PWA: From 0 to MS Paint with Project Fugu (Hands-on)

Progressive Web Apps are a great cross-platform application model, even if somewhat restricted in use—until now, that is. Project Fugu is an initiative led by Google, Microsoft, and Intel. Their goal: a more capable web. Home screen shortcuts, sharing files with other apps, clipboard, and file system access are only a few examples of Fugu’s powerful APIs. Are you ready to superpower your Progressive Web App?

In this workshop, you’ll learn how Progressive Web Apps and Project Fugu enable you to develop full productivity apps that feel virtually like native apps, using web technologies. We will implement a simple remake of a productivity app dinosaur: MS Paint. We will first implement the basic functionality, then make the app installable and offline-capable using the PWA APIs, and finally enrich the user experience even further with new Fugu APIs.

Transcript

1. PWA Workshop
   From 0 to MS Paint with Project Fugu
   (Hands-on)
   Christian Liebel
   @christianliebel
   Consultant
   

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2. Hello, it’s me.
   PWA Workshop
   From 0 to MS Paint with Project Fugu (Hands-on)
   Christian Liebel
   Twitter:
   @christianliebel
   Email:
   christian.liebel
   @thinktecture.com
   Angular & PWA
   Slides:
   thinktecture.com
   /christian-liebel
   

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3. PWA Workshop
   From 0 to MS Paint with Project Fugu (Hands-on)
   Timetable
   09:00–10:30 Block 1
   10:30–11:00 Break
   11:00–12:30 Block 2
   12:30–13:30 Lunch Break
   13:30–15:00 Block 3
   15:00–15:30 Break
   15:30–17:00 Block 4
   

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4. Things NOT to expect
   - Blueprint for PWA
   development
   - No AuthN/AuthZ
   Things To Expect
   - Extensive/up-to-date insights
   into PWA and Project Fugu
   - A productivity app use case
   that works on your desktop &
   smartphone
   - Lots of fun
   - Hands-on exercises
   From 0 to MS Paint with Project Fugu (Hands-on)
   PWA Workshop
   

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5. https://paint.js.org
   – Productivity app
   – Draw images
   – Lots of actions & tools
   – Installable
   – Read/save files
   – Copy/paste images
   from/to clipboard
   – Share files to other apps
   – Register for file extensions
   PWA Workshop
   From 0 to MS Paint with Project Fugu (Hands-on)
   Demo Use Case
   

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6. (Workshop Edition)
   – Productivity app
   – Draw images
   – Lots of actions & tools
   – Installable
   – Read/save files
   – Copy/paste images
   from/to clipboard
   – Share files to other apps
   – Register for file extensions
   PWA Workshop
   From 0 to MS Paint with Project Fugu (Hands-on)
   Demo Use Case
   

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7. Setup complete?
   (Node.js, Google Chrome, Editor, Git)
   PWA Workshop
   From 0 to MS Paint with Project Fugu (Hands-on)
   Setup (1/3)
   LAB #0
   

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8. Optional
   Download and install Chrome Canary:
   https://www.google.com/intl/de/chrome/canary/
   PWA Workshop
   From 0 to MS Paint with Project Fugu (Hands-on)
   Setup (2/3)
   LAB #0
   

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9. git clone https://github.com/thinktecture/
   ijs-muc-2022-pwa.git
   cd ijs-muc-2022-pwa
   npm i
   npm start
   PWA Workshop
   From 0 to MS Paint with Project Fugu (Hands-on)
   Setup (3/3)
   LAB #0
   

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10. Paint PWA Capabilities
    Progressive
    Enhancement
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Agenda
    

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11. Paint PWA Capabilities
    Progressive
    Enhancement
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Agenda
    

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12. Canvas
    – Plain bitmap for the web
    – Cross-platform, hardware-
    accelerated graphics
    operations
    – Supports different contexts
    (2D, 3D: WebGL, WebGL 2.0)
    – Supported on all evergreen
    browsers and on IE 9+
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    

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13. Canvas
    Add a canvas element to index.html:
    
    Query the canvas element in app.js:
    const canvas = document.querySelector('#canvas');
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    LAB #1
    

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14. Canvas 2D Context
    fillRect(x, y, width, height)
    strokeRect(x, y, width, height)
    beginPath()
    moveTo(x, y)
    lineTo(x, y)
    fill()
    stroke()
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    

