324 lines
10 KiB
QML
324 lines
10 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 LinearGradient
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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-gradient
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\brief Draws a linear gradient.
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A gradient is defined by two or more colors, which are blended seamlessly.
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The colors start from the given start point and end to the given end point.
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\table
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\header
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\li Effect applied
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\row
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\li \image LinearGradient.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 LinearGradient-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 starting point where the color at gradient
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position of 0.0 is rendered. Colors at larger position values are
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rendered linearly towards the end point. The point is given in pixels
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and the default value is Qt.point(0, 0). Setting the default values for
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the start and \l{LinearGradient::end}{end} results in a full height
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linear gradient on the y-axis.
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\table
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\header
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\li Output examples with different start values
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\li
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\li
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\row
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\li \image LinearGradient_start1.png
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\li \image LinearGradient_start2.png
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\li \image LinearGradient_start3.png
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\row
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\li \b { start: QPoint(0, 0) }
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\li \b { start: QPoint(150, 150) }
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\li \b { start: QPoint(300, 0) }
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\row
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\li \l end: QPoint(300, 300)
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\li \l end: QPoint(300, 300)
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\li \l end: QPoint(300, 300)
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\endtable
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*/
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property variant start: Qt.point(0, 0)
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/*!
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This property defines the ending point where the color at gradient
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position of 1.0 is rendered. Colors at smaller position values are
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rendered linearly towards the start point. The point is given in pixels
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and the default value is Qt.point(0, height). Setting the default values
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for the \l{LinearGradient::start}{start} and end results in a full
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height linear gradient on the y-axis.
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\table
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\header
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\li Output examples with different end values
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\li
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\li
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\row
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\li \image LinearGradient_end1.png
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\li \image LinearGradient_end2.png
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\li \image LinearGradient_end3.png
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\row
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\li \b { end: Qt.point(300, 300) }
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\li \b { end: Qt.point(150, 150) }
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\li \b { end: Qt.point(300, 0) }
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\row
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\li \l start: Qt.point(0, 0)
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\li \l start: Qt.point(0, 0)
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\li \l start: Qt.point(0, 0)
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\endtable
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*/
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property variant end: Qt.point(0, height)
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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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/*!
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This property defines the item that is going to be filled with gradient.
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Source item gets rendered into an intermediate pixel buffer and the
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alpha values from the result are used to determine the gradient's pixels
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visibility in the display. The default value for source is undefined and
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in that case whole effect area is filled with gradient.
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\table
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\header
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\li Output examples with different source values
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\li
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\li
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\row
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\li \image LinearGradient_maskSource1.png
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\li \image LinearGradient_maskSource2.png
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\row
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\li \b { source: undefined }
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\li \b { source: Image { source: images/butterfly.png } }
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\row
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\li \l start: Qt.point(0, 0)
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\li \l start: Qt.point(0, 0)
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\row
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\li \l end: Qt.point(300, 300)
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\li \l end: Qt.point(300, 300)
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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 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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A gradient is defined by two or more colors, which are blended
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seamlessly. The colors are specified as a set of GradientStop child
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items, each of which defines a position on the gradient from 0.0 to 1.0
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and a color. The position of each GradientStop is defined by the
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position property, and the color is definded by the color property.
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\table
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\header
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\li Output examples with different gradient values
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\li
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\li
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\row
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\li \image LinearGradient_gradient1.png
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\li \image LinearGradient_gradient2.png
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\li \image LinearGradient_gradient3.png
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\row
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\li \b {gradient:} \code
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Gradient {
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GradientStop {
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position: 0.000
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color: Qt.rgba(1, 0, 0, 1)
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}
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GradientStop {
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position: 0.167
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color: Qt.rgba(1, 1, 0, 1)
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}
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GradientStop {
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position: 0.333
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color: Qt.rgba(0, 1, 0, 1)
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}
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GradientStop {
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position: 0.500
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color: Qt.rgba(0, 1, 1, 1)
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}
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GradientStop {
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position: 0.667
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color: Qt.rgba(0, 0, 1, 1)
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}
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GradientStop {
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position: 0.833
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color: Qt.rgba(1, 0, 1, 1)
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}
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GradientStop {
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position: 1.000
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color: Qt.rgba(1, 0, 0, 1)
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}
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}
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\endcode
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\li \b {gradient:} \code
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Gradient {
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GradientStop {
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position: 0.0
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color: "#F0F0F0"
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}
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GradientStop {
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position: 0.5
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color: "#000000"
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}
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GradientStop {
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position: 1.0
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color: "#F0F0F0"
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}
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}
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\endcode
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\li \b {gradient:} \code
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Gradient {
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GradientStop {
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position: 0.0
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color: "#00000000"
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}
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GradientStop {
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position: 1.0
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color: "#FF000000"
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}
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}
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\endcode
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\row
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\li \l start: Qt.point(0, 0)
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\li \l start: Qt.point(0, 0)
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\li \l start: Qt.point(0, 0)
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\row
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\li \l end: Qt.point(300, 300)
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\li \l end: Qt.point(300, 300)
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\li \l end: Qt.point(300, 300)
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\endtable
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*/
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property Gradient gradient: Gradient {
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GradientStop { position: 0.0; color: "white" }
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GradientStop { position: 1.0; color: "black" }
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}
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SourceProxy {
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id: maskSourceProxy
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input: rootItem.source
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}
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ShaderEffectSource {
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id: gradientSource
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sourceItem: Rectangle {
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width: 16
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height: 256
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gradient: rootItem.gradient
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smooth: true
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}
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smooth: true
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hideSource: true
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visible: false
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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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anchors.fill: parent
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property variant source: gradientSource
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property variant maskSource: maskSourceProxy.output
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property variant startPoint: Qt.point(start.x / width, start.y / height)
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property real dx: end.x - start.x
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property real dy: end.y - start.y
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property real l: 1.0 / Math.sqrt(Math.pow(dx / width, 2.0) + Math.pow(dy / height, 2.0))
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property real angle: Math.atan2(dx, dy)
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property variant matrixData: Qt.point(Math.sin(angle), Math.cos(angle))
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vertexShader: "qrc:/qt-project.org/imports/QtGraphicalEffects/shaders/lineargradient.vert"
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fragmentShader: maskSource == undefined ? noMaskShader : maskShader
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onFragmentShaderChanged: lChanged()
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property string maskShader: "qrc:/qt-project.org/imports/QtGraphicalEffects/shaders/lineargradient_mask.frag"
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property string noMaskShader: "qrc:/qt-project.org/imports/QtGraphicalEffects/shaders/lineargradient_nomask.frag"
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}
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}
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