mutter/clutter/clutter-color.c
Neil Roberts e6570be339 * clutter/clutter-color.c (clutter_color_new): Remove CLAMP macros
around the component parameters because they are guint8 anyway so
	the CLAMP is redundant and it causes a warning.
2008-11-05 12:16:15 +00:00

961 lines
23 KiB
C

/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Authored By Matthew Allum <mallum@openedhand.com>
*
* Copyright (C) 2006 OpenedHand
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:clutter-color
* @short_description: Color management and manipulation.
*
* #ClutterColor is a simple type for representing colors.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <pango/pango-attributes.h>
#include <gobject/gvaluecollector.h>
#include "clutter-main.h"
#include "clutter-color.h"
#include "clutter-private.h"
#include "clutter-debug.h"
/**
* clutter_color_add:
* @src1: a #ClutterColor
* @src2: a #ClutterColor
* @dest: return location for the result
*
* Adds @src2 to @src1 and saves the resulting color
* inside @dest.
*
* The alpha channel of @dest is as the maximum value
* between the alpha channels of @src1 and @src2.
*/
void
clutter_color_add (const ClutterColor *src1,
const ClutterColor *src2,
ClutterColor *dest)
{
g_return_if_fail (src1 != NULL);
g_return_if_fail (src2 != NULL);
g_return_if_fail (dest != NULL);
dest->red = CLAMP (src1->red + src2->red, 0, 255);
dest->green = CLAMP (src1->green + src2->green, 0, 255);
dest->blue = CLAMP (src1->blue + src2->blue, 0, 255);
dest->alpha = MAX (src1->alpha, src2->alpha);
}
/**
* clutter_color_subtract:
* @src1: a #ClutterColor
* @src2: a #ClutterColor
* @dest: return location for the result
*
* Subtracts @src2 from @src1 and saves the resulting
* color inside @dest. This function assumes that the components
* of @src1 are greater than the components of @src2; the result is,
* otherwise, undefined.
*
* The alpha channel of @dest is set as the minimum value
* between the alpha channels of @src1 and @src2.
*/
void
clutter_color_subtract (const ClutterColor *src1,
const ClutterColor *src2,
ClutterColor *dest)
{
g_return_if_fail (src1 != NULL);
g_return_if_fail (src2 != NULL);
g_return_if_fail (dest != NULL);
dest->red = CLAMP (src1->red - src2->red, 0, 255);
dest->green = CLAMP (src1->green - src2->green, 0, 255);
dest->blue = CLAMP (src1->blue - src2->blue, 0, 255);
dest->alpha = MIN (src1->alpha, src2->alpha);
}
/**
* clutter_color_lighten:
* @src: a #ClutterColor
* @dest: return location for the lighter color
*
* Lightens @src by a fixed amount, and saves the changed
* color in @dest.
*/
void
clutter_color_lighten (const ClutterColor *src,
ClutterColor *dest)
{
/* 0x14ccd is ClutterFixed for 1.3 */
clutter_color_shadex (src, dest, 0x14ccd);
}
/**
* clutter_color_darken:
* @src: a #ClutterColor
* @dest: return location for the darker color
*
* Darkens @src by a fixed amount, and saves the changed color
* in @dest.
*/
void
clutter_color_darken (const ClutterColor *src,
ClutterColor *dest)
{
/* 0xb333 is ClutterFixed for 0.7 */
clutter_color_shadex (src, dest, 0xb333);
}
/**
* clutter_color_to_hlsx:
* @src: a #ClutterColor
* @hue: return location for the hue value or %NULL
* @luminance: return location for the luminance value or %NULL
* @saturation: return location for the saturation value or %NULL
*
* Converts @src to the HLS format. Returned hue is in degrees (0 .. 360),
* luminance and saturation from interval <0 .. 1>.
