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import QtQuick 2.12
import QtGraphicalEffects.private 1.12
/*!
\qmltype RectangularGlow
\inqmlmodule QtGraphicalEffects
\since QtGraphicalEffects 1.0
\inherits QtQuick2::Item
\ingroup qtgraphicaleffects-glow
\brief Generates a blurred and colorized rectangle, which gives
the impression that the source is glowing.
This effect is intended to have good performance. The shape of the glow is
limited to a rectangle with a custom corner radius. For situations where
custom shapes are required, consider \l {QtGraphicalEffects::Glow} {Glow}
effect.
\table
\header
\li Effect applied
\row
\li \image RectangularGlow_applied.png
\endtable
\note This effect is available when running with OpenGL.
\section1 Example
The following example shows how to apply the effect.
\snippet RectangularGlow-example.qml example
*/
Item {
id: rootItem
/*!
This property defines how many pixels outside the item area are reached
by the glow.
The value ranges from 0.0 (no glow) to inf (infinite glow). By default,
the property is set to \c 0.0.
\table
\header
\li Output examples with different glowRadius values
\li
\li
\row
\li \image RectangularGlow_glowRadius1.png
\li \image RectangularGlow_glowRadius2.png
\li \image RectangularGlow_glowRadius3.png
\row
\li \b { glowRadius: 10 }
\li \b { glowRadius: 20 }
\li \b { glowRadius: 40 }
\row
\li \l spread: 0
\li \l spread: 0
\li \l spread: 0
\row
\li \l color: #ffffff
\li \l color: #ffffff
\li \l color: #ffffff
\row
\li \l cornerRadius: 25
\li \l cornerRadius: 25
\li \l cornerRadius: 25
\endtable
*/
property real glowRadius: 0.0
/*!
This property defines how large part of the glow color is strengthened
near the source edges.
The value ranges from 0.0 (no strength increase) to 1.0 (maximum
strength increase). By default, the property is set to \c 0.0.
\table
\header
\li Output examples with different spread values
\li
\li
\row
\li \image RectangularGlow_spread1.png
\li \image RectangularGlow_spread2.png
\li \image RectangularGlow_spread3.png
\row
\li \b { spread: 0.0 }
\li \b { spread: 0.5 }
\li \b { spread: 1.0 }
\row
\li \l glowRadius: 20
\li \l glowRadius: 20
\li \l glowRadius: 20
\row
\li \l color: #ffffff
\li \l color: #ffffff
\li \l color: #ffffff
\row
\li \l cornerRadius: 25
\li \l cornerRadius: 25
\li \l cornerRadius: 25
\endtable
*/
property real spread: 0.0
/*!
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 RectangularGlow_color1.png
\li \image RectangularGlow_color2.png
\li \image RectangularGlow_color3.png
\row
\li \b { color: #ffffff }
\li \b { color: #55ff55 }
\li \b { color: #5555ff }
\row
\li \l glowRadius: 20
\li \l glowRadius: 20
\li \l glowRadius: 20
\row
\li \l spread: 0
\li \l spread: 0
\li \l spread: 0
\row
\li \l cornerRadius: 25
\li \l cornerRadius: 25
\li \l cornerRadius: 25
\endtable
*/
property color color: "white"
/*!
This property defines the corner radius that is used to draw a glow with
rounded corners.
The value ranges from 0.0 to half of the effective width or height of
the glow, whichever is smaller. This can be calculated with: \c{
min(width, height) / 2.0 + glowRadius}
By default, the property is bound to glowRadius property. The glow
behaves as if the rectangle was blurred when adjusting the glowRadius
property.
\table
\header
\li Output examples with different cornerRadius values
\li
\li
\row
\li \image RectangularGlow_cornerRadius1.png
\li \image RectangularGlow_cornerRadius2.png
\li \image RectangularGlow_cornerRadius3.png
\row
\li \b { cornerRadius: 0 }
\li \b { cornerRadius: 25 }
\li \b { cornerRadius: 50 }
\row
\li \l glowRadius: 20
\li \l glowRadius: 20
\li \l glowRadius: 20
\row
\li \l spread: 0
\li \l spread: 0
\li \l spread: 0
\row
\li \l color: #ffffff
\li \l color: #ffffff
\li \l color: #ffffff
\endtable
*/
property real cornerRadius: glowRadius
/*!
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
ShaderEffectSource {
id: cacheItem
anchors.fill: shaderItem
visible: rootItem.cached
smooth: true
sourceItem: shaderItem
live: true
hideSource: visible
}
ShaderEffect {
id: shaderItem
x: (parent.width - width) / 2.0
y: (parent.height - height) / 2.0
width: parent.width + rootItem.glowRadius * 2 + cornerRadius * 2
height: parent.height + rootItem.glowRadius * 2 + cornerRadius * 2
function clampedCornerRadius() {
var maxCornerRadius = Math.min(rootItem.width, rootItem.height) / 2 + glowRadius;
return Math.max(0, Math.min(rootItem.cornerRadius, maxCornerRadius))
}
property color color: rootItem.color
property real inverseSpread: 1.0 - rootItem.spread
property real relativeSizeX: ((inverseSpread * inverseSpread) * rootItem.glowRadius + cornerRadius * 2.0) / width
property real relativeSizeY: relativeSizeX * (width / height)
property real spread: rootItem.spread / 2.0
property real cornerRadius: clampedCornerRadius()
fragmentShader: "qrc:/qt-project.org/imports/QtGraphicalEffects/shaders/rectangularglow.frag"
}
}