[Chart] Grid + Legend problems

[Sacha Sokoloski]

So I've finally, at least partially, isolated an issue with Chart that 
has bothered me forever.

When using Grids, I've always noticed that even when the space weights 
are the same (i.e. (1,1)), the various sub-renderables would come out to 
be different sizes, proportionally. That is, one plot might take up 2/3 
of the screen, and the other 1/3.

I noticed that if I set the space weight to 0 for a pair of grids beside 
each other, then the grid with the longer legend (i.e. the one with more 
elements in the legend) would still be drawn larger, even though they 
should both only take one cell. This gets magnified when given full 
space weighting, so that plots with larger legends will take up more 
space. If I set legends to be Nothing in all the relevant layouts, then 
the grids end up equal in size.

On further inspection, setting the layout_margins and layout_plot_sizes 
records to 0 has the same effect.

So that's great! I still wouldn't have much idea as to how to fix this 
though. Is there anyway this could be moved along?

I also still have an implementation of contour plots kicking around 
which one day I should try to integrate into Chart properly, as well as 
animation tools which would fit nicely into Chart-gtk...

Cheers,

  - Sacha