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/****************************************************************************
**
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Graphical Effects module.
**
** $QT_BEGIN_LICENSE:LGPL$
** 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 The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
import QtQuick 2.12
import QtGraphicalEffects.private 1.12
/*!
\qmltype FastBlur
\inqmlmodule QtGraphicalEffects
\since QtGraphicalEffects 1.0
\inherits QtQuick2::Item
\ingroup qtgraphicaleffects-blur
\brief Applies a fast blur effect to one or more source items.
FastBlur offers lower blur quality than
\l{QtGraphicalEffects::GaussianBlur}{GaussianBlur}, but it is faster to
render. The FastBlur effect softens the source content by blurring it with
algorithm which uses the source content downscaling and bilinear filtering.
Use this effect in situations where the source content is rapidly changing
and the highest possible blur quality is not
needed.
\table
\header
\li Source
\li Effect applied
\row
\li \image Original_bug.png
\li \image FastBlur_bug.png
\endtable
\note This effect is available when running with OpenGL.
s
\section1 Example
The following example shows how to apply the effect.
\snippet FastBlur-example.qml example
*/
Item {
id: rootItem
/*!
This property defines the source item that is going to be blurred.
\note It is not supported to let the effect include itself, for
instance by setting source to the effect's parent.
*/
property variant source
/*!
This property defines the distance of the neighboring pixels which affect
the blurring of an individual pixel. A larger radius increases the blur
effect. FastBlur algorithm may internally reduce the accuracy of the radius in order to
provide good rendering performance.
The value ranges from 0.0 (no blur) to inf. Visual quality of the blur is reduced when
radius exceeds value 64. By default, the property is set to \c 0.0 (no blur).
\table
\header
\li Output examples with different blur values
\li
\li
\row
\li \image FastBlur_radius1.png
\li \image FastBlur_radius2.png
\li \image FastBlur_radius3.png
\row
\li \b { radius: 0 }
\li \b { radius: 32 }
\li \b { radius: 64 }
\endtable
*/
property real radius: 0.0
/*!
This property defines the blur behavior near the edges of the item,
where the pixel blurring is affected by the pixels outside the source
edges.
If the property is set to \c true, the pixels outside the source are
interpreted to be transparent, which is similar to OpenGL
clamp-to-border extension. The blur is expanded slightly outside the
effect item area.
If the property is set to \c false, the pixels outside the source are
interpreted to contain the same color as the pixels at the edge of the
item, which is similar to OpenGL clamp-to-edge behavior. The blur does
not expand outside the effect item area.
By default, the property is set to \c false.
\table
\header
\li Output examples with different transparentBorder values
\li
\li
\row
\li \image FastBlur_transparentBorder1.png
\li \image FastBlur_transparentBorder2.png
\row
\li \b { transparentBorder: false }
\li \b { transparentBorder: true }
\row
\li \l radius: 64
\li \l radius: 64
\endtable
*/
property bool transparentBorder: false
/*!
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.
*/
property bool cached: false
SourceProxy {
id: sourceProxy
input: rootItem.source
}
ShaderEffectSource {
id: cacheItem
anchors.fill: shaderItem
visible: rootItem.cached
sourceItem: shaderItem
live: true
hideSource: visible
smooth: rootItem.radius > 0
}
/*! \internal */
property string __internalBlurVertexShader: "qrc:/qt-project.org/imports/QtGraphicalEffects/shaders/fastblur_internal.vert"
/*! \internal */
property string __internalBlurFragmentShader: "qrc:/qt-project.org/imports/QtGraphicalEffects/shaders/fastblur_internal.frag"
ShaderEffect {
id: level0
property variant source: sourceProxy.output
anchors.fill: parent
visible: false
smooth: true
}
ShaderEffectSource {
id: level1
width: Math.ceil(shaderItem.width / 32) * 32
height: Math.ceil(shaderItem.height / 32) * 32
sourceItem: level0
hideSource: rootItem.visible
sourceRect: transparentBorder ? Qt.rect(-64, -64, shaderItem.width, shaderItem.height) : Qt.rect(0, 0, 0, 0)
visible: false
smooth: rootItem.radius > 0
}
ShaderEffect {
id: effect1
