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    ./demo/canvas-001.js ./demo/canvas-002.js ./demo/canvas-003.js ./demo/canvas-004.js ./demo/canvas-005.js ./demo/canvas-006.js ./demo/canvas-007.js ./demo/canvas-008.js ./demo/canvas-009.js ./demo/canvas-010.js ./demo/canvas-011.js ./demo/canvas-012.js ./demo/canvas-013.js ./demo/canvas-014.js ./demo/canvas-015.js ./demo/canvas-016.js ./demo/canvas-017.js ./demo/canvas-018.js ./demo/canvas-019.js ./demo/canvas-020.js ./demo/canvas-021.js ./demo/canvas-022.js ./demo/canvas-023.js ./demo/canvas-024.js ./demo/canvas-025.js ./demo/canvas-026.js ./demo/canvas-027.js ./demo/canvas-028.js ./demo/canvas-029.js ./demo/canvas-030.js ./demo/canvas-031.js ./demo/canvas-032.js ./demo/canvas-033.js ./demo/canvas-034.js ./demo/canvas-035.js ./demo/canvas-036.js ./demo/canvas-037.js ./demo/canvas-038.js ./demo/canvas-039.js ./demo/canvas-040.js ./demo/canvas-041.js ./demo/canvas-042.js ./demo/canvas-043.js ./demo/canvas-044.js ./demo/canvas-045.js ./demo/canvas-046.js ./demo/canvas-047.js ./demo/canvas-048.js ./demo/canvas-049.js ./demo/canvas-050.js ./demo/canvas-051.js ./demo/canvas-052.js ./demo/canvas-053.js ./demo/canvas-054.js ./demo/canvas-055.js ./demo/canvas-056.js ./demo/canvas-057.js ./demo/canvas-058.js ./demo/canvas-059.js ./demo/canvas-060.js ./demo/canvas-061.js ./demo/canvas-062.js ./demo/canvas-063.js ./demo/canvas-064.js ./demo/canvas-065.js ./demo/canvas-066.js ./demo/canvas-067.js ./demo/canvas-068.js ./demo/canvas-069.js ./demo/canvas-070.js ./demo/canvas-071.js ./demo/canvas-072.js ./demo/canvas-073.js ./demo/canvas-201.js ./demo/canvas-202.js ./demo/canvas-203.js ./demo/canvas-204.js ./demo/canvas-205.js ./demo/canvas-206.js ./demo/canvas-207.js ./demo/canvas-208.js ./demo/canvas-209.js ./demo/canvas-210.js ./demo/canvas-211.js ./demo/canvas-212.js ./demo/delaunator-001.js ./demo/delaunator-002.js ./demo/dom-001.js ./demo/dom-002.js ./demo/dom-003.js ./demo/dom-004.js ./demo/dom-005.js ./demo/dom-006.js ./demo/dom-007.js ./demo/dom-008.js ./demo/dom-009.js ./demo/dom-010.js ./demo/dom-011.js ./demo/dom-012.js ./demo/dom-013.js ./demo/dom-015.js ./demo/dom-016.js ./demo/dom-017.js ./demo/dom-018.js ./demo/dom-019.js ./demo/dom-020.js ./demo/dom-021.js ./demo/filters-001.js ./demo/filters-002.js ./demo/filters-003.js ./demo/filters-004.js ./demo/filters-005.js ./demo/filters-006.js ./demo/filters-007.js ./demo/filters-008.js ./demo/filters-009.js ./demo/filters-010.js ./demo/filters-011.js ./demo/filters-012.js ./demo/filters-013.js ./demo/filters-014.js ./demo/filters-015.js ./demo/filters-016.js ./demo/filters-017.js ./demo/filters-018.js ./demo/filters-019.js ./demo/filters-020.js ./demo/filters-021.js ./demo/filters-022.js ./demo/filters-023.js ./demo/filters-024.js ./demo/filters-025.js ./demo/filters-026.js ./demo/filters-027.js ./demo/filters-028.js ./demo/filters-029.js ./demo/filters-030.js ./demo/filters-031.js ./demo/filters-032.js ./demo/filters-033.js ./demo/filters-034.js ./demo/filters-035.js ./demo/filters-036.js ./demo/filters-037.js ./demo/filters-038.js ./demo/filters-039.js ./demo/filters-040.js ./demo/filters-041.js ./demo/filters-042.js ./demo/filters-101.js ./demo/filters-102.js ./demo/filters-103.js ./demo/filters-104.js ./demo/filters-105.js ./demo/filters-501.js ./demo/filters-502.js ./demo/filters-503.js ./demo/filters-504.js ./demo/filters-505.js ./demo/mediapipe-001.js ./demo/mediapipe-002.js ./demo/mediapipe-003.js ./demo/modules-001.js ./demo/modules-002.js ./demo/modules-003.js ./demo/modules-004.js ./demo/modules-005.js ./demo/modules-006.js ./demo/packets-001.js ./demo/packets-002.js ./demo/particles-001.js ./demo/particles-002.js ./demo/particles-003.js ./demo/particles-004.js ./demo/particles-005.js ./demo/particles-006.js ./demo/particles-007.js ./demo/particles-008.js ./demo/particles-009.js ./demo/particles-010.js ./demo/particles-011.js ./demo/particles-012.js ./demo/particles-013.js ./demo/particles-014.js ./demo/particles-015.js ./demo/particles-016.js ./demo/particles-017.js ./demo/snippets-001.js ./demo/snippets-002.js ./demo/snippets-003.js ./demo/snippets-004.js ./demo/snippets-005.js ./demo/snippets-006.js ./demo/temp-001.js ./demo/temp-shape-scale-investigation.js ./demo/tensorflow-001.js ./demo/tensorflow-002.js ./demo/utilities.js
  • §

