Qml text wrap (max width)

You can almost do this neatly with states. The problem is that attempting to set the width of the parent by assigning it to the paintedWidth of the text box means it then sets the width of the text box, which QML detects as influencing paintedWidth. It wouldn't recurse further than this, but QML still kicks out warnings. One way around the problem is to do as follows, and have a dummy invisible text box that just works out how wide the text is/should be. Its a bit of a hack, but it works nicely.

You could change the "when" property of the state to be dependent on the size of the dummy text box (rather than the length of the string) if you preferred a pixel limit on the width of the box.

import QtQuick 1.0

Rectangle {
    id: containing_rect
    property string text

    text: "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat"
    //text: "a short string"

    Text {
        id: text_field
        anchors.top: parent.top
        anchors.left: parent.left

        height: parent.height
        width: parent.width
        text: parent.text
        wrapMode: Text.WordWrap

    }

    Text {
        id: dummy_text
        text: parent.text
        visible: false
    }

    states: [
            State {
                name: "wide text"
                when: containing_rect.text.length > 20
                PropertyChanges {
                    target: containing_rect
                    width: 200
                    height: text_field.paintedHeight
                }
            },
            State {
                name: "not wide text"
                when: containing_rect.text.length <= 20
                PropertyChanges {
                    target: containing_rect
                    width: dummy_text.paintedWidth
                    height: text_field.paintedHeight
                }
            }
        ]
}

Very late to the party but the clean solution is to use an embedded TextMetrics object. Like this:

...
Text {
  id: textObj
  width: Math.min(textWidth, myThreshold)

  // access to binding-loop-free width and height:
  readonly property alias textWidth: textMetrics.boundingRect.width
  readonly property alias textHeight: textMetrics.boundingRect.height

  TextMetrics {
    id: textMetrics
    font: textObj.font
    text: textObj.text
    elide: textObj.elide
  }
}

Here's another way, which uses the Component.onCompleted script. It's more static than my other method, so I guess it depends on what you want to do with it.

import QtQuick 1.0

Rectangle {
    id: containing_rect
    property string text

    height: text_field.paintedHeight

    text: "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat"
    //text: "a short string"

    Text {
        id: text_field
        anchors.top: parent.top
        anchors.left: parent.left

        height: parent.height
        width: parent.width

        text: parent.text
        wrapMode: Text.WordWrap
    }

    Component.onCompleted: {
        if (text_field.paintedWidth > 200) {
            width = 200
        } else {
            width = text_field.paintedWidth
        }
    }     
}

You can also try something like this, using the dummy text box mentioned above:

width: Math.min(dummy_text.paintedWidth, 250)

This will use the painted size of the text unless it is greater than your specified pixel width.