When adding seam allowance to a pattern, there are 3 things that come into play:
- Does the user want seam allowance?
- How much seam allowance does the user want?
- How can we add seam allowance?
Let’s whip up a quick example for a moment to clarify how we will handle this:
As you can see from the source, we can descructure an
sa variable (short for
seam allowance) that will hold either:
falseif the user does not want seam allowance
- A value in
mmindicating how much seam allwance the user wants
To add seam allowance to our path, we just
offset it by
sa and add
some classes to it to style it. But, crucially, only if the user wants
if (sa) paths.sa = paths.shape .offset(sa) .addClass('fabric sa')
To refer back to our three question: Whether the user wants seam allowance, and
if so how much seam allowance is answered by the
sa value passed to our draft
And we add it with the
path.offset() method which will offset the path.
Our bib pattern does not require seam allowance as it will be finished with bias tape. But we can use this same technique to indicate that.
Before we do so though, we should talk about