    Demo Particles 013

    Seasons greetings

  • §

    Run code

    import * as scrawl from '../source/scrawl.js';
    
    import { reportSpeed } from './utilities.js';
  • §

    Scene setup

    const canvas = scrawl.findCanvas('mycanvas');
  • §

    Namespacing boilerplate

    const namespace = canvas.name;
    const name = (n) => `${namespace}-${n}`;
  • §

    Christmas tree Shape entity

    We generate a ‘twinkling’ particle Emitter using this entity’s shape as a generation field. We also position the ‘star’ particle Emitter on this entity’s path, alongside a set of 10 ‘candle’ Pictures

    const tree = scrawl.makeShape({
    
        name: name('my-tree'),
    
        pathDefinition: 'M 1049.6339,1050 C 1049.6339,1050 1030.0866,1022.855 1019.4084,1003.5845 C 991.5593,954.92478 986.46204,868.69686 979.32292,780.61374 C 979.32292,780.61374 1022.3499,838.11219 1052.1807,857.87889 C 1061.3371,863.94619 1085.4929,869.8246 1085.4929,869.8246 L 1138.1801,908.67848 C 1138.1801,908.67848 1229.7506,966.738 1241.4829,953.27545 C 1251.6457,941.61167 1177.0219,890.53297 1150.458,859.57897 C 1123.8942,828.625 1078.1083,775.02293 1085.4929,768.6793 C 1085.4929,768.6793 1120.9803,809.96348 1147.5318,819.95537 C 1153.1541,822.07274 1165.8575,819.22515 1170.5407,822.98904 C 1201.6335,847.96874 1239.8905,866.16504 1276.7703,883.65648 C 1326.4934,907.2406 1432.0937,928.36623 1432.4404,911.839 C 1432.5948,904.4776 1364.7319,871.36397 1299.0621,817.82956 C 1228.6904,760.458 1163.527,674.95463 1152.9663,662.29841 C 1142.675,649.96363 1234.3802,721.91704 1276.7703,717.313 C 1280.7075,716.88726 1280.1051,706.69523 1283.8876,707.86808 C 1314.0423,717.21997 1345.6886,727.02011 1370.4551,732.13167 C 1437.8515,746.0453 1438.1332,733.547 1437.5631,724.27404 C 1437.0206,715.44937 1237.418,666.37808 1105.4596,514.91526 C 1100.3923,509.09889 1156.4895,551.98167 1185.1454,544.04793 C 1189.2891,542.90045 1188.6277,535.21482 1192.8987,535.71104 C 1218.2777,538.65445 1299.3631,566.90467 1298.7537,545.06011 C 1298.4037,532.51386 1230.5378,512.781 1170.7235,471.37556 C 1119.3785,435.83445 1080.4259,400.30745 1058.2683,379.16489 C 1052.6276,373.78271 1096.7566,406.8033 1116.3075,400.52452 C 1119.2343,399.58567 1116.8789,394.74197 1119.9305,395.11415 C 1136.9769,397.18074 1195.0389,429.0623 1200.81,409.55219 C 1202.0804,405.25545 1148.0173,376.24119 1101.588,340.34766 C 1055.1587,304.45412 1015.8333,263.80146 1015.8333,263.80146 C 1028.2571,271.14877 1044.0133,281.27599 1054.2258,279.95934 C 1055.7326,279.10224 1058.8007,278.21978 1057.0348,273.17309 C 1063.5569,274.37696 1103.9124,294.83721 1107.0658,281.63969 C 1108.7025,277.62489 1044.8219,244.56483 1009.291,216.46406 C 971.49092,186.56734 933.15826,149.99997 933.15826,149.99997 C 933.15826,149.99997 894.82544,186.56734 857.02537,216.46406 C 821.49448,244.56483 757.61385,277.62489 759.25055,281.63969 C 