How does Scanahand calculate side bearings?

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William
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How does Scanahand calculate side bearings?

Post by William » Mon Jun 10, 2013 2:10 pm

I am wondering how Scanahand calculates side bearings.

I am trying to produce a font using Scanahand 4.

For this particular font, no scanning is involved.

I am producing the artwork using Microsoft Paint using png files of the Basic and Extended Characters template.

From time to time I am adding a few glyphs to the artwork and then I am producing a new version of the font.

Thus far I have added 26 lowercase letters, some capitals and a few accented letters.

I have also added a vertical line from descender to ascender in the cell for the vertical bar character so as to fix the overall height of the characters.

Here is some transcript from my notes.

----

Friday 7 June 2013

7:08 am

Try a capital E by adapting a copy of H.

Try an F by adapting a copy of E.

Try an L by adapting a copy of E.

Try a T by adapting a copy of E.

Try an I by adapting a copy of T.

Try making the font MyTest_013.ttf using Scanahand 4.0 (build 151).

Regular
Auto
Smooth

----

I studied the font in FontCreator 7.0.

I note that in the MyTest_013.ttf font, when studied in FontCreator 7.0, that some of the capitals have negative values of one or both of the side bearings. This seems strange.
T_from_the_MyTest_013_font.png
T from the MyTest_013 font
T_from_the_MyTest_013_font.png (18.47 KiB) Viewed 1377 times

Is this what is to be expected?

I am wondering whether this is an effect of not having a complete of capitals artwork.

So I am wondering how Scanahand calculates side bearings please.

William Overington

10 June 2013

Erwin Denissen
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Re: How does Scanahand calculate side bearings?

Post by Erwin Denissen » Mon Jun 10, 2013 2:31 pm

It uses a simplified version of the Optical Metrics which is now part of FontCreator. It works best if you have a full character set, meaning at least a-z and A-Z and 0-9.
Erwin Denissen
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William
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Posts: 1956
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Location: Worcestershire, England
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Re: How does Scanahand calculate side bearings?

Post by William » Mon Jun 10, 2013 5:47 pm

Thank you.

I will try to add some more glyphs.

Incidentally I have noticed a sort of pattern with which capitals have one or more negative side bearings and on which side. It seems to be something to do with something like where the ink is half way vertically up the letter.

The MyTest_013 font has seven capitals, namely E F H I L O T.

E right side bearing slightly negative
F right side bearing negative
H both side bearings positive
I both side bearings positive
L right side bearing negative
O both side bearings positive
T both side bearings negative

William Overington

10 June 2013

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