TypeError: Property 'sizedHeight' of object [object Object] is not a function

[Rich v]

I have some code that has worked in Qt5 but is giving me trouble in Qt6 and I haven't figured it out. I'm a bit stumped - any suggestions are appreciated.

I get the below runtime error:

qrc:/myappuri/main.qml:53:9: TypeError: Property 'sizedHeight' of object [object Object] is not a function

I have a basic main.qml that imports a qml module:

// main.qml
import QtQuick 2.15
import QtQuick.Controls 2.15
import QtQuick.Window 2.15
import QtQuick.Layouts 1.12
import mylib1 1.0

Window
{
    width: 1024
    height: 600
    x: 0
    y: 0
    color: "darkgray"
    visible: true

    MyType1
    {
        width: 600
//        height: 200
        height: Qt.binding(BCSize.sizedHeight(100, 200))
        color: "purple"
        y: 200
    }
}

The module contains the BCSize singleton that has some sizing functions:

// BCSize.qml
pragma Singleton
import QtQuick 2.0
import QtQuick.Window 2.2
import QtQml 2.2

QtObject
{

    // nominal sizes that the screens were designed to.
    readonly property int largeScreenDesignWidth: 1024
    readonly property int largeScreenDesignHeight: 600
    readonly property int smallScreenDesignWidth:  320
    readonly property int smallScreenDesignHeight: 240

    // Our initial and current screen size
    // On the desktop, we'll mimic the Littlefoot/Jupiter display
    // You can mimic different screen sizes by re-setting these in code
    // which is a good way to test resolution independence

    // note that this crashes on the printer if you go less than about 870 x 520 - looks like a Qt bug
    property int screenWidth:  1024
    property int screenHeight: 600

    property bool isSmallScreenSize: screenWidth <= smallScreenDesignWidth

    // general-purpose size calculator. You can use it but it is probably easier to use the ones below
    function sizedValue( designedMin, designedMax, screenSize, screenMin, screenMax )
    {
        // We want to calculate "size" given the current screenSize
        // This formula shows equal ratios between the designed object sizes and the design screen sizes
        //     (size - designedMin) / (designedMax - designedMin) = (screenSize - screenMin) / (screenMax - screenMin)
        //
        // A little algebra solving for size and we get this formula:
        var size = designedMin + ((screenSize - screenMin) * (designedMax - designedMin) / (screenMax - screenMin));

        // don't allow negative sizes
        return Math.max( 0, size );
    }


    // returns an item's height given its size for the large screen and the size for the small screen
    // can also be used for vertical positions
    function sizedHeight( designedSmall, designedLarge )
    {
        return sizedValue( designedSmall, designedLarge, screenHeight, smallScreenDesignHeight, largeScreenDesignHeight );
    }

    // returns an item's width given its size for the large screen and the size for the small screen
    // can also be used for horizontal positions
    function sizedWidth( designedSmall, designedLarge )
    {
        return sizedValue( designedSmall, designedLarge, screenWidth, smallScreenDesignWidth, largeScreenDesignWidth );
    }

    // use this function if you want 'expand' animation (from smalldimension to actual dimension)
    // returns appropriate height for the 'current height'
    // at the end of the animation, this function eventually returns same as 'sizedHeight'
    function sizedHeightAnimate( designedSmall, designedLarge, currentHeight )
    {
        return sizedValue( designedSmall, designedLarge, currentHeight, smallScreenDesignHeight, largeScreenDesignHeight );
    }

    // use this function if you want 'expand' animation (from smalldimension to actual dimension)
    // returns appropriate width for the 'current width'
    // at the end of the animation, this function eventually returns same as 'sizedWidth'
    function sizedWidthAnimate( designedSmall, designedLarge, currentWidth )
    {
        return sizedValue( designedSmall, designedLarge, currentWidth, smallScreenDesignWidth, largeScreenDesignWidth );
    }

    // returns an item's count (any property which is not width or height) given its count for the large screen
    // and the count for the small screen
    function sizedCount( designedSmall, designedLarge )
    {
        return sizedValue( designedSmall, designedLarge, screenWidth, smallScreenDesignWidth, largeScreenDesignWidth );
    }

    // returns an item's height given its size for the large screen scaled linearly to the small screen
    function scaledHeight( designedLarge )
    {
        var result = designedLarge * screenHeight / largeScreenDesignHeight;
        return result;
    }

    // returns an item's width given its size for the large screen scaled linearly to the small screen
    function scaledWidth( designedLarge )
    {
        var result = designedLarge * screenWidth / largeScreenDesignWidth;
        return result;
    }
}

[Rich v]

Figured out that I didn't have 'singleton' assigned to the BCSize.qml file in the qmldir, which is now auto-generated. I had to add:

set_source_files_properties(BCSize.qml
PROPERTIES
QT_QML_SINGLETON_TYPE TRUE
)