Notes on ScriptXtoCP and ScriptCPtoX

Both ScriptCPtoX and ScriptXtoCP functions work only within runs and require the results of a previous ScriptShape call.

The client must establish which run a given caret offset or x position is within before passing it to ScriptCPtoX or ScriptXtoCP.

Cluster information in the logical cluster array is used to share the width of a cluster of glyphs equally among the logical characters they represent.

For example, the lam alef glyph is divided into four areas:

• The leading half of the lam.
• The trailing half of the lam.
• The leading half of the alef.
• The trailing half of the alef.

The ScriptXtoCP function has knowledge of the caret position conventions of each script:

• For Indian and Thai, caret positions are snapped to cluster boundaries.
• For Arabic and Hebrew, caret positions are interpolated with clusters.