Answered migx - grouping or "paging" results

<?php

$tvname = $modx->getOption('tvname', $scriptProperties, '');
$groupLimit = $modx->getOption('groupLimit', $scriptProperties, '0');
$outputvalue = $modx->getOption('value', $scriptProperties, '');
$docid = $modx->getOption('docid', $scriptProperties, (isset($modx->resource) ? $modx->resource->get('id') : 1));

if (!empty($tvname)) {
    if ($tv = $modx->getObject('modTemplateVar', array('name' => $tvname))) {
        $outputvalue = empty($outputvalue) ? $tv->renderOutput($docid) : $outputvalue;
    }
}

$items = $modx->fromJSON($outputvalue);
$output = array();
$groupidx = 1;
$count = 1;
$total = count($items);
foreach($items as $item){
    $item['_groupidx'] = $groupidx;
    $item['_groupopen'] = $groupidx==1? '1' : '0';
    $item['_groupclose'] = $count==$total ? '1' : '0';
        
    if (!empty($grouplimit) && $groupidx == $grouplimit){
        $item['_groupclose'] = '1';
        $groupidx = 0;
    }
    $output[]=$item;
    $groupidx++;
    $count++;
}

$properties = $scriptProperties;
$properties['value'] = $modx->toJson($output);

return $modx->runSnippet('getImageList',$properties);


/*
[[groupJson? &groupLimit=`5` &tvname=`myMigxTv` &tpl=`imageTpl`]]

imageTpl:
[[+_groupopen:is=`1`:then=`<div>`:else=``]]
<img src="[[+image]]" />
[[+_groupclose:is=`1`:then=`</div>`:else=``]]

*/

$item['_groupclose'] = $count==$total ? '1' : '0';
         
    if (!empty($grouplimit) && $groupidx == $grouplimit){
        $item['_groupclose'] = '1';
        $groupidx = 0;
    }

if(!empty($groupLimit) && $groupidx == $groupLimit) {
        $image['groupclose'] = '1';
        $groupidx = '0';
    } elseif ($count == $total) {
        $image['groupclose'] = '1';
    }

return $modx->runSnippet('getImageList', $properties);

<?php
/**
 * @description MODx MIGX getImageList wrapper snippet to allow grouping of output items (basically to make columns on the fly)
 *
 * @author exside
 * @licence free beer or do whatever you like with it licence
 * @credits
 *         - Bruno Perner, the creator of the amazing MIGX addon
 *         - http://forums.modx.com/thread/76778/migx---grouping-or-paging-results
 *
 * @compatibility Tested with MODx Revolution 2.2.6pl
 * 
 * @version 1.0.0pl
 * @modified 06.04.2013
 *
 * @changelog
 * - 1.0.0pl
 *         - refactoring code from forum post
 * 
 * @todo
 * 
 * @param groups optional int The amount of groups that should be created from the migx grid items
 * 
 * @usage [[!getImageListGrouped? &tvname=`migx.tv.name` &groups=`2` &tpl=`chunk.name` &docid=`100`]]
 * in your &tpl chunk you then will have the placeholders
 * 		[[+groupidx]] = the group the item belongs to (int)
 * 		[[+groupopen]] = equals 1 if the item is the first in it's group, usage like [[+groupopen:is=`1`:then=`<div class="wrapper">`:else=``]]
 * 		[[+groupclose]] = equals 1 if the item is the last in it's group, usage like [[+groupclose:is=`1`:then=`</div>`:else=``]]
 * 
 * @package migx
 **/

// packageparams
$version = '1.0.0pl';
$packagename = 'getImageListGrouped';

// enable debugging via &debug=`1` in the snippet params or directly by setting it to true here
if ( $debug = isset($debug) ? $debug : false ) { $modx->setLogLevel(modX::LOG_LEVEL_INFO); }

// addon options/settings that can be set via snippet params and make them accessible with $settings['param']
$settings		=& $scriptProperties;
$docid			= isset($settings['docid']) ? $settings['docid'] : ( isset($modx->resource) ? $modx->resource->get('id') : 1 ); // Resource id
$tvname			= isset($settings['tvname']) ? $settings['tvname'] : ''; // name of the migx tv to read
$tvvalue		= isset($settings['value']) ? $settings['value'] : ''; // if a value is passed in the snippet params, take it
$groups			= isset($settings['groups']) ? $settings['groups'] : 1; // sets the amount of groups to create


if ( !empty($tvname) ) {
	if ( $tv = $modx->getObject('modTemplateVar', array('name' => $tvname)) ) {
		$tvvalue = empty($tvvalue) ? $tv->renderOutput($docid) : $tvvalue;
	} else {
		if ( $debug ) { $modx->log(modX::LOG_LEVEL_INFO, '[' . $packagename . '] The TV you specified could not be found: ' . $tvname); }
	}
}

$items = $modx->fromJSON($tvvalue);
$output = array();
$groupidx = 1;
$groupcount = 1;
$totalcount = 1;
$totalitems = count($items);
$grouplimit = round($totalitems / $groups);

foreach ($items as $item) {
	$item['groupidx'] = $groupidx;
	$item['groupopen'] = $groupcount == 1 ? '1' : '0';
	$item['groupclose'] = $groupcount == $grouplimit ? '1' : ( $totalcount == $totalitems ? '1' : '0' );

	if ( $item['groupclose'] ) {
		++$groupidx;
		$groupcount = 1;
		++$totalcount;
	} else {
		++$groupcount;
		++$totalcount;
	}

	$output[] = $item;
}

$properties = $scriptProperties;
$properties['value'] = $modx->toJson($output);

// disable debugging
if ( $debug ) { $modx->setLogLevel(modX::LOG_LEVEL_ERROR); }

return $modx->runSnippet('getImageList', $properties);