when wride my own widget, how to keep the rate of the widget's height and width at a constant value

["chao yeaj" <yeajchao gmail com>]

Hello everyone
           First ,i apologize for my poor English

           I am writing my own gtk widget for my application
           What i want to achieve is that: when the user change the
widget's size with his mouse,i want  the widget keep this:
height/width =  3/4      .
               i did not knowe how to write the widget's
"gtk_xxxx_size_allocate" function to achieve this

By the way ,i need some material about  the X ,but i do not know where
has the material i need.I have been  to the website :www.x.org,  but
got nothing!

         i need your help
Any comments would be much appreciated,thank you in advance !