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15. Canvas 2D Context
    Get the 2D context and prepare the canvas in app.js:
    const canvas = document.querySelector('#canvas');
    const ctx = canvas.getContext('2d');
    ctx.fillStyle = 'white';
    ctx.fillRect(0, 0, canvas.width, canvas.height);
    ctx.fillStyle = 'black';
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    LAB #2
    

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16. Low-latency Rendering
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    Web pages need to synchronize
    with the DOM on graphics updates
    causing latencies that can make
    drawing difficult
    Low-latency rendering skips
    syncing with the DOM with can lead
    to a more natural experience
    Supported on Chrome (Chrome OS
    and Windows only)
    

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17. Low-latency Rendering
    Opt-in to low-latency rendering (app.js):
    const ctx = canvas.getContext('2d', {
    desynchronized: true
    });
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    LAB #3
    

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18. Pointer Events
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    Users nowadays use different
    input methods, cross-platform
    apps should cover all of them
    Pointer Events offer an
    abstract interface to catch all
    input methods (pointerdown,
    pointermove, pointerup)
    event.offsetX/event.offsetY
    contain the pointer’s position
    relative to the listener
    

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19. Pointer Events
    Add event listeners (bottom of app.js):
    canvas.addEventListener('pointerdown', event => {});
    canvas.addEventListener('pointermove', event => {
    ctx.fillRect(event.offsetX, event.offsetY, 2, 2);
    });
    canvas.addEventListener('pointerup', () => {});
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    LAB #4
    

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20. Bresenham Line Algorithm
    The user may move faster than
    the input can be processed
    For this case, we need to
    remember the previous point
    and interpolate the points in
    between
    The Bresenham line algorithm
    calculates the missing pixels
    between two given points
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    

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21. Bresenham Line Algorithm
    1. Add the following import to the top of app.js (“.js” is required, otherwise the request will 404):
    import {bresenhamLine} from "./helpers.js";
    2. Then, adjust the event listeners:
    a) In the pointerdown event handler, store event.offsetX/event.offsetY in a variable called
    previousPoint
    b) In pointermove
    i. only draw if the pointer is down
    ii. retrieve the current point (event.offsetX|Y)
    iii. In a for…of loop, call bresenhamLine() with previousPoint.x|y & currentPoint.x|y and
    draw a 2x2 rectangle for each returned point.
    iv. store current point in previousPoint
    c) In pointerup, set previousPoint to null again.
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    LAB #5
    

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22. Bresenham Line Algorithm
    let previousPoint = null;
    canvas.addEventListener('pointerdown', event => previousPoint = {x: event.offsetX, y:
    event.offsetY});
    canvas.addEventListener('pointermove', event => {
    if (previousPoint) {
    const currentPoint = {x: event.offsetX, y: event.offsetY};
    for(let {x, y} of bresenhamLine(previousPoint.x, previousPoint.y,
    currentPoint.x, currentPoint.y)) {
    ctx.fillRect(x, y, 2, 2);
    }
    previousPoint = currentPoint;
    }
    });
    canvas.addEventListener('pointerup', () => previousPoint = null);
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    

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23. Color Selection
    For this demo, we will only
    implement the brush tool. However,
    we want to bring in some color.
    A simple method to implement a
    color selection is to use the HTML
    color-type input element that
    shows the native color picker:
    
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    

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24. Color Selection
    1. In index.html, add the following input to the node:
    
    2. In app.js, add the following code at the bottom:
    const txtColor = document.querySelector('#color');
    txtColor.addEventListener('change', () => {
    ctx.fillStyle = txtColor.value;
    });
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Paint
    LAB #6
    

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25. Paint PWA Capabilities
    Progressive
    Enhancement
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Agenda
    

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26. From 0 to MS Paint with Project Fugu (Hands-on)
    PWA Workshop
    Responsive Linkable Discoverable Installable App-like
    Connectivity
    Independent
    Fresh Safe Re-engageable Progressive
    

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27. PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Web App
    Manifest
    Service
    Worker
    

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28. Web App Manifest
    Distinguishes Web Apps from
    Websites
    JSON-based file containing
    metadata for apps only
    Apps can be identified by search
    engines, app store providers, etc.
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    

