Char very small when delivered by email and chart is blured when resized manually

Hello

 I need your help  please  to resolve my problem :

 

 I generate  report  with template ( xsl fo), but when I  deliver it by email,  the chart  is very small ( see  attached file Report_Received_by_email.gif).

 I need the chart takes the  (90%) width of the email  (like screenshot Report_on_BiPublisher.gif)

 

 I have manually resized the chart on rtf template before generating the xsl source, but the result is a little blurred (see screenshot Report_on_BiPublisher.gif))

 

 I attach the screenshot and code source of xls.

 

Thank’s for your help

Djam