*/
void
clutter_color_to_hlsx (const ClutterColor *src,
ClutterFixed *hue,
ClutterFixed *luminance,
ClutterFixed *saturation)
{
ClutterFixed red, green, blue;
ClutterFixed min, max, delta;
ClutterFixed h, l, s;
g_return_if_fail (src != NULL);
red = COGL_FIXED_FROM_INT (src->red) / 255;
green = COGL_FIXED_FROM_INT (src->green) / 255;
blue = COGL_FIXED_FROM_INT (src->blue) / 255;
if (red > green)
{
if (red > blue)
max = red;
else
max = blue;
if (green < blue)
min = green;
else
min = blue;
}
else
{
if (green > blue)
max = green;
else
max = blue;
if (red < blue)
min = red;
else
min = blue;
}
l = (max + min) / 2;
s = 0;
h = 0;
if (max != min)
{
if (l <= COGL_FIXED_0_5)
s = COGL_FIXED_FAST_DIV ((max - min), (max + min));
else
s = COGL_FIXED_FAST_DIV ((max - min),
(COGL_FIXED_FROM_INT (2) - max - min));
delta = max - min;
if (red == max)
h = COGL_FIXED_FAST_DIV ((green - blue), delta);
else if (green == max)
{
h = COGL_FIXED_FROM_INT (2)
+ COGL_FIXED_FAST_DIV ((blue - red), delta);
}
else if (blue == max)
{
h = COGL_FIXED_FROM_INT (4)
+ COGL_FIXED_FAST_DIV ((red - green), delta);
}
h *= 60;
if (h < 0)
h += COGL_FIXED_360;
}
if (hue)
*hue = h;
if (luminance)
*luminance = l;
if (saturation)
*saturation = s;
}
/**
* clutter_color_from_hlsx:
* @dest: return location for a #ClutterColor
* @hue: hue value (0 .. 360)
* @luminance: luminance value (0 .. 1)
* @saturation: saturation value (0 .. 1)
*
* Converts a color expressed in HLS (hue, luminance and saturation)
* values into a #ClutterColor.
*/
void
clutter_color_from_hlsx (ClutterColor *dest,
ClutterFixed hue,
ClutterFixed luminance,
ClutterFixed saturation)
{
ClutterFixed h, l, s;
ClutterFixed m1, m2;
g_return_if_fail (dest != NULL);
l = luminance;
s = saturation;
if (l <= COGL_FIXED_0_5)
m2 = COGL_FIXED_FAST_MUL (l, (COGL_FIXED_1 + s));
else
m2 = l + s - COGL_FIXED_FAST_MUL (l, s);
m1 = 2 * l - m2;
if (s == 0)
{
dest->red = (guint8) COGL_FIXED_TO_INT (l * 255);
dest->green = (guint8) COGL_FIXED_TO_INT (l * 255);
dest->blue = (guint8) COGL_FIXED_TO_INT (l * 255);
}
else
{
h = hue + COGL_FIXED_120;
while (h > COGL_FIXED_360)
h -= COGL_FIXED_360;
while (h < 0)
h += COGL_FIXED_360;
if (h < COGL_FIXED_60)
{
CoglFixed tmp;
tmp = (m1 + COGL_FIXED_FAST_MUL ((m2 - m1), h) / 60);
dest->red = (guint8) COGL_FIXED_TO_INT (tmp * 255);
}
else if (h < COGL_FIXED_180)
dest->red = (guint8) COGL_FIXED_TO_INT (m2 * 255);
else if (h < COGL_FIXED_240)
{
CoglFixed tmp;
tmp = (m1 + COGL_FIXED_FAST_MUL ((m2 - m1), (COGL_FIXED_240 - h)))
/ 60;
dest->red = (guint8) COGL_FIXED_TO_INT (tmp * 255);
}
else
dest->red = (guint8) COGL_FIXED_TO_INT (m1 * 255);
h = hue;
while (h > COGL_FIXED_360)
h -= COGL_FIXED_360;
while (h < 0)
h += COGL_FIXED_360;
if (h < COGL_FIXED_60)
{
CoglFixed tmp;
tmp = (m1 + COGL_FIXED_FAST_MUL ((m2 - m1), h) / 60);
dest->green = (guint8) COGL_FIXED_TO_INT (tmp * 255);
}
else if (h < COGL_FIXED_180)
dest->green = (guint8) COGL_FIXED_TO_INT (m2 * 255);
else if (h < COGL_FIXED_240)
{
CoglFixed tmp;
tmp = (m1 + COGL_FIXED_FAST_MUL ((m2 - m1) , (COGL_FIXED_240 - h)))
/ 60;
dest->green = (guint8) COGL_FIXED_TO_INT (tmp * 255);
}
else
dest->green = (guint8) COGL_FIXED_TO_INT (m1 * 255);
