在flickabke 中用scale 进行非中心点的缩放，导致图片有些部分不能拖拽回来

[jimfar]

import QtQuick.Window 2.2
import QtQuick 2.0
Window {
id:root1
visible: true
width: 600
height: 600
title: qsTr("Hello World")
property double lastContentXdelta:0
property double lastContentYdelta:0
MouseArea{
id: dragRegion1
anchors.fill: parent
onWheel : {
if (wheel.modifiers & Qt.ControlModifier){
// prevcenter=tform.origin;
if (wheel.angleDelta.y > 0)
{

            tform.xScale += 0.01
            tform.yScale += 0.01
        }
        else
        {
            if( tform.xScale>0.01){
                tform.xScale -= 0.01
                tform.yScale -= 0.01

            }


        }


    }
    else{
        wheel.accepted=false
    }
}
// Attach scrollbars to the right and bottom edges of the view.
ScrollBar {
    id: verticalScrollBar
    width: 12; height: flickview.height
    anchors.right: flickview.right
    opacity: 1
    z:1000;
    orientation: Qt.Vertical
    position: (flickview.contentY - flickview.originY) * (flickview.height / flickview.contentHeight)
    pageSize: flickview.visibleArea.heightRatio
    //targetflick:flickview

}

ScrollBar {
    id: horizontalScrollBar
    width: flickview.width; height: 12
    anchors.bottom: flickview.bottom
    opacity: 1
    z:1000;
    orientation: Qt.Horizontal
    position: (flickview.contentX - flickview.originX) * (flickview.width / flickview.contentWidth)
    pageSize: flickview.visibleArea.widthRatio
    // targetflick:flickview

}

// Create a flickable to view a large image.
Flickable {
    id: flickview
    leftMargin: 10
    anchors.fill: parent
    contentWidth: picture.width*tform.xScale
    contentHeight: picture.height*tform.yScale
    onContentWidthChanged: {
        // flickview.originX-=(flickview.width-flickview.width*tform.xScale )/2

    }
    onContentHeightChanged: {
         //flickview.originY-=(flickview.height-flickview.height*tform.xScale )/2
    }
    Image {
        id: picture
        source: "./pics/niagara_falls.jpg"
        asynchronous: true
        transform: Scale {
            id: tform
            origin.x:  flickview.contentX +flickview.width/2
            origin.y: flickview.contentY +flickview.height/2
            xScale: 1
            yScale: 1
        }
        Component.onCompleted:
        {

        }
    }

    // Only show the scrollbars when the view is moving.
    states: State {
        name: "ShowBars"
        when: view.movingVertically || view.movingHorizontally
        PropertyChanges { target: verticalScrollBar; opacity: 1 }
        PropertyChanges { target: horizontalScrollBar; opacity: 1 }
    }

    transitions: Transition {
        NumberAnimation { properties: "opacity"; duration: 400 }
    }
}

}

}

[jimfar]

ok it resolved by using this QuickQanava library