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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-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/dom-017.js ./demo/dom-018.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-028.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/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/tensorflow-001.js ./demo/tensorflow-002.js ./demo/utilities.js

- §

  # Demo Particles 007

  Particle Force objects: generation and functionality

- §

  Run code

      import * as scrawl from '../source/scrawl.js'

      import { reportSpeed } from './utilities.js';

- §

  #### Scene setup

      const canvas = scrawl.library.artefact.mycanvas;

      scrawl.importDomImage('#bunny');

- §

  Define some filters

      scrawl.makeFilter({
          name: 'grayscale',
          method: 'grayscale',
      }).clone({
          name: 'sepia',
          method: 'sepia',
      }).clone({
          name: 'invert',
          method: 'invert',
      });

      scrawl.makeFilter({
          name: 'tint',
          method: 'tint',
          redInRed: 0.5,      redInGreen: 1,      redInBlue: 0.9,
          greenInRed: 0,      greenInGreen: 0.3,  greenInBlue: 0.8,
          blueInRed: 0.8,     blueInGreen: 0.8,   blueInBlue: 0.4,
      });

      scrawl.makeFilter({
          name: 'pixelate',
          method: 'pixelate',
          tileWidth: 4,
          tileHeight: 4,
      });

      scrawl.makeFilter({
          name: 'blur',
          method: 'gaussianBlur',
          radius: 5,
      });

      scrawl.makeFilter({
          name: 'matrix',
          method: 'matrix',
          weights: [-1, -1, 0, -1, 1, 1, 0, 1, 1],
      });

- §

  Create a Block entity which covers the entire canvas; this will act as the area in which particles will be generated by the Emitter entity

      scrawl.makeBlock({

          name: 'field-block',

          width: '100%',
          height: '100%',

          method: 'none',
      });

- §

  #### Particle physics animation scene

- §

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

      const myWorld = scrawl.makeWorld({

          name: 'demo-world',
          tickMultiplier: 2,

          userAttributes: [
              {
                  key: 'brownianIntensity',
                  defaultValue: 2,
              },
          ],
      });

- §

  Create some Force objects

      scrawl.makeForce({

          name: 'brownian-motion',
      /* eslint-disable-next-line */
          action: (particle, world, host) => {

              const {load} = particle;

- §

  @ts-expect-error

              const intensity = world.brownianIntensity;

              load.vectorAdd({
                  x: (Math.random() * intensity * 2) - intensity,
                  y: (Math.random() * intensity * 2) - intensity,
              });
          },
      });

      scrawl.makeForce({

          name: 'mouse-disruptor',
      /* eslint-disable-next-line */
          action: (particle, world, host) => {

              const {load, position} = particle;
              const {here} = canvas;

              if (here.active) {

                  const v = scrawl.requestVector(here).vectorSubtract(position);

                  const mag = v.getMagnitude();

                  if (mag < 100) load.vectorAdd(v);

                  scrawl.releaseVector(v);
              }
          },
      });

      const myEmitter = scrawl.makeEmitter({

          name: 'field-emitter',
          world: myWorld,

          generationRate: 100,
          particleCount: 50,

          generateInArea: 'field-block',
          killBeyondCanvas: true,

- §

  Add the forces to all Particles that this Emitter entity generates

          forces: ['brownian-motion', 'mouse-disruptor'],

          artefact: 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,
              noDeltaUpdates: true,
          }),

          stampAction: function (artefact, particle, host) {

              const [ , , ...start] = particle.history[0];
              artefact.simpleStamp(host, {start});
          },
      });

- §

  #### 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 => {

              const 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

  For this demo we will suppress touchmove functionality over the canvas

      scrawl.addNativeListener('touchmove', (e) => {

          e.preventDefault();
          e.returnValue = false;

      }, canvas.domElement);

- §

  Setup form observer functionality

      scrawl.makeUpdater({

          event: ['input', 'change'],
          origin: '.controlItem',

          target: myWorld,

          useNativeListener: true,
          preventDefault: true,

          updates: {

              brownianIntensity: ['brownianIntensity', 'float'],
          },
      });

      scrawl.makeUpdater({

          event: ['input', 'change'],
          origin: '.controlItem',

          target: myEmitter,

          useNativeListener: true,
          preventDefault: true,

          updates: {

              particleCount: ['particleCount', 'int'],
          },
      });

- §

  When we set a filter on an Emitter entity, all the entity’s visual output will be filtered

      const filterChoice = function (e) {

          e.preventDefault();
          e.returnValue = false;

          const val = e.target.value;

          myEmitter.clearFilters();
          if (val) myEmitter.addFilters(val);
      };
      scrawl.addNativeListener(['input', 'change'], filterChoice, '#filter');

- §

  Set DOM form initial input values @ts-expect-error

      document.querySelector('#filter').value = '';

- §

  @ts-expect-error

      document.querySelector('#particleCount').value = 50;

- §

  @ts-expect-error

      document.querySelector('#brownianIntensity').value = 2;

- §

  #### Development and testing

      console.log(scrawl.library);