[Plugin: VoucherPress] Some plugins customizzations

I’ve customization this plugins. I’ve got a complete voucher in jpeg format. This voucher include name, slogan and term of conditions. This voucher has dark tones.
The plugins can’t write a white text and hide some text.
To do this I edited the source code of voucerpress.php and inserted at line 2195 my code:

//set font color
$pdf->SetTextColor(255,255,255,false);

the numbers represent RGB color.

To hide some text I insert two if condition. The adminuser can show or hide some text just writing two different keyword.
If Voucher-title is “voucher” the title is not visible on voucher.
and
If Voucher-text is “hide” the text is not printed on voucher.

My code:

//Manage voucher title. If Voucher title is "voucher" the title is not visible on voucher. (by polecat)
		if($voucher->name == "voucher") {
			$vouchername = " ";
		} else
		{
			$vouchername = $voucher->name;
		}
		//This code $voucher->name must be replace into stripslashes function to set the original code (by polecat)
		// print title
		$pdf->writeHTML( stripslashes( $vouchername ), $ln=true, $fill=false, $reseth=false, $cell=false, $align='C');

and

//Manage voucher text. If Voucher text is "hide" the text is not printed on voucher. (by polecat)
		if($voucher->text == "hide") {
			$vouchertext = "";
		} else
		{
			$vouchertext = $voucher->text;
		}
		// print text
		$pdf->Write( 5,  stripslashes( $vouchertext ), $link = '', $fill = 0, $align = 'C', $ln = true);

http://wordpress.org/extend/plugins/voucherpress/