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29. manifest.webmanifest
    {
    "short_name": "Paint",
    "name": "Paint Workshop",
    "theme_color": "white",
    "icons": [{
    "src": "icon.png",
    "sizes": "512x512"
    }],
    "start_url": "/index.html",
    "display": "standalone",
    "shortcuts": [/* … */]
    }
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    Names
    Icons
    Display Mode
    Shortcuts
    Start URL
    Theme color (status bar/window bar)
    

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30. Manifest Display Modes
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    browser minimal-ui standalone fullscreen
    

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31. Manifest Icon Purposes
    (any)
    any context (e.g. app icon)
    monochrome
    different color requirements
    (at risk)
    maskable
    user agent masks icon as required
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    Safe Zone
    Windows iOS Android
    

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32. Web App Manifest
    1. In index.html, add the following tag to the document’s node (e.g., after the
    stylesheet):
    
    2. Create the new file manifest.webmanifest and set:
    a) name and short_name to values of your choice
    b) display to standalone
    c) theme_color to #000080 and background_color to #808080
    d) start_url to /index.html and scope to /
    e) icons to [{ "src": "icon.png", "sizes": "512x512" }]
    3. Test manifest in DevTools: F12 > Application > Manifest
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    LAB #7
    

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33. Manifest Shortcuts
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    Secondary entrypoints for your
    application (e.g., home screen
    quick actions, jump lists, …)
    Static definition in Web App
    Manifest
    Dynamic API may follow in the
    future
    Supported by Google Chrome
    for Android, macOS and
    Windows
    

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34. Web App Manifest
    1. In manifest.webmanifest, add (at least) the following shortcut:
    "shortcuts": [{
    "name": "About Paint",
    "short_name": "About",
    "description": "Show information about Paint",
    "url": "/about.html",
    "icons": [{ "src": "icon.png", "sizes": "512x512" }]
    }],
    2. Test in DevTools: F12 > Application > Manifest
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    LAB #8
    

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35. Web App Manifest – Chrome Install Criteria
    1. Web App is not already installed
    2. Meets a user engagement heuristic (user has interacted and clicked
    with origin for at least 30 seconds)
    3. Includes a Web App Manifest that has short_name or name, at least a
    192px and 512px icon, a start_url and a display mode of
    fullscreen, standalone or minimal-ui
    4. Served over HTTPS
    5. Has a registered service worker with a fetch event handler (subject
    to change)
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    https://web.dev/install-criteria/
    

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36. Service Worker
    JavaScript snippet executed in an
    own thread, registered by the website
    Acts as a controller, proxy, or
    interceptor
    Has a cache to store responses (for
    offline availability and performance)
    Can wake up even when the website
    is closed and perform background
    tasks (e.g., push notifications or sync)
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    

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37. Service Worker
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    Service
    Worker
    Internet
    Website
    HTML/JS
    Cache
    fetch
    

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38. Workbox
    Toolchain by Google
    Includes a CLI
    Generates a service worker
    implementation from directory
    contents (e.g., build output, or
    our development directory)
    Allows you to modify the
    service worker behavior
    (maximum flexibility)
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    

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39. Service Worker
    1. In your console, run:
    a) npm run workbox wizard (use “src” as project root and defaults for the rest)
    b) npm run workbox generateSW
    2. In index.html, add the following script to the bottom of the node:
    <br/>if (navigator.serviceWorker) {<br/>navigator.serviceWorker.register('sw.js');<br/>}<br/>
    3. Test in DevTools: F12 > Application > Service Worker
    4. Install the app: Address Bar > Install
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    LAB #9
    

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40. Service Worker Debugging
    More information on installed
    service workers can be found on
    • about://serviceworker-
    internals (Chromium-based
    browsers)
    • about:serviceworkers
    (Mozilla Firefox)
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    

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41. Service Worker Debugging
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    

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42. Lighthouse
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    Auditing tool by Google,
    integrated in Chrome DevTools
    Automatically checks
    performance metrics, PWA
    support, accessibility, SEO and
    other best practices and gives
    tips on how to improve
    Can simulate mobile devices
    

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43. Lighthouse
    1. Make sure only one tab/window of your PWA is open
    2. Open DevTools: F12 > Lighthouse
    3. Make sure to select at least the “Progressive Web App” category
    4. Click “Generate report”
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    PWA
    LAB #10
    

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44. Paint PWA Capabilities
    Progressive
    Enhancement
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Agenda
    

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45. PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    

