handle = playoutiter:GetRun()

When iterating by run, at the end of each line, there's a position with a NULL run, so this function can return a NULL handle. The NULL run at the end of each line ensures that all lines have at least one run, even lines consisting of only a newline. You can use pglyphitem:IsNull() to check if a glyph item is NULL.

Use the faster playoutiter:GetRunReadonly() if you do not plan to modify the contents of the run (glyphs, glyph widths, etc.).

handle

the current run as a Pango glyph item