squircle.qml Example File

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  ** This file is part of the examples of the Qt Toolkit.
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  import QtQuick 2.0
  import "../contents"
  import "../../shared"

  Item {
      id: container
      width: 320
      height: 480

      Column {
          spacing: 6
          anchors.fill: parent
          anchors.topMargin: 12
          Text {
              font.pointSize: 24
              font.bold: true
              text: "Squircles"
              anchors.horizontalCenter: parent.horizontalCenter
              color: "#777"
          }

          Image {
              anchors.horizontalCenter: parent.horizontalCenter
              source: "squircle.png"
              width: 250
              height: 25
          }

          Canvas {
              id: canvas
              width: 320
              height: 250
              antialiasing: true

              property color strokeStyle: Qt.darker(fillStyle, 1.2)
              property color fillStyle: "#6400aa"

              property int lineWidth: 2
              property int nSize: nCtrl.value
              property real radius: rCtrl.value
              property bool fill: true
              property bool stroke: false
              property real px: width/2
              property real py: height/2 + 10
              property real alpha: 1.0

              onRadiusChanged: requestPaint();
              onLineWidthChanged: requestPaint();
              onNSizeChanged: requestPaint();
              onFillChanged: requestPaint();
              onStrokeChanged: requestPaint();

              onPaint: squircle();

              function squircle() {
                  var ctx = canvas.getContext("2d");
                  var N = canvas.nSize;
                  var R = canvas.radius;

                  N=Math.abs(N);
                  var M=N;
                  if (N>100) M=100;
                  if (N<0.00000000001) M=0.00000000001;

                  ctx.save();
                  ctx.globalAlpha =canvas.alpha;
                  ctx.fillStyle = "white";
                  ctx.fillRect(0, 0, canvas.width, canvas.height);

                  ctx.strokeStyle = canvas.strokeStyle;
                  ctx.fillStyle = canvas.fillStyle;
                  ctx.lineWidth = canvas.lineWidth;

                  ctx.beginPath();
                  var i = 0, x, y;
                  for (i=0; i<(2*R+1); i++){
                      x = Math.round(i-R) + canvas.px;
                      y = Math.round(Math.pow(Math.abs(Math.pow(R,M)-Math.pow(Math.abs(i-R),M)),1/M)) + canvas.py;

                      if (i == 0)
                          ctx.moveTo(x, y);
                      else
                          ctx.lineTo(x, y);
                  }

                  for (i=(2*R); i<(4*R+1); i++){
                      x =Math.round(3*R-i)+canvas.px;
                      y = Math.round(-Math.pow(Math.abs(Math.pow(R,M)-Math.pow(Math.abs(3*R-i),M)),1/M)) + canvas.py;
                      ctx.lineTo(x, y);
                  }
                  ctx.closePath();
                  if (canvas.stroke) {
                      ctx.stroke();
                  }

                  if (canvas.fill) {
                      ctx.fill();
                  }
                  ctx.restore();
              }
          }

      }
      Column {
          anchors.bottom: parent.bottom
          anchors.bottomMargin: 12
          Slider {id: nCtrl ; min: 1 ; max: 10 ; init: 2 ; name: "N"}
          Slider {id: rCtrl ; min: 30 ; max: 180 ; init: 60 ; name: "Radius"}
      }
  }