The tutorial of Filter

The tutorial of Filter

In this tutorial, the easy filter for understanding a contents filter is created.
The filter to create creates the filter which indicates the specific keyword in contents by highlight.

Step1. The filter which applies a filter is defined.

Favorite namespace is defined and the base of a filter is defined.
Since the keyword is indicated by highlight this time, a keyword is also described together.

(function(){

	var yournamesapce = this.yournamesapce = {};
	
	yournamesapce.KeywordFilter = {

		keywords: ['ipsum', 'sapien', 'lobortis', 'leo'] //Keyword list

	}

}.call(this));

Step2. Processing when displayed on a filter is defined.

Next, the processing at the time is described that the page was displayed.
It is the processing which indicates the important keyword by highlight.

//The contents are indicated by highlight.
activate: function(content){
	var html = '',
		element = null,
		replaceKeywords = '',
		replaceContent = '',
		replaceTarget = null,
		replaceValue = '',
		isHighlight = false;

	//It changes into an element from a content object. 
	element = $(content);

	//Status is acquired from data store, and already case highlighted, it skips.
	isHighlight = element.retrieve('content:highlight');

	if (isHighlight === true){
		return;
	}

	html = element.get('html');

	//The keyword in contents is emphasized with a strong element.
	replaceKeywords = this.keywords.join('|');

	replaceTarget = new RegExp('(' + replaceKeywords + ')', 'g');
	replaceValue = '<strong class="highlight">$1</strong>';

	replaceContent = html.replace(replaceTarget, replaceValue);

	element.set('html', replaceContent)
		.store('content:html', html)		//The contents before a highlight are backed up. 
		.store('content:highlight', true);	//It uses ending with a highlight.
}

Step3. Processing when it becomes undisplayed is defined as a filter.

Next, processing when a page becomes undisplayed is described.
Although the keyword is indicated by the highlight, the processing returned to the original state here is put in.
Although I think that it is unnecessary, since it serves also as description of a filter, it incorporates and sees this time.

//It restores to a front state from the state where it has highlighted.
deactivate: function(content){

	var element = null,
		beforeContent = '',
		isHighlight = false;

	//It changes into an element from a content object. 
	element = $(content);

	isHighlight = element.retrieve('content:highlight');
	if (isHighlight !== true){
		return;
	}

	beforeContent = element.retrieve('content:html');

	element.set('html', beforeContent)
		.store('content:highlight', false);	//It cancels ending with a highlight.

}

Step4. A filter is registered.

A filter is registered using an addFilter method.
The rest performs a start method and starts a slide.

(function(yournamesapce){

this.addEvent('domready', function(){

	var p = new Presentation('presentation');

	p.addFilter(yournamesapce.KeywordFilter);

	p.displayFullScreen().start();

});

}.call(this, yournamesapce));

Step5. The code of a final filter

The code of a final filter turns into the following codes. Download of yournamesapce.keyword-filter.js

(function(yournamesapce){

	var yournamesapce = this.yournamesapce = yournamesapce;

	yournamesapce.KeywordFilter = {

		keywords: ['ipsum', 'sapien', 'lobortis', 'leo'],
	
		//The contents are indicated by highlight.
		activate: function(content){
			var html = '',
				element = null,
				replaceKeywords = '',
				replaceContent = '',
				replaceTarget = null,
				replaceValue = '',
				isHighlight = false;
	
			//It changes into an element from a content object. 
			element = $(content);
	
			//Status is acquired from data store, and already case highlighted, it skips.
			isHighlight = element.retrieve('content:highlight');
	
			if (isHighlight === true){
				return;
			}

			html = element.get('html');

			//The keyword in contents is emphasized with a strong element.
			replaceKeywords = this.keywords.join('|');
	
			replaceTarget = new RegExp('(' + replaceKeywords + ')', 'g');
			replaceValue = '<strong class="highlight">$1</strong>';

			replaceContent = html.replace(replaceTarget, replaceValue);
	
			element.set('html', replaceContent)
				.store('content:html', html)		//The contents before a highlight are backed up. 
				.store('content:highlight', true);	//It uses ending with a highlight.
		},

		//It restores to a front state from the state where it has highlighted.
		deactivate: function(content){
	
			var element = null,
				beforeContent = '',
				isHighlight = false;
	
			//It changes into an element from a content object. 
			element = $(content);
	
			isHighlight = element.retrieve('content:highlight');
			if (isHighlight !== true){
				return;
			}
	
			beforeContent = element.retrieve('content:html');
	
			element.set('html', beforeContent)
				.store('content:highlight', false);	//It cancels ending with a highlight.
	
		}

	}

}.call(this, this.yournamesapce || {}));

The tutorial of a filter is an end now.
Thank you for everything.