Moves the alignments of the view to the position specified by column and
path. If column is 0, then no horizontal scrolling occurs. Likewise, if
path is 0, no vertical scrolling occurs. At a minimum, one of column or
path needs to be non-zero. row_align determines where the row is placed,
and col_align determines where column is placed. Both are expected to be
between 0.0 and 1.0. 0.0 means left/top alignment, 1.0 means right/bottom
alignment, 0.5 means center.
If row_align exists, then col_align must exist, otherwise neither will be
used. If neither are used, the tree does the minimum amount of work to
scroll the cell onto the screen. This means that the cell will be scrolled
to the edge closest to its current position. If the cell is currently
visible on the screen, nothing is done.
This function only works if the model is set, and path is a valid row on
the model. If the model changes before the view is realized, the centered
path will be modifed to reflect this change.
GTK2.TreeView()->row_expanded()