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** this package.
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****************************************************************************/

import QtQuick 1.0
import org.kde.qtextracomponents 0.1

Item {
    id: container

    property variant scrollArea
    property variant orientation: Qt.Vertical

    function position()
    {
        var ny = 0;
        if (container.orientation == Qt.Vertical)
            ny = scrollArea.visibleArea.yPosition * container.height;
        else
            ny = scrollArea.visibleArea.xPosition * container.width;
        if (ny > 2) return ny; else return 2;
    }

    function size()
    {
        var nh, ny;

        if (container.orientation == Qt.Vertical)
            nh = scrollArea.visibleArea.heightRatio * container.height;
        else
            nh = scrollArea.visibleArea.widthRatio * container.width;

        if (container.orientation == Qt.Vertical)
            ny = scrollArea.visibleArea.yPosition * container.height;
        else
            ny = scrollArea.visibleArea.xPosition * container.width;

        if (ny > 3) {
            var t;
            if (container.orientation == Qt.Vertical)
                t = Math.ceil(container.height - 3 - ny);
            else
                t = Math.ceil(container.width - 3 - ny);
            if (nh > t) return t; else return nh;
        } else return nh + ny;
    }

    Item {
        id: scrollPainter
        anchors.fill: parent
        opacity: 0
        Rectangle { anchors.fill: parent; color: "Black"; opacity: 0.5 }

        Rectangle {
            color: "white"
            radius: 2
            x: container.orientation == Qt.Vertical ? 2 : position()
            width: container.orientation == Qt.Vertical ? container.width - 4 : size()
            y: container.orientation == Qt.Vertical ? position() : 2
            height: container.orientation == Qt.Vertical ? size() : container.height - 4
        }
    }
    QIconItem {
        id: topButton
        anchors {
            bottom: parent.bottom
            right: parent.left
            bottomMargin: 8
        }
        icon: QIcon("go-top")
        width: theme.hugeIconSize
        height: width
        opacity: 0
        MouseArea {
            anchors.fill: parent
            onPressed: SequentialAnimation {
                PropertyAnimation { target: topButton; properties: "scale"; to: 0.8; duration: 50; }
                PropertyAnimation { target: topButton; properties: "scale"; to: 1; duration: 50; }
            }
            onClicked: ParallelAnimation{
                PropertyAnimation { target: topButton; properties: "opacity"; to: 0; duration: 200; }
                PropertyAnimation {
                    target: scrollArea; properties: "contentX,contentY";
                    to: 0; duration: 400; easing.type: Easing.InOutQuint;
                }
            }
        }
    }

    states: [
        State {
            name: "ScrollingUp"
            when: ((container.orientation == Qt.Vertical ? scrollArea.movingVertically : scrollArea.movingHorizontally) &&             scrollArea.verticalVelocity < -0 && scrollArea.contentY > header.height+200)
            PropertyChanges { target: scrollPainter; opacity: 1.0 }
            PropertyChanges { target: topButton; opacity: 1.0 }
        },
        State {
            name: "Scrolling"
            when: ( (container.orientation == Qt.Vertical ? scrollArea.movingVertically : scrollArea.movingHorizontally))
            PropertyChanges { target: scrollPainter; opacity: 1.0 }
            PropertyChanges { target: topButton; opacity: 0.0 }
        }
    ]

    transitions: [
        Transition {
            to: "ScrollingUp"
            SequentialAnimation {
                PauseAnimation { duration: 400; }
                PropertyAnimation { target: topButton; properties: "opacity"; easing.type: Easing.InOutQuad; duration: 150 }
            }
        },
        Transition {
            to: "ScrollingUp"
            SequentialAnimation {
                PauseAnimation { duration: 400; }
                PropertyAnimation { target: topButton; properties: "opacity"; easing.type: Easing.InOutQuad; duration: 150 }
            }
        },
        Transition {
            from: "ScrollingUp"
            SequentialAnimation {
                PauseAnimation { duration: 1000; }
                PropertyAnimation { target: topButton; properties: "opacity"; easing.type: Easing.InOutQuad; duration: 150 }
            }
        },
        Transition {
            to: ""
            PropertyAnimation { properties: "opacity"; easing.type: Easing.InOutQuad; duration: 300 }
        },
        Transition {
            from: ""; to: "Scrolling"
            PropertyAnimation { target: scrollPainter; properties: "opacity"; easing.type: Easing.InOutQuad; duration: 300 }
        }
    ]
}
