Hello,

I am using Roassal2 (StephanEggermont.40) in Pharo 4. The attached picture displays a common visualization for inference of local ancestry in population genetics, I have attached what I am getting now with Grapher. Input data for such visualization is for example:

1:454 2:1488 1:2546 2:5711 1:14253 2:24411 1:31490 0:41585

(those are like Associations with key 0, 1 or 2 and value 454, 1488, ... etc)

In the attached picture

Min X is 0 and
Max X is 41500

so the X axis (chromosome positions) is rendered in intervals between 10000.

This is what I am trying now (code is commented where I tried to configure X axis interval)

| b intv |

intv := 0 to: 40000 by: 10000.
b := RTGrapher new.

ds := RTStackedDataSet new.
ds dotShape color: Color red.
ds
    points: #(1 2 1 2 1 2 1 0);
    x: intv. "????"
ds barShape width: 99; color: Color red.
"b
    minX: 0;
    maxX: 41500."
b add: ds.
b axisX noLabel; noTick. b axisY noDecimal.
b build.

I have some questions:

1) There is support to add an interval label to the X axis but preserving the space relation with the real chromosome position (the X axis) for the data (points in my example = 454 1488 2546 5711 14253 24411 31490 41585)?

2) How to clear the bar filling?

Any advice or help would be really nice.

Hernán