- Qt 5.3
- Qt Quick
- Qt Quick Examples - Canvas
- clip.qml Example File
- Qt 5.3.2 Reference Documentation

# clip.qml Example File

canvas/clip/clip.qml

    /****************************************************************************
    **
    ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
    ** Contact: http://www.qt-project.org/legal
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** You may use this file under the terms of the BSD license as follows:
    **
    ** "Redistribution and use in source and binary forms, with or without
    ** modification, are permitted provided that the following conditions are
    ** met:
    **   * Redistributions of source code must retain the above copyright
    **     notice, this list of conditions and the following disclaimer.
    **   * Redistributions in binary form must reproduce the above copyright
    **     notice, this list of conditions and the following disclaimer in
    **     the documentation and/or other materials provided with the
    **     distribution.
    **   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
    **     of its contributors may be used to endorse or promote products derived
    **     from this software without specific prior written permission.
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    ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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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"}
        }
    }