- Qt 5.15
- Qt Graphical Effects
- QML Types
- OpacityMask QML Type
- Qt 5.15.18 Reference Documentation

# OpacityMask QML Type

Masks the source item with another item. More...

Import Statement: | import QtGraphicalEffects 1.15
Since: | QtGraphicalEffects 1.0

- List of all members, including inherited members

## Properties

- cached : bool
- invert : bool
- maskSource : variant
- source : variant

## Detailed Description

Source | MaskSource | Effect applied
--- | --- | ---

Note: This effect is available when running with OpenGL.

## Example

The following example shows how to apply the effect.

     import QtQuick 2.12
     import QtGraphicalEffects 1.12

     Item {
         width: 300
         height: 300

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

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

         OpacityMask {
             anchors.fill: bug
             source: bug
             maskSource: mask
         }
     }

## 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`.

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

invert : bool

This property controls how the alpha values of the sourceMask will behave.

If this property is `false`, the resulting opacity is the source alpha multiplied with the mask alpha, `As * Am`.

If this property is `true`, the resulting opacity is the source alpha multiplied with the inverse of the mask alpha, `As * (1 - Am)`.

The default is `false`.

This property was introduced in Qt 5.7.

maskSource : variant

This property defines the item that is going to be used as the mask. The mask item gets rendered into an intermediate pixel buffer and the alpha values from the result are used to determine the source item's pixels visibility in the display.

Original | Mask | Effect applied
--- | --- | ---

source : variant

This property defines the source item that is going to be masked.

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