Re: XYcolor plots

[Jean Bréfort <jean brefort free fr>]

Le samedi 13 novembre 2021 à 10:51 -0700, John Denker via gnumeric-list
a écrit :
> On 11/13/21 10:20 AM, Jean Bréfort wrote:
>
> > to delete a map, you can just erase the file in
> > ~/.goffice/colormaps
>
> Wow, that's useful. I never would have guessed. I tried
> looking in the .gnumeric file without seeing any hint
> of this directory.
>
> I assume I can edit those files, and also create my own
> maps and stick them in there.

Editing an existing file is not a good idea because actually each color
map has a unique ID (UUID). It's better to duplicate and delete the
original file if needed. In all cases, the map is saved in the gnumeric
file which uses it with the exception of the default one.

> > I don't think it has been documented anywhere.
>
> Some documentation would help.
> Right now it's quite mysterious.
>
> >  I might add Edit and Delete buttons.
>
> That would be nice.

As explained above, it is actually not a good idea,I just did not
remember how things work.
> //////////////////////////////
>
> Here's another mystery:
>
> Using the default map: five stops exist, 0 through 4 inclusive.
> Color axis scale: min=0, max=4.
> My data: five data points, Z=0 through 4 inclusive.
>
> Observations: In the resulting plot:
> Point 0 is blue as expected.
> Point 4 is red as expected.
>
> Point 2 I expected to be green but it comes out as (127,255,0) which is weird.
>
> Point 1 I expected to be bright cyan but it comes out as (0,255,127) which is weird.
>
> Point 3 I expected to be bright yellow but it comes out as (255,189,0) which is super-weird.
>
> Observations were performed by saving the plot as .svg and using
> the inkscape eye-dropper to examine the colors.
> Directly eyeballing the .svg file produces the same observations,
> expressed as percent rather than per255.
>
> Is this a bug, or do I not understand what is supposed to happen?
>
> It's very mysterious.

This is because the axis is mapped to 0..5 and not 0..4, set the
maximum of the axis to 4 and things should work.