For any insertion point, the number of bytes between that insertion point and the end of the line is returned. If the insertion point is -1, the cursor position is used. If the line contains a hard line-break, it is counted as one byte.

The term line means a line on the display after the application of word-wrap. It does not mean a line as defined by the CR LF line-break sequence, although a display line might be terminated by such a sequence.