Hi.  Here's how I'm using GanttChart - for process monitoring,  I have some process that run throughout the day, and I like to be able to see back a bit how often the fail (or don't run) over the month.  For this view, I group them up at the day period.

Here's the script (picture below):

green := Color green alpha: 0.4.
red := Color red alpha: 0.6.
gray := Color gray alpha: 0.4.
data := {
{ #good. 0. 18. #P1. green. }. { #good. 24. 31. #P1. green. }.
{ #good. 0. 23. #P2. green. }. {#good. 24. 31. #P2. green. }.
{ #good. 0. 8. #P3. green. }. { #failed. 8. 9. #P3. red. }. {#good. 9. 31. #P3. green. }.
{ #good. 0. 24. #P4. green. }. {#good. 25. 31. #P4. green. }.
}.

b := RTTimeline new.
s := RTTimelineSet new.
s objects: data.
s lineIdentifier: #fourth.
s start: #second.
s end: #third.
s shape fillColor: #fifth.
b add: s.
b axisX 
numberOfLabels: 5;
labelRotation: -45;
labelConversion: [ :v | Date year: 2015 day: v + 107 ]. 
d := RTVerticalTickLineDecorator new.
d shape line color: Color white.
b axisX numberOfDecoratorTicks: 31.
b addDecorator: d.
b open.

Inline image 1
Each veritcal bar is a day.  Did this with changing RTVerticalTickLineDecorator to check for a different step than the label step - basically, caused the decorator to use a sub-tick number (using b axisX numberOfDecoratorTicks: 31 - new method added).

So, the request - is there a correct way to do this?

-cbc