forked from AuroraMiddleware/gtk
577 lines
14 KiB
C
577 lines
14 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 "gdkrgbaprivate.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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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 color, in a way that is compatible
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* with cairo’s notion of color.
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*
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* `GdkRGBA` is a convenient way to pass colors around. It’s based on
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* cairo’s way to deal with colors and mirrors its behavior. All values
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* 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
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* be clamped to this range when drawing.
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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 [method@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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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`.
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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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/**
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* gdk_rgba_is_clear:
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* @rgba: a `GdkRGBA`
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*
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* Checks if an @rgba value is transparent.
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*
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* That is, drawing with the value would not produce any change.
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*
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* Returns: %TRUE if the @rgba is clear
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*/
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gboolean
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gdk_rgba_is_clear (const GdkRGBA *rgba)
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{
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return rgba->alpha < ((float) 0x00ff / (float) 0xffff);
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}
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/**
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* gdk_rgba_is_opaque:
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* @rgba: a `GdkRGBA`
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*
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* Checks if an @rgba value is opaque.
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*
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* That is, drawing with the value will not retain any results
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* from previous contents.
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*
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* Returns: %TRUE if the @rgba is opaque
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*/
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gboolean
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gdk_rgba_is_opaque (const GdkRGBA *rgba)
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{
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return rgba->alpha > ((float)0xff00 / (float)0xffff);
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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 [ 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 char *str,
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char **endp,
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double *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.
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*
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* The string can be either one of:
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*
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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 hexadecimal value in the form “\#rgba”, “\#rrggbbaa”,
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* or ”\#rrrrggggbbbbaaaa”
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* - A RGB color in the form “rgb(r,g,b)” (In this case the color
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* will 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,
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* blue and alpha color values. In the last two cases, “r”, “g”,
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* and “b” are either integers in the range 0 to 255 or percentage
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* values in the range 0% to 100%, and a is a floating point value
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* 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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gboolean
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gdk_rgba_parse (GdkRGBA *rgba,
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const char *spec)
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{
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gboolean has_alpha;
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double r, g, b, a;
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char *str = (char *) spec;
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char *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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guint16 alpha;
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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_with_alpha (&pango_color, &alpha, 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 = alpha / 65535.;
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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`
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*
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* A hash function suitable for using for a hash
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* table that stores `GdkRGBA`s.
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*
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* Returns: The hash value for @p
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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`
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* @p2: (type GdkRGBA): another `GdkRGBA`
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*
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* Compares two `GdkRGBA` 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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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 `rgba(r,g,b,a)`, where “r”, “g”, “b” and
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* “a” represent the red, green, blue and alpha values
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* respectively. “r”, “g”, and “b” are represented as integers
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* in the range 0 to 255, and “a” is represented as a floating
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* point value in the range 0 to 1.
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*
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* These string forms are string forms that are supported by
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* the CSS3 colors module, and can be parsed by [method@Gdk.RGBA.parse].
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*
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* Note that this string representation may lose some precision,
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* since “r”, “g” and “b” are represented as 8-bit integers. If
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* this is a concern, you should use a different representation.
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*
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* Returns: A newly allocated text string
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*/
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char *
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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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char 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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static gboolean
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parse_color_channel_value (GtkCssParser *parser,
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float *value,
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gboolean is_percentage)
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{
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double dvalue;
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if (is_percentage)
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{
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if (!gtk_css_parser_consume_percentage (parser, &dvalue))
