ng-imago

An AngularJS module to manage images responsiveness and sequential loading.

Module License: MIT

Added by: Sam Deering

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panurge-ws/ng-imago

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Panurge-ws
Panurge-ws

Module Description

Ng-Imago


Ng-Imago is a module for AngularJS that aims to be a comprehensive library for managing images into your project.

Currently it's focused on:

  1. Multi resolutions sources (responsive images)
  2. Sequential loading (automatic or manual)
  3. Auto-resize to parent (contain / cover)

Requirements


Install


Download the production version or the development version.

HTML: import the script in your HTML

<script src="[path_to_library]/ng-imago.min.js"></script>

Javascript: inject the module in Angular

var app = angular.module('app', ['ngImago']);

Here you can also configure the default values. See below (Configuration).

HOW TO USE


1. Multi resolutions sources


Use ng-imago to load images according to a given resolution (or media query), exactly as you usually do with Media queries inside CSS.

In your HTML, insert a img tag and add the ng-imago directive. You can choose two alternative methods:

  1. Attributes: set attibutes for each resolution you want to support, passing inside the attribute the url of the image:
<img ng-imago      
     default="default.jpg" 
     small="small.jpg"
     medium="medium.jpg"  
     large="large.jpg"
     xlarge="xlarge.jpg"  />
  1. A properties object: set the attibute "sources" with a JSON object with size and image path(s):
<img ng-imago
     sources="{'default':'default.jpg', 'medium':'medium.jpg'}" />

Each attribute/property checks for a corrispettive media query value (e.g.: 'medium' checks for 'only screen and (min-width: 768px)'. If the query matches, it will load the image's url within the attribute.

For the default values of each attribute, please see below (Defaults).

If "sources" object is defined, attributes values will be ignored.

You can override the value of each attribute for a single image, or you can override them globally. Furthermore, you can also add your customized attributes.

Attention: you can't set the "src" attribute using Ng-Imago, otherwise, the sequential loading won't work properly.

Pixel density support (Retina)

If you want to support different pixel densities, you can simply set two urls (comma separated) in the attribute: if one of them has the "@2x" suffix in the name, Ng-Imago will load it in screens with pixel density > 1.

<img ng-imago
     medium="medium.jpg,medium@2x.jpg"  />
<img ng-imago
     sources="{'medium':'medium.jpg,medium@2x.jpg'}"  />

Orientation support

(Still in test) If you set an attibute with a "-portrait" suffix, Ng-Imago will load that source if:

  1. the resolution matches the attribute (medium => (min-width: 768px) and
  2. if the device orientation is portrait
<img ng-imago  
     medium="medium.jpg"  
     medium-portrait="medium-portrait.jpg"  />

Angular templates

You can naturally use the AngularJS templates style to set the attibute's value. Those values are bindable, at least until the image is loaded. (See the default settings unbind_when_loaded below for further details).

<img ng-imago  
     medium="{{url_medium}}"  
     large="{{url_large}}"  />
<img ng-imago
     sources="{{my_sources_object}}"  />

Overriding single image

If you want that an image follows its own rules, you can pass to the ng-imago attribute an object of overriding values either for sizes or for settings.

<img ng-imago="{ small:'only screen and (min-width:320px)', loaded_class:'my-loaded-class' }"
     small="{{url_small}}-override-loaded-when-min-width-is-320px" 
     medium="{{url_medium}}" 
     large="{{url_large}}" 
     xlarge="{{url_xlarge}}"  />
     
Or, if you use a directive tag, insert the values inside an "override" attribute:

<ng-imago override="{ small:'only screen and (min-width:320px)', loaded_class:'my-loaded-class' }"
     small="{{url_small}}-override-loaded-when-min-width-is-320px" 
     medium="{{url_medium}}" 
     large="{{url_large}}" 
     xlarge="{{url_xlarge}}"></ng-imago>  
             

Using with other tags or with ng-imago tag

You can use the directive ng-imago also in elements that aren't "img" tags, as "div", "span", etc... In few words, all the elements that accept a background-image style. The module will load an Image object and then it will pass the url to the background-image CSS style. You can also use the ng-imago directive as a tag.

<div            style="width:500px;height:200px;overflow:hidden;"
     ng-imago
     auto-load="false"
     medium="medium.jpg"
     class="div_to_load"
     imago-resize="{scale:'contain', center:false}">
 </div>
 <ng-imago     style="width:500px;height:200px;overflow:hidden;"
     auto-load="false"
     medium="medium.jpg"
     class="div_to_load"
     imago-resize="{scale:'cover', center:true}">
 </ng-imago>

Are you wondering why? "Can't we use simply the CSS?" Yes, you can, but you can't control sequential loading...

2. Sequential loading


(Complete documentation coming soon)

Automatic queueing (AKA The "queue-index" attribute )

The queue-index attribute helps you to load images sequentially. It creates a queue of images based on the attribute's value. If you set an attribute (queue-index="1"), the images with that attributes will be loaded after all the other images with no queue attribute (or with "queue-index=0") have been loaded. And so on... Attention: to start the loading sequence, you must insert at least a queue-index="0" image (or omit the attribute).

<img  ng-imago 
      queue-index="1"
      default="delayed-default.jpg" 
      medium="delayed-medium.jpg" />

Manual queueing / loading

You can set an attribute (auto-load="false") which prevents the image to be immediately loaded. You can load it later, as you need, with some methods.

