squircle.qml Example File

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import QtQuick 2.0
import "../contents"
Item {
  id:container
  width:320
  height:480

  Column {
    spacing:5
    anchors.fill:parent
    Text { font.pointSize:15; text:"Squircles"; anchors.horizontalCenter:parent.horizontalCenter}
    Image {
       anchors.horizontalCenter:parent.horizontalCenter
       source:"squircle.png"
       width:250
       height:25
    }
    Canvas {
        id:canvas
        width:320
        height:250
        antialiasing: true

        property string strokeStyle:"blue"
        property string fillStyle:"steelblue"
        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:xCtrl.value
        property real py:yCtrl.value
        property real alpha:alphaCtrl.value

        onAlphaChanged:requestPaint();
        onRadiusChanged:requestPaint();
        onLineWidthChanged:requestPaint();
        onNSizeChanged:requestPaint();
        onFillChanged:requestPaint();
        onStrokeChanged:requestPaint();
        onPxChanged:requestPaint();
        onPyChanged:requestPaint();

        onPaint: squcirle();

        function squcirle() {
          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 = "gray";
          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.fillStyle = "yellow";
          ctx.font = "Helvetica  16px";
          ctx.fillText("|X-" + Math.round(canvas.px) + "|^" + N + " + |Y-"+Math.round(canvas.py)+"|^" + N + " = |" + Math.round(R) + "|^" + N, canvas.px - 125, canvas.py);
          ctx.restore();
        }
    }

    Rectangle {
        id:controls
        width:320
        height:150
        Column {
          spacing:3
          Slider {id:nCtrl; width:300; height:20; min:1; max:10; init:4; name:"N"}
          Slider {id:rCtrl; width:300; height:20; min:30; max:180; init:100; name:"Radius"}
          Slider {id:xCtrl; width:300; height:20; min:50; max:300; init:180; name:"X"}
          Slider {id:yCtrl; width:300; height:20; min:30; max:300; init:220; name:"Y"}
          Slider {id:alphaCtrl; width:300; height:20; min:0; max:1; init:1; name:"Alpha"}
        }
    }
  }
}