Lawrence  Lesch

Lawrence Lesch

1664370906

JavaScript, SCSS Helpers for Rendering High-resolution Image Variants

retina.js

JavaScript, Sass, Less, and Stylus helpers for rendering high-resolution image variants

retina.js makes it easy to serve high-resolution images to devices with displays that support them. You can prepare images for as many levels of pixel density as you want and let retina.js dynamically serve the right image to the user.

How it works

There are 4 ways to use retina.js:

  1. Automatically swapping out src paths on img tags.
  2. Automatically swapping out background image URLs in inline styles.
  3. Manually specifying the location of a high-res image variant (works for src attributes and inline styles).
  4. Automatically creating media queries for CSS background images.

Img Tags

retina.js assumes you are using Apple's prescribed high-resolution modifiers (@2x, @3x, etc) to denote high-res image variants on your server. It also assumes that if you have prepared a variant for a given high-res environment, that you have also prepared variants for each environment below it. For example, if you have prepared 3x variants, retina.js will assume that you have also prepared 2x variants.

With this in mind, you'll specify your highest environment level with the data-rjs attribute and let retina.js take it from there.

Let's say you have an image on your page that looks like this:

<img src="/images/my_image.png" data-rjs="3" />

In this case, we've set our resolution cap at "3", denoting that we've prepared 3x and 2x image variants. When the page loads, retina.js will check the actual resolution of the device environment to decide whether it should really serve up a 3x image. If the user happens to be in a 2x environment, retina.js will serve up the 2x image instead, assuming it will find the image at /images/my_image@2x.png.

If the environment does have 3x capabilities, retina.js will serve up the 3x image. It will expect that url to be /images/my_image@3x.png. If the environment has the ability to display images at higher densities than 3x, retina.js will serve up the image of the highest resolution that you've provided, in this case 3x.

Inline Styles

Previous versions of retina.js were unable to target background images set via inline styles. Now, if you apply a data-rjs attribute to any kind of element other than an img, the script will target inline background images instead of src attributes.

So if you created an element like this:

<div style="background: url(/images/my_image.png)" data-rjs="3"></div>

retina.js would convert it to something like this:

<div style="background: url(/images/my_image@3x.png)" data-rjs="3"></div>

The logic behind image swapping is exactly the same when dealing with background images as it is when dealing with src attributes. If the user's environment only supports 2x variants, retina.js will load the 2x variant instead of the 3x.

Note that it is up to you in a case like this to correctly apply background sizing and any other necessary background-related styles to the element. retina.js will not affect these.

Manually Specifying a High-Res URL

In previous versions, you could tell the script where to find your high-res file by using the data-at2x attribute. Now, if you pass a URL to the data-rjs attribute, retina.js will use the image at the path you specify for all high-resolution environments instead of trying to dynamically serve an auto-suffixed image path based on the environment's capabilities. This will work for both src attributes on img tags and inline background images on all other tags.

For example, you might write something like this:

<img
  src="/images/my_image.png"
  data-rjs="/images/2x/my-image.png" />

<!-- or -->

<div
  style="background: url(/images/my_image.png)"
  data-rjs="/images/2x/my-image.png">
</div>

If the user then loads the page in any kind of high-resolution environment, they'll get the following:

<img
  src="/images/2x/my-image.png"
  data-rjs="/images/2x/my-image.png" />

<!-- or -->

<div
  style="background: url(/images/2x/my-image.png)"
  data-rjs="/images/2x/my-image.png">
</div>

Media Queries

retina.js comes with mixins for SCSS, Sass, Less, and Stylus. These mixins work similarly to the JavaScript version in that they will dynamically serve images for as many high-res environments as you've prepared image variants for. Previously, these mixins were named "at2x" but because they now serve images for multiple environments, they have been renamed "retina".

In each language, the retina mixin allows 4 parameters:

  1. path - The path to your standard resolution image.
  2. cap - Optional. The highest resolution level for which you have prepared images. Defaults to 2.
  3. size- Optional. A value to be applied to the background-size property. Defaults to auto auto.
  4. extras- Optional. Any other values to be added to the background property. Defaults to nothing.

Here is an example wherein we are specifying that we have prepared images for both 2x and 3x environments:

SCSS

#item {
  @include retina('/images/my_image.png', 3, cover, center center no-repeat);
}

Sass

#item
  +retina('/images/my_image.png', 3, cover, center center no-repeat)

Less

#item {
  .retina('/images/my_image.png', 3, cover, center center no-repeat);
}

Stylus

#item
  retina('/images/my_image.png', 3, cover, center center no-repeat)

Regardless of the dialect, the output is effectively the same:

#item {
  background: url("/images/my_image.png") center center no-repeat;
  background-size: cover;
}

@media all and (-webkit-min-device-pixel-ratio: 1.5),
       all and (-o-min-device-pixel-ratio: 3 / 2),
       all and (min--moz-device-pixel-ratio: 1.5),
       all and (min-device-pixel-ratio: 1.5) {
  #item {
    background: url("/images/my_image@2x.png") center center no-repeat;
    background-size: cover;
  }
}

@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
  #item {
    background: url("/images/my_image@2x.png") center center no-repeat;
    background-size: cover;
  }
}

@media (-webkit-min-device-pixel-ratio: 3), (min-resolution: 288dpi) {
  #item {
    background: url("/images/my_image@3x.png") center center no-repeat;
    background-size: cover;
  }
}

Compatibility

retina.js is compatible with all modern browsers and should not throw errors in old browsers all the way back through IE6.

Installing & Launching

JavaScript

There are 2 ways to use the JavaScript version of retina.js:

  1. The old-school way (manually dropping the script into an html file).
  2. The new-school way (importing it into a larger JavaScript build process).

Old-School

To use retina.js the old-school way, download retina.min.js and put it on your server. Then, include the script in your html file at the bottom of your template, before your closing </body> tag.

<script type="text/javascript" src="/scripts/retina.min.js"></script>

Using this technique, retina.js will run automatically on page load. It will also create a globally available function called retinajs. Whenever you'd like to manually re-initialize the script, simply call window.retinajs().

If you don't pass any arguments to the retinajs function, it will only attempt to process images that have not previously been processed by the script. Optionally, you can pass a collection of HTML elements to the script, in which case it will only attempt to process elements in that collection, specifically the ones that have not been processed before. Your collection may take the form of an Array, NodeList, or jQuery selection.

retinajs();
// Finds all images not previously processed and processes them.

retinajs( [img, img, img] );
// Only attempts to process the images in the collection.

retinajs( $('img') );
// Same.

retinajs( document.querySelectorAll('img') );
// Same.

New-School

To use retina.js the new-school way, you'll want to require it (or import it if you're using ES6) into your Gulp/Webpack/Grunt/CommonJS/etc application. In this case, the script won't run automatically. Instead, it'll let you determine when you'd like it to run.

import retina from 'retina';

window.addEventListener('load', retina);

Notice that the retina function can be called as often as you need in order to re-initialize the image swapping.

If you don't pass any arguments to the retina function, it will only attempt to process images that have not previously been processed by the script. Optionally, you can pass a collection of HTML elements to the script, in which case it will only attempt to process elements in that collection, specifically the ones that have not been processed before. Your collection may take the form of an Array, NodeList, or jQuery selection.

retina();
// Finds all images not previously processed and processes them.

retina( [img, img, img] );
// Only attempts to process the images in the collection.

retina( $('img') );
// Same.

retina( document.querySelectorAll('img') );
// Same.

