I want to use Inkscape in my company to "highlight" on top of construction drawings when we do estimates. Currently, we highlight the actual paper drawing to mark it as estimated, then enter a quantity into Excel. I want to duplicate this process in Inkscape, and get away from paper + Excel.

Ideally in Inkscape, we would highlight over a part of the drawing and then enter some information about what we highlighted. For example, highlight some pipe, and then enter how many feet the pipe is and the material type.

I can do this by drawing paths over the pipe, changing the fill/stroke/opacity, and then entering the pipe information into the Object Properties dialog. Then I can read the SVG in python, and interpret the data in the Object Properties box to summarize our estimate.

However, I need to make it as simple as possible for my actual users.

At first, I thought I could write a custom drawing tool that would set the appropriate fill/stroke/opacity depending on which button they pressed: pipe, valve, 90 elbow etc. But custom tools are not implemented in Inkscape yet according to the wiki.

So now I'm wondering if there is a way to at least save fill/stroke/opacity settings into some sort of list, so that my users could just click on Pipe, and start drawing on top of the pipe, and all the fill/stroke/opacity settings would be set for them.

Is there any way to achieve this?

You could write an inkscape extension to do this! I've been doing something similar, and posted an article about figuring how how to make this work a few months ago: http://sugarpillstudios.com/wp/?p=142

As far as I can tell from the Wiki, I either can't write an extension to do this, or at least there is no documentation explaining it.

This page tells me that I could write an effect, but I don't want users to have to draw a line, and then select an effect from a menu, for each line they draw:
http://wiki.inkscape.org/wiki/index.php ... _subsystem

According to that page, it seems like I want to write a "tool" extension, or maybe a "path effect", neither of which is documented/implemented yet.