Qt 5.6 | Qt Quick Extras | Qt Quick Extras - Dashboard | DashboardGaugeStyle.qml Example File

Qt 5.6.3 Reference Documentation

# DashboardGaugeStyle.qml Example File

dashboard/qml/DashboardGaugeStyle.qml

      /****************************************************************************
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      ** Copyright (C) 2015 The Qt Company Ltd.
      ** Contact: http://www.qt.io/licensing/
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      ** This file is part of the examples of the Qt Toolkit.
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      ** $QT_BEGIN_LICENSE:BSD$
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      import QtQuick 2.2
      import QtQuick.Controls.Styles 1.4

      CircularGaugeStyle {
          tickmarkInset: toPixels(0.04)
          minorTickmarkInset: tickmarkInset
          labelStepSize: 20
          labelInset: toPixels(0.23)

          property real xCenter: outerRadius
          property real yCenter: outerRadius
          property real needleLength: outerRadius - tickmarkInset * 1.25
          property real needleTipWidth: toPixels(0.02)
          property real needleBaseWidth: toPixels(0.06)
          property bool halfGauge: false

          function toPixels(percentage) {
              return percentage * outerRadius;
          }

          function degToRad(degrees) {
              return degrees * (Math.PI / 180);
          }

          function radToDeg(radians) {
              return radians * (180 / Math.PI);
          }

          function paintBackground(ctx) {
              if (halfGauge) {
                  ctx.beginPath();
                  ctx.rect(0, 0, ctx.canvas.width, ctx.canvas.height / 2);
                  ctx.clip();
              }

              ctx.beginPath();
              ctx.fillStyle = "black";
              ctx.ellipse(0, 0, ctx.canvas.width, ctx.canvas.height);
              ctx.fill();

              ctx.beginPath();
              ctx.lineWidth = tickmarkInset;
              ctx.strokeStyle = "black";
              ctx.arc(xCenter, yCenter, outerRadius - ctx.lineWidth / 2, outerRadius - ctx.lineWidth / 2, 0, Math.PI * 2);
              ctx.stroke();

              ctx.beginPath();
              ctx.lineWidth = tickmarkInset / 2;
              ctx.strokeStyle = "#222";
              ctx.arc(xCenter, yCenter, outerRadius - ctx.lineWidth / 2, outerRadius - ctx.lineWidth / 2, 0, Math.PI * 2);
              ctx.stroke();

              ctx.beginPath();
              var gradient = ctx.createRadialGradient(xCenter, yCenter, outerRadius * 0.8, xCenter, yCenter, outerRadius);
              gradient.addColorStop(0, Qt.rgba(1, 1, 1, 0));
              gradient.addColorStop(0.7, Qt.rgba(1, 1, 1, 0.13));
              gradient.addColorStop(1, Qt.rgba(1, 1, 1, 1));
              ctx.fillStyle = gradient;
              ctx.arc(xCenter, yCenter, outerRadius - tickmarkInset, outerRadius - tickmarkInset, 0, Math.PI * 2);
              ctx.fill();
          }

          background: Canvas {
              onPaint: {
                  var ctx = getContext("2d");
                  ctx.reset();
                  paintBackground(ctx);
              }

              Text {
                  id: speedText
                  font.pixelSize: toPixels(0.3)
                  text: kphInt
                  color: "white"
                  horizontalAlignment: Text.AlignRight
                  anchors.horizontalCenter: parent.horizontalCenter
                  anchors.top: parent.verticalCenter
                  anchors.topMargin: toPixels(0.1)

                  readonly property int kphInt: control.value
              }
              Text {
                  text: "km/h"
                  color: "white"
                  font.pixelSize: toPixels(0.09)
                  anchors.top: speedText.bottom
                  anchors.horizontalCenter: parent.horizontalCenter
              }
          }

          needle: Canvas {
              implicitWidth: needleBaseWidth
              implicitHeight: needleLength

              property real xCenter: width / 2
              property real yCenter: height / 2

              onPaint: {
                  var ctx = getContext("2d");
                  ctx.reset();

                  ctx.beginPath();
                  ctx.moveTo(xCenter, height);
                  ctx.lineTo(xCenter - needleBaseWidth / 2, height - needleBaseWidth / 2);
                  ctx.lineTo(xCenter - needleTipWidth / 2, 0);
                  ctx.lineTo(xCenter, yCenter - needleLength);
                  ctx.lineTo(xCenter, 0);
                  ctx.closePath();
                  ctx.fillStyle = Qt.rgba(0.66, 0, 0, 0.66);
                  ctx.fill();

                  ctx.beginPath();
                  ctx.moveTo(xCenter, height)
                  ctx.lineTo(width, height - needleBaseWidth / 2);
                  ctx.lineTo(xCenter + needleTipWidth / 2, 0);
                  ctx.lineTo(xCenter, 0);
                  ctx.closePath();
                  ctx.fillStyle = Qt.lighter(Qt.rgba(0.66, 0, 0, 0.66));
                  ctx.fill();
              }
          }

          foreground: null
      }