Properties - General - Font Header Flags

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Properties - General - Font Header Flags

The Font Header Flags give global information about the font.

Baseline for font at y=0

Set this field when the baseline for all glyphs is at y= 0 (that is, the x-axis).

Left side bearing point at x=0

Set this field when the x-position of the leftmost black bit is assumed to be the left side bearing. This field can be ignored, as FontCreator will ensure this field is correct when a font is exported.

Instructions may depend on point size

Set this flag when there are instructions that depend on point size. Instructions may use point size explicitly in place of pixels per em. This means that scaling a 12 point screen font to obtain the equivalent printer font may not produce the identical result as requesting a 12 point printer font.

Force ppem to integer values for all internal scaler math

When this field is selected integer scaling will be used instead of fractional scaling. Fractional ppem sizes may be used if this field is not selected.

Instructions may alter advance width

When this field is set it allows the font to alter device dependent widths (the advance widths might not scale linearly).

Apple specific field 5

This field should be set in fonts that are intended to be laid out vertically, and in which the glyphs have been drawn such that an x-coordinate of 0 corresponds to the desired vertical baseline.


Reserved, do not check this field

Apple specific field 7

This field should be set if the font requires layout for correct linguistic rendering (e.g. Arabic fonts).

Apple specific field 8

This field should be set for a GX font which has one or more metamorphosis effects designated as happening by default.

Apple specific field 9

This field should be set if the font contains any strong right-to-left glyphs.

Apple specific field 10

This field should be set if the font contains Indic-style rearrangement effects.

Font data is 'lossless'

Set this flag when font data is 'lossless', as a result of having been compressed and decompressed with the Agfa MicroType Express engine.

Font converted

Set this flag when the font is converted (produce compatible metrics).

Font optimised for ClearType

Set this field if the font is optimised for ClearType

Last resort font

If set, indicates that the glyphs are simply generic symbolic representations of the assigned code-point ranges and don’t truly represent support for those code-points. If unset, indicates that the glyphs represent proper support for those code-points.


Reserved, do not check this field


Note: The Apple specific fields should be set according to Apple's specification. However, they are not implemented in OpenType.