h = hue - COGL_FIXED_120;
while (h > COGL_FIXED_360)
h -= COGL_FIXED_360;
while (h < 0)
h += COGL_FIXED_360;
if (h < COGL_FIXED_60)
{
CoglFixed tmp;
tmp = (m1 + COGL_FIXED_FAST_MUL ((m2 - m1), h) / 60);
dest->blue = (guint8) COGL_FIXED_TO_INT (tmp * 255);
}
else if (h < COGL_FIXED_180)
dest->blue = (guint8) COGL_FIXED_TO_INT (m2 * 255);
else if (h < COGL_FIXED_240)
{
CoglFixed tmp;
tmp = (m1 + COGL_FIXED_FAST_MUL ((m2 - m1), (COGL_FIXED_240 - h)))
/ 60;
dest->blue = (guint8) COGL_FIXED_TO_INT (tmp * 255);
}
else
dest->blue = (guint8) COGL_FIXED_TO_INT (m1 * 255);
}
}
/**
* clutter_color_to_hls:
* @src: a #ClutterColor
* @hue: return location for the hue value or %NULL
* @luminance: return location for the luminance value or %NULL
* @saturation: return location for the saturation value or %NULL
*
* Converts @src to the HLS format. Returned HLS values are from interval
* 0 .. 255.
*/
void
clutter_color_to_hls (const ClutterColor *src,
guint8 *hue,
guint8 *luminance,
guint8 *saturation)
{
ClutterFixed h, l, s;
clutter_color_to_hlsx (src, &h, &l, &s);
if (hue)
*hue = (guint8) COGL_FIXED_TO_INT (h * 255) / 360;
if (luminance)
*luminance = (guint8) COGL_FIXED_TO_INT (l * 255);
if (saturation)
*saturation = (guint8) COGL_FIXED_TO_INT (s * 255);
}
/**
* clutter_color_from_hls:
* @dest: return location for a #ClutterColor
* @hue: hue value (0 .. 255)
* @luminance: luminance value (0 .. 255)
* @saturation: saturation value (0 .. 255)
*
* Converts a color expressed in HLS (hue, luminance and saturation)
* values into a #ClutterColor.
*/
void
clutter_color_from_hls (ClutterColor *dest,
guint8 hue,
guint8 luminance,
guint8 saturation)
{
ClutterFixed h, l, s;
h = COGL_FIXED_FROM_INT (hue * 360) / 255;
l = COGL_FIXED_FROM_INT (luminance) / 255;
s = COGL_FIXED_FROM_INT (saturation) / 255;
clutter_color_from_hlsx (dest, h, l, s);
}
/**
* clutter_color_shade:
* @src: a #ClutterColor
* @dest: return location for the shaded color
* @shade: the shade factor to apply
*
* Shades @src by the factor of @shade and saves the modified
* color into @dest.
*/
void
clutter_color_shade (const ClutterColor *src,
ClutterColor *dest,
gdouble shade)
{
clutter_color_shadex (src, dest, COGL_FIXED_FROM_FLOAT (shade));
}
/**
* clutter_color_shadex:
* @src: a #ClutterColor
* @dest: return location for the shaded color
* @shade: #ClutterFixed the shade factor to apply
*
* Fixed point version of clutter_color_shade().
*
* Shades @src by the factor of @shade and saves the modified
* color into @dest.
*
* Since: 0.2
*/
void
clutter_color_shadex (const ClutterColor *src,
ClutterColor *dest,
ClutterFixed shade)
{
ClutterFixed h, l, s;
g_return_if_fail (src != NULL);
g_return_if_fail (dest != NULL);
clutter_color_to_hlsx (src, &h, &l, &s);
l = COGL_FIXED_FAST_MUL (l, shade);
if (l > COGL_FIXED_1)
l = COGL_FIXED_1;
else if (l < 0)
l = 0;
s = COGL_FIXED_FAST_MUL (s, shade);
if (s > COGL_FIXED_1)
s = COGL_FIXED_1;
else if (s < 0)
s = 0;
clutter_color_from_hlsx (dest, h, l, s);
dest->alpha = src->alpha;
}
/**
* clutter_color_to_pixel:
* @src: a #ClutterColor
*
* Converts @src into a packed 32 bit integer, containing
* all the four 8 bit channels used by #ClutterColor.
