forked from AuroraMiddleware/gtk
378 lines
9.2 KiB
C
378 lines
9.2 KiB
C
/* GDK - The GIMP Drawing Kit
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* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* Modified by the GTK+ Team and others 1997-2000. See the AUTHORS
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* file for a list of people on the GTK+ Team. See the ChangeLog
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* files for a list of changes. These files are distributed with
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* GTK+ at ftp://ftp.gtk.org/pub/gtk/.
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*/
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#include "config.h"
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#include "gdkrgba.h"
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#include <string.h>
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#include <errno.h>
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#include <math.h>
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#include "fallback-c89.c"
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/**
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* SECTION:rgba_colors
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* @Short_description: RGBA colors
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* @Title: RGBA Colors
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*
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* #GdkRGBA is a convenient way to pass rgba colors around.
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* It’s based on cairo’s way to deal with colors and mirrors its behavior.
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* All values are in the range from 0.0 to 1.0 inclusive. So the color
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* (0.0, 0.0, 0.0, 0.0) represents transparent black and
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* (1.0, 1.0, 1.0, 1.0) is opaque white. Other values will be clamped
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* to this range when drawing.
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*/
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G_DEFINE_BOXED_TYPE (GdkRGBA, gdk_rgba,
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gdk_rgba_copy, gdk_rgba_free)
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/**
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* GdkRGBA:
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* @red: The intensity of the red channel from 0.0 to 1.0 inclusive
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* @green: The intensity of the green channel from 0.0 to 1.0 inclusive
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* @blue: The intensity of the blue channel from 0.0 to 1.0 inclusive
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* @alpha: The opacity of the color from 0.0 for completely translucent to
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* 1.0 for opaque
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*
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* A #GdkRGBA is used to represent a (possibly translucent)
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* color, in a way that is compatible with cairo’s notion of color.
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*/
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/**
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* gdk_rgba_copy:
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* @rgba: a #GdkRGBA
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*
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* Makes a copy of a #GdkRGBA.
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*
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* The result must be freed through gdk_rgba_free().
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*
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* Returns: A newly allocated #GdkRGBA, with the same contents as @rgba
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*
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* Since: 3.0
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*/
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GdkRGBA *
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gdk_rgba_copy (const GdkRGBA *rgba)
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{
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return g_slice_dup (GdkRGBA, rgba);
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}
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/**
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* gdk_rgba_free:
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* @rgba: a #GdkRGBA
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*
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* Frees a #GdkRGBA created with gdk_rgba_copy()
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*
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* Since: 3.0
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*/
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void
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gdk_rgba_free (GdkRGBA *rgba)
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{
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g_slice_free (GdkRGBA, rgba);
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}
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#define SKIP_WHITESPACES(s) while (*(s) == ' ') (s)++;
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/* Parses a single color component from a rgb() or rgba() specification
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* according to CSS3 rules. Compared to exact CSS3 parsing we are liberal
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* in what we accept as follows:
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*
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* - For non-percentage values, we accept floats in the range 0-255
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* not just [0-9]+ integers
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* - For percentage values we accept any float, not just
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* [ 0-9]+ | [0-9]* “.” [0-9]+
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* - We accept mixed percentages and non-percentages in a single
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* rgb() or rgba() specification.
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*/
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static gboolean
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parse_rgb_value (const gchar *str,
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gchar **endp,
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gdouble *number)
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{
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const char *p;
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*number = g_ascii_strtod (str, endp);
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if (errno == ERANGE || *endp == str ||
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isinf (*number) || isnan (*number))
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return FALSE;
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p = *endp;
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SKIP_WHITESPACES (p);
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if (*p == '%')
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{
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*endp = (char *)(p + 1);
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*number = CLAMP(*number / 100., 0., 1.);
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}
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else
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{
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*number = CLAMP(*number / 255., 0., 1.);
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}
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return TRUE;
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}
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/**
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* gdk_rgba_parse:
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* @rgba: the #GdkRGBA to fill in
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* @spec: the string specifying the color
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*
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* Parses a textual representation of a color, filling in
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* the @red, @green, @blue and @alpha fields of the @rgba #GdkRGBA.
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*
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* The string can be either one of:
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* - A standard name (Taken from the X11 rgb.txt file).
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* - A hexadecimal value in the form “\#rgb”, “\#rrggbb”,
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* “\#rrrgggbbb” or ”\#rrrrggggbbbb”
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* - A RGB color in the form “rgb(r,g,b)” (In this case the color will
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* have full opacity)
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* - A RGBA color in the form “rgba(r,g,b,a)”
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*
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* Where “r”, “g”, “b” and “a” are respectively the red, green, blue and
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* alpha color values. In the last two cases, r g and b are either integers
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* in the range 0 to 255 or percentage values in the range 0% to 100%, and
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* a is a floating point value in the range 0 to 1.
