Cursive Attachment

Cursive attachment joins neighboring glyphs through entry and exit points. It is useful for connected scripts and connecting italic or script designs whose joins need more than a fixed advance width.

A glyph's entry point receives a connection and its exit point supplies the next connection. The GPOS curs feature describes those relationships. This differs from a base-and-mark attachment: it connects the flowing glyph sequence rather than placing a combining mark above or below a base.

The #entry and #exit names used by FontLab's glyph recipes express a related source-construction idea. They can position parts while building a glyph. Their presence alone does not prove that a production font contains a curs lookup. Inspect or author that layout data explicitly; the mark/mkmk generation command is not a general cursive-feature generator.

A simplified Arabic-oriented FEA example, requiring the named glyphs, is:

languagesystem arab dflt;

feature curs {
    script arab;
    lookup JoinMeem {
        lookupflag RightToLeft;
        pos cursive meem.medi <anchor 500 20> <anchor 0 20>;
        pos cursive meem.fina <anchor 500 20> <anchor NULL>;
    } JoinMeem;
} curs;

Each rule lists the entry anchor first and the exit anchor second. The coordinates here are examples to be replaced by positions appropriate to the actual drawings. NULL identifies an absent connection; it is not equivalent to an anchor at (0, 0).

Unlike ordinary substitution or pair positioning, cursive positioning has a defined use for the RightToLeft lookup flag. It affects how the attached sequence relates to the baseline. The script and text direction still establish the shaping context; the flag is not a replacement for that context.

For a connecting design, inspect the point where the outgoing stroke should meet the next glyph's incoming stroke. Test the relevant initial, medial, and final forms, not only two repeated medial glyphs. Some glyphs deliberately lack an entry or exit because the script or design breaks the connection there.

Use compiled feature preview to judge the complete text behavior. Check joining height, continuity, spacing, and how a chain sits on the baseline. A correct point coincidence can still expose a mismatch in stroke angle or thickness that needs outline work.

Connecting italics use the same positioning idea without making every italic a connected design. Only add cursive attachment where the intended joining behavior requires it. A slanted drawing or an italic style name does not by itself establish an entry/exit relationship.

Keep the authored layout and the source construction coordinated. Changing a recipe anchor can improve an assembled glyph without updating a separately handwritten curs rule. Recompile and test the feature after relevant drawing or coordinate changes, including each intended master or static output.

Compilation and the separate responsibilities of authored curs and generated mark/mkmk are covered in Mark Features and Export.