LegendItem.qml Example File

qmllegend/qml/qmllegend/LegendItem.qml
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 import QtQuick 2.1
 import QtQuick.Layouts 1.0
 import QtQuick.Window 2.1
 import QtDataVisualization 1.0

 Rectangle {
     property Theme3D theme
     property Bar3DSeries series
     property point previousSelection

     id: legendItem
     state: "unselected"

     // Workaround for a layout bug that in some situations causes changing from fully opaque color
     // to a transparent one to use black background instead of what is actually under the items.
     // Having the control always slighthly transparent forces the background to be refreshed
     // properly.
     opacity: 0.999

     RowLayout {
         anchors.fill: parent
         spacing: 0
         clip: true
         Item {
             id: markerSpace
             Layout.minimumWidth: 20
             Layout.minimumHeight: 20
             Layout.fillWidth: true
             Layout.fillHeight: true
             Layout.alignment: Qt.AlignVCenter
             Rectangle {
                 x: parent.x + parent.width / 4
                 y: parent.y + parent.height / 4
                 width: parent.width / 2
                 height: width
                 border.color: "black"
                 color: series.baseColor
             }
         }
         Item {
             height: markerSpace.height
             Layout.fillWidth: true
             Layout.fillHeight: true
             Layout.alignment: Qt.AlignVCenter
             Layout.minimumWidth: 100
             Text {
                 anchors.fill: parent
                 text: series.name
                 verticalAlignment: Text.AlignVCenter
                 clip: true
                 color: theme.labelTextColor
                 font: theme.font
             }
         }
     }

     MouseArea {
         id: mouseArea
         anchors.fill: legendItem
         onClicked: {
             if (legendItem.state === "selected") {
                 series.selectedBar = series.invalidSelectionPosition
             } else {
                 series.selectedBar = previousSelection
             }
         }
     }

     Connections {
         target: series
         onSelectedBarChanged: {
             if (position != series.invalidSelectionPosition) {
                 previousSelection = position
             }
         }
     }

     states: [
         State  {
             name: "selected"
             when: series.selectedBar != series.invalidSelectionPosition
             PropertyChanges {
                 target: legendItem
                 color: series.singleHighlightColor
             }
         },
         State  {
             name: "unselected"
             when: series.selectedBar == series.invalidSelectionPosition
             PropertyChanges {
                 target: legendItem
                 color: theme.labelBackgroundColor
             }
         }
     ]
 }