762.40389,294.83721 802.75948,274.37696 809.28155,273.17309 C 807.51567,278.21978 810.58381,279.10224 812.09059,279.95934 C 822.30307,281.27599 838.05918,271.14877 850.48307,263.80146 C 850.48307,263.80146 811.15767,304.45412 764.72841,340.34766 C 718.29911,376.24119 664.23589,405.25545 665.50633,409.55219 C 671.27744,429.0623 729.33944,397.18074 746.38589,395.11415 C 749.43744,394.74197 747.08207,399.58567 750.00885,400.52452 C 769.5597,406.8033 813.68878,373.78271 808.04807,379.16489 C 785.89052,400.30745 746.93789,435.83445 695.59281,471.37556 C 635.77859,512.781 567.91263,532.51386 567.56263,545.06011 C 566.95322,566.90467 648.03863,538.65445 673.4177,535.71104 C 677.68863,535.21482 677.02726,542.90045 681.171,544.04793 C 709.82685,551.98167 765.92404,509.09889 760.8567,514.91526 C 628.89841,666.37808 429.2957,715.44937 428.75322,724.27404 C 428.18315,733.547 428.46481,746.0453 495.86126,732.13167 C 520.62778,727.02011 552.27407,717.21997 582.42874,707.86808 C 586.21126,706.69523 585.60889,716.88726 589.54604,717.313 C 631.93615,721.91704 723.64137,649.96363 713.35007,662.29841 C 702.78933,674.95463 637.626,760.458 567.25422,817.82956 C 501.58452,871.36397 433.72152,904.4776 433.87596,911.839 C 434.22263,928.36623 539.82289,907.2406 589.54604,883.65648 C 626.42589,866.16504 664.68285,847.96874 695.77563,822.98904 C 700.45881,819.22515 713.1623,822.07274 718.78455,819.95537 C 745.33607,809.96348 780.82344,768.6793 780.82344,768.6793 C 788.20804,775.02293 742.42218,828.625 715.85833,859.57897 C 689.29448,890.53297 614.67067,941.61167 624.83348,953.27545 C 636.56578,966.738 728.13626,908.67848 728.13626,908.67848 L 780.82344,869.8246 C 780.82344,869.8246 804.97922,863.94619 814.13567,857.87889 C 843.96641,838.11219 886.99344,780.61374 886.99344,780.61374 C 879.85433,868.69686 874.75704,954.92478 846.90796,1003.5845 C 836.22978,1022.855 816.68115,1050 816.68115,1050 C 894.33207,1050 971.983,1050 1049.6339,1050 z',
    
        start: ['center', '60%'],
        handle: ['center', 'center'],
    
        fillStyle: 'darkgreen',
        lineWidth: 4,
    
        scale: 0.5,
    
        useAsPath: true,
        precision: 1,
    
        method: 'fill',
    });
  • §

    Greetings logo

    scrawl.makeQuadratic({
    
        name: name('message-guideline'),
    
        start: [50, 180],
        control: [300, -20],
        end: [550, 180],
    
        useAsPath: true,
        method: 'none',
    });
    
    scrawl.makeEnhancedLabel({
    
        name: name('message-text'),
        layoutTemplate: name('message-guideline'),
    
        fontString: '60px "Mountains Of Christmas"',
        text: 'HAPPY HOLIDAYS',
    
        textHandle: ['center', 'alphabetic'],
    
        useLayoutTemplateAsPath: true,
        breakTextOnSpaces: false,
    
        fillStyle: 'aliceblue',
        letterSpacing: '8px',
        pathPosition: 0.03,
    });
  • §

