[Development] Behaviour change of opacity property in QtQuick 2.0

[Kim M. Kalland]

On 18.07.2012 13:47, ext Nils Jeisecke wrote:
> Hi,
>
> In QtQuick 1 an element with opacity == 0 is treated as invisible
> (e.g. it won't see mouse events).
> This has changed in QtQuick 2.0 which breaks existing code that
> assumes that opacity == 0 means !visible.
>
> This example illustrates the change. A mouse click will print:
> QtQuick 1.1: "CLICKED A"
> QtQuick 2.0: "CLICKED B"
>
> A workaround is to set "visible: opacity > 0"
>
> Is this change intentional?
>
> ---
>
> //import QtQuick 2.0
> import QtQuick 1.1
>
> Rectangle {
>    width: 360
>    height: 360
>    MouseArea {
>      anchors.fill: parent
>      onClicked: console.log("CLICKED A")
>    }
>
>    Rectangle {
>      anchors.fill: parent
>      opacity: 0
>      MouseArea {
>        anchors.fill: parent
>        onClicked: console.log("CLICKED B")
>      }
>    }
> }
>
> ---
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Apparently, it was intentional: QTBUG-19193, and commit 
9bf96613c1be7d4df7132a9c3c9ac1a8740f698f. It would be nice to know what 
the arguments for changing the behaviour were...

Kim