Magento – How to change a currency symbol in Magento

Ok first of all I saw the event currency_display_options_forming and I thought that this would be so easy, but sadly that was not the case :( You can use this event to change the display of the currency across the whole site but the follow code stops the precision from working in all cases.

Under Mage_Directory_Model_Currency there is a function formatPrecision. Here it checks for the options and if it does not find one for precision it will hard code it to 2!

So the first thing I did as Marius said is to rewrite the Mage_Directory_Model_Currency::format I chose to set it up with xml (great minds think alike)

public function format($price, $options = array(), $includeContainer = true, $addBrackets = false)
{
    return $this->formatPrecision(
        $price,
        Mage::getStoreConfig(self::XML_PATH_CURRENCY_ALLOW), // Mage uses '2' here
        $options,
        $includeContainer,
        $addBrackets
    );
}

But that only changes the display. Most of the price displays all call Mage_Core_Model_Store::roundPrice and this again has a hard coded 2, I am starting to think this was a bad idea.

public function roundPrice($price)
{
    return round($price, 2);
}

So the obvious thing now is to rewrite the roundPrice function and again use the same xml config value.

public function roundPrice($fPrice)
{
    return round($fPrice, Mage::getStoreConfig(Sitewards_Currency_Model_Format::XML_PATH_CURRENCY_ALLOW));
}

Now that covers most of the front-end if you also want to change this in the admin section that would involve changing templates and rewriting at least Mage_Adminhtml_Block_Catalog_Product_Helper_Form_Price

public function getEscapedValue($iIndex=null)
{
    $fValue = $this->getValue();

    if (!is_numeric($fValue)) {
        return null;
    }

    return number_format($fValue, Mage::getStoreConfig(Sitewards_Currency_Model_Format::XML_PATH_CURRENCY_ALLOW), null, '');
}

One not on the template front, the one I know about now is catalog/product/edit/price/tier.phtml as again that has <?php echo sprintf('%.2f', $_item['price']) ?>

On one final note the admin grid actually does work with the first event currency_display_options_forming.

I will update this answer the more I find out, but it is still a work in progress.

Ok so I am not sure if this is the bug but if you compare the Magento 1.8 and Magento 1.7 versions of the function currency in Mage_Core_Model_Local you will notice a reference to a bug with Zend_Currency

Magento 1.7: Mage_Core_Model_Local->currency

/**
 * Create Zend_Currency object for current locale
 *
 * @param   string $currency
 * @return  Zend_Currency
 */
public function currency($currency)
{
    Varien_Profiler::start('locale/currency');
    if (!isset(self::$_currencyCache[$this->getLocaleCode()][$currency])) {
        try {
            $currencyObject = new Zend_Currency($currency, $this->getLocale());
        } catch (Exception $e) {
            $currencyObject = new Zend_Currency($this->getCurrency(), $this->getLocale());
            $options = array(
                    'name'      => $currency,
                    'currency'  => $currency,
                    'symbol'    => $currency
            );
            $currencyObject->setFormat($options);
        }

        self::$_currencyCache[$this->getLocaleCode()][$currency] = $currencyObject;
    }
    Varien_Profiler::stop('locale/currency');
    return self::$_currencyCache[$this->getLocaleCode()][$currency];
}

Magento 1.8: Mage_Core_Model_Local->currency

/**
 * Create Zend_Currency object for current locale
 *
 * @param   string $currency
 * @return  Zend_Currency
 */
public function currency($currency)
{
    Varien_Profiler::start('locale/currency');
    if (!isset(self::$_currencyCache[$this->getLocaleCode()][$currency])) {
        $options = array();
        try {
            $currencyObject = new Zend_Currency($currency, $this->getLocale());
        } catch (Exception $e) {
            /**
             * catch specific exceptions like "Currency 'USD' not found"
             * - back end falls with specific locals as Malaysia and etc.
             *
             * as we can see from Zend framework ticket
             * http://framework.zend.com/issues/browse/ZF-10038
             * zend team is not going to change it behaviour in the near time
             */
            $currencyObject = new Zend_Currency($currency);
            $options['name'] = $currency;
            $options['currency'] = $currency;
            $options['symbol'] = $currency;
        }

        $options = new Varien_Object($options);
        Mage::dispatchEvent('currency_display_options_forming', array(
            'currency_options' => $options,
            'base_code' => $currency
        ));

        $currencyObject->setFormat($options->toArray());
        self::$_currencyCache[$this->getLocaleCode()][$currency] = $currencyObject;
    }
    Varien_Profiler::stop('locale/currency');
    return self::$_currencyCache[$this->getLocaleCode()][$currency];
}

My suggestion would be to try updating the try catch to match that of Magento 1.8 (I know this is not the best solution and obviously I would not suggest editing the core files but adding a rewrite)