*
* Return value: a packed color
*/
guint32
clutter_color_to_pixel (const ClutterColor *src)
{
g_return_val_if_fail (src != NULL, 0);
return (src->alpha | src->blue << 8 | src->green << 16 | src->red << 24);
}
/**
* clutter_color_from_pixel:
* @dest: return location for a #ClutterColor
* @pixel: a 32 bit packed integer containing a color
*
* Converts @pixel from the packed representation of a four 8 bit channel
* color to a #ClutterColor.
*/
void
clutter_color_from_pixel (ClutterColor *dest,
guint32 pixel)
{
g_return_if_fail (dest != NULL);
dest->red = pixel >> 24;
dest->green = (pixel >> 16) & 0xff;
dest->blue = (pixel >> 8) & 0xff;
dest->alpha = pixel & 0xff;
}
/**
* clutter_color_parse:
* @color: a string specifiying a color (named color or #RRGGBBAA)
* @dest: return location for a #ClutterColor
*
* Parses a string definition of a color, filling the
* <structfield>red</structfield>, <structfield>green</structfield>,
* <structfield>blue</structfield> and <structfield>alpha</structfield>
* channels of @dest. If alpha is not specified it will be set full opaque.
* The color in @dest is not allocated.
*
* The color may be defined by any of the formats understood by
* <function>pango_color_parse</function>; these include literal color
* names, like <literal>Red</literal> or <literal>DarkSlateGray</literal>,
* or hexadecimal specifications like <literal>&num;3050b2</literal> or
* <literal>&num;333</literal>.
*
* Return value: %TRUE if parsing succeeded.
*
* Since: 0.2
*/
gboolean
clutter_color_parse (const gchar *color,
ClutterColor *dest)
{
PangoColor pango_color;
g_return_val_if_fail (color != NULL, FALSE);
g_return_val_if_fail (dest != NULL, FALSE);
/* parse ourselves to get alpha */
if (color[0] == '#')
{
gint32 result;
if (sscanf (color + 1, "%x", &result))
{
if (strlen (color) == 9)
{
dest->red = (result >> 24) & 0xff;
dest->green = (result >> 16) & 0xff;
dest->blue = (result >> 8) & 0xff;
dest->alpha = result & 0xff;
return TRUE;
}
else if (strlen (color) == 7)
{
dest->red = (result >> 16) & 0xff;
dest->green = (result >> 8) & 0xff;
dest->blue = result & 0xff;
dest->alpha = 0xff;
return TRUE;
}
}
}
/* Fall back to pango for named colors - note pango does not handle alpha */
if (pango_color_parse (&pango_color, color))
{
dest->red = pango_color.red;
dest->green = pango_color.green;
dest->blue = pango_color.blue;
dest->alpha = 0xff;
return TRUE;
}
return FALSE;
}
/**
* clutter_color_to_string:
* @color: a #ClutterColor
*
* Returns a textual specification of @color in the hexadecimal form
* <literal>&num;rrggbbaa</literal>, where <literal>r</literal>,
* <literal>g</literal>, <literal>b</literal> and <literal>a</literal> are
* hex digits representing the red, green, blue and alpha components
* respectively.
*
* Return value: a newly-allocated text string
*
* Since: 0.2
*/
gchar *
clutter_color_to_string (const ClutterColor *color)
{
g_return_val_if_fail (color != NULL, NULL);
return g_strdup_printf ("#%02x%02x%02x%02x",
color->red,
color->green,
color->blue,
color->alpha);
}
/**
* clutter_color_equal:
* @a: a #ClutterColor
* @b: a #ClutterColor
*
* Compares two #ClutterColor<!-- -->s and checks if they are the same.
