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From: Jessica on 6 Jul 2010 18:48
"Michael Robbins" <michael.robbins(a)us.cibc.com> wrote in message <eeb9f64.1(a)WebX.raydaftYaTP>...
> ...You should search the newsgroup before posting

I know this is an old post, but many people are still having this problem (I have searched through all of the discussions I could find on this topic and did not find a working solution). I don't know where in the newsgroup this supposed solution is, but I certainly didn't find it by searching "marker transparency" and "marker plot transparency". The only "solution" I found was to make all the markers patch objects, but that's just unrealistic for large amounts of data.

Michael, the fix you proposed does not work for me. It gives an error:

"??? Error using ==> set
There is no 'FaceAlpha' property in the 'scattergroup' class."

It gives the same error if I try it with plot instead of scatter as well. :(

Please, please, please, does anyone know how to make markers semi-transparent?
From: dpb on 6 Jul 2010 19:27
Jessica wrote:
....

> "??? Error using ==> set
> There is no 'FaceAlpha' property in the 'scattergroup' class."
>
> It gives the same error if I try it with plot instead of scatter as
> well. :(
>
> Please, please, please, does anyone know how to make markers
> semi-transparent?

I've no clue not being into the graphics much beyond routine plotting
but you can get the list of available properties for any object and
allowable values for enumerated ones by doing a set() on the handle.

--
From: Walter Roberson on 11 Jul 2010 11:46
Jessica wrote:

> Michael, the fix you proposed does not work for me. It gives an error:
>
> "??? Error using ==> set
> There is no 'FaceAlpha' property in the 'scattergroup' class."
>
> It gives the same error if I try it with plot instead of scatter as
> well. :(
>
> Please, please, please, does anyone know how to make markers
> semi-transparent?

A scattergroup object has Children, each of which are a patch object
with a single vertex, and with the Marker property set.

It would be a nuisance for me to try right at the moment, but *maybe* if
you set the patches to MarkerEdgeColor either 'none' or 'flat', and the
MarkerFaceColor to 'flat', and the FaceVertexCData to a color, and the
FaceVertexAlphaData to the desired transparency, then _possibly_ "The
color of each vertex controls the color of the marker that denotes it"
would be interpreted to include Alpha information. No promises.

> The only "solution" I found was to make all the markers patch
objects, > but that's just unrealistic for large amounts of data.

It seems to me that it would be realistic even for large amounts of
data. You would create the desired patch shape once, do the scatter
plot, and then it would just be a matter of looping through all of the
Children setting the marker off and the vertex data to the stored XData
plus the pre-determined relative patch X coordinates and to the stored
YData plus the pre-determined relative patch Y coordinates, and setting
the appropriate alpha. Shouldn't be more than roughly 5 lines.
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