contao-leaflet-libraries/assets/leaflet-loading/README.md

Leaflet.loading
===============

Leaflet.loading is a simple loading control for [Leaflet][]. An unobtrusive
loading indicator is added below the zoom control if one exists. The indicator
is visible when tiles are loading or when other data is loading, as indicated by
firing custom events on a map. The indicator can be an image, or a [spin.js][] 
spinner (image-less).


## Usage

Leaflet.loading is only tested on Leaflet version 0.6 or greater. It will almost
certainly not work with older versions of Leaflet.

Include `Control.Loading.js` and `Control.Loading.css`, then create a map with 
`loadingControl: true` in its options. 

By default, Leaflet.loading includes a base64-encoded animagted loading image in 
`Control.Loading.css`. You can customize this by changing `background-image` for
the selector `.leaflet-control-loading`. The simplest case would be adding a 16
x 16 loading gif in `.leaflet-control-loading`.

You can also set `spinjs: true` in the options, and load [spin.js][] to use that
instead of an image. A spin.js options object can be passed as the spin key when
initializing the control.

Whichever method you use, make sure you only use one.

Once the above is complete you will have a loading indicator that only appears
when tiles are loading. 

If you want to show the loading indicator while other AJAX requests or something
else is occurring, simply fire the `dataloading` event on your map when you 
begin loading and `dataload` when you are finished loading. The control tracks 
the number of concurrent loaders, so it is your responsibility to ensure that 
the `dataloading` and `dataload` are called symmetrically.

### Options

 - **position**: (string) Where you want the control to show up on the map (standard
   Leaflet control option). Optional, defaults to `topleft`
 - **separate**: (boolean) Whether the control should be separate from the zoom
   control or not, defaults to false.
 - **zoomControl**: (L.Control.Zoom) The zoom control that the control should be
   added to. This is only necessary when adding a loading control to a zoom 
   control that you added manually and do not want a separate loading control.
 - **spinjs**: (boolean) Enable the use of [spin.js][]. Optional, defaults to 
   `false`
 - **spin**: (object) A [spin.js][] options object. Optional, defaults to 

    ```
    { 
        lines: 7,
        length: 3,
        width: 3,
        radius: 5,
        rotate: 13,
        top: "83%" 
    }
    ```


## Demos

See Leaflet.loading in action (zoom or pan to make tiles load):

 - Using the [simplest setup][simple], with the loading indicator attached to
   the zoom control.
 - With the loading indicator [separate][] from the zoom control.
 - With the loading indicator and zoom control on the [top right][topright] of
   the map.
 - The [simplest example using spin.js](http://ebrelsford.github.io/Leaflet.loading/spinjs.html) instead of an image
 - Combined with a [fullscreen control][combined] (e.g. [https://github.com/brunob/leaflet.fullscreen]).


## License

Leaflet.loading is free software, and may be redistributed under the MIT
License.


 [Leaflet]: https://github.com/Leaflet/Leaflet
 [spin.js]: https://github.com/fgnass/spin.js/
 [simple]: http://ebrelsford.github.io/Leaflet.loading/simple.html
 [separate]: http://ebrelsford.github.io/Leaflet.loading/separate.html
 [topright]: http://ebrelsford.github.io/Leaflet.loading/topright.html
 [combined]: http://ebrelsford.github.io/Leaflet.loading/combined.html