Qt 5.8 | Qt Multimedia | QML Camera Example | ZoomControl.qml Example File

Qt 5.8.0 Reference Documentation

# ZoomControl.qml Example File

multimedia/declarative-camera/ZoomControl.qml

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      import QtQuick 2.0
      import QtMultimedia 5.0

      Item {
          id : zoomControl
          property real currentZoom : 1
          property real maximumZoom : 1
          signal zoomTo(real value)

          visible: zoomControl.maximumZoom > 1

          MouseArea {
              id : mouseArea
              anchors.fill: parent

              property real initialZoom : 0
              property real initialPos : 0

              onPressed: {
                  initialPos = mouseY
                  initialZoom = zoomControl.currentZoom
              }

              onPositionChanged: {
                  if (pressed) {
                      var target = initialZoom * Math.pow(5, (initialPos-mouseY)/zoomControl.height);
                      target = Math.max(1, Math.min(target, zoomControl.maximumZoom))
                      zoomControl.zoomTo(target)
                  }
              }
          }

          Item {
              id : bar
              x : 16
              y : parent.height/4
              width : 24
              height : parent.height/2

              Rectangle {
                  anchors.fill: parent

                  smooth: true
                  radius: 8
                  border.color: "white"
                  border.width: 2
                  color: "black"
                  opacity: 0.3
              }

              Rectangle {
                  id: groove
                  x : 0
                  y : parent.height * (1.0 - (zoomControl.currentZoom-1.0) / (zoomControl.maximumZoom-1.0))
                  width: parent.width
                  height: parent.height - y
                  smooth: true
                  radius: 8
                  color: "white"
                  opacity: 0.5
              }

              Text {
                  id: zoomText
                  anchors {
                      left: bar.right; leftMargin: 16
                  }
                  y: Math.min(parent.height - height, Math.max(0, groove.y - height / 2))
                  text: "x" + Math.round(zoomControl.currentZoom * 100) / 100
                  font.bold: true
                  color: "white"
                  style: Text.Raised; styleColor: "black"
                  opacity: 0.85
                  font.pixelSize: 18
              }
          }
      }