[matplotlib-devel] Request for feedback regarding creation of a plot-type object.

[Jordan D. <fre...@oc...>]

I have been hacking away at the colorbar( ) code because I wanted a more 
flexible colorbar facility for my figures.  However, the current 
figure/axes architechture presents a few problems for me.  My primary 
problem is this: I never, ever, ever use the colormap facilities in 
matplotlib; I specify the colors of each of my contour levels with rgb 
tuples, because I have grown super-obsessed with graphics design and I 
want exact control of the shades displayed.  Not using colormaps creates 
the problem that colorbar() doesn't work, as there is no colormap for it 
to plot.

Colormaps are, in my opinion, a horrible hack and one of the worst parts 
of Matlab.  In fact, one of the main reasons I have been using 
matplotlib is because it's much easier to turn colormaps off.  But this 
does present a problem for automated colorbars.

The solution that I am inclined to pursue is to create a set of 
'plot-type' objects; ie, objects called "contour", "contourf", "bar", 
"pie", "plot", etc, which all inherit from a parent class.  These 
objects would contain information about the levels plotted, the colors 
of the lines, links to the PolyCollections that are currently stored by 
the axes, etc.  This would allow colorbar() to, say, automatically grab 
the last contourf plotted, figure out the colors, space the color 
divisions in proportion to the data levels, and so on.  I could see if 
the axes have a contour plot as well as a contourf, and if the data 
levels agreed, it could plot the contour levels onto the colorbar as 
well.  It would also allow for more flexible legends, and it wouldn't 
neccessitate the abandonment of matlab compatibility, since colorbar() 
would still default to searching for a colormap first.

But I haven't been looking at the matplotlib code for that long, so I'm 
not sure this is actually a good idea.  Is there an obvious problem with 
this idea?  Is it worth me trying to start hacking something together?  
Thanks.

Jordan