*
* Return value: %TRUE if the two colors are the same.
*
* Since: 0.2
*/
gboolean
clutter_color_equal (const ClutterColor *a,
const ClutterColor *b)
{
g_return_val_if_fail (a != NULL, FALSE);
g_return_val_if_fail (b != NULL, FALSE);
if (a == b)
return TRUE;
return (a->red == b->red &&
a->green == b->green &&
a->blue == b->blue &&
a->alpha == b->alpha);
}
/**
* clutter_color_copy:
* @color: a #ClutterColor
*
* Makes a copy of the color structure. The result must be
* freed using clutter_color_free().
*
* Return value: an allocated copy of @color.
*
* Since: 0.2
*/
ClutterColor *
clutter_color_copy (const ClutterColor *color)
{
ClutterColor *result;
g_return_val_if_fail (color != NULL, NULL);
result = g_slice_new (ClutterColor);
*result = *color;
return result;
}
/**
* clutter_color_free:
* @color: a #ClutterColor
*
* Frees a color structure created with clutter_color_copy().
*
* Since: 0.2
*/
void
clutter_color_free (ClutterColor *color)
{
if (G_LIKELY (color))
g_slice_free (ClutterColor, color);
}
/**
* clutter_color_new:
* @red: red component of the color, between 0 and 255
* @green: green component of the color, between 0 and 255
* @blue: blue component of the color, between 0 and 255
* @alpha: alpha component of the color, between 0 and 255
*
* Creates a new #ClutterColor with the given values.
*
* Return value: the newly allocated color. Use clutter_color_free()
* when done
*
* Since: 0.8.4
*/
ClutterColor *
clutter_color_new (guint8 red,
guint8 green,
guint8 blue,
guint8 alpha)
{
ClutterColor *color;
color = g_slice_new (ClutterColor);
color->red = red;
color->green = green;
color->blue = blue;
color->alpha = alpha;
return color;
}
static void
clutter_value_transform_color_string (const GValue *src,
GValue *dest)
{
gchar *string = clutter_color_to_string (src->data[0].v_pointer);
g_value_take_string (dest, string);
}
static void
clutter_value_transform_string_color (const GValue *src,
GValue *dest)
{
ClutterColor color = { 0, };
clutter_color_parse (g_value_get_string (src), &color);
clutter_value_set_color (dest, &color);
}
GType
clutter_color_get_type (void)
{
static GType _clutter_color_type = 0;
if (G_UNLIKELY (_clutter_color_type == 0))
{
_clutter_color_type =
g_boxed_type_register_static (I_("ClutterColor"),
(GBoxedCopyFunc) clutter_color_copy,
(GBoxedFreeFunc) clutter_color_free);
g_value_register_transform_func (_clutter_color_type, G_TYPE_STRING,
clutter_value_transform_color_string);
g_value_register_transform_func (G_TYPE_STRING, _clutter_color_type,
clutter_value_transform_string_color);
}
return _clutter_color_type;
}
static void
clutter_value_init_color (GValue *value)
{
value->data[0].v_pointer = NULL;
}
static void
clutter_value_free_color (GValue *value)
{
if (!(value->data[1].v_uint & G_VALUE_NOCOPY_CONTENTS))
clutter_color_free (value->data[0].v_pointer);
}
static void
clutter_value_copy_color (const GValue *src,
GValue *dest)
{
dest->data[0].v_pointer = clutter_color_copy (src->data[0].v_pointer);
}
static gpointer
clutter_value_peek_color (const GValue *value)
{
return value->data[0].v_pointer;
}
static gchar *
clutter_value_collect_color (GValue *value,
guint n_collect_values,
GTypeCValue *collect_values,
guint collect_flags)
{
if (!collect_values[0].v_pointer)
value->data[0].v_pointer = NULL;
else
{
if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
{
value->data[0].v_pointer = collect_values[0].v_pointer;
value->data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
}
else
{
value->data[0].v_pointer =
clutter_color_copy (collect_values[0].v_pointer);
}
}
return NULL;
}
static gchar *
clutter_value_lcopy_color (const GValue *value,
guint n_collect_values,
GTypeCValue *collect_values,
guint collect_flags)
{
ClutterColor **color_p = collect_values[0].v_pointer;
if (!color_p)
return g_strdup_printf ("value location for `%s' passed as NULL",
G_VALUE_TYPE_NAME (value));
if (!value->data[0].v_pointer)
*color_p = NULL;
else
{
if (collect_flags & G_VALUE_NOCOPY_CONTENTS)
*color_p = value->data[0].v_pointer;
else
*color_p = clutter_color_copy (value->data[0].v_pointer);
}
return NULL;
}
/**
* clutter_value_set_color:
* @value: a #GValue initialized to #CLUTTER_TYPE_COLOR
* @color: the color to set
*
* Sets @value to @color.
