Type Ascender and Typ Descender

mda mike · Post by **mda mike** » Mon May 19, 2003 12:27 am

I have to use diacritics that extend above and below the settings for the Winascent and Windescent. I have changed those values, and now the glyphs all appear on my screen.

However, I was perplexed by the TypoAscender and TypoDescender settings, and how they relate to the unitsPerem? Should they be related to the unitsPerem in some way?

Should I also be changing the TypoAscender and TypoDescender when I have changed the Winascent and Windescent values?

Thank you again for your help!

Erwin Denissen · Post by **Erwin Denissen** » Mon May 19, 2003 3:54 pm

The Typo Ascender value should be greater than zero, the Typo Descender value should be negative and the value of (Typo Ascender - Typo Descender) is recommended to equal one em.

mda mike · Post by **mda mike** » Mon May 19, 2003 10:48 pm

Erwin,

Thank you for the reply, and the great program!

I have received permission from Agfa/Monotype to make changes to their Arial and Times New Roman fonts. So I am basing this information on what came with the Arial font.

TypoAscender = 1491
TypoDescender = -431
TypoLineGap = 307

Units per em = 2048
Ascender = 1854
Descender = -434
Linegap = 67

How do I know what 1 em is? When I add up the Typo*'s it comes up to a number that I can't find anywhere.

Thanks again for your help.

By the way, is it recommended that I change these values? The Winascent and Windescent made the font work, but SHOULD these Typo* values also be changed?[/b][/i]

Erwin Denissen · Post by **Erwin Denissen** » Mon May 19, 2003 11:18 pm

Units per em = 2048

One em contains xxx Units per em, so like most TrueType fonts your em has 2048 units.

A quote from Microsoft hinting and production guidelines specification:
"sTypoAscender, sTypoDescender, and sTypoLineGap are all typographic values left up to the designers discretion. sTypoLineGap should roughly equal 7-10% of the Em."

mda mike · Post by **mda mike** » Tue May 20, 2003 9:35 am

Well now! that was fairly obvious. It just throws me that the font originally did not = 1 em when the TypoAscender - TypoDescender is calculated. Thank you for your help!