I'm trying to put some names and descriptions close to a drawing i made. The drawing is mostly dark shapes, on a grey background - what i'd like to achieve is a black line from the name to the object, that has a blurry white background.
Using two strokes, one of which is fat, white and blurry is, of course, one way to go, but knowing the many nooks and crannies that Inkscape has i wondered: is there a way to do it in one, like giving a path the style "white background"?

I'm having trouble picturing what you want. It sounds like you know a way to make what you want, but you're asking if there's a better way? Can you show the effect you want and I can give suggestions on how I would do it.

The black line shows by itself on the lighter background, on the darker background the white blur gives contrast to it.

There is a way to make a line to be always a contrast-color to its background, but i do not like that effect. So the question is: White halo as one-click trick?
- Here goes: (sorry for the garish colors, and the weird size)

You can do this with Filter Effects although I don't know exactly without reading the docs.

You might find this example on how to create a drop-shadow useful - http://tavmjong.free.fr/INKSCAPE/MANUAL ... hadow.html

For straight lines you can use a gradient, if you need the line broken like in the image you can draw 2 lines that touch at the ends.

Here's how: draw a line, give it a wide stroke and color it with a black-to-white-to-transparent gradient, make the gradient Reflected and position it at a right angle towards the line, the black stop must be in the middle of the line and the white stop must be moved closer to the black one so you get a sharp transition from black to white.

The Gradient idea requires mulit-joint lines to be drawn as separate lines, that makes rearranging a little fiddly; - i'm still tinkering with the Filter solution: I thought a Color Matrix, that gets its input from a Guassian Blur of the source image (-> blurry black line)disregards it (all zeros in the first three columns), leaves the alpha from the blur (all zeros, and lastly a one in the fourth column), and then gives out white (topmost three get a one, last a zero in the fith column)(-> blurry white line) and merges this with the source image (so pretty much like the drop shadow filter in the manual, just with a color matrix in the chain to make a white drop shadow) . Works quite well, but with Matlab in the background, my RAM seems a little low (have only 1GB ) and everything gets very sluggish.

Thanks for the input!