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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-015a.js ./demo/canvas-016.js ./demo/canvas-017.js ./demo/canvas-018.js ./demo/canvas-019.js ./demo/canvas-019a.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/core-001.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/filters-001.js ./demo/filters-002.js ./demo/filters-002a.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-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/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/rapier-001.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-000.js ./demo/temp-001.js ./demo/temp-001a.js ./demo/temp-002.js ./demo/temp-003.js ./demo/temp-004.js ./demo/temp-005.js ./demo/temp-006.js ./demo/temp-007.js ./demo/temp-008.js ./demo/temp-009.js ./demo/temp-010.js ./demo/temp-011.js ./demo/temp-012.js ./demo/temp-013.js ./demo/temp-014.js ./demo/temp-015.js ./demo/temp-016.js ./demo/temp-017.js ./demo/temp-018.js ./demo/temp-018a.js ./demo/temp-019.js ./demo/temp-020.js ./demo/temp-021.js ./demo/temp-022.js ./demo/temp-023.js ./demo/temp-024.js ./demo/temp-025.js ./demo/temp-026.js ./demo/temp-027.js ./demo/temp-028.js ./demo/temp-029.js ./demo/temp-030.js ./demo/temp-031.js ./demo/temp-032.js ./demo/temp-033.js ./demo/temp-034.js ./demo/temp-035.js ./demo/temp-036.js ./demo/temp-037.js ./demo/temp-100.js ./demo/temp-101.js ./demo/temp-102.js ./demo/temp-103.js ./demo/temp-104.js ./demo/temp-200.js ./demo/temp-201.js ./demo/temp-301.js ./demo/temp-inkscapeSvgFilters.js ./demo/temp-lottie.js ./demo/tensorflow-001.js ./demo/tensorflow-002.js ./demo/utilities.js
  • §

    Demo Particles 003

    Position Emitter entity: start; pivot; mimic; path; mouse; drag-and-drop

  • §

    Run code

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

    Scene setup

    let canvas = scrawl.library.artefact.mycanvas;
    
    scrawl.importDomImage('#bunny');
  • §

    Create Block and Shape entitys that can be used as pivot, mimic and path objects for the Emitter entity

    scrawl.makeBlock({ 
    
        name: 'pivot-entity',
        dimensions: [50, 30],
        start: ['20%', '20%'],
        handle: ['center', 'center'],
        order: 1,
        roll: 90,
    
        strokeStyle: 'darkred',
        lineWidth: 5,
        method: 'draw',
    
    }).clone({
    
        name: 'mimic-entity',
        start: ['80%', '80%'],
    
        delta: {
            roll: 0.3,
        },
    
    });
    
    scrawl.makeShape({
    
        name: 'path-entity',
    
        pathDefinition: 'M266.2,703.1 h-178 L375.1,990 l287-286.9 H481.9 C507.4,365,683.4,91.9,911.8,25.5 877,15.4,840.9,10,803.9,10 525.1,10,295.5,313.4,266.2,703.1 z',
    
        start: ['center', 'center'],
        handle: ['center', 'center'],
    
        scale: 0.5,
        roll: -90,
        flipUpend: true,
        scaleOutline: false,
        useAsPath: true,
        precision: 2,
    
        strokeStyle: 'green',
        lineWidth: 3,
        method: 'draw',
    });
  • §

    Particle physics animation scene

  • §

    Create gradient

    scrawl.makeGradient({
        name: 'linear1',
        endX: '100%',
        colors: [
            [0, 'pink'],
            [999, 'darkgreen']
        ],
    });
  • §

    Create entitys that we can use with the particle emitter

    let wheel = scrawl.makeWheel({ 
    
        name: 'particle-wheel-entity',
        radius: 20, 
        handle: ['center', 'center'],
    
        startAngle: 20,
        endAngle: -20,
        includeCenter: true,
    
        fillStyle: 'linear1',
        method: 'fillThenDraw',
        visibility: false, 
    
        noUserInteraction: true,
        noPositionDependencies: true,
        noFilters: true,
        noDeltaUpdates: true,
    });
    
    let block = scrawl.makeBlock({ 
    
        name: 'particle-block-entity',
        dimensions: [40, 16],
        handle: ['center', 'center'],
    
        fillStyle: 'linear1',
        lockFillStyleToEntity: true,
    
        method: 'fillThenDraw',
        visibility: false, 
    
        noUserInteraction: true,
        noPositionDependencies: true,
        noFilters: true,
        noDeltaUpdates: true,
    });
    
    let star = scrawl.makeStar({
    
        name: 'particle-star-entity',
    
        radius1: 18,
        radius2: 12,
    
        points: 5,
    
        handle: ['center', 'center'],
    
        fillStyle: 'gold',
        method: 'fillThenDraw',
        visibility: false, 
    
        noUserInteraction: true,
        noPositionDependencies: true,
        noFilters: true,
        noDeltaUpdates: true,
    });
    
    let picture = scrawl.makePicture({
    
        name: 'particle-image-entity',
        asset: 'bunny',
    
        width: 26,
        height: 37,
    
        handle: ['center', 'center'],
    
        copyWidth: '100%',
        copyHeight: '100%',
    
        method: 'fill',
        visibility: false, 
    
        noUserInteraction: true,
        noPositionDependencies: true,
        noFilters: true,
        noDeltaUpdates: true,
    });
  • §