CSS Preprocessors

The process for including the CSS mixins is relatively straightforward. Here is a breakdown for each:

SCSS

Add the @mixin retina( ... ) mixin from _retina.scss to your SCSS stylesheet (or reference it in an @import). In your stylesheet, call the mixin using @include retina( ... ) anywhere instead of using background or background-image.

Sass

Add the =retina( ... ) mixin from _retina.sass to your Sass stylesheet (or reference it in an @import). In your stylesheet, call the mixin using +retina( ... ) anywhere instead of using background or background-image.

Less

Add the .retina( ... ) mixin from retina.less to your Less stylesheet (or reference it in an @import). In your stylesheet, call the mixin using .retina( ... ) anywhere instead of using background or background-image.

Stylus

Add the retina( ... ) mixin from retina.styl to your Stylus stylesheet (or reference it in an @import). In your stylesheet, call the mixin using retina( ... ) anywhere instead of using background or background-image.

Considerations for Ruby on Rails 3+

...or any framework that embeds some digest/hash to the asset URLs based on the contents, e.g. /images/image-{hash1}.jpg.

The problem with this is that the high-resolution version would have a different hash, and would not conform to the usual pattern, i.e. /images/image@2x-{hash2}.jpg. So automatic detection would fail because retina.js would check the existence of /images/image-{hash1}@2x.jpg.

There's no way for retina.js to know beforehand what the high-resolution image's hash would be without some sort of help from the server side. So in this case, there are a couple of options for handling it:

Bypass Digesting

One potential method is to bypass digesting altogether by implementing a process like team-umlaut's asset compile rake file which will generate non-digested asset files as necessary.

Use Manual Paths

Although it's not quite as fancy as dynamically serving up files based on the resolution of the user's environment, this may be a good time to pass a URL string to the data-rjs attribute so that you can manually tell retina.js exactly where to look for a high-resolution variant of your image.

Download Details:

Author: Strues
Source Code: https://github.com/strues/retinajs 
License: MIT license

#javascript #scss #sass #image 

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JavaScript, SCSS Helpers for Rendering High-resolution Image Variants
Queenie  Davis

Queenie Davis

1653123600

EasyMDE: Simple, Beautiful and Embeddable JavaScript Markdown Editor

EasyMDE - Markdown Editor 

This repository is a fork of SimpleMDE, made by Sparksuite. Go to the dedicated section for more information.

A drop-in JavaScript text area replacement for writing beautiful and understandable Markdown. EasyMDE allows users who may be less experienced with Markdown to use familiar toolbar buttons and shortcuts.

In addition, the syntax is rendered while editing to clearly show the expected result. Headings are larger, emphasized words are italicized, links are underlined, etc.

EasyMDE also features both built-in auto saving and spell checking. The editor is entirely customizable, from theming to toolbar buttons and javascript hooks.

Try the demo

Preview

Quick access

Install EasyMDE

Via npm:

npm install easymde

Via the UNPKG CDN:

<link rel="stylesheet" href="https://unpkg.com/easymde/dist/easymde.min.css">
<script src="https://unpkg.com/easymde/dist/easymde.min.js"></script>

Or jsDelivr:

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/easymde/dist/easymde.min.css">
<script src="https://cdn.jsdelivr.net/npm/easymde/dist/easymde.min.js"></script>

How to use

Loading the editor

After installing and/or importing the module, you can load EasyMDE onto the first textarea element on the web page:

<textarea></textarea>
<script>
const easyMDE = new EasyMDE();
</script>

Alternatively you can select a specific textarea, via JavaScript:

<textarea id="my-text-area"></textarea>
<script>
const easyMDE = new EasyMDE({element: document.getElementById('my-text-area')});
</script>

Editor functions

Use easyMDE.value() to get the content of the editor:

<script>
easyMDE.value();
</script>

Use easyMDE.value(val) to set the content of the editor:

