qml绘图

代码：

import QtQuick 2.6
import QtQuick.Window 2.2
import CapbCanvas 1.0
import CapbTextItem 1.0

Window {
    visible: true
    width: 640
    height: 480
    id:root
    color: "#3A3223"
    title: qsTr("CapbCanvas")
    property alias operMode: canvasId.drawMode     // 0:只拖动;1:测量,2:标记,3:面积
    Component.onCompleted:   {
        canvasId.setTextItem(canvasTextId); //
    }

    Item{
        width: parent.width
        height: parent.height-50
        CapbCanvas{
            id: canvasId
            width: parent.width
            height: parent.height
            clip: true
            onDrawFinished: {
//                operMode = 0;
            }
        }
        CapbTextItem{
            id: canvasTextId
            width: parent.width
            height: parent.height

        }
    }

    Item{
        width: parent.width
        height:  50
        y:parent.height-50
        Rectangle {
            id: rectangle
            x: 16
            y: 8
            width: 79
            height: 34
            color: "#ffffff"

            Text {
                id: text1
                x: 26
                y: 8
                width: 27
                height: 22
                text: qsTr("距离")
                font.pixelSize: 12
            }
            MouseArea{
                hoverEnabled: true
                anchors.fill: parent
                onClicked: operMode = 1;
            }
        }

        Rectangle {
            id: rectangle1
            x: 101
            y: 8
            width: 74
            height: 34
            color: "#ffffff"

            Text {
                id: text2
                x: 25
                y: 8
                width: 24
                height: 18
                text: qsTr("标记")
                font.pixelSize: 12
            }
            MouseArea{
                hoverEnabled: true
                anchors.fill: parent
                onClicked: operMode = 2;
            }
        }

        Rectangle {
            id: rectangle2
            x: 181
            y: 8
            width: 77
            height: 34
            color: "#ffffff"

            Text {
                id: text3
                x: 27
                y: 8
                width: 24
                height: 18
                text: qsTr("面积")
                font.pixelSize: 12
            }
            MouseArea{
                hoverEnabled: true
                anchors.fill: parent
                onClicked: operMode = 3;
            }
        }

        Rectangle {
            id: rectangle3
            x: 269
            y: 8
            width: 65
            height: 34
            color: "#ffffff"
            Text {
                id: text4
                x: 15
                y: 8
                width: 31
                height: 18
                text: qsTr("无")
                font.pixelSize: 12
            }
            MouseArea{
                hoverEnabled: true
                anchors.fill: parent
                onClicked: operMode = 0;
            }
        }

        Rectangle {
            id: rectangle4
            x: 340
            y: 8
            width: 70
            height: 34
            color: "#ffffff"
            Text {
                id: text5
                x: 8
                y: 8
                width: 48
                height: 15
                text: qsTr("清除")
                font.pixelSize: 12
            }
            MouseArea{
                hoverEnabled: true
                anchors.fill: parent
                onClicked: operMode = 4;
            }
        }
    }
}