372 lines
13 KiB
QML
372 lines
13 KiB
QML
/****************************************************************************
|
|
**
|
|
** Copyright (C) 2017 The Qt Company Ltd.
|
|
** Copyright (C) 2017 Jolla Ltd, author: <gunnar.sletta@jollamobile.com>
|
|
** 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 QtQuick.Window 2.12
|
|
import QtGraphicalEffects.private 1.12
|
|
|
|
/*!
|
|
\qmltype GaussianBlur
|
|
\inqmlmodule QtGraphicalEffects
|
|
\since QtGraphicalEffects 1.0
|
|
\inherits QtQuick2::Item
|
|
\ingroup qtgraphicaleffects-blur
|
|
\brief Applies a higher quality blur effect.
|
|
|
|
GaussianBlur effect softens the image by blurring it with an algorithm that
|
|
uses the Gaussian function to calculate the effect. The effect produces
|
|
higher quality than \l{QtGraphicalEffects::FastBlur}{FastBlur}, but is
|
|
slower to render.
|
|
|
|
\table
|
|
\header
|
|
\li Source
|
|
\li Effect applied
|
|
\row
|
|
\li \image Original_bug.png
|
|
\li \image GaussianBlur_bug.png
|
|
\endtable
|
|
|
|
\note This effect is available when running with OpenGL.
|
|
|
|
\section1 Example
|
|
|
|
The following example shows how to apply the effect.
|
|
\snippet GaussianBlur-example.qml example
|
|
|
|
Performing blur live is a costly operation. Fullscreen gaussian blur
|
|
with even a moderate number of samples will only run at 60 fps on highend
|
|
graphics hardware.
|
|
|
|
*/
|
|
Item {
|
|
id: root
|
|
|
|
/*!
|
|
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.
|
|
|
|
The ideal blur is achieved by selecting \c samples and \c radius such
|
|
that \c {samples = 1 + radius * 2}, such as:
|
|
|
|
\table
|
|
\header \li Radius \li Samples
|
|
\row \li 0 \e{(no blur)} \li 1
|
|
\row \li 1 \li 3
|
|
\row \li 2 \li 5
|
|
\row \li 3 \li 7
|
|
\endtable
|
|
|
|
The value ranges from 0.0 (no blur) to inf. By default, the property is
|
|
set to \c floor(samples / 2.0).
|
|
|
|
\table
|
|
\header
|
|
\li Output examples with different radius values
|
|
\li
|
|
\li
|
|
\row
|
|
\li \image GaussianBlur_radius1.png
|
|
\li \image GaussianBlur_radius2.png
|
|
\li \image GaussianBlur_radius3.png
|
|
\row
|
|
\li \b { radius: 0 }
|
|
\li \b { radius: 4 }
|
|
\li \b { radius: 8 }
|
|
\row
|
|
\li \l samples: 16
|
|
\li \l samples: 16
|
|
\li \l samples: 16
|
|
\row
|
|
\li \l deviation: 3
|
|
\li \l deviation: 3
|
|
\li \l deviation: 3
|
|
\endtable
|
|
|
|
*/
|
|
property real radius: Math.floor(samples / 2);
|
|
|
|
/*!
|
|
This property defines how many samples are taken per pixel when blur
|
|
calculation is done. Larger value produces better quality, but is slower
|
|
to render.
|
|
|
|
Ideally, this value should be twice as large as the highest required
|
|
radius value plus 1, for example, if the radius is animated between 0.0
|
|
and 4.0, samples should be set to 9.
|
|
|
|
By default, the property is set to \c 9.
|
|
|
|
\note This property is not intended to be animated. Changing this property may
|
|
cause the underlying OpenGL shaders to be recompiled.
|
|
|
|
*/
|
|
property int samples: 9
|
|
|
|
/*!
|
|
This property is a parameter to the gaussian function that is used when
|
|
calculating neighboring pixel weights for the blurring. A larger
|
|
deviation causes image to appear more blurry, but it also reduces the
|
|
quality of the blur. A very large deviation value causes the effect to
|
|
look a bit similar to what, for exmple, a box blur algorithm produces. A
|
|
too small deviation values makes the effect insignificant for the pixels
|
|
near the radius.
|
|
|
|
\inlineimage GaussianBlur_deviation_graph.png
|
|
\caption The image above shows the Gaussian function with two different
|
|
deviation values, yellow (1) and cyan (2.7). The y-axis shows the
|
|
weights, the x-axis shows the pixel distance.
|
|
|
|
The value ranges from 0.0 (no deviation) to inf (maximum deviation). By
|
|
default, devaition is binded to radius. When radius increases, deviation
|
|
is automatically increased linearly. With the radius value of 8, the
|
|
deviation default value becomes approximately 2.7034. This value
|
|
produces a compromise between the blur quality and overall blurriness.
|
|
|
|
\table
|
|
\header
|
|
\li Output examples with different deviation values
|
|
\li
|
|
\li
|
|
\row
|
|
\li \image GaussianBlur_deviation1.png
|
|
\li \image GaussianBlur_deviation2.png
|
|
\li \image GaussianBlur_deviation3.png
|
|
\row
|
|
\li \b { deviation: 1 }
|
|
\li \b { deviation: 2 }
|
|
\li \b { deviation: 4 }
|
|
\row
|
|
\li \l radius: 8
|
|
\li \l radius: 8
|
|
\li \l radius: 8
|
|
\row
|
|
\li \l samples: 16
|
|
\li \l samples: 16
|
|
\li \l samples: 16
|
|
\endtable
|
|
|
|
*/
|
|
property real deviation: (radius + 1) / 3.3333
|
|
|
|
/*!
