Change initial view port size in paper space

When I first draw something on a model space and click the Layout1 tab to see paper space.

The default view port size (the red box) looks like the following.

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But I want to maximize the view port size such that (for example) the dotted line to be the defualt view port size in the paper space.

Could I do this by code??

I am currently using ObjectARX 2007 in C#.

Thank you in advance.

Image may be NSFW.
Clik here to view.Image may be NSFW.
Clik here to view.Image may be NSFW.
Clik here to view.Image may be NSFW.
Clik here to view.Image may be NSFW.
Clik here to view.

Image may be NSFW.
Clik here to view.