<script>
easyMDE.value('New input for **EasyMDE**');
</script>

Configuration

Options list

  • autoDownloadFontAwesome: If set to true, force downloads Font Awesome (used for icons). If set to false, prevents downloading. Defaults to undefined, which will intelligently check whether Font Awesome has already been included, then download accordingly.
  • autofocus: If set to true, focuses the editor automatically. Defaults to false.
  • autosave: Saves the text that's being written and will load it back in the future. It will forget the text when the form it's contained in is submitted.
    • enabled: If set to true, saves the text automatically. Defaults to false.
    • delay: Delay between saves, in milliseconds. Defaults to 10000 (10 seconds).
    • submit_delay: Delay before assuming that submit of the form failed and saving the text, in milliseconds. Defaults to autosave.delay or 10000 (10 seconds).
    • uniqueId: You must set a unique string identifier so that EasyMDE can autosave. Something that separates this from other instances of EasyMDE elsewhere on your website.
    • timeFormat: Set DateTimeFormat. More information see DateTimeFormat instances. Default locale: en-US, format: hour:minute.
    • text: Set text for autosave.
  • autoRefresh: Useful, when initializing the editor in a hidden DOM node. If set to { delay: 300 }, it will check every 300 ms if the editor is visible and if positive, call CodeMirror's refresh().
  • blockStyles: Customize how certain buttons that style blocks of text behave.
    • bold: Can be set to ** or __. Defaults to **.
    • code: Can be set to ``` or ~~~. Defaults to ```.
    • italic: Can be set to * or _. Defaults to *.
  • unorderedListStyle: can be *, - or +. Defaults to *.
  • scrollbarStyle: Chooses a scrollbar implementation. The default is "native", showing native scrollbars. The core library also provides the "null" style, which completely hides the scrollbars. Addons can implement additional scrollbar models.
  • element: The DOM element for the textarea element to use. Defaults to the first textarea element on the page.
  • forceSync: If set to true, force text changes made in EasyMDE to be immediately stored in original text area. Defaults to false.
  • hideIcons: An array of icon names to hide. Can be used to hide specific icons shown by default without completely customizing the toolbar.
  • indentWithTabs: If set to false, indent using spaces instead of tabs. Defaults to true.
  • initialValue: If set, will customize the initial value of the editor.
  • previewImagesInEditor: - EasyMDE will show preview of images, false by default, preview for images will appear only for images on separate lines.
  • imagesPreviewHandler: - A custom function for handling the preview of images. Takes the parsed string between the parantheses of the image markdown ![]( ) as argument and returns a string that serves as the src attribute of the <img> tag in the preview. Enables dynamic previewing of images in the frontend without having to upload them to a server, allows copy-pasting of images to the editor with preview.
  • insertTexts: Customize how certain buttons that insert text behave. Takes an array with two elements. The first element will be the text inserted before the cursor or highlight, and the second element will be inserted after. For example, this is the default link value: ["[", "](http://)"].
    • horizontalRule
    • image
    • link
    • table
  • lineNumbers: If set to true, enables line numbers in the editor.
  • lineWrapping: If set to false, disable line wrapping. Defaults to true.
  • minHeight: Sets the minimum height for the composition area, before it starts auto-growing. Should be a string containing a valid CSS value like "500px". Defaults to "300px".
  • maxHeight: Sets fixed height for the composition area. minHeight option will be ignored. Should be a string containing a valid CSS value like "500px". Defaults to undefined.
  • onToggleFullScreen: A function that gets called when the editor's full screen mode is toggled. The function will be passed a boolean as parameter, true when the editor is currently going into full screen mode, or false.
  • parsingConfig: Adjust settings for parsing the Markdown during editing (not previewing).
    • allowAtxHeaderWithoutSpace: If set to true, will render headers without a space after the #. Defaults to false.
    • strikethrough: If set to false, will not process GFM strikethrough syntax. Defaults to true.
    • underscoresBreakWords: If set to true, let underscores be a delimiter for separating words. Defaults to false.
  • overlayMode: Pass a custom codemirror overlay mode to parse and style the Markdown during editing.
    • mode: A codemirror mode object.
    • combine: If set to false, will replace CSS classes returned by the default Markdown mode. Otherwise the classes returned by the custom mode will be combined with the classes returned by the default mode. Defaults to true.
  • placeholder: If set, displays a custom placeholder message.
  • previewClass: A string or array of strings that will be applied to the preview screen when activated. Defaults to "editor-preview".
  • previewRender: Custom function for parsing the plaintext Markdown and returning HTML. Used when user previews.
  • promptURLs: If set to true, a JS alert window appears asking for the link or image URL. Defaults to false.
  • promptTexts: Customize the text used to prompt for URLs.
    • image: The text to use when prompting for an image's URL. Defaults to URL of the image:.
    • link: The text to use when prompting for a link's URL. Defaults to URL for the link:.
  • uploadImage: If set to true, enables the image upload functionality, which can be triggered by drag and drop, copy-paste and through the browse-file window (opened when the user click on the upload-image icon). Defaults to false.
  • imageMaxSize: Maximum image size in bytes, checked before upload (note: never trust client, always check the image size at server-side). Defaults to 1024 * 1024 * 2 (2 MB).
  • imageAccept: A comma-separated list of mime-types used to check image type before upload (note: never trust client, always check file types at server-side). Defaults to image/png, image/jpeg.
  • imageUploadFunction: A custom function for handling the image upload. Using this function will render the options imageMaxSize, imageAccept, imageUploadEndpoint and imageCSRFToken ineffective.
    • The function gets a file and onSuccess and onError callback functions as parameters. onSuccess(imageUrl: string) and onError(errorMessage: string)
  • imageUploadEndpoint: The endpoint where the images data will be sent, via an asynchronous POST request. The server is supposed to save this image, and return a JSON response.
    • if the request was successfully processed (HTTP 200 OK): {"data": {"filePath": "<filePath>"}} where filePath is the path of the image (absolute if imagePathAbsolute is set to true, relative if otherwise);
    • otherwise: {"error": "<errorCode>"}, where errorCode can be noFileGiven (HTTP 400 Bad Request), typeNotAllowed (HTTP 415 Unsupported Media Type), fileTooLarge (HTTP 413 Payload Too Large) or importError (see errorMessages below). If errorCode is not one of the errorMessages, it is alerted unchanged to the user. This allows for server-side error messages. No default value.
  • imagePathAbsolute: If set to true, will treat imageUrl from imageUploadFunction and filePath returned from imageUploadEndpoint as an absolute rather than relative path, i.e. not prepend window.location.origin to it.
  • imageCSRFToken: CSRF token to include with AJAX call to upload image. For various instances like Django, Spring and Laravel.
  • imageCSRFName: CSRF token filed name to include with AJAX call to upload image, applied when imageCSRFToken has value, defaults to csrfmiddlewaretoken.
  • imageCSRFHeader: If set to true, passing CSRF token via header. Defaults to false, which pass CSRF through request body.
  • imageTexts: Texts displayed to the user (mainly on the status bar) for the import image feature, where #image_name#, #image_size# and #image_max_size# will replaced by their respective values, that can be used for customization or internationalization:
    • sbInit: Status message displayed initially if uploadImage is set to true. Defaults to Attach files by drag and dropping or pasting from clipboard..
    • sbOnDragEnter: Status message displayed when the user drags a file to the text area. Defaults to Drop image to upload it..
    • sbOnDrop: Status message displayed when the user drops a file in the text area. Defaults to Uploading images #images_names#.
    • sbProgress: Status message displayed to show uploading progress. Defaults to Uploading #file_name#: #progress#%.
    • sbOnUploaded: Status message displayed when the image has been uploaded. Defaults to Uploaded #image_name#.
    • sizeUnits: A comma-separated list of units used to display messages with human-readable file sizes. Defaults to B, KB, MB (example: 218 KB). You can use B,KB,MB instead if you prefer without whitespaces (218KB).
  • errorMessages: Errors displayed to the user, using the errorCallback option, where #image_name#, #image_size# and #image_max_size# will replaced by their respective values, that can be used for customization or internationalization:
    • noFileGiven: The server did not receive any file from the user. Defaults to You must select a file..
    • typeNotAllowed: The user send a file type which doesn't match the imageAccept list, or the server returned this error code. Defaults to This image type is not allowed..
    • fileTooLarge: The size of the image being imported is bigger than the imageMaxSize, or if the server returned this error code. Defaults to Image #image_name# is too big (#image_size#).\nMaximum file size is #image_max_size#..
    • importError: An unexpected error occurred when uploading the image. Defaults to Something went wrong when uploading the image #image_name#..
  • errorCallback: A callback function used to define how to display an error message. Defaults to (errorMessage) => alert(errorMessage).
  • renderingConfig: Adjust settings for parsing the Markdown during previewing (not editing).
    • codeSyntaxHighlighting: If set to true, will highlight using highlight.js. Defaults to false. To use this feature you must include highlight.js on your page or pass in using the hljs option. For example, include the script and the CSS files like:
      <script src="https://cdn.jsdelivr.net/highlight.js/latest/highlight.min.js"></script>
      <link rel="stylesheet" href="https://cdn.jsdelivr.net/highlight.js/latest/styles/github.min.css">
    • hljs: An injectible instance of highlight.js. If you don't want to rely on the global namespace (window.hljs), you can provide an instance here. Defaults to undefined.
    • markedOptions: Set the internal Markdown renderer's options. Other renderingConfig options will take precedence.
    • singleLineBreaks: If set to false, disable parsing GitHub Flavored Markdown (GFM) single line breaks. Defaults to true.
    • sanitizerFunction: Custom function for sanitizing the HTML output of Markdown renderer.
  • shortcuts: Keyboard shortcuts associated with this instance. Defaults to the array of shortcuts.
  • showIcons: An array of icon names to show. Can be used to show specific icons hidden by default without completely customizing the toolbar.
  • spellChecker: If set to false, disable the spell checker. Defaults to true. Optionally pass a CodeMirrorSpellChecker-compliant function.
  • inputStyle: textarea or contenteditable. Defaults to textarea for desktop and contenteditable for mobile. contenteditable option is necessary to enable nativeSpellcheck.
  • nativeSpellcheck: If set to false, disable native spell checker. Defaults to true.
  • sideBySideFullscreen: If set to false, allows side-by-side editing without going into fullscreen. Defaults to true.
  • status: If set to false, hide the status bar. Defaults to the array of built-in status bar items.
    • Optionally, you can set an array of status bar items to include, and in what order. You can even define your own custom status bar items.
  • styleSelectedText: If set to false, remove the CodeMirror-selectedtext class from selected lines. Defaults to true.
  • syncSideBySidePreviewScroll: If set to false, disable syncing scroll in side by side mode. Defaults to true.
  • tabSize: If set, customize the tab size. Defaults to 2.
  • theme: Override the theme. Defaults to easymde.
  • toolbar: If set to false, hide the toolbar. Defaults to the array of icons.
  • toolbarTips: If set to false, disable toolbar button tips. Defaults to true.
  • direction: rtl or ltr. Changes text direction to support right-to-left languages. Defaults to ltr.

