squircle.qml Example File

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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"}
     }
 }