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46. Project Fugu
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    »Let’s bring the web
    back – API by API«
    Thomas Steiner, Google
    

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47. PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    Contacts
    Picker
    Screen Wake
    Lock API
    File System
    Access API
    Shape
    Detection API
    

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48. PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    https://goo.gle/fugu-api-tracker
    

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49. Fugu Process
    – Write an Explainer (https://github.com/WICG/native-file-
    system/blob/master/EXPLAINER.md)
    – Discuss capability with developers, browser vendors, standard orgs
    – Iterate
    – Compile a design document
    – W3C TAG Review (https://github.com/w3ctag/design-
    reviews/issues/390)
    – Formal spec within Web Incubator Community Group (WICG,
    https://wicg.github.io/native-file-system/)
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    

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50. Fugu Process
    – Implementation in Chromium
    – Launches behind a flag (chrome://flags/#enable-experimental-web-
    platform-features)
    – Origin Trial (https://developers.chrome.com/origintrials/)
    – Transfer to W3C Working Group + Recommendation?
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    

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51. Browser
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    navigator.share({ url: 'http://example.com' });
    ShareIntent DataTransferManager
    …
    NSSharingServicePicker
    

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52. File System Access API
    Some applications heavily rely
    on working with files (e.g.
    Visual Studio Code, Adobe
    Photoshop, …)
    File System Access API allows
    you to open, save and override
    files and directories
    Supported by Chrome, Edge
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    

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53. File System Access API
    1. Add the following buttons to the bar in index.html (before the color input):
    Open
    Save
    Copy
    Paste
    Share
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    LAB #11
    

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54. File System Access API
    2. At the top of app.js, change the import as follows:
    import {bresenhamLine, getImage, toBlob} from "./helpers.js";
    3. Add the following lines at the bottom of app.js:
    const fileOptions = {
    types: [{
    description: 'PNG files',
    accept: {'image/png': ['.png']}
    }]
    };
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    LAB #11
    

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55. File System Access API
    4. Add the following lines at the bottom of app.js:
    const btnSave = document.querySelector('#save');
    btnSave.addEventListener('click', async () => {
    const blob = await toBlob(canvas);
    const handle = await window.showSaveFilePicker(fileOptions);
    const writable = await handle.createWritable();
    await writable.write(blob);
    await writable.close();
    });
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    LAB #11
    

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56. File System Access API
    Add the following code at the end of app.js:
    const btnOpen = document.querySelector('#open');
    btnOpen.addEventListener('click', async () => {
    const [handle] = await window.showOpenFilePicker(fileOptions);
    const file = await handle.getFile();
    const image = await getImage(file);
    ctx.drawImage(image, 0, 0);
    });
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    LAB #12
    

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57. Async Clipboard API
    Allows reading from/writing to
    the clipboard in an
    asynchronous manner (UI won’t
    freeze during long-running
    operations)
    Reading from the clipboard
    requires user consent first
    (privacy!)
    Supported by Chrome, Edge
    and Safari and Firefox (plain-
    text only)
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    

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58. Async Clipboard API
    Add the following code at the end of app.js:
    const btnCopy = document.querySelector('#copy');
    btnCopy.addEventListener('click', async () => {
    await navigator.clipboard.write([
    new ClipboardItem({'image/png': toBlob(canvas)})
    ]);
    });
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    LAB #13
    

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59. Async Clipboard API
    const btnPaste = document.querySelector('#paste');
    btnPaste.addEventListener('click', async () => {
    const clipboardItems = await navigator.clipboard.read();
    for (const clipboardItem of clipboardItems) {
    for (const type of clipboardItem.types) {
    if (type === 'image/png') {
    const blob = await clipboardItem.getType(type);
    const image = await getImage(blob);
    ctx.drawImage(image, 0, 0);
    }
    }
    }
    });
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    LAB #14
    

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60. Web Share API
    Allows sharing a title, URL, text, or
    files
    API can only be invoked as a
    result of a user action (i.e. a click
    or keypress)
    Supported by Chrome, Edge,
    Safari and Firefox (Android only)
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    

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61. Web Share API
    const btnShare = document.querySelector('#share');
    btnShare.addEventListener('click', async () => {
    const blob = await toBlob(canvas);
    const file = new File([blob], 'untitled.png', {type: 'image/png'});
    const item = {files: [file], title: 'untitled.png'};
    if (navigator.canShare(item)) {
    await navigator.share(item);
    }
    });
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    LAB #15
    

