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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 DOM 019

    Screen Capture API - apply a filter to a browser web page

  • §

    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}`;
  • §

    Create demo filters

    scrawl.makeFilter({
    
        name: name('grayscale'),
        method: 'grayscale',
    
    }).clone({
    
        name: name('sepia'),
        method: 'sepia',
    
    }).clone({
    
        name: name('invert'),
        method: 'invert',
    
    }).clone({
    
        name: name('red'),
        method: 'red',
    });
    
    scrawl.makeFilter({
    
        name: name('pixelate'),
        method: 'pixelate',
        tileWidth: 4,
        tileHeight: 4,
    });
    
    scrawl.makeFilter({
    
        name: name('background-blur'),
        method: 'gaussianBlur',
        radius: 2,
    });
  • §
    Import and use stream capture
    let myBackground;
  • §

    Capture the media stream

    • Function invoked when user clicks a button (set up below)
    const requestScreenCapture = () => {
    
        console.log('attempting to capture screen');
    
        scrawl.importScreenCapture({
            name: name('my-screen-capture'),
            audio: {
                suppressLocalAudioPlayback: true,
            },
        })
        .then(mycamera => {
    
            dom.screen_request_button.setAttribute('disabled', '');
  • §

    Take the media stream and display it in our canvas element

            myBackground = scrawl.makePicture({
    
                name: name('background'),
                asset: mycamera.name,
                order: 2,
    
                dimensions: ['100%', '100%'],
                copyDimensions: ['100%', '100%'],
            });
    
            console.log('screen capture should be working');
        })
        .catch(err => {
    
            console.log(err.message);
            dom.screen_request_button.removeAttribute('disabled');
        });
    };
  • §

    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,
    });
  • §

    User interaction

    const dom = scrawl.initializeDomInputs([
        ['select', 'backgroundFilter', 0],
        ['button', 'screen_request_button', 'Request screen capture'],
    ]);
  • §

    Event listeners

    scrawl.addNativeListener(['input', 'change'], (e) => {
    
        if (e && e.target) {
    
            e.preventDefault();
            e.returnValue = false;
    
            if (myBackground) {
    
                const val = e.target.value;
    
                myBackground.clearFilters();
    
                if (val) myBackground.addFilters(name(val));
            }
        }
    }, dom.backgroundFilter);
  • §

    Attach the screen capture function to the button

    scrawl.addNativeListener('click', requestScreenCapture, dom.screen_request_button);
  • §

    Development and testing

    console.log(scrawl.library);