*
* Since: 0.8.4
*/
void
clutter_value_set_color (GValue *value,
const ClutterColor *color)
{
g_return_if_fail (CLUTTER_VALUE_HOLDS_COLOR (value));
value->data[0].v_pointer = clutter_color_copy (color);
}
/**
* clutter_value_get_color:
* @value: a #GValue initialized to #CLUTTER_TYPE_COLOR
*
* Gets the #ClutterColor contained in @value.
*
* Return value: the colors inside the passed #GValue
*
* Since: 0.8.4
*/
G_CONST_RETURN ClutterColor *
clutter_value_get_color (const GValue *value)
{
g_return_val_if_fail (CLUTTER_VALUE_HOLDS_COLOR (value), NULL);
return value->data[0].v_pointer;
}
static void
param_color_init (GParamSpec *pspec)
{
ClutterParamSpecColor *cspec = CLUTTER_PARAM_SPEC_COLOR (pspec);
cspec->default_value = NULL;
}
static void
param_color_finalize (GParamSpec *pspec)
{
ClutterParamSpecColor *cspec = CLUTTER_PARAM_SPEC_COLOR (pspec);
clutter_color_free (cspec->default_value);
}
static void
param_color_set_default (GParamSpec *pspec,
GValue *value)
{
value->data[0].v_pointer = CLUTTER_PARAM_SPEC_COLOR (pspec)->default_value;
value->data[1].v_uint = G_VALUE_NOCOPY_CONTENTS;
}
static gint
param_color_values_cmp (GParamSpec *pspec,
const GValue *value1,
const GValue *value2)
{
guint32 color1, color2;
color1 = clutter_color_to_pixel (value1->data[0].v_pointer);
color2 = clutter_color_to_pixel (value2->data[0].v_pointer);
if (color1 < color2)
return -1;
else if (color1 == color2)
return 0;
else
return 1;
}
static const GTypeValueTable _clutter_color_value_table = {
clutter_value_init_color,
clutter_value_free_color,
clutter_value_copy_color,
clutter_value_peek_color,
"p",
clutter_value_collect_color,
"p",
clutter_value_lcopy_color
};
GType
clutter_param_color_get_type (void)
{
static GType pspec_type = 0;
if (G_UNLIKELY (pspec_type == 0))
{
const GParamSpecTypeInfo pspec_info = {
sizeof (ClutterParamSpecColor),
16,
param_color_init,
CLUTTER_TYPE_COLOR,
param_color_finalize,
param_color_set_default,
NULL,
param_color_values_cmp,
};
pspec_type = g_param_type_register_static (I_("ClutterParamSpecColor"),
&pspec_info);
}
return pspec_type;
}
/**
* clutter_param_spec_color:
* @name: name of the property
* @nick: short name
* @blurb: description (can be translatable)
* @default_value: default value
* @flags: flags for the param spec
*
* Creates a #GParamSpec for properties using #ClutterColor.
*
* Return value: the newly created #GParamSpec
*
* Since: 0.8.4
*/
GParamSpec *
clutter_param_spec_color (const gchar *name,
const gchar *nick,
const gchar *blurb,
const ClutterColor *default_value,
GParamFlags flags)
{
ClutterParamSpecColor *cspec;
cspec = g_param_spec_internal (CLUTTER_TYPE_PARAM_COLOR,
name, nick, blurb, flags);
cspec->default_value = clutter_color_copy (default_value);
return G_PARAM_SPEC (cspec);
}