Metrics

This page consists of a set of spacing fields and font design flags. On the Format menu, click Settings, and then click the Metrics tab.

The typographic ascender for this font. Remember that this is not the same as the Ascender value in the Header tab, which Apple defines in a far different manner.

The suggested usage for TypoAscender is that it be used in conjunction with unitsPerEm to compute a typographically correct default line spacing. The goal is to free applications from Macintosh or Windows-specific metrics which are constrained by backward compatibility requirements. These new metrics, when combined with the character design widths, will allow applications to lay out documents in a typographically correct and portable fashion.

For CJK (Chinese, Japanese, and Korean) fonts that are intended to be used for vertical writing (in addition to horizontal writing), the required value for TypoAscender is that which describes the top of the design space (aka, em-square). For example, if the design space of the font extends from coordinates 0,-120 to 1000,880 (that is, a 1000x1000 box set 120 design units below the Latin baseline), then the value of TypoAscender must be set to 880. Failing to adhere to these requirements will result in incorrect vertical layout.

The typographic descender for this font. Remember that this is not the same as the Descender value in the Header tab, which Apple defines in a far different manner.

The suggested usage for Typo Descender is that it be used in conjunction with unitsPerEm to compute a typographically correct default line spacing. The goal is to free applications from Macintosh or Windows-specific metrics, which are constrained by backward compatibility requirements. These new metrics, when combined with the character design widths, will allow applications to lay out documents in a typographically correct and portable fashion.

For CJK (Chinese, Japanese, and Korean) fonts that are intended to be used for vertical writing (in addition to horizontal writing), the required value for Typo Descender is that which describes the bottom of the design space (aka, em-square). For example, if the design space of the font extends from coordinates 0,-120 to 1000,880 (that is, a 1000x1000 box set 120 design units below the Latin baseline), then the value of Typo Descender must be set to -120. Failing to adhere to these requirements will result in incorrect vertical layout.

The typographic line gap for this font. Remember that this is not the same as the Line Gap value, which Apple defines in a far different manner.

The suggested usage for Typo Line Gap is that it be used in conjunction with unitsPerEm to compute a typographically correct default line spacing. Typical values average 7-10% of units per em.

The ascender metric for Windows. This, too, is distinct from Apple's Ascender value and from the Typo Ascender value. Win Ascent is computed as the yMax for all characters in the Windows ANSI character set. Win Ascent is used to compute the Windows font height and default line spacing. For Symbol fonts, it is the same as yMax.

The descender metric for Windows. This, too, is distinct from Apple's Descender value and from the Typo Descender value. Win Descent is computed as the -yMin for all characters in the Windows ANSI character set. Win Descent is used to compute the Windows font height and default line spacing. For Symbol fonts, it is the same as -yMin.

Typographic line gap. Negative Line Gap values are treated as zero in Windows 3.1.

Tip: To automatically calculate ascender and descender values press the Calculate button.

Italic	Font contains Italic characters, otherwise they are upright.
Underscore	Characters are underscored.
Negative	Characters have their foreground and background reversed.
Outlined	Outline (hollow) characters, otherwise they are solid.
Strikeout	Characters are overstruck.
Bold	Characters are emboldened.
Regular	Characters are in the standard weight/style for the font.

Comments: These fields contain information on the original design of the font. Italic and Bold can be used to determine if the font was designed with these features or whether some type of machine simulation was performed on the font to achieve this appearance. Underscore, Negative, Outlined and Strikeout are rarely used fields that indicate the font is primarily a decorative or special purpose font.

If the Regular flag is set, then the Italic and Bold flags must be clear, else the behavior is undefined. The settings of the Italic and Bold flags must be reflected in the Mac Style flags. While the Regular flag set implies that both Mac Style flags Italic and Bold are clear (along with the Font Design flags Italic and Bold), the reverse is not true. The Mac Style flags (and the Font Design flags Italic and Bold) may be clear and that does not give any indication of whether or not the Regular flag is clear (e.g., Arial Light would have all flags cleared; it is not the regular version of Arial).

Note that Mac Style fields should agree with the Font Design fields. These Font Design fields are used over the Mac Style fields. The PANOSE values in the Classification tab and 'post' settings in the post tab are ignored for determining bold or italic fonts.