    Create a World object which we can then assign to the particle emitter

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

    Create the particle Emitter entity

    const myemitter = scrawl.makeEmitter({
    
        name: 'position-tester',
        world: myWorld,
  • §

    Start coordinates (relative to Cell dimensions)

        start: ['40%', '60%'],
  • §

    Pivot

        pivot: 'pivot-entity',
        addPivotRotation: true,
  • §

    Mimic

        mimic: 'mimic-entity',
        useMimicStart: true,
        useMimicRotation: true,
  • §

    Path

        path: 'path-entity',
        pathPosition: 0,
        addPathRotation: true,
    
        delta: {
            pathPosition: 0.0004,
        },
  • §

    Particle generation

        historyLength: 1,
        generationRate: 50,
        killAfterTime: 5,
  • §

    Another way to kill particles is to set the killBeyondCanvas flag. This will kill any particle that moves beyond the borders of its Cell’s <canvas> element

        killBeyondCanvas: true,
    
        artefact: star,
  • §

    These range settings will create a fountain effect, with the particle stars shrinking and fading as they age

        rangeX: 40,
        rangeFromX: -20,
    
        rangeY: -40,
        rangeFromY: -10,
    
        rangeZ: -1,
        rangeFromZ: -0.2,
  • §

    Emitter entitys do not have dimensions as such; their width and height attributes are linked directly to their hitRadius attribute. Setting the hitRadius lets users drag-and-drop the Emitter around the canvas.

        hitRadius: 20,
        showHitRadius: true,
        hitRadiusColor: 'red',
  • §

    stampAction function

        stampAction: function (artefact, particle, host) {
    
            let history = particle.history,
                remaining, globalAlpha, scale, start, z,
  • §

    @ts-expect-error

                roll = this.get('roll');
    
            history.forEach((p, index) => {
    
                [remaining, z, ...start] = p;
                globalAlpha = remaining / 6;
                scale = 1 + (z / 3);
    
                if (globalAlpha > 0 && scale > 0) {
  • §

    Note that simpleStamp will work with both linear and radial gradients, but will ignore any attempt to add a filter to the Emitter entity.

    • If a filter is required, apply it to the Emitter entity itself.
                    artefact.simpleStamp(host, {start, scale, globalAlpha, roll});
                }
            });
        },
    });
  • §

    Scene animation

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

    const particlenames = scrawl.library.particlenames,
        particle = scrawl.library.particle;
    
    const report = reportSpeed('#reportmessage', function () {
  • §

    ParticleHistory arrays are not saved in the Scrawl-canvas library; instead we need to count them in each particle

        let historyCount = 0;
        particlenames.forEach(n => {
    
            let p = particle[n];
            if (p) historyCount += p.history.length;
        });
    
        return `    Particles: ${particlenames.length}
        Stamps per display: ${historyCount}`;
    });
  • §

    Create the Display cycle animation

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

    User interaction

    Make the Emitter draggable

    • KNOWN BUG - the emitter is not draggable on first user mousedown, but is draggable afterwards
    scrawl.makeGroup({
    
        name: 'my-draggable-group',
    
    }).addArtefacts('position-tester');
    
    scrawl.makeDragZone({
    
        zone: canvas,
        collisionGroup: 'my-draggable-group',
        endOn: ['up', 'leave'],
        preventTouchDefaultWhenDragging: true,
    });
  • §

    Setup form observer functionality

    scrawl.observeAndUpdate({
    
        event: ['input', 'change'],
        origin: '.controlItem',
    
        target: myemitter,
    
        useNativeListener: true,
        preventDefault: true,
    
        updates: {
            position: ['lockTo', 'raw'],
        },
    });
    
    const useArtefact = function () {
    
        const selector = document.querySelector('#artefact');
    
        let choice, val;
    
        return function () {
  • §

    @ts-expect-error

            val = selector.value;
            choice;
    
            switch (val) {
    
                case 'star' :
                    choice = star;
                    break;
    
                case 'wheel' :
                    choice = wheel;
                    break;
    
                case 'block' :
                    choice = block;
                    break;
    
                case 'picture' :
                    choice = picture;
                    break;
            }
    
            if (choice) {
    
                myemitter.set({
                    artefact: choice,
                });
            }
        }
    }();
    scrawl.addNativeListener(['input', 'change'], useArtefact, '#artefact');
  • §

    Initialize form values @ts-expect-error

    document.querySelector('#artefact').value = 'star';
  • §

    @ts-expect-error

    document.querySelector('#position').value = 'start';
  • §

    Development and testing

    console.log(scrawl.library);