Qt 5.13 | Qt Quick Demo - Calqlatr

Qt 5.13.2 Reference Documentation

# Qt Quick Demo - Calqlatr

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      import QtQuick 2.0
      import QtQuick.Window 2.0

      Item {
          id: display
          property real fontSize: Math.floor(Screen.pixelDensity * 5.0)
          property bool enteringDigits: false
          property int maxDigits: (width / fontSize) + 1
          property string displayedOperand
          property string errorString: qsTr("ERROR")
          property bool isError: displayedOperand === errorString

          function displayOperator(operator)
          {
              listView.model.append({ "operator": operator, "operand": "" })
              enteringDigits = true
              listView.positionViewAtEnd()
          }

          function newLine(operator, operand)
          {
              displayedOperand = displayNumber(operand)
              listView.model.append({ "operator": operator, "operand": displayedOperand })
              enteringDigits = false
              listView.positionViewAtEnd()
          }

          function appendDigit(digit)
          {
              if (!enteringDigits)
                  listView.model.append({ "operator": "", "operand": "" })
              var i = listView.model.count - 1;
              listView.model.get(i).operand = listView.model.get(i).operand + digit;
              enteringDigits = true
              listView.positionViewAtEnd()
          }

          function setDigit(digit)
          {
              var i = listView.model.count - 1;
              listView.model.get(i).operand = digit;
              listView.positionViewAtEnd()
          }

          function clear()
          {
              displayedOperand = ""
              if (enteringDigits) {
                  var i = listView.model.count - 1
                  if (i >= 0)
                      listView.model.remove(i)
                  enteringDigits = false
              }
          }

          // Returns a string representation of a number that fits in
          // display.maxDigits characters, trying to keep as much precision
          // as possible. If the number cannot be displayed, returns an
          // error string.
          function displayNumber(num) {
              if (typeof(num) != "number")
                  return errorString;

              var intNum = parseInt(num);
              var intLen = intNum.toString().length;

              // Do not count the minus sign as a digit
              var maxLen = num < 0 ? maxDigits + 1 : maxDigits;

              if (num.toString().length <= maxLen) {
                  if (isFinite(num))
                      return num.toString();
                  return errorString;
              }

              // Integer part of the number is too long - try
              // an exponential notation
              if (intNum == num || intLen > maxLen - 3) {
                  var expVal = num.toExponential(maxDigits - 6).toString();
                  if (expVal.length <= maxLen)
                      return expVal;
              }

              // Try a float presentation with fixed number of digits
              var floatStr = parseFloat(num).toFixed(maxDigits - intLen - 1).toString();
              if (floatStr.length <= maxLen)
                  return floatStr;

              return errorString;
          }

          Item {
              id: theItem
              width: parent.width + 32
              height: parent.height

              Rectangle {
                  id: rect
                  x: 16
                  color: "white"
                  height: parent.height
                  width: display.width - 16
              }
              Image {
                  anchors.right: rect.left
                  source: "images/paper-edge-left.png"
                  height: parent.height
                  fillMode: Image.TileVertically
              }
              Image {
                  anchors.left: rect.right
                  source: "images/paper-edge-right.png"
                  height: parent.height
                  fillMode: Image.TileVertically
              }

              Image {
                  id: grip
                  source: "images/paper-grip.png"
                  anchors.horizontalCenter: parent.horizontalCenter
                  anchors.bottom: parent.bottom
                  anchors.bottomMargin: 20
              }

              ListView {
                  id: listView
                  x: 16; y: 30
                  width: display.width
                  height: display.height - 50 - y
                  delegate: Item {
                      height: display.fontSize * 1.1
                      width: parent.width
                      Text {
                          id: operator
                          x: 6
                          font.pixelSize: display.fontSize
                          color: "#6da43d"
                          text: model.operator
                      }
                      Text {
                          id: operand
                          font.pixelSize: display.fontSize
                          anchors.right: parent.right
                          anchors.rightMargin: 22
                          text: model.operand
                      }
                  }
                  model: ListModel { }
              }

          }

      }