_seg = gimp_gradient_segment_get_last (start_seg);
left = start_seg->left;
right = end_seg->right;
/* Build flipped segments */
prev = NULL;
oseg = end_seg;
tmp = NULL;
do
{
seg = gimp_gradient_segment_new ();
if (prev == NULL)
{
seg->left = left;
tmp = seg; /* Remember first segment */
}
else
seg->left = left + right - oseg->right;
seg->middle = left + right - oseg->middle;
seg->right = left + right - oseg->left;
seg->left_color_type = oseg->right_color_type;
seg->left_color = oseg->right_color;
seg->right_color_type = oseg->left_color_type;
seg->right_color = oseg->left_color;
switch (oseg->type)
{
case GIMP_GRADIENT_SEGMENT_SPHERE_INCREASING:
seg->type = GIMP_GRADIENT_SEGMENT_SPHERE_DECREASING;
break;
case GIMP_GRADIENT_SEGMENT_SPHERE_DECREASING:
seg->type = GIMP_GRADIENT_SEGMENT_SPHERE_INCREASING;
break;
default:
seg->type = oseg->type;
}
switch (oseg->color)
{
case GIMP_GRADIENT_SEGMENT_HSV_CCW:
seg->color = GIMP_GRADIENT_SEGMENT_HSV_CW;
break;
case GIMP_GRADIENT_SEGMENT_HSV_CW:
seg->color = GIMP_GRADIENT_SEGMENT_HSV_CCW;
break;
default:
seg->color = oseg->color;
}
seg->prev = prev;
seg->next = NULL;
if (prev)
prev->next = seg;
prev = seg;
oaseg = oseg;
oseg = oseg->prev; /* Move backwards! */
}
while (oaseg != start_seg);
seg->right = right; /* Squish accumulative error */
/* Free old segments */
lseg = start_seg->prev;
rseg = end_seg->next;
oseg = start_seg;
do
{
oaseg = oseg->next;
gimp_gradient_segment_free (oseg);
oseg = oaseg;
}
while (oaseg != rseg);
/* Link in new segments */
if (lseg)
lseg->next = tmp;
else
gradient->segments = tmp;
tmp->prev = lseg;
seg->next = rseg;
if (rseg)
rseg->prev = seg;
/* Reset selection */
if (final_start_seg)
*final_start_seg = tmp;
if (final_end_seg)
*final_end_seg = seg;
/* Done */
gimp_data_thaw (GIMP_DATA (gradient));
}
void
gimp_gradient_segment_range_replicate (GimpGradient *gradient,
GimpGradientSegment *start_seg,
GimpGradientSegment *end_seg,
gint replicate_times,
GimpGradientSegment **final_start_seg,
GimpGradientSegment **final_end_seg)
{
gdouble sel_left, sel_right, sel_len;
gdouble new_left;
gdouble factor;
GimpGradientSegment *prev, *seg, *tmp;
GimpGradientSegment *oseg, *oaseg;
GimpGradientSegment *lseg, *rseg;
gint i;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
if (! end_seg)
end_seg = gimp_gradient_segment_get_last (start_seg);
if (replicate_times < 2)
{
*final_start_seg = start_seg;
*final_end_seg = end_seg;
return;
}
gimp_data_freeze (GIMP_DATA (gradient));
/* Remember original parameters */
sel_left = start_seg->left;
sel_right = end_seg->right;
sel_len = sel_right - sel_left;
factor = 1.0 / replicate_times;
/* Build replicated segments */
prev = NULL;
seg = NULL;
tmp = NULL;
for (i = 0; i < replicate_times; i++)
{
/* Build one cycle */
new_left = sel_left + i * factor * sel_len;
oseg = start_seg;
do
{
seg = gimp_gradient_segment_new ();
if (prev == NULL)
{
seg->left = sel_left;
tmp = seg; /* Remember first segment */
}
else
{
seg->left = new_left + factor * (oseg->left - sel_left);
}
seg->middle = new_left + factor * (oseg->middle - sel_left);
seg->right = new_left + factor * (oseg->right - sel_left);
seg->left_color_type = oseg->left_color_type;
seg->left_color = oseg->left_color;
seg->right_color_type = oseg->right_color_type;
seg->right_color = oseg->right_color;
seg->type = oseg->type;
seg->color = oseg->color;
seg->prev = prev;
seg->next = NULL;
if (prev)
prev->next = seg;
prev = seg;
oaseg = oseg;
oseg = oseg->next;
}
while (oaseg != end_seg);
}
seg->right = sel_right; /* Squish accumulative error */
/* Free old segments */
lseg = start_seg->prev;
rseg = end_seg->next;
oseg = start_seg;
do
{
oaseg = oseg->next;
gimp_gradient_segment_free (oseg);
oseg = oaseg;
}
while (oaseg != rseg);
/* Link in new segments */
if (lseg)
lseg->next = tmp;
else
gradient->segments = tmp;
tmp->prev = lseg;
seg->next = rseg;
if (rseg)
rseg->prev = seg;
/* Reset selection */
if (final_start_seg)
*final_start_seg = tmp;
if (final_end_seg)
*final_end_seg = seg;
/* Done */
gimp_data_thaw (GIMP_DATA (gradient));
}
void
gimp_gradient_segment_range_split_midpoint (GimpGradient *gradient,
