1 /****************************************************************************
3 ** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
4 ** Contact: http://www.qt-project.org/
6 ** This file is part of the QtGui module of the Qt Toolkit.
8 ** $QT_BEGIN_LICENSE:LGPL$
9 ** GNU Lesser General Public License Usage
10 ** This file may be used under the terms of the GNU Lesser General Public
11 ** License version 2.1 as published by the Free Software Foundation and
12 ** appearing in the file LICENSE.LGPL included in the packaging of this
13 ** file. Please review the following information to ensure the GNU Lesser
14 ** General Public License version 2.1 requirements will be met:
15 ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
17 ** In addition, as a special exception, Nokia gives you certain additional
18 ** rights. These rights are described in the Nokia Qt LGPL Exception
19 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
21 ** GNU General Public License Usage
22 ** Alternatively, this file may be used under the terms of the GNU General
23 ** Public License version 3.0 as published by the Free Software Foundation
24 ** and appearing in the file LICENSE.GPL included in the packaging of this
25 ** file. Please review the following information to ensure the GNU General
26 ** Public License version 3.0 requirements will be met:
27 ** http://www.gnu.org/copyleft/gpl.html.
30 ** Alternatively, this file may be used in accordance with the terms and
31 ** conditions contained in a signed written agreement between you and Nokia.
40 ****************************************************************************/
42 #include <private/qdrawhelper_p.h>
47 QDrawHelperGammaTables::QDrawHelperGammaTables(qreal smoothing)
49 const qreal gray_gamma = 2.31;
50 for (int i=0; i<256; ++i)
51 qt_pow_gamma[i] = uint(qRound(qPow(i / qreal(255.), gray_gamma) * 2047));
52 for (int i=0; i<2048; ++i)
53 qt_pow_invgamma[i] = uchar(qRound(qPow(i / qreal(2047.0), 1 / gray_gamma) * 255));
58 void QDrawHelperGammaTables::refresh(qreal smoothing)
60 for (int i=0; i<256; ++i) {
61 qt_pow_rgb_gamma[i] = uchar(qRound(qPow(i / qreal(255.0), smoothing) * 255));
62 qt_pow_rgb_invgamma[i] = uchar(qRound(qPow(i / qreal(255.), 1 / smoothing) * 255));