I have been developing a simple php file which can generate a Calc file (Calc is like Excel for Linux). Although, we have many pre-built classes like Spreadsheet_Excel_Writer already available, I wish to develop my own. After all, we are here to learn right?

So, I have a simple tab delimited data outputted as calc file (or .xls file) like:

PHP Code:
header("Content-Type: application/octet-stream");
header("Content-Type: application/vnd.ms-excel");
header("Content-Disposition: attachment; filename=report.xls");
header("Pragma: no-cache");
header("Expires: 0");

The above works great! However I was trying some formatting where I am now stuck.

I tried :

PHP Code:
echo "<b>Jack</b>\t"//***...etc, i.e. using html tags for bold 
...but the html tags arent parsed at all.

also I tried embedding picture file by :
PHP Code:
echo "<img src='jack.jpg />"
...which failed too.

Could you turn me toward the right direction?