In some of the printed diagrams of an old pattern system I was transcribing on Wikisource, mention is made of “Graded/Graudated tapes”.
These seem to be a scaled tape based on the ratio of the stated value of the tape, to a nominal ‘base’ measure (typicaly chest or waist) on which the pattern was drafted originally.,
This can easily be implemented as a 'graduated_value_scale" by an appropriate formulae, assuming the ‘base’ tape is known. In the example system I was working with the base tape was an ‘18’ where 1 inch on the 18 tape represented 1 inch in reality (i.e 1/18th).
For a higher or lower valued tape such as “36” The ratio would be tape_value/18 (which should also work for values in mm.) . This scale was then further divded into subdivisons of eighths.
Alternatively, would anyone find a graded’ tape functionality in Seamly, useful ?