    Particle physics

    The world object will be used by multiple Emitter entitys

    const myWorld = scrawl.makeWorld({
    
        name: name('my-world'),
        tickMultiplier: 2,
    });
  • §

    Star decoration

    The tree topper decoration is a star which generates a cloud of multicoloured stars

    • Uses a point-based Emitter entity positioned along the tree Shape entity’s path
    scrawl.makeEmitter({
    
        name: name('star-particles'),
        world: myWorld,
    
        path: name('my-tree'),
        pathPosition: 0.484,
        lockTo: 'path',
    
        generationRate: 10,
        killAfterTime: 6,
    
        rangeX: 10,
        rangeFromX: -5,
    
        rangeY: -10,
        rangeFromY: -5,
    
        rangeZ: -1,
        rangeFromZ: -0.2,
    
        fillMinimumColor: 'pink',
        fillMaximumColor: 'white',
  • §

    Define the artefact used to visualize the particles as part of the Emitter factory function

        artefact: scrawl.makeStar({
    
            name: name('particle-star'),
    
            radius1: 12,
            radius2: 21,
    
            points: 7,
            roll: 45,
    
            handle: ['center', 'center'],
    
            method: 'fill',
            visibility: false,
    
            noUserInteraction: true,
            noPositionDependencies: true,
            noFilters: true,
            noDeltaUpdates: true,
        }),
    
        stampFirst: 'newest',
        stampAction: function (artefact, particle, host) {
    
            const history = particle.history;
    
            let remaining, globalAlpha, scale, start, z;
  • §

    These particles only keep data for their most recent position

            if (history.length) {
    
                [remaining, z, ...start] = history[0];
                globalAlpha = remaining / 6;
                scale = 1 + (z / 3);
    
                if (globalAlpha > 0 && scale > 0) {
    
                    artefact.simpleStamp(host, {
                        start,
                        scale,
                        globalAlpha,
                        fillStyle: particle.fill,
                    });
                }
            }
        },
    });
  • §

    The static star goes over the top of the Emitter entity’s stars

    scrawl.makeStar({
    
        name: name('main-star'),
    
        radius1: 12,
        radius2: 21,
        points: 7,
        roll: 45,
    
        path: name('my-tree'),
        pathPosition: 0.484,
        lockTo: 'path',
    
        handle: ['center', 'center'],
    
        fillStyle: 'yellow',
        strokeStyle: 'gold',
        lineWidth: 2,
        method: 'fillThenDraw',
    });
  • §

    Tree spangles

    The tree spangles decoration is a set of stars within the tree which fade in, rotate andf elongate over the course of their lives

    • Uses an area-based Emitter entity positioned within the tree Shape entity’s path
    scrawl.makeEmitter({
    
        name: name('spangles-particles'),
    
        world: myWorld,
    
        generateInArea: tree,
    
        particleCount: 100,
        generationRate: 10,
    
        killAfterTime: 30,
        killAfterTimeVariation: 5,
    
        fillMinimumColor: 'lightgray',
        fillMaximumColor: 'white',
    
        artefact: scrawl.makeStar({
    
            name: name('particle-spangle-entity'),
    
            radius1: 2,
            radius2: 6,
    
            points: 4,
    
            handle: ['center', 'center'],
    
            method: 'fill',
            visibility: false,
    
            delta: {
                roll: 0.6,
            },
    
            noUserInteraction: true,
            noPositionDependencies: true,
            noFilters: true,
        }),
    
        stampAction: function (artefact, particle, host) {
    
            const history = particle.history;
  • §

    These particles only keep data for their most recent position

            if (history.length) {
    
                const [remaining, , ...start] = history[0];
  • §

    This function handles fadein/out, and spangle shape. Spangle rotation is handled by the spangle entity itself, using a delta animation

                let globalAlpha = 1,
                    radius2 = 6;
  • §

    Fade in young particles

                if (remaining > 18) {
    
                    globalAlpha = 1 / (remaining - 18);
                }
  • §

    Fade out old particles

                else if (remaining < 2) {
    
                    globalAlpha = remaining / 2;
                }
  • §

    Limit the globalAlpha value to between 0 and 1

                if (globalAlpha > 1) globalAlpha = 1;
  • §

    Grow and shrink the spangle’s spikes as it matures

                if (remaining < 8) {
    
                    if (remaining > 4) radius2 = 6 + ((8 - remaining) * 5);
                    else radius2 = 6 + (remaining * 5);
                }
    
                artefact.simpleStamp(host, {
                    start,
                    fillStyle: particle.fill,
                    globalAlpha,
                    radius2,
                });
            }
        },
    });
  • §

    Candles with flames

    The scene uses ten candles with a particle-based flame effect. Rather than create all ten candles, with ten Emitters, we can instead define one candle + one Emitter in its own Cell, then use that Cell as the asset for ten Picture entitys - a much more efficient approach.