property variant source: level1
property real yStep: 1/height
property real xStep: 1/width
anchors.fill: level2
visible: false
smooth: true
vertexShader: __internalBlurVertexShader
fragmentShader: __internalBlurFragmentShader
}
ShaderEffectSource {
id: level2
width: level1.width / 2
height: level1.height / 2
sourceItem: effect1
hideSource: rootItem.visible
visible: false
smooth: true
}
ShaderEffect {
id: effect2
property variant source: level2
property real yStep: 1/height
property real xStep: 1/width
anchors.fill: level3
visible: false
smooth: true
vertexShader: __internalBlurVertexShader
fragmentShader: __internalBlurFragmentShader
}
ShaderEffectSource {
id: level3
width: level2.width / 2
height: level2.height / 2
sourceItem: effect2
hideSource: rootItem.visible
visible: false
smooth: true
}
ShaderEffect {
id: effect3
property variant source: level3
property real yStep: 1/height
property real xStep: 1/width
anchors.fill: level4
visible: false
smooth: true
vertexShader: __internalBlurVertexShader
fragmentShader: __internalBlurFragmentShader
}
ShaderEffectSource {
id: level4
width: level3.width / 2
height: level3.height / 2
sourceItem: effect3
hideSource: rootItem.visible
visible: false
smooth: true
}
ShaderEffect {
id: effect4
property variant source: level4
property real yStep: 1/height
property real xStep: 1/width
anchors.fill: level5
visible: false
smooth: true
vertexShader: __internalBlurVertexShader
fragmentShader: __internalBlurFragmentShader
}
ShaderEffectSource {
id: level5
width: level4.width / 2
height: level4.height / 2
sourceItem: effect4
hideSource: rootItem.visible
visible: false
smooth: true
}
ShaderEffect {
id: effect5
property variant source: level5
property real yStep: 1/height
property real xStep: 1/width
anchors.fill: level6
visible: false
smooth: true
vertexShader: __internalBlurVertexShader
fragmentShader: __internalBlurFragmentShader
}
ShaderEffectSource {
id: level6
width: level5.width / 2
height: level5.height / 2
sourceItem: effect5
hideSource: rootItem.visible
visible: false
smooth: true
}
Item {
id: dummysource
width: 1
height: 1
visible: false
}
ShaderEffectSource {
id: dummy
width: 1
height: 1
sourceItem: dummysource
visible: false
smooth: false
live: false
}
ShaderEffect {
id: shaderItem
property variant source1: level1
property variant source2: level2
property variant source3: level3
property variant source4: level4
property variant source5: level5
property variant source6: level6
property real lod: Math.sqrt(rootItem.radius / 64.0) * 1.2 - 0.2
property real weight1
property real weight2
property real weight3
property real weight4
property real weight5
property real weight6
x: transparentBorder ? -64 : 0
y: transparentBorder ? -64 : 0
width: transparentBorder ? parent.width + 128 : parent.width
height: transparentBorder ? parent.height + 128 : parent.height
function weight(v) {
if (v <= 0.0)
return 1.0
if (v >= 0.5)
return 0.0
return 1.0 - v * 2.0
}
function calculateWeights() {
var w1 = weight(Math.abs(lod - 0.100))
var w2 = weight(Math.abs(lod - 0.300))
var w3 = weight(Math.abs(lod - 0.500))
var w4 = weight(Math.abs(lod - 0.700))
var w5 = weight(Math.abs(lod - 0.900))
var w6 = weight(Math.abs(lod - 1.100))
var sum = w1 + w2 + w3 + w4 + w5 + w6;
weight1 = w1 / sum;
weight2 = w2 / sum;
weight3 = w3 / sum;
weight4 = w4 / sum;
weight5 = w5 / sum;
weight6 = w6 / sum;
upateSources()
}
function upateSources() {
var sources = new Array();
var weights = new Array();
if (weight1 > 0) {
sources.push(level1)
weights.push(weight1)
}
if (weight2 > 0) {
sources.push(level2)
weights.push(weight2)
}
if (weight3 > 0) {
sources.push(level3)
weights.push(weight3)
}
if (weight4 > 0) {
sources.push(level4)
weights.push(weight4)
}
if (weight5 > 0) {
sources.push(level5)
weights.push(weight5)
}
if (weight6 > 0) {
sources.push(level6)
weights.push(weight6)
}
for (var j = sources.length; j < 6; j++) {
sources.push(dummy)
weights.push(0.0)
}
source1 = sources[0]
source2 = sources[1]
source3 = sources[2]
source4 = sources[3]
source5 = sources[4]
source6 = sources[5]
weight1 = weights[0]
weight2 = weights[1]
weight3 = weights[2]
weight4 = weights[3]
weight5 = weights[4]
weight6 = weights[5]
}
Component.onCompleted: calculateWeights()
onLodChanged: calculateWeights()
fragmentShader: "qrc:/qt-project.org/imports/QtGraphicalEffects/shaders/fastblur.frag"
}
}
|