need Help on building a GeometryApplication

Question

hi , I m trying to build a geometry application in which upon selection of a figure by a user a seperate window opens for him to punch in the dimension based on these dimensions (ex upon selection of rectangle one has to enter length,breadth ,if a circle is selected then the box should change accepting radius or Diameter)after the dimensions are give the figure is generated and this should be saved as a bitmap 1.>My Q is how do i get this save option i.e how do i save the generated figure as a bitmap 2.>Currently in my application the dimensions are hardcoded into the program I want to make this variable i.e the user should be able to give the dimensions based on these dimensions the figure must be generated. I have already written the code for ellipse,rectangle and need help regarding the above mentioned problems. please help me regarding this actually any help regarding this would be a great help....this is a software for use by visually Impaired.... thank you cheers!! Arun....