DropShadow QML Type

Generates a colorized and blurred shadow image of the source and places it behind the original, giving the impression that source item is raised from the background. More...

Import Statement: import Qt5Compat.GraphicalEffects
Since: QtGraphicalEffects 1.0
Inherits:

Item

Properties

Detailed Description

SourceEffect applied

Example

The following example shows how to apply the effect.

import QtQuick
import Qt5Compat.GraphicalEffects

Item {
    width: 300
    height: 300

    Rectangle {
        anchors.fill: parent
    }

    Image {
        id: butterfly
        source: "images/butterfly.png"
        sourceSize: Qt.size(parent.width, parent.height)
        smooth: true
        visible: false
    }

    DropShadow {
        anchors.fill: butterfly
        horizontalOffset: 3
        verticalOffset: 3
        radius: 8.0
        color: "#80000000"
        source: butterfly
    }
}

Property Documentation

cached : bool

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 false.


color : color

This property defines the RGBA color value which is used for the shadow.

By default, the property is set to "black".

Output examples with different color values

color: #000000 color: #0000ff color: #aa000000
radius: 8radius: 8radius: 8
horizontalOffset: 0horizontalOffset: 0horizontalOffset: 0
verticalOffset: 20verticalOffset: 20verticalOffset: 20
spread: 0spread: 0spread: 0

horizontalOffset : real

HorizontalOffset and verticalOffset properties define the offset for the rendered shadow compared to the DropShadow item position. Often, the DropShadow item is anchored so that it fills the source element. In this case, if the HorizontalOffset and verticalOffset properties are set to 0, the shadow is rendered exactly under the source item. By changing the offset properties, the shadow can be positioned relatively to the source item.

The values range from -inf to inf. By default, the properties are set to 0.

Output examples with different horizontalOffset values

horizontalOffset: -20 horizontalOffset: 0 horizontalOffset: 20
radius: 4radius: 4radius: 4
color: #000000color: #000000color: #000000
verticalOffset: 0verticalOffset: 0verticalOffset: 0
spread: 0spread: 0spread: 0

radius : real

Radius defines the softness of the shadow. A larger radius causes the edges of the shadow to appear more blurry.

The value ranges from 0.0 (no blur) to inf. By default, the property is set to 0.0 (no blur).

Output examples with different radius values

radius: 0 radius: 6 radius: 12
color: #000000color: #000000color: #000000
horizontalOffset: 0horizontalOffset: 0horizontalOffset: 0
verticalOffset: 20verticalOffset: 20verticalOffset: 20
spread: 0spread: 0spread: 0

source : variant

This property defines the source item that is going to be used as the source for the generated shadow.

Note: It is not supported to let the effect include itself, for instance by setting source to the effect's parent.


spread : real

This property defines how large part of the shadow color is strenghtened near the source edges.

The value ranges from 0.0 to 1.0. By default, the property is set to 0.5.

Output examples with different spread values

spread: 0.0 spread: 0.5 spread: 1.0
radius: 8radius: 8radius: 8
color: #000000color: #000000color: #000000
horizontalOffset: 0horizontalOffset: 0horizontalOffset: 0
verticalOffset: 20verticalOffset: 20verticalOffset: 20

transparentBorder : bool

This property determines whether or not the effect has a transparent border.

When set to true, the exterior of the item is padded with a 1 pixel wide 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.

In the image below, the Rectangle on the left has transparent borders and has blurred edges, whereas the Rectangle on the right does not:

import QtQuick
import Qt5Compat.GraphicalEffects

Rectangle {
    width: 180
    height: 100

    Row {
        anchors.centerIn: parent
        spacing: 16

        Rectangle {
            id: normalRect
            width: 60
            height: 60
            radius: 10
            color: "steelblue"
            layer.enabled: true
            layer.effect: DropShadow {
                transparentBorder: false
                horizontalOffset: 8
                verticalOffset: 8
            }
        }

        Rectangle {
            id: transparentBorderRect
            width: 60
            height: 60
            radius: 10
            color: "steelblue"
            layer.enabled: true
            layer.effect: DropShadow {
                transparentBorder: true
                horizontalOffset: 8
                verticalOffset: 8
            }
        }
    }
}


verticalOffset : real

HorizontalOffset and verticalOffset properties define the offset for the rendered shadow compared to the DropShadow item position. Often, the DropShadow item is anchored so that it fills the source element. In this case, if the HorizontalOffset and verticalOffset properties are set to 0, the shadow is rendered exactly under the source item. By changing the offset properties, the shadow can be positioned relatively to the source item.

The values range from -inf to inf. By default, the properties are set to 0.

Output examples with different horizontalOffset values

horizontalOffset: -20 horizontalOffset: 0 horizontalOffset: 20
radius: 4radius: 4radius: 4
color: #000000color: #000000color: #000000
verticalOffset: 0verticalOffset: 0verticalOffset: 0
spread: 0spread: 0spread: 0

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