Options example

Most options demonstrate the non-default behavior:

const editor = new EasyMDE({
    autofocus: true,
    autosave: {
        enabled: true,
        uniqueId: "MyUniqueID",
        delay: 1000,
        submit_delay: 5000,
        timeFormat: {
            locale: 'en-US',
            format: {
                year: 'numeric',
                month: 'long',
                day: '2-digit',
                hour: '2-digit',
                minute: '2-digit',
            },
        },
        text: "Autosaved: "
    },
    blockStyles: {
        bold: "__",
        italic: "_",
    },
    unorderedListStyle: "-",
    element: document.getElementById("MyID"),
    forceSync: true,
    hideIcons: ["guide", "heading"],
    indentWithTabs: false,
    initialValue: "Hello world!",
    insertTexts: {
        horizontalRule: ["", "\n\n-----\n\n"],
        image: ["![](http://", ")"],
        link: ["[", "](https://)"],
        table: ["", "\n\n| Column 1 | Column 2 | Column 3 |\n| -------- | -------- | -------- |\n| Text     | Text      | Text     |\n\n"],
    },
    lineWrapping: false,
    minHeight: "500px",
    parsingConfig: {
        allowAtxHeaderWithoutSpace: true,
        strikethrough: false,
        underscoresBreakWords: true,
    },
    placeholder: "Type here...",

    previewClass: "my-custom-styling",
    previewClass: ["my-custom-styling", "more-custom-styling"],

    previewRender: (plainText) => customMarkdownParser(plainText), // Returns HTML from a custom parser
    previewRender: (plainText, preview) => { // Async method
        setTimeout(() => {
            preview.innerHTML = customMarkdownParser(plainText);
        }, 250);

        return "Loading...";
    },
    promptURLs: true,
    promptTexts: {
        image: "Custom prompt for URL:",
        link: "Custom prompt for URL:",
    },
    renderingConfig: {
        singleLineBreaks: false,
        codeSyntaxHighlighting: true,
        sanitizerFunction: (renderedHTML) => {
            // Using DOMPurify and only allowing <b> tags
            return DOMPurify.sanitize(renderedHTML, {ALLOWED_TAGS: ['b']})
        },
    },
    shortcuts: {
        drawTable: "Cmd-Alt-T"
    },
    showIcons: ["code", "table"],
    spellChecker: false,
    status: false,
    status: ["autosave", "lines", "words", "cursor"], // Optional usage
    status: ["autosave", "lines", "words", "cursor", {
        className: "keystrokes",
        defaultValue: (el) => {
            el.setAttribute('data-keystrokes', 0);
        },
        onUpdate: (el) => {
            const keystrokes = Number(el.getAttribute('data-keystrokes')) + 1;
            el.innerHTML = `${keystrokes} Keystrokes`;
            el.setAttribute('data-keystrokes', keystrokes);
        },
    }], // Another optional usage, with a custom status bar item that counts keystrokes
    styleSelectedText: false,
    sideBySideFullscreen: false,
    syncSideBySidePreviewScroll: false,
    tabSize: 4,
    toolbar: false,
    toolbarTips: false,
});

Toolbar icons

Below are the built-in toolbar icons (only some of which are enabled by default), which can be reorganized however you like. "Name" is the name of the icon, referenced in the JavaScript. "Action" is either a function or a URL to open. "Class" is the class given to the icon. "Tooltip" is the small tooltip that appears via the title="" attribute. Note that shortcut hints are added automatically and reflect the specified action if it has a key bind assigned to it (i.e. with the value of action set to bold and that of tooltip set to Bold, the final text the user will see would be "Bold (Ctrl-B)").

Additionally, you can add a separator between any icons by adding "|" to the toolbar array.

NameActionTooltip
Class
boldtoggleBoldBold
fa fa-bold
italictoggleItalicItalic
fa fa-italic
strikethroughtoggleStrikethroughStrikethrough
fa fa-strikethrough
headingtoggleHeadingSmallerHeading
fa fa-header
heading-smallertoggleHeadingSmallerSmaller Heading
fa fa-header
heading-biggertoggleHeadingBiggerBigger Heading
fa fa-lg fa-header
heading-1toggleHeading1Big Heading
fa fa-header header-1
heading-2toggleHeading2Medium Heading
fa fa-header header-2
heading-3toggleHeading3Small Heading
fa fa-header header-3
codetoggleCodeBlockCode
fa fa-code
quotetoggleBlockquoteQuote
fa fa-quote-left
unordered-listtoggleUnorderedListGeneric List
fa fa-list-ul
ordered-listtoggleOrderedListNumbered List
fa fa-list-ol
clean-blockcleanBlockClean block
fa fa-eraser
linkdrawLinkCreate Link
fa fa-link
imagedrawImageInsert Image
fa fa-picture-o
tabledrawTableInsert Table
fa fa-table
horizontal-ruledrawHorizontalRuleInsert Horizontal Line
fa fa-minus
previewtogglePreviewToggle Preview
fa fa-eye no-disable
side-by-sidetoggleSideBySideToggle Side by Side
fa fa-columns no-disable no-mobile
fullscreentoggleFullScreenToggle Fullscreen
fa fa-arrows-alt no-disable no-mobile
guideThis linkMarkdown Guide
fa fa-question-circle
undoundoUndo
fa fa-undo
redoredoRedo
fa fa-redo

Toolbar customization

Customize the toolbar using the toolbar option.

Only the order of existing buttons:

const easyMDE = new EasyMDE({
    toolbar: ["bold", "italic", "heading", "|", "quote"]
});

All information and/or add your own icons

const easyMDE = new EasyMDE({
    toolbar: [
        {
            name: "bold",
            action: EasyMDE.toggleBold,
            className: "fa fa-bold",
            title: "Bold",
        },
        "italics", // shortcut to pre-made button
        {
            name: "custom",
            action: (editor) => {
                // Add your own code
            },
            className: "fa fa-star",
            title: "Custom Button",
            attributes: { // for custom attributes
                id: "custom-id",
                "data-value": "custom value" // HTML5 data-* attributes need to be enclosed in quotation marks ("") because of the dash (-) in its name.
            }
        },
        "|" // Separator
        // [, ...]
    ]
});

