My first jQuery plugin - blurStuff()

Question

I've played with jQuery for some time now but have never written my own plugin.

A question was asked: "can I blur an image using jQuery?" and I thought this to be a decent candidate to play with.

Here's my code so far:

(function ($) {
    $.fn.blurStuff = function (options) {
        var defaults = {blurRadius:2, deblurOnHover:false};
        var settings = $.extend(defaults, options);

        $(this).wrap('<div data-blurimage />');

        var blurContainers = $(this).closest('[data-blurimage]');

        blurContainers.each(function () {
            var img = $(this).children();

            $(this).css({
                'width': img.width(),
                'height': img.height(),
                'overflow': 'hidden',
                'position': 'relative'
            });

            var clone = img.clone();
            clone.css({
                'opacity': 0.2,
                'position': 'absolute'
            });

            $(this).append(clone.clone().css({'left': +settings.blurRadius, 'top': +settings.blurRadius}));
            $(this).append(clone.clone().css({'left': -settings.blurRadius, 'top': +settings.blurRadius}));
            $(this).append(clone.clone().css({'left': +settings.blurRadius, 'top': -settings.blurRadius}));
            $(this).append(clone.clone().css({'left': -settings.blurRadius, 'top': -settings.blurRadius}));
        });

        if (settings.deblurOnHover == true) {
            blurContainers.hover(function () {
                $(this).children('img:gt(0)').toggle();
            });
        }

        return blurContainers;
    };
})(jQuery);

In action: http://jsfiddle.net/gvee/xvvWj/

Example usage:

$('img').blurStuff({deblurOnHover: true, blurRadius: 2});

My working logic is to wrap the selector in a parent container and then append 4 translucent clones to this, where each clone is positioned slightly off centre.

This works pretty well so far and I'm pleased with my progress but I can conceive a couple of potential bugs that I wanted some opinions on!

1. Is my approach reasonable? I realise that I'm appending an extra 4 elements to the DOM on each call which is not ideal (I could get away with using just two, laterally or diagonally, but I think 4 produces a better effect)...
2. What to do if a user passes a fixed position element? This will break existing flow.
3. Should I bother validating/sanity checking the parameter values? If so, how should I approach this? Previously I had a parameter called blurOpacity but I removed this because I realised that the wrong values (e.g. 1) effectively "breaks" things.

Answer 1

In the code I only would modify the variable declarations:

var defaults = {blurRadius:2, deblurOnHover:false},
settings = $.extend(defaults, options),
img, blurContainers, clone;

Personal preference, but you can read a discusion about it here.

Answering your questions:

1. The efect work great. I think the approach is good, don't think that adding four elements would be a big cost.
2. You could check if the has the fixed property to avoid breaking anything.
3. By the parameters you have rigth now I shouldn't bother. If you decide to add the opacity again it would be a good idea to check it. If greater than 0.x use the default instead.

Answer 2

overall it's pretty good! But I have a few minor points:

• The constant references to $(this) are bad. That call creates a jQuery collection each time. You could just save this as a variable.

  var $this = $(this);
  $this.append(...);
  $this.append(...);
  

• You could combine your defaults and settings to save a reference;

  var settings = $.extend({
    blurRadius: 2, 
    deblurOnHover: false
  }, options);