* SUMMARY *

jQuery Resize And Crop (jrac) is a jQuery plugin that build a viewport around a
given image permitting to visually resize an image and place a crop. Then it is
possible to use the coordinates data to be used for any purpose.


* DEMO *

http://www.trepmag.ch/z/jrac/example/


* FEATURES *

- Resize and move image
- Resize and move crop
- Resize viewport
- Aims to be integrated with any server side image processor


* INSTRUCTIONS *

The 'jrac' method implement the whole business which can take an optional 
setting object argument:

  $('img').jrac();

The default setting object is the following:

  var settings = {
    'crop_width': 200,
    'crop_height': 100,
    // The two following properties define the crop position (relative to the 
    // image).
    'crop_x': 0,
    'crop_y': 0,
    'crop_resize': true,
    'image_width': null,
    'image_height': null,
    'zoom_min': 100,
    'zoom_max': 3000,
    'viewport_image_surrounding': false, // Set the viewport to surround the image on load
    'viewport_width': null,
    'viewport_height': null,
    'viewport_resize': true,
    // The two following properties allow to position the content (negative 
    // value allowed). It can be use to focus the viewport on the cropped 
    // part of the image. 
    'viewport_content_x': 0,
    'viewport_content_y': 0,
    // Submit here a callback function (context is the viewport), see below.
    'viewport_onload': null
  };

The 'viewport_onload' property can take an function callback which interface is:

  function() // which the context is $viewport

The $viewport context is a div jQuery wrapped element that surround the target
image. This object get the following subsequent properties:

  - $viewport.$container: a container holding the viewport and the zoom widget.
  - $viewport.$image: the target image jQuery wrapped.
  - $viewport.$crop: the crop object.
  - $viewport.observator: an object which process all events of the viewport.

The main method of the $viewport.observator is 'register' which register an
element for an event:

  $viewport.observator.register(String event_name, jQuery wrapped elements[, callback onevent_callback])

To unregister an event use:

  $viewport.observator.unregister(string event_name)

The observator events are the following which you can then trigger some actions 
on with the jQuery bind method or by giving a function to the onvevent_callback 
argument:

  jrac_crop_x
  jrac_crop_y
  jrac_crop_width
  jrac_crop_height
  jrac_image_width
  jrac_image_height

Example:

  $('img').jrac({'viewport_onload', function() {
    var $viewport = this;
    $viewport.register('jrac_crop_x', $('input#cropx'), function(event_name, element, value) {
      element.val(value);
    }
  }

There is also an event 'jrac_events' which is triggered on every events of
the previous decribed viewport observator. Use the jQuery bind methode to act on
it.

Destroy jrac (not much tested) is done by running jrac with the 'destroy' argument:

  $('img').jrac('destroy');


* REQUIEREMENTS *

jrac use jQuery and jQuery-UI.

- Developped with jQuery 1.6.1 and jQuery-UI 1.8.13
- Tested with jQuery 1.4.4 and jQuery-UI 1.8.7


* ACKNOWLEDGEMENT *

- The jrac/images/loading.gif image file come from http://www.ajaxload.info/.
- The picture used in the example is provided (perhaps) by courtesy of Loulou 
from Sos-Chats Geneve http://www.sos-chats.ch/.
- Syntax Highlighting in JavaScript (SHJS) used for the display of the code in 
the example, http://shjs.sourceforge.net/.


* DOWNLOAD *

https://github.com/trepmag/jrac