Put some buttons on dropdown menu

const easyMDE = new EasyMDE({
    toolbar: [{
                name: "heading",
                action: EasyMDE.toggleHeadingSmaller,
                className: "fa fa-header",
                title: "Headers",
            },
            "|",
            {
                name: "others",
                className: "fa fa-blind",
                title: "others buttons",
                children: [
                    {
                        name: "image",
                        action: EasyMDE.drawImage,
                        className: "fa fa-picture-o",
                        title: "Image",
                    },
                    {
                        name: "quote",
                        action: EasyMDE.toggleBlockquote,
                        className: "fa fa-percent",
                        title: "Quote",
                    },
                    {
                        name: "link",
                        action: EasyMDE.drawLink,
                        className: "fa fa-link",
                        title: "Link",
                    }
                ]
            },
        // [, ...]
    ]
});

Keyboard shortcuts

EasyMDE comes with an array of predefined keyboard shortcuts, but they can be altered with a configuration option. The list of default ones is as follows:

Shortcut (Windows / Linux)Shortcut (macOS)Action
Ctrl-'Cmd-'"toggleBlockquote"
Ctrl-BCmd-B"toggleBold"
Ctrl-ECmd-E"cleanBlock"
Ctrl-HCmd-H"toggleHeadingSmaller"
Ctrl-ICmd-I"toggleItalic"
Ctrl-KCmd-K"drawLink"
Ctrl-LCmd-L"toggleUnorderedList"
Ctrl-PCmd-P"togglePreview"
Ctrl-Alt-CCmd-Alt-C"toggleCodeBlock"
Ctrl-Alt-ICmd-Alt-I"drawImage"
Ctrl-Alt-LCmd-Alt-L"toggleOrderedList"
Shift-Ctrl-HShift-Cmd-H"toggleHeadingBigger"
F9F9"toggleSideBySide"
F11F11"toggleFullScreen"

Here is how you can change a few, while leaving others untouched:

const editor = new EasyMDE({
    shortcuts: {
        "toggleOrderedList": "Ctrl-Alt-K", // alter the shortcut for toggleOrderedList
        "toggleCodeBlock": null, // unbind Ctrl-Alt-C
        "drawTable": "Cmd-Alt-T", // bind Cmd-Alt-T to drawTable action, which doesn't come with a default shortcut
    }
});

Shortcuts are automatically converted between platforms. If you define a shortcut as "Cmd-B", on PC that shortcut will be changed to "Ctrl-B". Conversely, a shortcut defined as "Ctrl-B" will become "Cmd-B" for Mac users.

The list of actions that can be bound is the same as the list of built-in actions available for toolbar buttons.

Advanced use

Event handling

You can catch the following list of events: https://codemirror.net/doc/manual.html#events

const easyMDE = new EasyMDE();
easyMDE.codemirror.on("change", () => {
    console.log(easyMDE.value());
});

Removing EasyMDE from text area

You can revert to the initial text area by calling the toTextArea method. Note that this clears up the autosave (if enabled) associated with it. The text area will retain any text from the destroyed EasyMDE instance.

const easyMDE = new EasyMDE();
// ...
easyMDE.toTextArea();
easyMDE = null;

If you need to remove registered event listeners (when the editor is not needed anymore), call easyMDE.cleanup().

Useful methods

The following self-explanatory methods may be of use while developing with EasyMDE.

const easyMDE = new EasyMDE();
easyMDE.isPreviewActive(); // returns boolean
easyMDE.isSideBySideActive(); // returns boolean
easyMDE.isFullscreenActive(); // returns boolean
easyMDE.clearAutosavedValue(); // no returned value

How it works

EasyMDE is a continuation of SimpleMDE.

SimpleMDE began as an improvement of lepture's Editor project, but has now taken on an identity of its own. It is bundled with CodeMirror and depends on Font Awesome.

CodeMirror is the backbone of the project and parses much of the Markdown syntax as it's being written. This allows us to add styles to the Markdown that's being written. Additionally, a toolbar and status bar have been added to the top and bottom, respectively. Previews are rendered by Marked using GitHub Flavored Markdown (GFM).

SimpleMDE fork

I originally made this fork to implement FontAwesome 5 compatibility into SimpleMDE. When that was done I submitted a pull request, which has not been accepted yet. This, and the project being inactive since May 2017, triggered me to make more changes and try to put new life into the project.

Changes include:

  • FontAwesome 5 compatibility
  • Guide button works when editor is in preview mode
  • Links are now https:// by default
  • Small styling changes
  • Support for Node 8 and beyond
  • Lots of refactored code
  • Links in preview will open in a new tab by default
  • TypeScript support

My intention is to continue development on this project, improving it and keeping it alive.

Hacking EasyMDE

You may want to edit this library to adapt its behavior to your needs. This can be done in some quick steps:

  1. Follow the prerequisites and installation instructions in the contribution guide;
  2. Do your changes;
  3. Run gulp command, which will generate files: dist/easymde.min.css and dist/easymde.min.js;
  4. Copy-paste those files to your code base, and you are done.

Contributing

Want to contribute to EasyMDE? Thank you! We have a contribution guide just for you!


Author: Ionaru
Source Code: https://github.com/Ionaru/easy-markdown-editor
License: MIT license

#react-native #react 

Lawrence  Lesch

Lawrence Lesch

1664370906

JavaScript, SCSS Helpers for Rendering High-resolution Image Variants

retina.js

JavaScript, Sass, Less, and Stylus helpers for rendering high-resolution image variants

retina.js makes it easy to serve high-resolution images to devices with displays that support them. You can prepare images for as many levels of pixel density as you want and let retina.js dynamically serve the right image to the user.

How it works

There are 4 ways to use retina.js:

  1. Automatically swapping out src paths on img tags.
  2. Automatically swapping out background image URLs in inline styles.
  3. Manually specifying the location of a high-res image variant (works for src attributes and inline styles).
  4. Automatically creating media queries for CSS background images.

Img Tags

retina.js assumes you are using Apple's prescribed high-resolution modifiers (@2x, @3x, etc) to denote high-res image variants on your server. It also assumes that if you have prepared a variant for a given high-res environment, that you have also prepared variants for each environment below it. For example, if you have prepared 3x variants, retina.js will assume that you have also prepared 2x variants.

With this in mind, you'll specify your highest environment level with the data-rjs attribute and let retina.js take it from there.

Let's say you have an image on your page that looks like this:

<img src="/images/my_image.png" data-rjs="3" />

In this case, we've set our resolution cap at "3", denoting that we've prepared 3x and 2x image variants. When the page loads, retina.js will check the actual resolution of the device environment to decide whether it should really serve up a 3x image. If the user happens to be in a 2x environment, retina.js will serve up the 2x image instead, assuming it will find the image at /images/my_image@2x.png.

If the environment does have 3x capabilities, retina.js will serve up the 3x image. It will expect that url to be /images/my_image@3x.png. If the environment has the ability to display images at higher densities than 3x, retina.js will serve up the image of the highest resolution that you've provided, in this case 3x.

Inline Styles

Previous versions of retina.js were unable to target background images set via inline styles. Now, if you apply a data-rjs attribute to any kind of element other than an img, the script will target inline background images instead of src attributes.

So if you created an element like this:

<div style="background: url(/images/my_image.png)" data-rjs="3"></div>

retina.js would convert it to something like this:

<div style="background: url(/images/my_image@3x.png)" data-rjs="3"></div>

The logic behind image swapping is exactly the same when dealing with background images as it is when dealing with src attributes. If the user's environment only supports 2x variants, retina.js will load the 2x variant instead of the 3x.

