matplotlib-devel Mailing List for matplotlib

moved from matplotlib-users:

http://sourceforge.net/mailarchive/forum.php?thread_name=CAN06%3DCx2zgh8YrnF2WRaJ%3D0E8i3ROLdYW4VuurtqKrx3mdkeEg%40mail.gmail.com&forum_name=matplotlib-users


On 10/22/2011 09:31 AM, Friedrich Romstedt wrote:
> 2011/10/21 Friedrich Romstedt<fri...@gm...>:
>> I will try to dig out that emails.
>
> Did that, the email I meant dates back to 10 November 2010!  Here's the snippet:
>
> <snippet>
>
> (Ben Root):
>> I am curious, could this approach you have done be generalized to any sort
>> of color transformation?  Admittedly, a gray mode is probably the most
>> common request, but what if someone wants a different transformation?  Maybe
>> even apply a filter that would produce sepia colors, or high-contrast
>> colors, or a different grayscale transform?  Heck, I could imagine a use
>> where a user might want to do a color substitution?
>
> Oh Yes, this is *ealily* possible.  The new framework in the
> ColorConverter class just uses a filter function, if we want to see it
> like that, already.  It's just the apply_rc_gray_setting() function or
> sth like that.  If you want to, you can try to add the functionality.
> But we should discuss beforehand how to design it.  There are several
> possibilites.  In fact, I like this filter function quite a lot!
>
> 1)  Hardcoding other filters in ColorConverter (what a decent name!),
> and switching them on or off
> 2)  Inserting filters as functions on runtime into the ColorConverter
> instance, some hooking mechanism
> 3)  Providing a dedicated Filter class, that can be fed to
> set_filter() instead of set_gray().  This I like best.
>
> I will, when i find some time, first implement the propagation of gray
> settings by allowing objects in set_gray().  Might be a good time to
> rename it to set_filter() right away, or maybe not do it, if
> set_gray() goes in, and expects a bool, it might break compat when
> changing the argument spec later.  So later set_gray() would just call
> set_filter() or add_filter() or whatever.
>
> </snippet>
>
> So the filter idea was Ben's idea.  I still like idea (3) for the
> design best.  I will check if it is possible to inject the filter code
> into the renderer framework, since all colour settings arguments
> somewhen flow into a call into the renderer.  Pro: No rcParams
> addition necessary, no modification of the peculiar colors.py
> ColorConverter framework necessary, just leaving those things
> untouched and hence no worries and headaches about them.  No disabling
> of higher-level caching and at the same time negligible small impact
> if there is no filter active.  Con: I don't know yet if it works.  I
> vaguely remember there were some problems when I checked that
> possibility last time (with pixmaps or something like that).  I think
> I will find out soon enough.
>
> Eric, Ben, do you think we should go off-list with this now?  I would
> prefer on-list now.  There might be people following but not
> responding.
>
> Friedrich

Friedrich,

The matplotlib-devel list is really the place for this, and I think that 
it will be very helpful to move the discussion there.  So, I am doing 
that now by simply addressing this to matplotlib-devel and removing 
-users from the address list.

Eric