Qt 5.6 | Qt Quick | Qt Quick Examples - Canvas | clip.qml Example File

Qt 5.6.3 Reference Documentation

# clip.qml Example File

canvas/clip/clip.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 2.0
      import "../contents"
      import "../../shared"

      Item {
          id:container
          width: 320
          height: 480

          Column {
              spacing:5
              anchors.fill: parent
              anchors.topMargin: 12
              Text {
                  font.pointSize: 24
                  font.bold: true
                  text: "Squircle with Clip"
                  anchors.horizontalCenter: parent.horizontalCenter
                  color: "#777"
              }
              Canvas {
                  id: canvas
                  width: 320
                  height: 280
                  property color strokeStyle: Qt.darker(fillStyle, 1.2)
                  property color fillStyle:"#14aaff" // green
                  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 + 20
                  property real alpha: 1.0
                  property string imagefile:"../contents/qt-logo.png"
                  antialiasing: true
                  Component.onCompleted:loadImage(canvas.imagefile);

                  onRadiusChanged:requestPaint();
                  onLineWidthChanged:requestPaint();
                  onNSizeChanged:requestPaint();
                  onFillChanged:requestPaint();
                  onStrokeChanged:requestPaint();
                  onImageLoaded : 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 = "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.clip();
                      ctx.drawImage(canvas.imagefile, 0, 0);

                      ctx.restore();
                  }
              }
          }
          Column {
              id: controls
              anchors.bottom: parent.bottom
              anchors.bottomMargin: 12
              Slider {id: nCtrl; min: 1; max: 10; init: 4; name:"N"}
              Slider {id: rCtrl; min: 30; max: 180; init: 80; name:"Radius"}
          }
      }