Note that it is up to you in a case like this to correctly apply background sizing and any other necessary background-related styles to the element. retina.js will not affect these.

Manually Specifying a High-Res URL

In previous versions, you could tell the script where to find your high-res file by using the data-at2x attribute. Now, if you pass a URL to the data-rjs attribute, retina.js will use the image at the path you specify for all high-resolution environments instead of trying to dynamically serve an auto-suffixed image path based on the environment's capabilities. This will work for both src attributes on img tags and inline background images on all other tags.

For example, you might write something like this:

<img
  src="/images/my_image.png"
  data-rjs="/images/2x/my-image.png" />

<!-- or -->

<div
  style="background: url(/images/my_image.png)"
  data-rjs="/images/2x/my-image.png">
</div>

If the user then loads the page in any kind of high-resolution environment, they'll get the following:

<img
  src="/images/2x/my-image.png"
  data-rjs="/images/2x/my-image.png" />

<!-- or -->

<div
  style="background: url(/images/2x/my-image.png)"
  data-rjs="/images/2x/my-image.png">
</div>

Media Queries

retina.js comes with mixins for SCSS, Sass, Less, and Stylus. These mixins work similarly to the JavaScript version in that they will dynamically serve images for as many high-res environments as you've prepared image variants for. Previously, these mixins were named "at2x" but because they now serve images for multiple environments, they have been renamed "retina".

In each language, the retina mixin allows 4 parameters:

  1. path - The path to your standard resolution image.
  2. cap - Optional. The highest resolution level for which you have prepared images. Defaults to 2.
  3. size- Optional. A value to be applied to the background-size property. Defaults to auto auto.
  4. extras- Optional. Any other values to be added to the background property. Defaults to nothing.

Here is an example wherein we are specifying that we have prepared images for both 2x and 3x environments:

SCSS

#item {
  @include retina('/images/my_image.png', 3, cover, center center no-repeat);
}

Sass

#item
  +retina('/images/my_image.png', 3, cover, center center no-repeat)

Less

#item {
  .retina('/images/my_image.png', 3, cover, center center no-repeat);
}

Stylus

#item
  retina('/images/my_image.png', 3, cover, center center no-repeat)

Regardless of the dialect, the output is effectively the same:

#item {
  background: url("/images/my_image.png") center center no-repeat;
  background-size: cover;
}

@media all and (-webkit-min-device-pixel-ratio: 1.5),
       all and (-o-min-device-pixel-ratio: 3 / 2),
       all and (min--moz-device-pixel-ratio: 1.5),
       all and (min-device-pixel-ratio: 1.5) {
  #item {
    background: url("/images/my_image@2x.png") center center no-repeat;
    background-size: cover;
  }
}

@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
  #item {
    background: url("/images/my_image@2x.png") center center no-repeat;
    background-size: cover;
  }
}

@media (-webkit-min-device-pixel-ratio: 3), (min-resolution: 288dpi) {
  #item {
    background: url("/images/my_image@3x.png") center center no-repeat;
    background-size: cover;
  }
}

Compatibility

retina.js is compatible with all modern browsers and should not throw errors in old browsers all the way back through IE6.

Installing & Launching

JavaScript

There are 2 ways to use the JavaScript version of retina.js:

  1. The old-school way (manually dropping the script into an html file).
  2. The new-school way (importing it into a larger JavaScript build process).

Old-School

To use retina.js the old-school way, download retina.min.js and put it on your server. Then, include the script in your html file at the bottom of your template, before your closing </body> tag.

<script type="text/javascript" src="/scripts/retina.min.js"></script>

Using this technique, retina.js will run automatically on page load. It will also create a globally available function called retinajs. Whenever you'd like to manually re-initialize the script, simply call window.retinajs().

If you don't pass any arguments to the retinajs function, it will only attempt to process images that have not previously been processed by the script. Optionally, you can pass a collection of HTML elements to the script, in which case it will only attempt to process elements in that collection, specifically the ones that have not been processed before. Your collection may take the form of an Array, NodeList, or jQuery selection.

retinajs();
// Finds all images not previously processed and processes them.

retinajs( [img, img, img] );
// Only attempts to process the images in the collection.

retinajs( $('img') );
// Same.

retinajs( document.querySelectorAll('img') );
// Same.

New-School

To use retina.js the new-school way, you'll want to require it (or import it if you're using ES6) into your Gulp/Webpack/Grunt/CommonJS/etc application. In this case, the script won't run automatically. Instead, it'll let you determine when you'd like it to run.

import retina from 'retina';

window.addEventListener('load', retina);

Notice that the retina function can be called as often as you need in order to re-initialize the image swapping.

If you don't pass any arguments to the retina function, it will only attempt to process images that have not previously been processed by the script. Optionally, you can pass a collection of HTML elements to the script, in which case it will only attempt to process elements in that collection, specifically the ones that have not been processed before. Your collection may take the form of an Array, NodeList, or jQuery selection.

retina();
// Finds all images not previously processed and processes them.

retina( [img, img, img] );
// Only attempts to process the images in the collection.

retina( $('img') );
// Same.

retina( document.querySelectorAll('img') );
// Same.

CSS Preprocessors

The process for including the CSS mixins is relatively straightforward. Here is a breakdown for each:

SCSS

Add the @mixin retina( ... ) mixin from _retina.scss to your SCSS stylesheet (or reference it in an @import). In your stylesheet, call the mixin using @include retina( ... ) anywhere instead of using background or background-image.

Sass

Add the =retina( ... ) mixin from _retina.sass to your Sass stylesheet (or reference it in an @import). In your stylesheet, call the mixin using +retina( ... ) anywhere instead of using background or background-image.

Less

Add the .retina( ... ) mixin from retina.less to your Less stylesheet (or reference it in an @import). In your stylesheet, call the mixin using .retina( ... ) anywhere instead of using background or background-image.

Stylus

Add the retina( ... ) mixin from retina.styl to your Stylus stylesheet (or reference it in an @import). In your stylesheet, call the mixin using retina( ... ) anywhere instead of using background or background-image.

Considerations for Ruby on Rails 3+

...or any framework that embeds some digest/hash to the asset URLs based on the contents, e.g. /images/image-{hash1}.jpg.

The problem with this is that the high-resolution version would have a different hash, and would not conform to the usual pattern, i.e. /images/image@2x-{hash2}.jpg. So automatic detection would fail because retina.js would check the existence of /images/image-{hash1}@2x.jpg.

There's no way for retina.js to know beforehand what the high-resolution image's hash would be without some sort of help from the server side. So in this case, there are a couple of options for handling it:

Bypass Digesting

One potential method is to bypass digesting altogether by implementing a process like team-umlaut's asset compile rake file which will generate non-digested asset files as necessary.

Use Manual Paths

Although it's not quite as fancy as dynamically serving up files based on the resolution of the user's environment, this may be a good time to pass a URL string to the data-rjs attribute so that you can manually tell retina.js exactly where to look for a high-resolution variant of your image.

Download Details:

Author: Strues
Source Code: https://github.com/strues/retinajs 
License: MIT license

#javascript #scss #sass #image 

Toby Rogers

Toby Rogers

1665991784

Drag and Drop File Upload with HTML, CSS and JavaScript

In this tutorial, you'll learn how to create a drag-and-drop file upload with HTML, CSS and JavaScript.

