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/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the documentation of the Qt Graphical Effects module.
**
** $QT_BEGIN_LICENSE:FDL$
** GNU Free Documentation License
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms
** and conditions contained in a signed written agreement between you
** and Nokia.
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\qmltype MaskedBlur
\inqmlmodule QtGraphicalEffects 1.0
\since QtGraphicalEffects 1.0
\inherits QtQuick2::Item
\ingroup qtgraphicaleffects-blur
\brief Applies a blur effect with a varying intesity.
MaskedBlur effect softens the image by blurring it. The intensity of the blur
can be controlled for each pixel using maskSource so that some parts of the
source are blurred more than others. By default the effect produces a high quality
result, thus the rendering speed may not be the highest possible.
The rendering speed is reduced especially if the \l{MaskedBlur::samples}{samples} is large.
For use cases that require faster rendering speed and the highest possible visual
quality is not necessary, property \l{MaskedBlur::fast}{fast} can be set to true.
\table
\header
\li Source
\li MaskSource
\li Effect applied
\row
\li \image Original_bug.png
\li \image MaskedBlur_mask.png
\li \image MaskedBlur_bug.png
\endtable
\section1 Example
The following example shows how to apply the effect.
\snippet snippets/MaskedBlur-example.qml example
*/
/*!
\qmlproperty variant QtGraphicalEffects1::MaskedBlur::source
This property defines the source item that is going to be blurred.
*/
/*!
\qmlproperty variant QtGraphicalEffects1::MaskedBlur::maskSource
This property defines the item that is controlling the final intensity of the
blur. The pixel alpha channel value from maskSource defines the actual blur
radius that is going to be used for blurring the corresponding source pixel.
Opaque maskSource pixels produce blur with specified \l{MaskedBlur::radius}{radius}, while transparent
pixels suppress the blur completely. Semitransparent maskSource pixels produce
blur with a radius that is interpolated according to the pixel transparency
level.
*/
/*!
\qmlproperty real QtGraphicalEffects1::MaskedBlur::radius
This property defines the distance of the neighboring pixels which affect
the blurring of an individual pixel. A larger radius increases the blur
effect.
Depending on the radius value, value of the \l{MaskedBlur::samples}{samples} should be set to
sufficiently large to ensure the visual quality.
The value ranges from 0.0 (no blur) to inf. By default, the property is set to
\c 0.0 (no blur).
\table
\header
\li Output examples with different radius values
\li
\li
\row
\li \image MaskedBlur_radius1.png
\li \image MaskedBlur_radius2.png
\li \image MaskedBlur_radius3.png
\row
\li \b { radius: 0 }
\li \b { radius: 8 }
\li \b { radius: 16 }
\row
\li \l samples: 24
\li \l samples: 24
\li \l samples: 24
\row
\li \l transparentBorder: false
\li \l transparentBorder: false
\li \l transparentBorder: false
\row
\li \l fast: false
\li \l fast: false
\li \l fast: false
\endtable
*/
/*!
\qmlproperty int QtGraphicalEffects1::MaskedBlur::samples
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, for example, if the radius is animated between 0.0 and 4.0, samples
should be set to 8.
The value ranges from 0 to 32. By default, the property is set to \c 0.
This property is not intended to be animated. Changing this property may
cause the underlying OpenGL shaders to be recompiled.
When \l{MaskedBlur::fast}{fast} property is set to true, this property has no effect.
*/
/*!
\qmlproperty bool QtGraphicalEffects1::MaskedBlur::transparentBorder
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 MaskedBlur_transparentBorder1.png
\li \image MaskedBlur_transparentBorder2.png
\row
\li \b { transparentBorder: false }
\li \b { transparentBorder: true }
\row
\li \l radius: 64
\li \l radius: 64
\row
\li \l samples: 24
\li \l samples: 24
\row
\li \l fast: true
\li \l fast: true
\endtable
*/
/*!
\qmlproperty bool QtGraphicalEffects1::MaskedBlur::fast
This property selects the blurring algorithm that is used to produce the
blur. Setting this to true enables fast algorithm, setting value to false
produces higher quality result.
By default, the property is set to \c false.
\table
\header
\li Output examples with different fast values
\li
\li
\row
\li \image MaskedBlur_fast1.png
\li \image MaskedBlur_fast2.png
\row
\li \b { fast: false }
\li \b { fast: true }
\row
\li \l radius: 16
\li \l radius: 16
\row
\li \l samples: 24
\li \l samples: 24
\row
\li \l transparentBorder: false
\li \l transparentBorder: false
\endtable
*/
/*!
\qmlproperty bool QtGraphicalEffects1::MaskedBlur::cached
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.
*/
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