This document provides a roadmap for Jcrop implementation.
Jcrop is a powerful image cropping engine for jQuery.
It's been designed so developers can easily integrate an advanced image cropping functionality directly into any web-based application without sacrificing power and flexibility (or the weeks of coding, testing and debugging). Jcrop also features clean, well-organized code that works well across most modern web browsers.
Here you'll find the documentation for Jcrop itself. This guide assumes that you have a basic knowledge of HTML and including files into a web page. At the end of the article, there are links to more advanced concepts and implementation techniques.
In the page <head> you'll need to load the requisite files. That includes:
It should look something like this:
<script src="js/jquery.min.js"></script> <script src="js/jquery.Jcrop.min.js"></script> <link rel="stylesheet" href="css/jquery.Jcrop.css" type="text/css" />
Please note: These are only example paths, you probably will need to adjust them when you actually use them, to match the location of the files on your server. Jcrop will not function properly if you don't.
Let's suppose we have this image our markup:
<img src="flowers.jpg" id="target" />
To convert this into a Jcrop widget, insert the following script:
Jcrop's default behavior is activated. Since there are no event handlers attached, it won't do anything cool, but you can see how easy it is to implement Jcrop into your page.
Jcrop's two primary event handlers are onChange and onSelect.
|onSelect||callback||Called when selection is completed|
|onChange||callback||Called when the selection is moving|
Jcrop has a sense of state, whether there is an active selection or not. To detect when the interface is released, there is also a handler for these events:
|onRelease||callback||Called when the selection is released|
Define an event handler function:
Attach event handlers like this:
This is a conventional jQuery syntax. Note that the last property does not have a comma following (also applies if there is only one property specified). Also be sure to leave off parenthesis on callback functions (you're referring to the named function, not calling it).
Jcrop options allow you to alter appearance and behavior.
|Option Name||Value Type||Description||Default|
|aspectRatio||decimal||Aspect ratio of w/h (e.g. 1 for square)||n/a|
|minSize||array [ w, h ]||Minimum width/height, use 0 for unbounded dimension||n/a|
|maxSize||array [ w, h ]||Maximum width/height, use 0 for unbounded dimension||n/a|
|setSelect||array [ x, y, x2, y2 ]||Set an initial selection area||n/a|
|bgColor||color value||Set color of background container||'black'|
|bgOpacity||decimal 0 - 1||Opacity of outer image when cropping||.6|
Set these options in the same way as event handlers.
Here's an example:
Note a few things about the format of the options object: