[Feature request] Add "button_vertical_offset" to themerc (and more)

Submitted by Spass

Assigned to Olivier Fourdan @olivier

Description

Created attachment 7806 screenshot of a theme

Hello. I've recently created a simple theme for Xfwm4 and I have two suggestions that would help the theme creators a lot.

Add "button_vertical_offset=X" (default to 0) option to the themerc configuration file to make it easier to position the buttons where they should be. The workaround now is making the button image taller with some transparency on top.
Add an option to cut/crop/hide X pixels from the top of the titlebar when window is maximized. Something like "maximized_crop=X" (default to 0) option.

To explain it a bit more - first take a look at this theme - https://www.xfce-look.org/p/1242107/ Like you can see, the theme has thick (5px) border around the window and the titlebar. To position the window buttons lower I had to add some "empty space" on top of the image files, to lower them. I assume they just get centered vertically as a default behaviour.

Explaining 2) - On that theme, on maximized windows, the top coloured border is still visible, while the side and bottom ones are hidden. It would be nice if I could cut some of the titlebar when the window is maximized, to hide that unwanted frame (element of the image file). So for example "maximized_crop=5" would hide the top 5 pixels of the titlebar when the window gets maximized.

Xubuntu 17.10, Xfwm 4.12.4

Attachment 7806, "screenshot of a theme":

Version: 4.12.0