GimpContext *context,
GimpGradientSegment *start_seg,
GimpGradientSegment *end_seg,
GimpGradientSegment **final_start_seg,
GimpGradientSegment **final_end_seg)
{
GimpGradientSegment *seg, *lseg, *rseg;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (GIMP_IS_CONTEXT (context));
gimp_data_freeze (GIMP_DATA (gradient));
if (! end_seg)
end_seg = gimp_gradient_segment_get_last (start_seg);
seg = start_seg;
do
{
gimp_gradient_segment_split_midpoint (gradient, context,
seg, &lseg, &rseg);
seg = rseg->next;
}
while (lseg != end_seg);
if (final_start_seg)
*final_start_seg = start_seg;
if (final_end_seg)
*final_end_seg = rseg;
gimp_data_thaw (GIMP_DATA (gradient));
}
void
gimp_gradient_segment_range_split_uniform (GimpGradient *gradient,
GimpContext *context,
GimpGradientSegment *start_seg,
GimpGradientSegment *end_seg,
gint parts,
GimpGradientSegment **final_start_seg,
GimpGradientSegment **final_end_seg)
{
GimpGradientSegment *seg, *aseg, *lseg, *rseg, *lsel;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
g_return_if_fail (GIMP_IS_CONTEXT (context));
if (! end_seg)
end_seg = gimp_gradient_segment_get_last (start_seg);
if (parts < 2)
{
*final_start_seg = start_seg;
*final_end_seg = end_seg;
return;
}
gimp_data_freeze (GIMP_DATA (gradient));
seg = start_seg;
lsel = NULL;
do
{
aseg = seg;
gimp_gradient_segment_split_uniform (gradient, context, seg,
parts,
&lseg, &rseg);
if (seg == start_seg)
lsel = lseg;
seg = rseg->next;
}
while (aseg != end_seg);
if (final_start_seg)
*final_start_seg = lsel;
if (final_end_seg)
*final_end_seg = rseg;
gimp_data_thaw (GIMP_DATA (gradient));
}
void
gimp_gradient_segment_range_delete (GimpGradient *gradient,
GimpGradientSegment *start_seg,
GimpGradientSegment *end_seg,
GimpGradientSegment **final_start_seg,
GimpGradientSegment **final_end_seg)
{
GimpGradientSegment *lseg, *rseg, *seg, *aseg, *next;
gdouble join;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
if (! end_seg)
end_seg = gimp_gradient_segment_get_last (start_seg);
/* Remember segments to the left and to the right of the selection */
lseg = start_seg->prev;
rseg = end_seg->next;
/* Cannot delete all the segments in the gradient */
if ((lseg == NULL) && (rseg == NULL))
goto premature_return;
gimp_data_freeze (GIMP_DATA (gradient));
/* Calculate join point */
join = (start_seg->left +
end_seg->right) / 2.0;
if (lseg == NULL)
join = 0.0;
else if (rseg == NULL)
join = 1.0;
/* Move segments */
if (lseg != NULL)
gimp_gradient_segment_range_compress (gradient, lseg, lseg,
lseg->left, join);
if (rseg != NULL)
gimp_gradient_segment_range_compress (gradient, rseg, rseg,
join, rseg->right);
/* Link */
if (lseg)
lseg->next = rseg;
if (rseg)
rseg->prev = lseg;
/* Delete old segments */
seg = start_seg;
do
{
next = seg->next;
aseg = seg;
gimp_gradient_segment_free (seg);
seg = next;
}
while (aseg != end_seg);
/* Change selection */
if (rseg)
{
if (final_start_seg)
*final_start_seg = rseg;
if (final_end_seg)
*final_end_seg = rseg;
}
else
{
if (final_start_seg)
*final_start_seg = lseg;
if (final_end_seg)
*final_end_seg = lseg;
}
if (lseg == NULL)
gradient->segments = rseg;
gimp_data_thaw (GIMP_DATA (gradient));
return;
premature_return:
*final_start_seg = start_seg;
*final_end_seg = end_seg;
}
void
gimp_gradient_segment_range_recenter_handles (GimpGradient *gradient,
GimpGradientSegment *start_seg,
GimpGradientSegment *end_seg)
{
GimpGradientSegment *seg, *aseg;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
gimp_data_freeze (GIMP_DATA (gradient));
if (! end_seg)
end_seg = gimp_gradient_segment_get_last (start_seg);
seg = start_seg;
do
{
seg->middle = (seg->left + seg->right) / 2.0;
aseg = seg;
seg = seg->next;
}
while (aseg != end_seg);
gimp_data_thaw (GIMP_DATA (gradient));
}
void
gimp_gradient_segment_range_redistribute_handles (GimpGradient *gradient,
GimpGradientSegment *start_seg,
GimpGradientSegment *end_seg)
{
GimpGradientSegment *seg, *aseg;
gdouble left, right, seg_len;
gint num_segs;
gint i;
g_return_if_fail (GIMP_IS_GRADIENT (gradient));
gimp_data_freeze (GIMP_DATA (gradient));
if (! end_seg)
