Fade in/out images on low resources device

[luca]

Hi all,
I need to fade in/out two images on a simple QML application that runs on a BeagleBone Black board.

At the moment I tried with two Images (same size and same position) and changing the opacity of the first with a NumberAnimation.

It works well on a Desktop PC but on a linux embedded board it isn't very good to see, it's not so smooth.

What is the best way to fade images without the need of a lot of graphics resources?

Thanks

[sierdzio]

Could an Animator help here, perhaps? http://doc.qt.io/qt-5/qml-qtquick-animator.html

[Julien B]

Hello @luca,

Have you an exemple of the full QML code you are using?

edit: It was usefull for me to use this FPS indicator to check performances.

[luca]

@sierdzio Thanks, using an OpacityAnimator it seems soother than a NumberAnimation on opacity.

@Julien-B The code is very simple. Two Images and the animator on the opacity of the first image:

Image {
        id: image1
        src: XXXXX
        anchors.fill: parent
}

Image {
        id: image0
        src: YYYYY
        anchors.fill: parent
}

OpacityAnimator {
      
        target: image0
        from: 1
        to: 0
        duration: 1000
        running: false
    }

Than I have a qml function called from C++ that start the animation when required.

[Julien B]

@luca ,

Do you use any graphical effects in your application?

Do you have the possibility to put some item visibility to false when not used or not visible on screen?

I found a lot of infos in Performance Considerations And Suggestions ans some tips worked in our case.

[luca]

@Julien-B Thanks for the link!
Reading the doc seems it's better for me to set visibility to false when animator ends.
I'll try to see if there are improvements.