In the Windows panel of Format | Settings, a new font in Font Creator Program 4.5.1 has the following values: Typo Ascender 1491, Typo Descender -431, Typo LineGap 307.
My Quest Chess font has those values in it, simply because they have never been altered since starting a New font in Font Creator Program 4.5, and I am thinking that they are quite possibly inappropriate or maybe totally wrong.
I have looked at section 4.5.9.4 of the manual yet am no further forward with this.
In the Quest Chess font all of the glyphs are square, being 2816 font units square, horizontally from 0 to 2816 and vertically from -768 to 2048. They are meant to fit against each other both horizontally and vertically with no spacing between them. They appear to do that satisfactorily in Word 97 and pdfs produced using Serif Page Plus 9.04 when viewed on a Windows 98 PC.
William Overington
23 October 2004
Ascender, Descender and LineGap are Macintosh-specific.
Windows uses the WinAscent and WinDescent values. Word also uses the LineGap.
According to Microsoft’s recommendations, the typo values should free applications from Macintosh- or Windows-specific metrics which are constrained by backward compatibility requirements. I don’t know if these values are (already?) used.
Below you will find some guidelines you might find helpful:
Set Typo Ascender to the y-value of the top of the lowercase d
Set Typo Descender to the y-value of the bottom of the lowercase p
Set Typo LineGap to 10% of units per em
Set WinAscent to the yMax for all characters in the Windows ANSI character set.
Set WinDescent to the yMin for all characters in the Windows ANSI character set.
Ascender = WinAscent
Descender = WinDescent
Set LineGap to (115% of units per em) – (Ascender + Descender)
Make sure
LineGap >= 0
LineGap >= (yMax - yMin) - (Ascender - Descender)
Comments on these guidelines are welcome.
Update 31-05-2019:
The above recommendations are outdated, please read the new tutorial about how to set compatible vertical metrics.