end_seg = gimp_gradient_segment_get_last (start_seg);
/* Count number of segments in selection */
num_segs = 0;
seg = start_seg;
do
{
num_segs++;
aseg = seg;
seg = seg->next;
}
while (aseg != end_seg);
/* Calculate new segment length */
left = start_seg->left;
right = end_seg->right;
seg_len = (right - left) / num_segs;
/* Redistribute */
seg = start_seg;
for (i = 0; i < num_segs; i++)
{
seg->left = left + i * seg_len;
seg->right = left + (i + 1) * seg_len;
seg->middle = (seg->left + seg->right) / 2.0;
seg = seg->next;
}
/* Fix endpoints to squish accumulative error */
start_seg->left = left;
end_seg->right = right;
gimp_data_thaw (GIMP_DATA (gradient));
}
gdouble
gimp_gradient_segment_range_move (GimpGradient *gradient,
GimpGradientSegment *range_l,
GimpGradientSegment *range_r,
gdouble delta,
gboolean control_compress)
{
gdouble lbound, rbound;
gint is_first, is_last;
GimpGradientSegment *seg, *aseg;
g_return_val_if_fail (GIMP_IS_GRADIENT (gradient), 0.0);
gimp_data_freeze (GIMP_DATA (gradient));
if (! range_l)
range_r = gimp_gradient_segment_get_last (range_l);
/* First or last segments in gradient? */
is_first = (range_l->prev == NULL);
is_last = (range_r->next == NULL);
/* Calculate drag bounds */
if (! control_compress)
{
if (!is_first)
lbound = range_l->prev->middle + EPSILON;
else
lbound = range_l->left + EPSILON;
if (!is_last)
rbound = range_r->next->middle - EPSILON;
else
rbound = range_r->right - EPSILON;
}
else
{
if (!is_first)
lbound = range_l->prev->left + 2.0 * EPSILON;
else
lbound = range_l->left + EPSILON;
if (!is_last)
rbound = range_r->next->right - 2.0 * EPSILON;
else
rbound = range_r->right - EPSILON;
}
/* Fix the delta if necessary */
if (delta < 0.0)
{
if (!is_first)
{
if (range_l->left + delta < lbound)
delta = lbound - range_l->left;
}
else
if (range_l->middle + delta < lbound)
delta = lbound - range_l->middle;
}
else
{
if (!is_last)
{
if (range_r->right + delta > rbound)
delta = rbound - range_r->right;
}
else
if (range_r->middle + delta > rbound)
delta = rbound - range_r->middle;
}
/* Move all the segments inside the range */
seg = range_l;
do
{
if (!((seg == range_l) && is_first))
seg->left += delta;
seg->middle += delta;
if (!((seg == range_r) && is_last))
seg->right += delta;
/* Next */
aseg = seg;
seg = seg->next;
}
while (aseg != range_r);
/* Fix the segments that surround the range */
if (!is_first)
{
if (! control_compress)
range_l->prev->right = range_l->left;
else
gimp_gradient_segment_range_compress (gradient,
range_l->prev, range_l->prev,
range_l->prev->left, range_l->left);
}
if (!is_last)
{
if (! control_compress)
range_r->next->left = range_r->right;
else
gimp_gradient_segment_range_compress (gradient,
range_r->next, range_r->next,
range_r->right, range_r->next->right);
}
gimp_data_thaw (GIMP_DATA (gradient));
return delta;
}
/* private functions */
static GimpGradientSegment *
gimp_gradient_get_segment_at_internal (GimpGradient *gradient,
GimpGradientSegment *seg,
gdouble pos)
{
/* handle FP imprecision at the edges of the gradient */
pos = CLAMP (pos, 0.0, 1.0);
if (! seg)
seg = gradient->segments;
while (seg)
{
if (pos >= seg->left)
{
if (pos <= seg->right)
{
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_STRFUNC, pos);
return NULL;
}
static inline 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 inline gdouble
gimp_gradient_calc_curved_factor (gdouble middle,
gdouble pos)
{
if (middle < EPSILON)
middle = EPSILON;
return pow (pos, log (0.5) / log (middle));
}
static inline 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 inline gdouble
gimp_gradient_calc_sphere_increasing_factor (gdouble middle,
gdouble pos)
{
pos = gimp_gradient_calc_linear_factor (middle, pos) - 1.0;
/* Works for convex increasing and concave decreasing */
return sqrt (1.0 - pos * pos);
}
static inline gdouble
gimp_gradient_calc_sphere_decreasing_factor (gdouble middle,
gdouble pos)
{
pos = gimp_gradient_calc_linear_factor (middle, pos);
/* Works for convex decreasing and concave increasing */
return 1.0 - sqrt(1.0 - pos * pos);
}
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