/**************************************************************************** ** ** Copyright (C) 2015 The Qt Company Ltd. ** Copyright (C) 2015 Jolla Ltd, author: ** Contact: http://www.qt.io/licensing/ ** ** This file is part of the Qt Graphical Effects module. ** ** $QT_BEGIN_LICENSE:BSD$ ** You may use this file under the terms of the BSD license as follows: ** ** "Redistribution and use in source and binary forms, with or without ** modification, are permitted provided that the following conditions are ** met: ** * Redistributions of source code must retain the above copyright ** notice, this list of conditions and the following disclaimer. ** * Redistributions in binary form must reproduce the above copyright ** notice, this list of conditions and the following disclaimer in ** the documentation and/or other materials provided with the ** distribution. ** * Neither the name of The Qt Company Ltd nor the names of its ** contributors may be used to endorse or promote products derived ** from this software without specific prior written permission. ** ** ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." ** ** $QT_END_LICENSE$ ** ****************************************************************************/ import QtQuick 2.0 import QtGraphicalEffects.private 1.0 /*! \qmltype Glow \inqmlmodule QtGraphicalEffects \since QtGraphicalEffects 1.0 \inherits QtQuick2::Item \ingroup qtgraphicaleffects-glow \brief Generates a halo like glow around the source item. The Glow effect blurs the alpha channel of the source and colorizes it with \l {Glow::color}{color} and places it behind the source, resulting in a halo or glow around the object. The quality of the blurred edge can be controlled using \l samples and \l radius and the strenght of the glow can be changed using \l spread. \table \header \li Source \li Effect applied \row \li \image Original_butterfly_black.png \li \image Glow_butterfly.png \endtable The glow is created by blurring the image live using a gaussian blur. 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. \section1 Example The following example shows how to apply the effect. \snippet Glow-example.qml example */ Item { id: root DropShadowBase { id: dps anchors.fill: parent color: "white" spread: 0.5 horizontalOffset: 0 verticalOffset: 0 } /*! This property defines the source item that is going to be used as source for the generated glow. \note It is not supported to let the effect include itself, for instance by setting source to the effect's parent. */ property alias source: dps.source /*! Radius defines the softness of the glow. A larger radius causes the edges of the glow to appear more blurry. Depending on the radius value, value of the \l{Glow::samples}{samples} should be set to sufficiently large to ensure the visual quality. The ideal blur is acheived 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 By default, the property is set to \c {floor(samples/2)}. \table \header \li Output examples with different radius values \li \li \row \li \image Glow_radius1.png \li \image Glow_radius2.png \li \image Glow_radius3.png \row \li \b { radius: 0 } \li \b { radius: 6 } \li \b { radius: 12 } \row \li \l samples: 25 \li \l samples: 25 \li \l samples: 25 \row \li \l color: #ffffff \li \l color: #ffffff \li \l color: #ffffff \row \li \l spread: 0 \li \l spread: 0 \li \l spread: 0 \endtable */ property alias radius: dps.radius /*! This property defines how many samples are taken per pixel when edge softening 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 one, 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 By default, the property is set to \c 9. This property is not intended to be animated. Changing this property will cause the underlying OpenGL shaders to be recompiled. */ property alias samples: dps.samples /*! This property defines how large part of the glow color is strenghtened near the source edges. The values range from 0.0 to 1.0. By default, the property is set to \c 0.5. \table \header \li Output examples with different spread values \li \li \row \li \image Glow_spread1.png \li \image Glow_spread2.png \li \image Glow_spread3.png \row \li \b { spread: 0.0 } \li \b { spread: 0.5 } \li \b { spread: 1.0 } \row \li \l radius: 8 \li \l radius: 8 \li \l radius: 8 \row \li \l samples: 17 \li \l samples: 17 \li \l samples: 17 \row \li \l color: #ffffff \li \l color: #ffffff \li \l color: #ffffff \endtable */ property alias spread: dps.spread /*! This property defines the RGBA color value which is used for the glow. By default, the property is set to \c "white". \table \header \li Output examples with different color values \li \li \row \li \image Glow_color1.png \li \image Glow_color2.png \li \image Glow_color3.png \row \li \b { color: #ffffff } \li \b { color: #00ff00 } \li \b { color: #aa00ff00 } \row \li \l radius: 8 \li \l radius: 8 \li \l radius: 8 \row \li \l samples: 17 \li \l samples: 17 \li \l samples: 17 \row \li \l spread: 0.5 \li \l spread: 0.5 \li \l spread: 0.5 \endtable */ property alias color: dps.color /*! \internal Starting Qt 5.6, this property has no effect. It is left here for source compatibility only. ### Qt 6: remove */ property bool fast: 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 alias cached: dps.cached /*! This property determines whether or not the effect has a transparent border. When set to \c true, the exterior of the item is padded with a transparent edge, making sampling outside the source texture use transparency instead of the edge pixels. Without this property, an image which has opaque edges will not get a blurred edge. By default, the property is set to \c true. Set it to false if the source already has a transparent edge to make the blurring a tiny bit faster. In the snippet below, the Rectangle on the left has transparent borders and has blurred edges, whereas the Rectangle on the right does not. \snippet Glow-transparentBorder-example.qml example \image Glow-transparentBorder.png */ property alias transparentBorder: dps.transparentBorder }