Re: [matplotlib-devel] alpha/transparency now failing in scatter (after upgrade to Ubuntu 9.10)

[Michael D. <md...@st...>]

Have you tried:

ax1.scatter(sanjose_y,sanjose_x,color=(0.9,0.9,0.0),label='SanJose',alpha=0.1)

That's what the scatter_demo2.py example does, and it appears to be working.

In general, alpha support is a bit inconsistent, and is the source of a 
number of these kinds of bugs -- where RGBA values are supported in some 
places but not in others.  It's on the TODO list to fix, but it's rather 
pervasive so hasn't been tackled yet.

Mike

Boo...@cs... wrote:
> Reporting this as a matplotlib bug because that's where I see the error.
>
> I have some code which was running fine, drawing a scatter plot with transparent/alpha for the colour, like this...
>
> ax1.scatter(sanjose_y,sanjose_x,color=(0.9,0.9,0.0,0.1),label='SanJose')
>
> This used to draw a very faint transparent series of points which (where there were a lot of points) built up a fairly solid colour.  Now, after an upgrade to Ubuntu 9.10 I see only solid colour, no transparency/alpha at all.  Also (a different problem), I get an error message (when adding a legend, that no labels were defined).  This is also changed behaviour since the upgrade.  Seems like scatter has changed... but why?
>
> I tried downloading matplotlib source code and compiling -- and despite a few glitches (like, it was by default Mac compilation) -- I think I got that going OK.  Still, I see exactly the same behaviour.  Scatter is behaving differently, and I really need that alpha/transparency!!!
>
> Neither of these problems were evident on Ubuntu 9.04, and I was using the inbuilt matplotlib for that.
>
> Please excuse if this report is in the wrong place -- my first attempt to report a bug in this package.
>
> Cheers
> A
>
> --
> Andrew 'Boo' Davie
>
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-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA