/*
* Copyright © 2003 Maxim Stepin (maxst@hiend3d.com)
*
* Copyright © 2010 Cameron Zemek (grom@zeminvaders.net)
*
* Copyright © 2011 Tamme Schichler (tamme.schichler@googlemail.com)
* Copyright © 2012 A. Eduardo García (arcnorj@gmail.com)
*
* This file is part of hqx-java.
*
* hqx-java 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 3 of the License, or
* (at your option) any later version.
*
* hqx-java 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 hqx-java. If not, see <http://www.gnu.org/licenses/>.
*/
package com.opendoorlogistics.codefromweb.hqx;
public final class RgbYuv {
private static final int rgbMask = 0x00FFFFFF;
private static int[] RGBtoYUV = new int[0x1000000];
/**
* Returns the 24bit YUV equivalent of the provided 24bit RGB color.<b>Any alpha component is dropped</b>
*
* @param rgb a 24bit rgb color
* @return the corresponding 24bit YUV color
*/
static int getYuv(final int rgb) {
return RGBtoYUV[rgb & rgbMask];
}
/**
* Calculates the lookup table. <b>MUST</b> be called (only once) before doing anything else
*/
public static void hqxInit() {
/* Initalize RGB to YUV lookup table */
int r, g, b, y, u, v;
for (int c = 0x1000000 - 1; c >= 0; c--) {
r = (c & 0xFF0000) >> 16;
g = (c & 0x00FF00) >> 8;
b = c & 0x0000FF;
y = (int) (+0.299d * r + 0.587d * g + 0.114d * b);
u = (int) (-0.169d * r - 0.331d * g + 0.500d * b) + 128;
v = (int) (+0.500d * r - 0.419d * g - 0.081d * b) + 128;
RGBtoYUV[c] = (y << 16) | (u << 8) | v;
}
}
/// <summary>
/// Releases the reference to the lookup table.
/// <para>The table has to be calculated again for the next lookup.</para>
/// </summary>
/**
* Releases the reference to the lookup table. <b>The table has to be calculated again for the next lookup.</b>
*/
public static void hqxDeinit() {
RGBtoYUV = null;
}
}