|
|
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 GaussianBlur_transparentBorder1.png
|
|
\li \image GaussianBlur_transparentBorder2.png
|
|
\row
|
|
\li \b { transparentBorder: false }
|
|
\li \b { transparentBorder: true }
|
|
\row
|
|
\li \l radius: 8
|
|
\li \l radius: 8
|
|
\row
|
|
\li \l samples: 16
|
|
\li \l samples: 16
|
|
\row
|
|
\li \l deviation: 2.7
|
|
\li \l deviation: 2.7
|
|
\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
|
|
|
|
|
|
// private members...
|
|
/*! \internal */
|
|
property int _paddedTexWidth: transparentBorder ? width + 2 * radius: width;
|
|
/*! \internal */
|
|
property int _paddedTexHeight: transparentBorder ? height + 2 * radius: height;
|
|
/*! \internal */
|
|
property int _kernelRadius: Math.max(0, samples / 2);
|
|
/*! \internal */
|
|
property int _kernelSize: _kernelRadius * 2 + 1;
|
|
/*! \internal */
|
|
property int _dpr: Screen.devicePixelRatio;
|
|
/*! \internal */
|
|
property bool _alphaOnly: false;
|
|
/*! \internal */
|
|
property var _maskSource: undefined
|
|
|
|
/*! \internal */
|
|
property alias _output: sourceProxy.output;
|
|
/*! \internal */
|
|
property alias _outputRect: sourceProxy.sourceRect;
|
|
/*! \internal */
|
|
property alias _color: verticalBlur.color;
|
|
/*! \internal */
|
|
property real _thickness: 0;
|
|
|
|
onSamplesChanged: _rebuildShaders();
|
|
on_KernelSizeChanged: _rebuildShaders();
|
|
onDeviationChanged: _rebuildShaders();
|
|
on_DprChanged: _rebuildShaders();
|
|
on_MaskSourceChanged: _rebuildShaders();
|
|
Component.onCompleted: _rebuildShaders();
|
|
|
|
/*! \internal */
|
|
function _rebuildShaders() {
|
|
var params = {
|
|
radius: _kernelRadius,
|
|
// Limit deviation to something very small avoid getting NaN in the shader.
|
|
deviation: Math.max(0.00001, deviation),
|
|
alphaOnly: root._alphaOnly,
|
|
masked: _maskSource != undefined,
|
|
fallback: root.radius != _kernelRadius
|
|
}
|
|
var shaders = ShaderBuilder.gaussianBlur(params);
|
|
horizontalBlur.fragmentShader = shaders.fragmentShader;
|
|
horizontalBlur.vertexShader = shaders.vertexShader;
|
|
}
|
|
|
|
SourceProxy {
|
|
id: sourceProxy
|
|
interpolation: SourceProxy.LinearInterpolation
|
|
input: root.source
|
|
sourceRect: root.transparentBorder
|
|
? Qt.rect(-root.radius, 0, root._paddedTexWidth, parent.height)
|
|
: Qt.rect(0, 0, 0, 0)
|
|
}
|
|
|
|
ShaderEffect {
|
|
id: horizontalBlur
|
|
width: root.transparentBorder ? root._paddedTexWidth : root.width
|
|
height: root.height;
|
|
|
|
// Used by all shaders
|
|
property Item source: sourceProxy.output;
|
|
property real spread: root.radius / root._kernelRadius;
|
|
property var dirstep: Qt.vector2d(1 / (root._paddedTexWidth * root._dpr), 0);
|
|
|
|
// Used by fallback shader (sampleCount exceeds number of varyings)
|
|
property real deviation: root.deviation
|
|
|
|
// Only in use for DropShadow and Glow
|
|
property color color: "white"
|
|
property real thickness: Math.max(0, Math.min(0.98, 1 - root._thickness * 0.98));
|
|
|
|
// Only in use for MaskedBlur
|
|
property var mask: root._maskSource;
|
|
|
|
layer.enabled: true
|
|
layer.smooth: true
|
|
layer.sourceRect: root.transparentBorder
|
|
? Qt.rect(0, -root.radius, width, root._paddedTexHeight)
|
|
: Qt.rect(0, 0, 0, 0)
|
|
visible: false
|
|
blending: false
|
|
}
|
|
|
|
ShaderEffect {
|
|
id: verticalBlur
|
|
x: transparentBorder ? -root.radius : 0
|
|
y: x;
|
|
width: root.transparentBorder ? root._paddedTexWidth: root.width
|
|
height: root.transparentBorder ? root._paddedTexHeight : root.height;
|
|
fragmentShader: horizontalBlur.fragmentShader
|
|
vertexShader: horizontalBlur.vertexShader
|
|
|
|
property Item source: horizontalBlur
|
|
property real spread: horizontalBlur.spread
|
|
property var dirstep: Qt.vector2d(0, 1 / (root._paddedTexHeight * root._dpr));
|
|
|
|
property real deviation: horizontalBlur.deviation
|
|
|
|
property color color: "black"
|
|
property real thickness: horizontalBlur.thickness;
|
|
|
|
property var mask: horizontalBlur.mask;
|
|
|
|
visible: true
|
|
}
|
|
|
|
ShaderEffectSource {
|
|
id: cacheItem
|
|
anchors.fill: verticalBlur
|
|
visible: root.cached
|
|
smooth: true
|
|
sourceItem: verticalBlur
|
|
hideSource: visible
|
|
}
|
|
|
|
}
|