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/*
* Pidgin - Internet Messenger
* Copyright (C) Pidgin Developers <devel@pidgin.im>
*
* Pidgin is the legal property of its developers, whose names are too numerous
* to list here. Please refer to the COPYRIGHT file distributed with this
* source distribution.
*
* 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 library; if not, see <https://www.gnu.org/licenses/>.
*/
#include "pidgincolor.h"
/******************************************************************************
* Public API
*****************************************************************************/
void
pidgin_color_calculate_for_text(const gchar *text, GdkRGBA *color) {
GdkRGBA background;
GChecksum *checksum = NULL;
guchar digest[20];
gsize digest_len = sizeof(digest);
gfloat hue = 0, red = 0, green = 0, blue = 0;
g_return_if_fail(color != NULL);
#warning figure out how to get the background color
gdk_rgba_parse(&background, "#FFFFFFFF");
/* hash the string and get the first 2 bytes of the digest */
checksum = g_checksum_new(G_CHECKSUM_SHA1);
if(text != NULL) {
g_checksum_update(checksum, (const guchar *)text, -1);
}
g_checksum_get_digest(checksum, digest, &digest_len);
g_checksum_free(checksum);
/* Calculate the hue based on the digest. We need a value between 0 and 1
* so we divide the value by 65535 which is the maximum value for 2 bytes.
*/
hue = (digest[0] << 8 | digest[1]) / 65535.0f;
/* Get the rgb values for the hue at full saturation and value. */
gtk_hsv_to_rgb(hue, 1.0f, 1.0f, &red, &green, &blue);
/* Finally calculate the color summing 20% of the inverted background color
* with 80% of the color.
*/
color->red = (0.2f * (1 - background.red)) + (0.8f * red);
color->green = (0.2f * (1 - background.green)) + (0.8f * green);
color->blue = (0.2f * (1 - background.blue)) + (0.8f * blue);
color->alpha = 1.0f;
}
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