backgrounds/components/Snow.qml

0001 /*
0002  * SPDX-FileCopyrightText: 2020 Han Young <hanyoung@protonmail.com>
0003  * SPDX-FileCopyrightText: 2020 Devin Lin <espidev@gmail.com>
0004  *
0005  * SPDX-License-Identifier: GPL-2.0-or-later
0006  */
0007 import QtQuick
0008 import QtQuick.Layouts
0009 Canvas {
0010     id: mycanvas
0011
0012     property var particles: []
0013
0014     renderStrategy: Canvas.Threaded
0015     onPaint: {
0016         var ctx = getContext("2d");
0017         ctx.strokeStyle = 'rgba(255,255,255,0.5)';
0018         ctx.lineWidth = 3;
0019         ctx.lineCap = 'round';
0020         ctx.clearRect(0, 0, width, height);
0021
0022         function draw() {
0023             for (var c = 0; c < particles.length; c++) {
0024                 var p = particles[c];
0025                 ctx.beginPath();
0026                 context.arc(p.x, p.y + p.ys, p.l, 0, 2 * Math.PI, false);
0027                 context.fillStyle = Qt.rgba(255,255,255,p.a);
0028                 context.fill();
0029             }
0030             move();
0031         }
0032
0033         function move() {
0034             for (var b = 0; b < particles.length; b++) {
0035                 var p = particles[b];
0036                 p.y += p.ys;
0037                 if (p.x < 1 || p.x > width || p.y > height) {
0038                     p.x = Math.random() * width;
0039                     p.y = -20;
0040                 }
0041             }
0042         }
0043         draw();
0044     }
0045     Timer {
0046         id: animationTimer
0047         interval: 16
0048         running: true
0049         repeat: true
0050         onTriggered: parent.requestPaint()
0051     }
0052
0053     Component.onCompleted: {
0054         var init = [];
0055         var maxParts = 80;
0056
0057         for (var a = 0; a < maxParts; a++) {
0058             init.push({
0059                           x: Math.random() * width,
0060                           y: Math.random() * height,
0061                           l: 5 + Math.random() * 10,
0062                           ys: Math.random(),
0063                           a: 0.4 + Math.random() * 0.6
0064                       })
0065         }
0066
0067         particles = [];
0068         for (var b = 0; b < maxParts; b++) {
0069             particles[b] = init[b];
0070         }
0071     }
0072 }