Page width as config option

[mwood7]

For some applications the default width (994px) is wider than optimal. It would be useful to have a command line option to allow the user to choose an effective browser page width.

[edwardsun]

I've a similar feature request. Currently the output pdf leave wider blank space on the left side than on the right side.
yellow lines here are page boundaries.

Thanks a lot for the great tool!