1/**************************************************************************** 2** 3** Copyright (C) 2017 The Qt Company Ltd. 4** Contact: https://www.qt.io/licensing/ 5** 6** This file is part of the Qt Graphical Effects module. 7** 8** $QT_BEGIN_LICENSE:LGPL$ 9** Commercial License Usage 10** Licensees holding valid commercial Qt licenses may use this file in 11** accordance with the commercial license agreement provided with the 12** Software or, alternatively, in accordance with the terms contained in 13** a written agreement between you and The Qt Company. For licensing terms 14** and conditions see https://www.qt.io/terms-conditions. For further 15** information use the contact form at https://www.qt.io/contact-us. 16** 17** GNU Lesser General Public License Usage 18** Alternatively, this file may be used under the terms of the GNU Lesser 19** General Public License version 3 as published by the Free Software 20** Foundation and appearing in the file LICENSE.LGPL3 included in the 21** packaging of this file. Please review the following information to 22** ensure the GNU Lesser General Public License version 3 requirements 23** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. 24** 25** GNU General Public License Usage 26** Alternatively, this file may be used under the terms of the GNU 27** General Public License version 2.0 or (at your option) the GNU General 28** Public license version 3 or any later version approved by the KDE Free 29** Qt Foundation. The licenses are as published by the Free Software 30** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 31** included in the packaging of this file. Please review the following 32** information to ensure the GNU General Public License requirements will 33** be met: https://www.gnu.org/licenses/gpl-2.0.html and 34** https://www.gnu.org/licenses/gpl-3.0.html. 35** 36** $QT_END_LICENSE$ 37** 38****************************************************************************/ 39 40import QtQuick 2.12 41import QtGraphicalEffects.private 1.12 42 43/*! 44 \qmltype Desaturate 45 \inqmlmodule QtGraphicalEffects 46 \since QtGraphicalEffects 1.0 47 \inherits QtQuick2::Item 48 \ingroup qtgraphicaleffects-color 49 \brief Reduces the saturation of the colors. 50 51 Desaturated pixel values are calculated as averages of the original RGB 52 component values of the source item. 53 54 \table 55 \header 56 \li Source 57 \li Effect applied 58 \row 59 \li \image Original_bug.png 60 \li \image Desaturate_bug.png 61 \endtable 62 63 \note This effect is available when running with OpenGL. 64 65 \section1 Example 66 67 The following example shows how to apply the effect. 68 \snippet Desaturate-example.qml example 69 70*/ 71Item { 72 id: rootItem 73 74 /*! 75 This property defines the source item that provides the source pixels to 76 the effect. 77 78 \note It is not supported to let the effect include itself, for 79 instance by setting source to the effect's parent. 80 */ 81 property variant source 82 83 /*! 84 This property defines how much the source colors are desaturated. 85 86 The value ranges from 0.0 (no change) to 1.0 (desaturated). By default, 87 the property is set to \c 0.0 (no change). 88 89 \table 90 \header 91 \li Output examples with different desaturation values 92 \li 93 \li 94 \row 95 \li \image Desaturate_desaturation1.png 96 \li \image Desaturate_desaturation2.png 97 \li \image Desaturate_desaturation3.png 98 \row 99 \li \b { desaturation: 0.0 } 100 \li \b { desaturation: 0.5 } 101 \li \b { desaturation: 1.0 } 102 \endtable 103 */ 104 property real desaturation: 0.0 105 106 /*! 107 This property allows the effect output pixels to be cached in order to 108 improve the rendering performance. 109 110 Every time the source or effect properties are changed, the pixels in 111 the cache must be updated. Memory consumption is increased, because an 112 extra buffer of memory is required for storing the effect output. 113 114 It is recommended to disable the cache when the source or the effect 115 properties are animated. 116 117 By default, the property is set to \c false. 118 119 */ 120 property bool cached: false 121 122 SourceProxy { 123 id: sourceProxy 124 input: rootItem.source 125 interpolation: input && input.smooth ? SourceProxy.LinearInterpolation : SourceProxy.NearestInterpolation 126 } 127 128 ShaderEffectSource { 129 id: cacheItem 130 anchors.fill: parent 131 visible: rootItem.cached 132 smooth: true 133 sourceItem: shaderItem 134 live: true 135 hideSource: visible 136 } 137 138 ShaderEffect { 139 id: shaderItem 140 property variant source: sourceProxy.output 141 property real desaturation: rootItem.desaturation 142 143 anchors.fill: parent 144 145 fragmentShader: "qrc:/qt-project.org/imports/QtGraphicalEffects/shaders/desaturate.frag" 146 } 147} 148