366 lines
12 KiB
QML
366 lines
12 KiB
QML
/****************************************************************************
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**
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** Copyright (C) 2015 The Qt Company Ltd.
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** Contact: http://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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** $QT_BEGIN_LICENSE:BSD$
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** You may use this file under the terms of the BSD license as follows:
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**
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** "Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions are
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** met:
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** * Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** * Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in
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** the documentation and/or other materials provided with the
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** distribution.
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** * Neither the name of The Qt Company Ltd nor the names of its
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** contributors may be used to endorse or promote products derived
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** from this software without specific prior written permission.
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**
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**
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** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
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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 2.0
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import QtGraphicalEffects.private 1.0
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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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\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: "
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attribute highp vec4 qt_Vertex;
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attribute highp vec2 qt_MultiTexCoord0;
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uniform highp mat4 qt_Matrix;
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varying highp vec2 qt_TexCoord0;
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varying highp vec2 qt_TexCoord1;
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uniform highp vec2 startPoint;
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uniform highp float l;
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uniform highp vec2 matrixData;
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void main() {
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highp mat2 rot = mat2(matrixData.y, -matrixData.x,
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matrixData.x, matrixData.y);
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qt_TexCoord0 = qt_MultiTexCoord0;
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qt_TexCoord1 = qt_MultiTexCoord0 * l;
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qt_TexCoord1 -= startPoint * l;
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qt_TexCoord1 *= rot;
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gl_Position = qt_Matrix * qt_Vertex;
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}
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"
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fragmentShader: maskSource == undefined ? noMaskShader : maskShader
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onFragmentShaderChanged: lChanged()
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property string maskShader: "
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uniform lowp sampler2D source;
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uniform lowp sampler2D maskSource;
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uniform lowp float qt_Opacity;
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varying highp vec2 qt_TexCoord0;
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varying highp vec2 qt_TexCoord1;
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void main() {
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lowp vec4 gradientColor = texture2D(source, qt_TexCoord1);
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lowp float maskAlpha = texture2D(maskSource, qt_TexCoord0).a;
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gl_FragColor = gradientColor * maskAlpha * qt_Opacity;
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}
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"
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property string noMaskShader: "
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uniform lowp sampler2D source;
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uniform lowp float qt_Opacity;
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varying highp vec2 qt_TexCoord1;
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void main() {
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gl_FragColor = texture2D(source, qt_TexCoord1) * qt_Opacity;
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}
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"
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}
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}
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