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/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the documentation of the Qt Graphical Effects module.
**
** $QT_BEGIN_LICENSE:FDL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Free Documentation License Usage
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file. Please review the following information to ensure
** the GNU Free Documentation License version 1.3 requirements
** will be met: http://www.gnu.org/copyleft/fdl.html.
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\qmltype GammaAdjust
\inqmlmodule QtGraphicalEffects 1.0
\since QtGraphicalEffects 1.0
\inherits QtQuick2::Item
\ingroup qtgraphicaleffects-color
\brief Alters the luminance of the source item.
GammaAdjust is applied to each pixel according to the curve which is
pre-defined as a power-law expression, where the property gamma is used as the
reciprocal scaling exponent. Refer to the property documentation of \l{GammaAdjust::gamma}{gamma}
for more details.
\table
\header
\li Source
\li Effect applied
\row
\li \image Original_bug.png
\li \image GammaAdjust_bug.png
\endtable
\section1 Example
The following example shows how to apply the effect.
\snippet snippets/GammaAdjust-example.qml example
*/
/*!
\qmlproperty variant QtGraphicalEffects1::GammaAdjust::source
This property defines the source item for which the luminance is going to be
adjusted.
*/
/*!
\qmlproperty real QtGraphicalEffects1::GammaAdjust::gamma
This property defines the change factor for how the luminance of each pixel
is altered according to the equation:
\code luminance = pow(original_luminance, 1.0 / gamma); // The luminance is assumed to be between 0.0 and 1.0 \endcode
Setting the gamma values under 1.0 makes the image darker, the values
above 1.0 lighten it.
The value ranges from 0.0 (darkest) to inf (lightest). By default, the property
is set to \c 1.0 (no change).
\table
\header
\li Output examples with different gamma values
\li
\li
\row
\li \image GammaAdjust_gamma1.png
\li \image GammaAdjust_gamma2.png
\li \image GammaAdjust_gamma3.png
\row
\li \b { gamma: 0.5 }
\li \b { gamma: 1.0 }
\li \b { gamma: 2.0 }
\endtable
\table
\header
\li Pixel luminance curves of the above images.
\li
\li
\row
\li \image GammaAdjust_gamma1_graph.png
\li \image GammaAdjust_gamma2_graph.png
\li \image GammaAdjust_gamma3_graph.png
\row
\li Red curve: default gamma (1.0)
\li
\li
\row
\li Yellow curve: effect applied
\li
\li
\row
\li X-axis: pixel original luminance
\li
\li
\row
\li Y-axis: pixel luminance with effect applied
\li
\li
\endtable
*/
/*!
\qmlproperty bool QtGraphicalEffects1::GammaAdjust::cached
This property allows the effect output pixels to be cached in order to
improve the rendering performance.
Every time the source or effect properties are changed, the pixels in the
cache must be updated. Memory consumption is increased, because an extra
buffer of memory is required for storing the effect output.
It is recommended to disable the cache when the source or the effect
properties are animated.
By default, the property is set to \c false.
*/
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