---
authors: 1
caption: 'Scales, how do they work?'
date: '2018-01-04'
intro: 'Freesewing core v1.3.0 is out; Comes with fixes so good that we back-ported them to all your drafts'
title: 'Freesewing core v1.3.0 is out; Comes with fixes so good that we back-ported them to all your drafts'
---

On the last day of 2017, in our [monthly roundup of all the freesewing
news](/blog/roundup-2017-12/) , we wrote about the looming issue with
incorrectly scaled drafts, aka [Core issue #204 - The Inkscape default units
quandary](https://github.com/freesewing/core/issues/204).

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I won't go over [all that](/blog/roundup-2017-12/) again, but it boils down to
the fact that the [Inkscape](http://inkscape.org/) maintainers have changed
Inkscape's internal DPI (dots per inch) from 90 to 96. A change that goes in
effect from version 0.92 onwards.

Left unchecked, this change would cause all freesewing patterns to be
incorrectly scaled. That's because we assume 90DPI in our SVG output, and
scale accordingly.

![That 'oh-shit' moment when we realized the full impact of the DPI
change](https://posts.freesewing.org/uploads/oh_shit_90b4969a5d.gif)

When the switch to 96DPI goes into effect, all patterns would be off by 6.66%.
Which is really the kind of difference that is too small to notice when
eyeballing a pattern, yet large enough to completely mess up your garment.

The issue is also more troublesome than it would seem at the surface. First of
all because we can't just switch to 96DPI as there are now two versions out
there that use a different default DPI under the hood. We need a solution that
works for both.

![Screenshot of a freesewing pattern that is incorrectly scaled in the latest
Inkscape release](https://posts.freesewing.org/uploads/inkscape_b96e2bb510.png)

Furthermore, while any fix we implement would apply to new drafts, all existing
drafts generated before the fix would still be impacted.

In other words, if you drafted a pattern last week, or a month ago, that
pattern would not scale correctly in a recent version of Inkscape. And since
we use Inkscape in our SVG-to-PDF tool-chain, it would also be incorrectly
scaled if you came here and downloaded a PDF.

Clearly, something needed to be done. And fast.

## The fix for new drafts

From today's release of core v1.3.0 onwards, our SVG files no longer depend on
any DPI setting.

Rather than use the internal units and apply an SVG transform to scale the
entire pattern, we've bolted down the units to mm and updated the SVG viewBox
to apply the scaling.

Obviously, this is how we should have done it from the start. Everyday is a
school day.

If you're worried about the use of mm in your draft (because you're used to
imperial units), rest assured that those mm will stay under the hood. You won't
be able to tell the difference.

## The fix for pre-existing drafts

To avoid problems with pre-existing drafts, we needed to come up with a
solution for those too.

We essentially have two options:

- Re-draft all those drafts
- Patch them in-place without changing the draft itself

Re-drafting fixes the issue as every new draft will be handled by the latest
core version that does include the fix.

However, core also ships with regular updates, tweaks, and fixes in the
patterns themselves. So by re-drafting a draft generated on a previous version
of core, there's no guarantee the draft won't change.

In principle that change would always be an improvement. But one person's bug
is another person's feature, and we do prefer not to [move your
cheese](https://en.wikipedia.org/wiki/Who_Moved_My_Cheese%3F).

![Don't touch my
stuff](https://posts.freesewing.org/uploads/who_moved_my_cheese_0cd51a25d6.jpg)

So, instead we decided to patch all drafts we have on file in-place with the
new scaling code, without touching any other aspect of the draft.

As you're reading this, this has already been done, and all freesewing drafts
should now scale correctly. Everywhere.

## Also: version awareness

We've also made changes to our backend systems to store the version of
freesewing core that generated your draft.

If since you generated your draft we've rolled out new features or fixes,
you'll be notified that an update is available:

![If you draft is generated with an old version of freesewing core, we'll tell
you about it](https://posts.freesewing.org/uploads/upgrade_dee342e3fb.png)

Whether you update your draft or not is up to you. If you don't want to loose
the info in your _old_ draft, rather than update it in-place, you can fork it.
