11/4/2022 0 Comments Case open featureWhen only one alternate exists, this feature could toggle directly between the alternate and default forms.įeature interaction: This feature may be used in combination with other features.įunction: Substitutes the above-base form of a vowel. The application may assume that the first glyph in a set is the preferred form, so the font developer should order them accordingly. An application could display the forms sequentially in context, or present a palette showing all the forms at once, or give the user a choice between these approaches. UI suggestion: The application should indicate to the user which glyphs in the user’s document have alternative forms (i.e which are in the coverage table for 'aalt'), and provide some means for the user to select an alternate glyph. If so, the application retrieves the alternate glyphs mapped in the alternate substitution lookup. It then checks to see whether the glyph ID is found in the 'aalt' coverage table. The application determines the glyph ID for the default form of a given character (default glyph from the 'cmap' table with no features applied). This feature should be ordered first in the font, to take precedence over other features.Īpplication interface: Discretionary feature: can be applied to glyph runs based on document markup, user control or other application criteria. As in any one-from-many substitution, alternates present in more than one face should be ordered consistently across a family, so that those alternates can work correctly when switching between family members. The manufacturer may choose to build two tables (one for each lookup type) or only one which uses lookup type 3 for all substitutions. While many of these substitutions are one-to-one (GSUB lookup type 1), others require a selection from a set (GSUB lookup type 3). These units include the glyph which represents the default form for the underlying Unicode value stored by the application. Recommended implementation: The 'aalt' table groups glyphs into semantic units. Since many-to-one substitutions are not covered, ligatures would not appear in this table unless they were variant forms of another ligature.Įxample: A user inputs the P in Poetica, and is presented with a choice of the four standard capital forms, the eight swash capital forms, the initial capital form and the small capital form. This serves several purposes: An application may not support the feature by which the desired glyph would normally be accessed the user may need a glyph outside the context supported by the normal substitution, or the user may not know what feature produces the desired glyph. Function: This feature makes all variations of a selected character accessible.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |