# Usage of Pager component

This tutorial will cover installation and usage examples.

## Installation

    composer require "knplabs/knp-components:~1.2"

## Basic usage

As mentioned in [introduction](https://github.com/knplabs/knp-components/tree/master/doc/pager/intro.md)
paginator uses event listeners to paginate the given data. First we will start from the simplest data - array.
Lets add some code in **index.php** and see it in action:

``` php
<?php
// file: index.php
include 'autoloader.php';

// usage examples will continue here

use Knp\Component\Pager\Paginator; // used class name

// end of line and tab definition
define('EOL', php_sapi_name() === 'cli' ? PHP_EOL : '<br/>');
define('TAB', php_sapi_name() === 'cli' ? "\t" : '<span style="margin-left:25px"/>');

$paginator = new Paginator; // initializes default event dispatcher, with standard listeners
$target = range('a', 'z'); // an array to paginate
// paginate target and generate representation class, it can be overrided by event listener
$pagination = $paginator->paginate($target, 1/*page number*/, 10/*limit per page*/);

echo 'total count: '.$pagination->getTotalItemCount().EOL;
echo 'pagination items of page: '.$pagination->getCurrentPageNumber().EOL;
// iterate items
foreach ($pagination as $item) {
    //...
    echo TAB.'paginated item: '.$item.EOL;
}

$pagination = $paginator->paginate($target, 3/*page number*/, 10/*limit per page*/);
echo 'pagination items of page: '.$pagination->getCurrentPageNumber().EOL;
// iterate items
foreach ($pagination as $item) {
    //...
    echo TAB.'paginated item: '.$item.EOL;
}
```

### Rendering pagination

**$paginator->paginate($target...)** will return pagination class, which is by
default **SlidingPagination** it executes a **$pagination->renderer** callback
with all arguments reguired in view template. Its your decision to implement
it whatever way you like.

**Note:** this is the default method. There will be more examples on how to render pagination templates

So if you by default print the pagination you should see something like:

``` php
<?php
// continuing in file: index.php
// ...

echo $pagination; // outputs: "override in order to render a template"
```

Now if we override the renderer callback

``` php
<?php
// continuing in file: index.php
// ...

$pagination->renderer = function($data) {
    return EOL.TAB.'page range: '.implode(' ', $data['pagesInRange']).EOL;
};
echo $pagination; // outputs: "page range: 1 2 3"
```