The decimals property should work - but there is a bug in the JDom.
This is the code that should work - to set the decimal in a financial decimal...
echo JDom::_('html.fly.decimal.financial', array(
'currencyFormat' => '$ %s',
'decimals' => '0',
'dataKey' => 'total_cost',
'dataObject' => $row,
'emptyZero' => true
));
But there is a problem with the JDOM code financial.php at line 52 here...
Bad code:
if (empty($this->decimals))
$this->decimals = 2;
The code sees "decimal = 0" as empty - and defaults to 2 decimal places!
This code needs to be
if (!isset($this->decimals))
$this->decimals = 2;
To fix this you need to manually edit line 52 of /public_html/libraries/jdom/html/fly/decimal/financial.php