Qt 5.9 | Qt Multimedia | QML Camera Example | ZoomControl.qml Example File

Qt 5.9.4 Reference Documentation

# ZoomControl.qml Example File

multimedia/declarative-camera/ZoomControl.qml

      /****************************************************************************
      **
      ** Copyright (C) 2017 The Qt Company Ltd.
      ** Contact: https://www.qt.io/licensing/
      **
      ** This file is part of the examples of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:BSD$
      ** Commercial License Usage
      ** Licensees holding valid commercial Qt licenses may use this file in
      ** accordance with the commercial license agreement provided with the
      ** Software or, alternatively, in accordance with the terms contained in
      ** a written agreement between you and The Qt Company. For licensing terms
      ** and conditions see https://www.qt.io/terms-conditions. For further
      ** information use the contact form at https://www.qt.io/contact-us.
      **
      ** BSD License Usage
      ** Alternatively, you may use this file under the terms of the BSD license
      ** as follows:
      **
      ** "Redistribution and use in source and binary forms, with or without
      ** modification, are permitted provided that the following conditions are
      ** met:
      **   * Redistributions of source code must retain the above copyright
      **     notice, this list of conditions and the following disclaimer.
      **   * Redistributions in binary form must reproduce the above copyright
      **     notice, this list of conditions and the following disclaimer in
      **     the documentation and/or other materials provided with the
      **     distribution.
      **   * Neither the name of The Qt Company Ltd nor the names of its
      **     contributors may be used to endorse or promote products derived
      **     from this software without specific prior written permission.
      **
      **
      ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
      ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
      ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
      ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
      ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
      ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
      ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
      ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
      ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
      ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
      **
      ** $QT_END_LICENSE$
      **
      ****************************************************************************/

      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
              }
          }
      }