  • §

    Create a Cell in which to build our candle and flame animation

    canvas.buildCell({
    
        name: name('candle-cell'),
    
        width: 100,
        height: 100,
    
        shown: false,
    });
  • §

    We’ll apply a filter to the flame

    scrawl.makeFilter({
    
        name: name('blur'),
        method: 'blur',
        radius: 2,
        includeAlpha: true,
    });
  • §

    The flame animation uses a point-based Emitter entity positioned at the center of the Cell

    scrawl.makeEmitter({
    
        name: name('flame'),
        group: name('candle-cell'),
    
        world: myWorld,
    
        start: ['center', 'center'],
    
        generationRate: 25,
        killAfterTime: 4,
    
        rangeX: 2,
        rangeFromX: -1,
    
        rangeY: -5,
        rangeFromY: -0.5,
    
        rangeZ: 1,
        rangeFromZ: 0,
    
        fillMinimumColor: 'orange',
        fillMaximumColor: 'yellow',
    
        filters: name('blur'),
    
        stampAction: function (artefact, particle, host) {
    
            const engine = host.engine,
                history = particle.history,
                endRad = Math.PI * 2;
    
            let remaining, radius, alpha, x, y, z;
    
    /** @ts-expect-error */
            const colorFactory = this.fillColorFactory;
    
            engine.save();
            engine.resetTransform();
    
            history.forEach(p => {
    
                [remaining, z, x, y] = p;
                radius = 2 + z;
                alpha = remaining / 4;
    
                if (radius > 0 && alpha > 0) {
  • §

    We could have used a Wheel entity instead

                    engine.beginPath();
                    engine.moveTo(x, y);
                    engine.arc(x, y, radius, 0, endRad);
                    engine.globalAlpha = alpha;
                    engine.fillStyle = colorFactory.get(alpha);
                    engine.fill();
                }
            });
            engine.restore();
        },
    });
  • §

    The candle itself is just a Block entity

    scrawl.makeBlock({
    
        name: name('candle'),
        group: name('candle-cell'),
    
        start: ['center', 'center'],
        handle: ['center', '-10%'],
        dimensions: ['6%', '25%'],
    
        fillStyle: 'white',
        method: 'fill',
    });
  • §

    Define a Picture entity which will display the candle + flame animation

    • The entity is positioned along the tree Shape entity’s path
    scrawl.makePicture({
    
        name: name('candle-1'),
    
        width: 100,
        height: 100,
    
        copyWidth: '100%',
        copyHeight: '100%',
    
        path: name('my-tree'),
        pathPosition: 0.175,
        lockTo: 'path',
    
        handle: ['center', '74%'],
    
        asset: name('candle-cell'),
  • §

    The Picture entity gets cloned nine times

    }).clone({
    
        name: name('candle-2'),
        pathPosition: 0.793,
    
    }).clone({
    
        name: name('candle-3'),
        pathPosition: 0.272,
    
    }).clone({
    
        name: name('candle-4'),
        pathPosition: 0.696,
    
    }).clone({
    
        name: name('candle-5'),
        pathPosition: 0.352,
    
    }).clone({
    
        name: name('candle-6'),
        pathPosition: 0.616,
    
    }).clone({
    
        name: name('candle-7'),
        pathPosition: 0.413,
    
    }).clone({
    
        name: name('candle-8'),
        pathPosition: 0.555,
    
    }).clone({
    
        name: name('candle-9'),
        pathPosition: 0.459,
    
    }).clone({
    
        name: name('candle-10'),
        pathPosition: 0.509,
    });
  • §

    Scene animation

    Function to display frames-per-second data, and other information relevant to the demo

    const report = reportSpeed('#reportmessage');
  • §

    Create the Display cycle animation

    scrawl.makeRender({
    
        name: name('animation'),
        target: canvas,
        afterShow: report,
    });
  • §

    Development and testing

    console.log(scrawl.library);