<img  ng-imago 
      auto-load="false" 
      id="img_111" 
      load-group="group1"
      queue-index="1234"
      class="myImageClass"
      default="delayed-default.jpg" 
      medium="delayed-medium.jpg" />

You can use Javascript methods provided in the service called 'ngImagoService', injecting the service in your controller or directive. You can load the image above with the following methods.

// load images with attibutes and values
ngImagoService.loadByAttribute("load-group", "group1");

// load the images with a specified class
ngImagoService.loadByClass("myImageClass");

// load an image by id
ngImagoService.loadImageById('img_111');

// load imags by queue-index (if auto-load="false")
ngImagoService.loadQueueIndex(1234);

// changing the auto-load to true
var img = document.getElementById('img_111');
angular.element(img).attr('auto-load',"true");
// or exactly equivalent
//angular.element(img).isolateScope().load();

Manual load + automatic queue? Yes.

You can mix the two methods setting auto-load=false and queue-index. If you have a series of images with auto-load="false" and several queue-index values, at the time you will load that group, it will be loaded sequentially. E.g.:

<img  ng-imago id="img_0"
      auto-load="false"  
      load-group="group1"
      queue-index="0" 
      medium="delayed-medium0.jpg" />
<img  ng-imago id="img_1"
      auto-load="false"  
      load-group="group1"
      queue-index="2" 
      medium="delayed-medium1.jpg" />
<img  ng-imago id="img_2"
      auto-load="false"  
      load-group="group1"
      queue-index="2" 
      medium="delayed-medium2.jpg" />
ngImagoService.loadByAttribute("load-group", "group1");

It will load the three images but #img_1 and #img_2 will be loaded after #img_0 has been completely loaded.

As a final note, notice that you don't need to set stricly subsequent indeces (1,2,3...). You can set queue-index="3" and queue-index="123": "123" indeces will be loaded after "3", if there are no intermediate indeces...

Events

Ng-Imago dispatches some events related to loading actions via the $rootScope.


// all the images in queue are loaded
$rootScope.$on("$ngImagoLoadQueueComplete", function(event, data){

});
// when a single image is loaded
$rootScope.$on("$ngImagoImageLoaded", function(event, data, element){

});

// when a queue-index group is loaded
$rootScope.$on("$ngImagoQueueIndexComplete", function(event, index, data, element){

});

3. Auto resize


You can set an attibute "imago-resize" with self-explanatory object values.

<div style="width:500px;height:300px">
  <img ng-imago 
       medium="{{url_medium}}"
       imago-resize="{scale:'cover', center:true}" />
</div>

Ng-Imago will resize the image to the image's parent. You can set an additional param 'container':'window' if you want to scale it to the window's dimensions.

Configuration


(Complete documentation coming soon)

var app = angular.module('app', ['ngImago']).config(["ngImagoProvider",
    // configuring defaults option and sizez
    function(ngImagoProvider) {
        // see the defaults settings and sizes
        // used with no value, the following functions are getter
        var myDefaultSettings = ngImagoProvider.defaultsSettings();
        var myDefaultSizes = ngImagoProvider.defaultsSizes();
        // you can use these functions as a setter passing an object with your customized defaults
        // E.g.:
        ngImagoProvider.defaultsSettings({avoid_cache:false, loaded_class:'my-loaded-class'});
        
        // you can add a custom size attribute with custom media query
        ngImagoProvider.addDefaultSize('custom', 'only screen and (min-width:400px)');
        // or change a default
        ngImagoProvider.changeDefaultSize('small', 'only screen and (min-width:400px)');
        // or remove it (even it doesn't make a lot of sense... you can simply avoid using it)
        ngImagoProvider.removeDefaultSize('small', 'only screen and (min-width:400px)');
    }
]);

Default values


Default sizes

'default' => 'only screen and (min-width: 1px)'
'small'   => 'only screen and (min-width: 480px)'
'medium'  => 'only screen and (min-width: 768px)'
'large'   => 'only screen and (min-width: 1280px)'
'xlarge'  => 'only screen and (min-width: 1440px)'

Default settings

(Complete documentation coming soon)

// Appends a random string to the URL to force reload
avoid_cache: true,
// Removes the bindings of the attributes when the images is loaded for performance reasons
unbind_when_loaded: true,
// The name of the class added to the image when loaded
loaded_class: "ng-imago-loaded",
// The name of the class added to the image while it's loading
loading_class: "ng-imago-loading",
// The name of the class added to the image when an error has occurred
error_class: "ng-imago-error",
// set the loading/loaded/error class also on parent (if exists)
parent_classes: true

// auto-size
// Scale mode
scale: 'contain', // [contain | cover]
// Center the image
center: true, // center inside the container
// The container type to scale and/or center the image
container: 'parent' // ["parent" | "window"]

This project is currently in beta version. Use it at your own risk.


Contributors


Reporting issues is much appreciated. Please, wait some other days before pulling requests.

Thanks.

License

Copyright (c) 2014 Panurge Web Studio
Licensed under the MIT license.

Module stats last updated: 2015-06-04 11:08:46

Disclaimer: Some data on this page may have been gathered from the authors GitHub respository. If you see any mistakes or outdated information please let us know. Thanks!