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return FALSE;
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*value = CLAMP (dvalue, 0.0, 100.0) / 100.0;
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return TRUE;
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}
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else
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{
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if (!gtk_css_parser_consume_number (parser, &dvalue))
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return FALSE;
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*value = CLAMP (dvalue, 0.0, 255.0) / 255.0;
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return TRUE;
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}
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}
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static guint
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parse_color_channel (GtkCssParser *parser,
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guint arg,
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gpointer data)
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{
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GdkRGBA *rgba = data;
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double dvalue;
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switch (arg)
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{
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case 0:
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/* We abuse rgba->alpha to store if we use percentages or numbers */
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if (gtk_css_token_is (gtk_css_parser_get_token (parser), GTK_CSS_TOKEN_PERCENTAGE))
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rgba->alpha = 1.0;
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else
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rgba->alpha = 0.0;
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if (!parse_color_channel_value (parser, &rgba->red, rgba->alpha != 0.0))
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return 0;
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return 1;
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case 1:
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if (!parse_color_channel_value (parser, &rgba->green, rgba->alpha != 0.0))
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return 0;
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return 1;
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case 2:
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if (!parse_color_channel_value (parser, &rgba->blue, rgba->alpha != 0.0))
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return 0;
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return 1;
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case 3:
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if (!gtk_css_parser_consume_number (parser, &dvalue))
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return 0;
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rgba->alpha = CLAMP (dvalue, 0.0, 1.0);
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return 1;
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default:
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g_assert_not_reached ();
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return 0;
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}
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}
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static gboolean
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rgba_init_chars (GdkRGBA *rgba,
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const char s[8])
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{
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guint i;
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for (i = 0; i < 8; i++)
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{
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if (!g_ascii_isxdigit (s[i]))
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return FALSE;
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}
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rgba->red = (g_ascii_xdigit_value (s[0]) * 16 + g_ascii_xdigit_value (s[1])) / 255.0;
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rgba->green = (g_ascii_xdigit_value (s[2]) * 16 + g_ascii_xdigit_value (s[3])) / 255.0;
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rgba->blue = (g_ascii_xdigit_value (s[4]) * 16 + g_ascii_xdigit_value (s[5])) / 255.0;
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rgba->alpha = (g_ascii_xdigit_value (s[6]) * 16 + g_ascii_xdigit_value (s[7])) / 255.0;
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return TRUE;
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}
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gboolean
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gdk_rgba_parser_parse (GtkCssParser *parser,
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GdkRGBA *rgba)
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{
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const GtkCssToken *token;
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token = gtk_css_parser_get_token (parser);
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if (gtk_css_token_is_function (token, "rgb"))
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{
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if (!gtk_css_parser_consume_function (parser, 3, 3, parse_color_channel, rgba))
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return FALSE;
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rgba->alpha = 1.0;
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return TRUE;
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}
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else if (gtk_css_token_is_function (token, "rgba"))
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{
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return gtk_css_parser_consume_function (parser, 4, 4, parse_color_channel, rgba);
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}
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else if (gtk_css_token_is (token, GTK_CSS_TOKEN_HASH_ID) ||
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gtk_css_token_is (token, GTK_CSS_TOKEN_HASH_UNRESTRICTED))
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{
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const char *s = token->string.string;
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switch (strlen (s))
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{
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case 3:
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if (!rgba_init_chars (rgba, (char[8]) {s[0], s[0], s[1], s[1], s[2], s[2], 'F', 'F' }))
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{
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gtk_css_parser_error_value (parser, "Hash code is not a valid hex color.");
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return FALSE;
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}
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break;
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case 4:
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if (!rgba_init_chars (rgba, (char[8]) {s[0], s[0], s[1], s[1], s[2], s[2], s[3], s[3] }))
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{
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gtk_css_parser_error_value (parser, "Hash code is not a valid hex color.");
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return FALSE;
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}
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break;
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case 6:
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||
if (!rgba_init_chars (rgba, (char[8]) {s[0], s[1], s[2], s[3], s[4], s[5], 'F', 'F' }))
|
||
{
|
||
gtk_css_parser_error_value (parser, "Hash code is not a valid hex color.");
|
||
return FALSE;
|
||
}
|
||
break;
|
||
|
||
case 8:
|
||
if (!rgba_init_chars (rgba, s))
|
||
{
|
||
gtk_css_parser_error_value (parser, "Hash code is not a valid hex color.");
|
||
return FALSE;
|
||
}
|
||
break;
|
||
|
||
default:
|
||
gtk_css_parser_error_value (parser, "Hash code is not a valid hex color.");
|
||
return FALSE;
|
||
break;
|
||
}
|
||
|
||
gtk_css_parser_consume_token (parser);
|
||
return TRUE;
|
||
}
|
||
else if (gtk_css_token_is (token, GTK_CSS_TOKEN_IDENT))
|
||
{
|
||
if (gtk_css_token_is_ident (token, "transparent"))
|
||
{
|
||
*rgba = (GdkRGBA) { 0, 0, 0, 0 };
|
||
}
|
||
else if (gdk_rgba_parse (rgba, token->string.string))
|
||
{
|
||
/* everything's fine */
|
||
}
|
||
else
|
||
{
|
||
gtk_css_parser_error_syntax (parser, "\"%s\" is not a valid color name.", token->string.string);
|
||
return FALSE;
|
||
}
|
||
|
||
gtk_css_parser_consume_token (parser);
|
||
return TRUE;
|
||
}
|
||
else
|
||
{
|
||
gtk_css_parser_error_syntax (parser, "Expected a valid color.");
|
||
return FALSE;
|
||
}
|
||
}
|