Adding interface verbs
Introduction to Verbs
Commands in Inkscape are called 'Verbs'. They permit invoking internal functionality through menus and keyboard shortcuts. For example, they could allow you to assign a shortcut key to a set of actions you use a lot.
Verbs are not terribly difficult to add. You don't need to have much coding know-how in order to add a verb, and only a minimal knowledge of Inkscape internals. The aim of this page is to provide novice coders with a "paint by numbers" process that can be followed to add a new verb to Inkscape.
How to Add a Verb
First, add IDs for your new verbs to verbs.h:
The place of the ID in the list determines to which group it belongs (EditVerbs, FileVerbs, etc) - however, this is pretty arbitrary, so don't sweat if you can't find a perfect group for your verb, just use whichever makes most sense.
Then is the meat of the matter. In verbs.cpp, fill in the verb structure with the name, description, action ID, etc; also in the same file, write the actual commands that the verb will do, in a switch case in one of ::perform methods:
As you see, these verbs do different things depending on which tool you are in. Before verbification, this was coded into tool context files, and now we can remove that:
(the last one required writing two functions that will be called by the verb).
Now assign the keys to the newly created verbs:
and then copy inkscape.xml to default.xml.
Note: even if you are not assigning any key, you MUST list the new verb in inkscape.xml, using a <bind> without a key. Not only this file is a keymap, but it's also a reference for keymap writers, so it must have all verbs, assigned or not.
If you added a shortcut which didn't exist before, update also doc/keys.xml.
If you want the new verb in the menu, edit menus-skeleton.h and insert it there in an appropriate place.
Also review the other keymaps to see if you can assign the new verb to some key that would make sense. So in adobe-illustrator.xml, I assigned the new verbs to Alt+Ctrl+, which seems to be the same thing according to the comments:
Finally update the ReleaseNotes with your new work! :-)
Candidates for New Verbs
A couple words on what might be good candidates for verbification:
- anything that all tools do but which is still not a verb, such as Esc for deselection
- anything that is needed for more complete keymaps emulating other editors, for example as listed in this bug report
- any global action (i.e. which is not limited to some tool's context) for which it just makes sense to have a quick shortcut, even if it is already available via a dialog, a tool control, or some other more complicated way (example: centering selected objects; increasing/decreasing blur/opacity/stroke width in selection, etc.).
Requests for New Verbs
If the above sounds like something you're interested in doing, here is a listing of actions that have been requested, that we'll need verbs for.
- Align-middle-and-center: Need a shortcut key for aligning selected objects to their centers (horizontally and vertically). 
If you'd like to see a verb added for a new action, but can't implement it yourself, you can add it to the above list.