HTML:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Drag & Drop File Upload</title>
    <!-- Font Awesome Icons -->
    <link
      rel="stylesheet"
      href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.2.0/css/all.min.css"
    />
    <!-- Google Font -->
    <link
      href="https://fonts.googleapis.com/css2?family=Poppins&display=swap"
      rel="stylesheet"
    />
    <!-- Stylesheet -->
    <link rel="stylesheet" href="style.css" />
  </head>
  <body>
    <div class="container">
      <input type="file" id="upload-button" multiple accept="image/*" />
      <label for="upload-button"
        ><i class="fa-solid fa-upload"></i>&nbsp; Choose Or Drop Photos
      </label>
      <div id="error"></div>
      <div id="image-display"></div>
    </div>
    <!-- Script -->
    <script src="script.js"></script>
  </body>
</html>

CSS:

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
  font-family: "Poppins", sans-serif;
}
body {
  background-color: #f5f8ff;
}
.container {
  background-color: #ffffff;
  width: 60%;
  min-width: 37.5em;
  padding: 3.12em 1.87em;
  position: absolute;
  transform: translateX(-50%);
  left: 50%;
  top: 1em;
  box-shadow: 0 1.25em 3.43em rgba(0, 0, 0, 0.08);
  border-radius: 0.5em;
}
input[type="file"] {
  display: none;
}
label {
  display: block;
  position: relative;
  background-color: #025bee;
  color: #ffffff;
  font-size: 1.1em;
  text-align: center;
  width: 16em;
  padding: 1em 0;
  border-radius: 0.3em;
  margin: 0 auto 1em auto;
  cursor: pointer;
}
#image-display {
  position: relative;
  width: 90%;
  margin: 0 auto;
  display: flex;
  justify-content: space-evenly;
  gap: 1.25em;
  flex-wrap: wrap;
}
#image-display figure {
  width: 45%;
}
#image-display img {
  width: 100%;
}
#image-display figcaption {
  font-size: 0.8em;
  text-align: center;
  color: #5a5861;
}
.active {
  border: 0.2em dashed #025bee;
}
#error {
  text-align: center;
  color: #ff3030;
}

Javascript:

let uploadButton = document.getElementById("upload-button");
let chosenImage = document.getElementById("chosen-image");
let fileName = document.getElementById("file-name");
let container = document.querySelector(".container");
let error = document.getElementById("error");
let imageDisplay = document.getElementById("image-display");

const fileHandler = (file, name, type) => {
  if (type.split("/")[0] !== "image") {
    //File Type Error
    error.innerText = "Please upload an image file";
    return false;
  }
  error.innerText = "";
  let reader = new FileReader();
  reader.readAsDataURL(file);
  reader.onloadend = () => {
    //image and file name
    let imageContainer = document.createElement("figure");
    let img = document.createElement("img");
    img.src = reader.result;
    imageContainer.appendChild(img);
    imageContainer.innerHTML += `<figcaption>${name}</figcaption>`;
    imageDisplay.appendChild(imageContainer);
  };
};

//Upload Button
uploadButton.addEventListener("change", () => {
  imageDisplay.innerHTML = "";
  Array.from(uploadButton.files).forEach((file) => {
    fileHandler(file, file.name, file.type);
  });
});

container.addEventListener(
  "dragenter",
  (e) => {
    e.preventDefault();
    e.stopPropagation();
    container.classList.add("active");
  },
  false
);

container.addEventListener(
  "dragleave",
  (e) => {
    e.preventDefault();
    e.stopPropagation();
    container.classList.remove("active");
  },
  false
);

container.addEventListener(
  "dragover",
  (e) => {
    e.preventDefault();
    e.stopPropagation();
    container.classList.add("active");
  },
  false
);

container.addEventListener(
  "drop",
  (e) => {
    e.preventDefault();
    e.stopPropagation();
    container.classList.remove("active");
    let draggedData = e.dataTransfer;
    let files = draggedData.files;
    imageDisplay.innerHTML = "";
    Array.from(files).forEach((file) => {
      fileHandler(file, file.name, file.type);
    });
  },
  false
);

window.onload = () => {
  error.innerText = "";
};

Related Videos

Simple Drag and Drop File Upload Tutorial - HTML, CSS & JavaScript

Drag & Drop or Browse - File Upload Tutorial using HTML CSS and JavaScript

Drag & Drop or Browse - File upload Feature using HTML CSS & JavaScript

#html #css #javascript

Beth  Cooper

Beth Cooper

1659694200

Easy Activity Tracking for Models, Similar to Github's Public Activity

PublicActivity

public_activity provides easy activity tracking for your ActiveRecord, Mongoid 3 and MongoMapper models in Rails 3 and 4.

Simply put: it can record what happens in your application and gives you the ability to present those recorded activities to users - in a similar way to how GitHub does it.

!! WARNING: README for unreleased version below. !!

You probably don't want to read the docs for this unreleased version 2.0.

For the stable 1.5.X readme see: https://github.com/chaps-io/public_activity/blob/1-5-stable/README.md

About

Here is a simple example showing what this gem is about:

Example usage

Tutorials

Screencast

Ryan Bates made a great screencast describing how to integrate Public Activity.

Tutorial

A great step-by-step guide on implementing activity feeds using public_activity by Ilya Bodrov.

Online demo

You can see an actual application using this gem here: http://public-activity-example.herokuapp.com/feed

The source code of the demo is hosted here: https://github.com/pokonski/activity_blog

Setup

Gem installation

You can install public_activity as you would any other gem:

gem install public_activity

or in your Gemfile:

gem 'public_activity'

Database setup

By default public_activity uses Active Record. If you want to use Mongoid or MongoMapper as your backend, create an initializer file in your Rails application with the corresponding code inside:

For Mongoid:

# config/initializers/public_activity.rb
PublicActivity.configure do |config|
  config.orm = :mongoid
end

For MongoMapper:

# config/initializers/public_activity.rb
PublicActivity.configure do |config|
  config.orm = :mongo_mapper
end

(ActiveRecord only) Create migration for activities and migrate the database (in your Rails project):

rails g public_activity:migration
rake db:migrate

Model configuration

Include PublicActivity::Model and add tracked to the model you want to keep track of:

For ActiveRecord:

class Article < ActiveRecord::Base
  include PublicActivity::Model
  tracked
end

For Mongoid:

class Article
  include Mongoid::Document
  include PublicActivity::Model
  tracked
end

For MongoMapper:

class Article
  include MongoMapper::Document
  include PublicActivity::Model
  tracked
end

And now, by default create/update/destroy activities are recorded in activities table. This is all you need to start recording activities for basic CRUD actions.

Optional: If you don't need #tracked but still want the comfort of #create_activity, you can include only the lightweight Common module instead of Model.

Custom activities

You can trigger custom activities by setting all your required parameters and triggering create_activity on the tracked model, like this:

@article.create_activity key: 'article.commented_on', owner: current_user

See this entry http://rubydoc.info/gems/public_activity/PublicActivity/Common:create_activity for more details.

Displaying activities

To display them you simply query the PublicActivity::Activity model:

# notifications_controller.rb
def index
  @activities = PublicActivity::Activity.all
end

And in your views:

<%= render_activities(@activities) %>

Note: render_activities is an alias for render_activity and does the same.