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*
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* Returns: %TRUE if the parsing succeeded
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*
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* Since: 3.0
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*/
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gboolean
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gdk_rgba_parse (GdkRGBA *rgba,
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const gchar *spec)
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{
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gboolean has_alpha;
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gdouble r, g, b, a;
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gchar *str = (gchar *) spec;
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gchar *p;
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g_return_val_if_fail (spec != NULL, FALSE);
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if (strncmp (str, "rgba", 4) == 0)
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{
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has_alpha = TRUE;
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str += 4;
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}
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else if (strncmp (str, "rgb", 3) == 0)
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{
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has_alpha = FALSE;
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a = 1;
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str += 3;
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}
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else
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{
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PangoColor pango_color;
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/* Resort on PangoColor for rgb.txt color
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* map and '#' prefixed colors
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*/
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if (pango_color_parse (&pango_color, str))
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{
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if (rgba)
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{
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rgba->red = pango_color.red / 65535.;
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rgba->green = pango_color.green / 65535.;
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rgba->blue = pango_color.blue / 65535.;
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rgba->alpha = 1;
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}
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return TRUE;
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}
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else
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return FALSE;
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}
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SKIP_WHITESPACES (str);
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if (*str != '(')
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return FALSE;
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str++;
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/* Parse red */
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SKIP_WHITESPACES (str);
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if (!parse_rgb_value (str, &str, &r))
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return FALSE;
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SKIP_WHITESPACES (str);
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if (*str != ',')
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return FALSE;
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str++;
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/* Parse green */
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SKIP_WHITESPACES (str);
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if (!parse_rgb_value (str, &str, &g))
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return FALSE;
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SKIP_WHITESPACES (str);
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if (*str != ',')
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return FALSE;
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str++;
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/* Parse blue */
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SKIP_WHITESPACES (str);
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if (!parse_rgb_value (str, &str, &b))
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return FALSE;
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SKIP_WHITESPACES (str);
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if (has_alpha)
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{
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if (*str != ',')
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return FALSE;
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str++;
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SKIP_WHITESPACES (str);
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a = g_ascii_strtod (str, &p);
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if (errno == ERANGE || p == str ||
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isinf (a) || isnan (a))
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return FALSE;
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str = p;
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SKIP_WHITESPACES (str);
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}
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if (*str != ')')
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return FALSE;
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str++;
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SKIP_WHITESPACES (str);
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if (*str != '\0')
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return FALSE;
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if (rgba)
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{
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rgba->red = CLAMP (r, 0, 1);
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rgba->green = CLAMP (g, 0, 1);
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rgba->blue = CLAMP (b, 0, 1);
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rgba->alpha = CLAMP (a, 0, 1);
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}
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return TRUE;
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}
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#undef SKIP_WHITESPACES
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/**
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* gdk_rgba_hash:
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* @p: (type GdkRGBA): a #GdkRGBA pointer
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*
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* A hash function suitable for using for a hash
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* table that stores #GdkRGBAs.
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*
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* Returns: The hash value for @p
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*
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* Since: 3.0
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*/
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guint
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gdk_rgba_hash (gconstpointer p)
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{
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const GdkRGBA *rgba = p;
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return ((guint) (rgba->red * 65535) +
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((guint) (rgba->green * 65535) << 11) +
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((guint) (rgba->blue * 65535) << 22) +
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((guint) (rgba->alpha * 65535) >> 6));
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}
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/**
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* gdk_rgba_equal:
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* @p1: (type GdkRGBA): a #GdkRGBA pointer
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* @p2: (type GdkRGBA): another #GdkRGBA pointer
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*
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* Compares two RGBA colors.
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*
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* Returns: %TRUE if the two colors compare equal
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*
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* Since: 3.0
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*/
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gboolean
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gdk_rgba_equal (gconstpointer p1,
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gconstpointer p2)
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{
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const GdkRGBA *rgba1, *rgba2;
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rgba1 = p1;
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rgba2 = p2;
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if (rgba1->red == rgba2->red &&
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rgba1->green == rgba2->green &&
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rgba1->blue == rgba2->blue &&
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rgba1->alpha == rgba2->alpha)
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return TRUE;
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return FALSE;
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}
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/**
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* gdk_rgba_to_string:
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* @rgba: a #GdkRGBA
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*
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* Returns a textual specification of @rgba in the form
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* `rgb (r, g, b)` or
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* `rgba (r, g, b, a)`,
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* where “r”, “g”, “b” and “a” represent the red, green,
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* blue and alpha values respectively. r, g, and b are
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* represented as integers in the range 0 to 255, and a
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* is represented as floating point value in the range 0 to 1.
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*
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* These string forms are string forms those supported by
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* the CSS3 colors module, and can be parsed by gdk_rgba_parse().
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*
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* Note that this string representation may lose some
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* precision, since r, g and b are represented as 8-bit
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* integers. If this is a concern, you should use a
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* different representation.
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*
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* Returns: A newly allocated text string
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*
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* Since: 3.0
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*/
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gchar *
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gdk_rgba_to_string (const GdkRGBA *rgba)
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{
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if (rgba->alpha > 0.999)
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{
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return g_strdup_printf ("rgb(%d,%d,%d)",
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(int)(0.5 + CLAMP (rgba->red, 0., 1.) * 255.),
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(int)(0.5 + CLAMP (rgba->green, 0., 1.) * 255.),
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(int)(0.5 + CLAMP (rgba->blue, 0., 1.) * 255.));
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}
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else
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{
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gchar alpha[G_ASCII_DTOSTR_BUF_SIZE];
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g_ascii_formatd (alpha, G_ASCII_DTOSTR_BUF_SIZE, "%g", CLAMP (rgba->alpha, 0, 1));
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return g_strdup_printf ("rgba(%d,%d,%d,%s)",
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(int)(0.5 + CLAMP (rgba->red, 0., 1.) * 255.),
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(int)(0.5 + CLAMP (rgba->green, 0., 1.) * 255.),
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(int)(0.5 + CLAMP (rgba->blue, 0., 1.) * 255.),
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alpha);
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}
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}
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