215 lines
7.1 KiB
QML
215 lines
7.1 KiB
QML
/****************************************************************************
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**
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** Copyright (C) 2017 The Qt Company Ltd.
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** Contact: https://www.qt.io/licensing/
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**
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** This file is part of the Qt Graphical Effects module.
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**
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** $QT_BEGIN_LICENSE:LGPL$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and The Qt Company. For licensing terms
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** and conditions see https://www.qt.io/terms-conditions. For further
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** information use the contact form at https://www.qt.io/contact-us.
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**
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** GNU Lesser General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** General Public License version 3 as published by the Free Software
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** Foundation and appearing in the file LICENSE.LGPL3 included in the
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** packaging of this file. Please review the following information to
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** ensure the GNU Lesser General Public License version 3 requirements
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** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
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**
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** GNU General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU
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** General Public License version 2.0 or (at your option) the GNU General
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** Public license version 3 or any later version approved by the KDE Free
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** Qt Foundation. The licenses are as published by the Free Software
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** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
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** included in the packaging of this file. Please review the following
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** information to ensure the GNU General Public License requirements will
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** be met: https://www.gnu.org/licenses/gpl-2.0.html and
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** https://www.gnu.org/licenses/gpl-3.0.html.
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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import QtQuick 2.12
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import QtGraphicalEffects.private 1.12
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/*!
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\qmltype ThresholdMask
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\inqmlmodule QtGraphicalEffects
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\since QtGraphicalEffects 1.0
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\inherits QtQuick2::Item
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\ingroup qtgraphicaleffects-mask
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\brief Masks the source item with another item and applies a threshold
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value.
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The masking behavior can be controlled with the \l threshold value for the
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mask pixels.
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\table
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\header
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\li Source
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\li MaskSource
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\li Effect applied
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\row
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\li \image Original_bug.png
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\li \image ThresholdMask_mask.png
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\li \image ThresholdMask_bug.png
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\endtable
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\note This effect is available when running with OpenGL.
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\section1 Example
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The following example shows how to apply the effect.
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\snippet ThresholdMask-example.qml example
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*/
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Item {
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id: rootItem
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/*!
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This property defines the source item that is going to be masked.
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\note It is not supported to let the effect include itself, for
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instance by setting source to the effect's parent.
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*/
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property variant source
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/*!
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This property defines the item that is going to be used as the mask.
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Mask item gets rendered into an intermediate pixel buffer and the alpha
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values from the result are used to determine the source item's pixels
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visibility in the display.
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\table
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\header
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\li Original
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\li Mask
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\li Effect applied
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\row
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\li \image Original_bug.png
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\li \image ThresholdMask_mask.png
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\li \image ThresholdMask_bug.png
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\endtable
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\note It is not supported to let the effect include itself, for
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instance by setting maskSource to the effect's parent.
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*/
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property variant maskSource
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/*!
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This property defines a threshold value for the mask pixels. The mask
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pixels that have an alpha value below this property are used to
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completely mask away the corresponding pixels from the source item. The
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mask pixels that have a higher alpha value are used to alphablend the
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source item to the display.
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The value ranges from 0.0 (alpha value 0) to 1.0 (alpha value 255). By
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default, the property is set to \c 0.0.
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\table
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\header
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\li Output examples with different threshold values
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\li
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\li
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\row
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\li \image ThresholdMask_threshold1.png
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\li \image ThresholdMask_threshold2.png
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\li \image ThresholdMask_threshold3.png
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\row
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\li \b { threshold: 0.0 }
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\li \b { threshold: 0.5 }
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\li \b { threshold: 0.7 }
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\row
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\li \l spread: 0.2
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\li \l spread: 0.2
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\li \l spread: 0.2
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\endtable
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*/
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property real threshold: 0.0
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/*!
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This property defines the smoothness of the mask edges near the
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\l{ThresholdMask::threshold}{threshold} alpha value. Setting spread to
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0.0 uses mask normally with the specified threshold. Setting higher
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spread values softens the transition from the transparent mask pixels
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towards opaque mask pixels by adding interpolated values between them.
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The value ranges from 0.0 (sharp mask edge) to 1.0 (smooth mask edge).
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By default, the property is set to \c 0.0.
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\table
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\header
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\li Output examples with different spread values
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\li
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\li
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\row
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\li \image ThresholdMask_spread1.png
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\li \image ThresholdMask_spread2.png
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\li \image ThresholdMask_spread3.png
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\row
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\li \b { spread: 0.0 }
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\li \b { spread: 0.2 }
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\li \b { spread: 0.8 }
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\row
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\li \l threshold: 0.4
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\li \l threshold: 0.4
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\li \l threshold: 0.4
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\endtable
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*/
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property real spread: 0.0
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/*!
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This property allows the effect output pixels to be cached in order to
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improve the rendering performance.
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Every time the source or effect properties are changed, the pixels in
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the cache must be updated. Memory consumption is increased, because an
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extra buffer of memory is required for storing the effect output.
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It is recommended to disable the cache when the source or the effect
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properties are animated.
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By default, the property is set to \c false.
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*/
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property bool cached: false
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SourceProxy {
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id: sourceProxy
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input: rootItem.source
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}
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SourceProxy {
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id: maskSourceProxy
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input: rootItem.maskSource
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}
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ShaderEffectSource {
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id: cacheItem
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anchors.fill: parent
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visible: rootItem.cached
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smooth: true
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sourceItem: shaderItem
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live: true
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hideSource: visible
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}
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ShaderEffect {
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id: shaderItem
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property variant source: sourceProxy.output
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property variant maskSource: maskSourceProxy.output
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property real threshold: rootItem.threshold
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property real spread: rootItem.spread
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anchors.fill: parent
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fragmentShader: "qrc:/qt-project.org/imports/QtGraphicalEffects/shaders/thresholdmask.frag"
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}
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}
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