Layouts

You can also pass options to both activity#render and #render_activity methods, which are passed deeper to the internally used render_partial method. A useful example would be to render activities wrapped in layout, which shares common elements of an activity, like a timestamp, owner's avatar etc:

<%= render_activities(@activities, layout: :activity) %>

The activity will be wrapped with the app/views/layouts/_activity.html.erb layout, in the above example.

Important: please note that layouts for activities are also partials. Hence the _ prefix.

Locals

Sometimes, it's desirable to pass additional local variables to partials. It can be done this way:

<%= render_activity(@activity, locals: {friends: current_user.friends}) %>

Note: Before 1.4.0, one could pass variables directly to the options hash for #render_activity and access it from activity parameters. This functionality is retained in 1.4.0 and later, but the :locals method is preferred, since it prevents bugs from shadowing variables from activity parameters in the database.

Activity views

public_activity looks for views in app/views/public_activity.

For example, if you have an activity with :key set to "activity.user.changed_avatar", the gem will look for a partial in app/views/public_activity/user/_changed_avatar.html.(|erb|haml|slim|something_else).

Hint: the "activity." prefix in :key is completely optional and kept for backwards compatibility, you can skip it in new projects.

If you would like to fallback to a partial, you can utilize the fallback parameter to specify the path of a partial to use when one is missing:

<%= render_activity(@activity, fallback: 'default') %>

When used in this manner, if a partial with the specified :key cannot be located it will use the partial defined in the fallback instead. In the example above this would resolve to public_activity/_default.html.(|erb|haml|slim|something_else).

If a view file does not exist then ActionView::MisingTemplate will be raised. If you wish to fallback to the old behaviour and use an i18n based translation in this situation you can specify a :fallback parameter of text to fallback to this mechanism like such:

<%= render_activity(@activity, fallback: :text) %>

i18n

Translations are used by the #text method, to which you can pass additional options in form of a hash. #render method uses translations when view templates have not been provided. You can render pure i18n strings by passing {display: :i18n} to #render_activity or #render.

Translations should be put in your locale .yml files. To render pure strings from I18n Example structure:

activity:
  article:
    create: 'Article has been created'
    update: 'Someone has edited the article'
    destroy: 'Some user removed an article!'

This structure is valid for activities with keys "activity.article.create" or "article.create". As mentioned before, "activity." part of the key is optional.

Testing

For RSpec you can first disable public_activity and add require helper methods in the rails_helper.rb with:

#rails_helper.rb
require 'public_activity/testing'

PublicActivity.enabled = false

In your specs you can then blockwise decide whether to turn public_activity on or off.

# file_spec.rb
PublicActivity.with_tracking do
  # your test code goes here
end

PublicActivity.without_tracking do
  # your test code goes here
end

Documentation

For more documentation go here

Common examples

Set the Activity's owner to current_user by default

You can set up a default value for :owner by doing this:

  1. Include PublicActivity::StoreController in your ApplicationController like this:
class ApplicationController < ActionController::Base
  include PublicActivity::StoreController
end
  1. Use Proc in :owner attribute for tracked class method in your desired model. For example:
class Article < ActiveRecord::Base
  tracked owner: Proc.new{ |controller, model| controller.current_user }
end

Note: current_user applies to Devise, if you are using a different authentication gem or your own code, change the current_user to a method you use.

Disable tracking for a class or globally

If you need to disable tracking temporarily, for example in tests or db/seeds.rb then you can use PublicActivity.enabled= attribute like below:

# Disable p_a globally
PublicActivity.enabled = false

# Perform some operations that would normally be tracked by p_a:
Article.create(title: 'New article')

# Switch it back on
PublicActivity.enabled = true

You can also disable public_activity for a specific class:

# Disable p_a for Article class
Article.public_activity_off

# p_a will not do anything here:
@article = Article.create(title: 'New article')

# But will be enabled for other classes:
# (creation of the comment will be recorded if you are tracking the Comment class)
@article.comments.create(body: 'some comment!')

# Enable it again for Article:
Article.public_activity_on

Create custom activities

Besides standard, automatic activities created on CRUD actions on your model (deactivatable), you can post your own activities that can be triggered without modifying the tracked model. There are a few ways to do this, as PublicActivity gives three tiers of options to be set.

Instant options

Because every activity needs a key (otherwise: NoKeyProvided is raised), the shortest and minimal way to post an activity is:

@user.create_activity :mood_changed
# the key of the action will be user.mood_changed
@user.create_activity action: :mood_changed # this is exactly the same as above

Besides assigning your key (which is obvious from the code), it will take global options from User class (given in #tracked method during class definition) and overwrite them with instance options (set on @user by #activity method). You can read more about options and how PublicActivity inherits them for you here.

Note the action parameter builds the key like this: "#{model_name}.#{action}". You can read further on options for #create_activity here.

To provide more options, you can do:

@user.create_activity action: 'poke', parameters: {reason: 'bored'}, recipient: @friend, owner: current_user

In this example, we have provided all the things we could for a standard Activity.

Use custom fields on Activity

Besides the few fields that every Activity has (key, owner, recipient, trackable, parameters), you can also set custom fields. This could be very beneficial, as parameters are a serialized hash, which cannot be queried easily from the database. That being said, use custom fields when you know that you will set them very often and search by them (don't forget database indexes :) ).

Set owner and recipient based on associations

class Comment < ActiveRecord::Base
  include PublicActivity::Model
  tracked owner: :commenter, recipient: :commentee

  belongs_to :commenter, :class_name => "User"
  belongs_to :commentee, :class_name => "User"
end

Resolve parameters from a Symbol or Proc

class Post < ActiveRecord::Base
  include PublicActivity::Model
  tracked only: [:update], parameters: :tracked_values
  
  def tracked_values
   {}.tap do |hash|
     hash[:tags] = tags if tags_changed?
   end
  end
end

Setup

Skip this step if you are using ActiveRecord in Rails 4 or Mongoid

The first step is similar in every ORM available (except mongoid):

PublicActivity::Activity.class_eval do
  attr_accessible :custom_field
end

place this code under config/initializers/public_activity.rb, you have to create it first.

To be able to assign to that field, we need to move it to the mass assignment sanitizer's whitelist.

Migration

If you're using ActiveRecord, you will also need to provide a migration to add the actual field to the Activity. Taken from our tests:

class AddCustomFieldToActivities < ActiveRecord::Migration
  def change
    change_table :activities do |t|
      t.string :custom_field
    end
  end
end

Assigning custom fields

Assigning is done by the same methods that you use for normal parameters: #tracked, #create_activity. You can just pass the name of your custom variable and assign its value. Even better, you can pass it to #tracked to tell us how to harvest your data for custom fields so we can do that for you.

class Article < ActiveRecord::Base
  include PublicActivity::Model
  tracked custom_field: proc {|controller, model| controller.some_helper }
end

Help

If you need help with using public_activity please visit our discussion group and ask a question there:

https://groups.google.com/forum/?fromgroups#!forum/public-activity

Please do not ask general questions in the Github Issues.


Author: public-activity
Source code: https://github.com/public-activity/public_activity
License: MIT license

#ruby  #ruby-on-rails 

Rahul Jangid

1622207074

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