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62. File Handling API
    Register your PWA as a
    handler for file extensions
    Requires installing the
    application first
    Declare supported extensions
    in Web App Manifest and add
    imperative code to your
    application logic
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    

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63. File Handling API
    1. Add the following property to your manifest (manifest.webmanifest):
    "file_handlers": [{
    "action": "/index.html",
    "accept": {
    "image/png": [".png"]
    }
    }]
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    LAB #16
    

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64. File Handling API
    2. Add the following code to the bottom of app.js:
    if ('launchQueue' in window) {
    launchQueue.setConsumer(async params => {
    const [handle] = params.files;
    if (handle) {
    const file = await handle.getFile();
    const image = await getImage(file);
    ctx.drawImage(image, 0, 0);
    }
    });
    }
    3. Re-generate Service Worker: npm run workbox generateSW
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    LAB #16
    

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65. Summary
    - Project Fugu helps the web to become more and more capable
    - Project Fugu APIs could bring many more app experiences to the web
    (IDEs, productivity apps, etc.)
    - But: Web is threatened by alternative approaches and platforms,
    support for modern Web API varies from platform to platform
    - You can make a difference!
    - File bugs in browser engine bugtrackers
    - File Fugu requests: https://goo.gle/new-fugu-request
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Capabilities
    

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66. Paint PWA Capabilities
    Progressive
    Enhancement
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Agenda
    

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67. Overview
    Use available interfaces and functions of
    a system (opposite of Graceful
    Degradation)
    Users with modern, feature-rich
    browsers get a better experience
    Apps are available on older browsers, but
    with limited functionality
    Concept: Browser feature support should
    grow over time—thereby more users can
    enjoy an increasing number of features
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Progressive Enhancement
    

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68. Overview
    if ('serviceWorker' in navigator) {
    navigator.serviceWorker.register(…)
    .then(() => /* … */);
    }
    In JavaScript: check whether an API/feature is available. If yes—use it!
    Otherwise:
    1. Disable the functionality
    2. Fall back to an alternative API (if available)
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Progressive Enhancement
    

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69. Disabling unsupported features
    In app.js, disable the buttons in case the respective API does not exist, e.g.:
    btnSave.disabled = !('showSaveFilePicker' in window);
    1. Save: !('showSaveFilePicker' in window)
    2. Open: !('showOpenFilePicker' in window)
    3. Copy: !('clipboard' in navigator && 'write' in navigator.clipboard)
    4. Paste: !('clipboard' in navigator && 'read' in navigator.clipboard)
    5. Share: !('canShare' in navigator)
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Progressive Enhancement
    LAB #17
    

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70. Providing an alternative implementation
    1. In app.js, test for the existence of the showSaveFilePicker() method
    on the window object.
    2. If the method does not exist, fall back to the following code for save:
    const anchor = document.createElement('a');
    const url = URL.createObjectURL(blob);
    anchor.href = url;
    anchor.download = '';
    anchor.click();
    URL.revokeObjectURL(url);
    3. Remove the code that disabled the button.
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Progressive Enhancement
    LAB #18
    

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71. Deployment
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Electron/Capacitor
    JS
    HTML
    CSS
    .ipa
    .exe .app ELF
    .apk .appx
    Single-Page
    Application
    Capacitor
    Electron
    

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72. (Simplified)
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Store Deployments
    https://example.com
    .appx
    .apk
    Server
    Microsoft
    Store
    Play
    Store
    Source
    Files
    

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73. Run app on your device
    npm run workbox generateSW
    https://ngrok.com/download
    ngrok http 3000
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    LAB #19
    

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74. Crunch Time
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    LAB #20
    

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75. Q&A
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    

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76. New powerful APIs regularly ship with new releases of Chromium-based
    browsers
    Some only add minor finishing touches, others enable whole application
    categories as productivity apps to finally make the shift to the web
    Some APIs already made their way into other browsers (e.g., Web Share)
    Fugu process makes sure that capabilities are implemented in a secure,
    privacy-preserving manner
    Let’s make the web a more capable platform!
    PWA Workshop
    From 0 to MS Paint with Project Fugu (Hands-on)
    Summary
    

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77. Thank you
    for your kind attention!
    Christian Liebel
    @christianliebel
    christian.liebel@thinktecture.com
    

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