Fills visible_rect with the currently-visible region of the
buffer, in tree coordinates. Convert to bin_window coordinates with
TreeView.convertTreeToBinWindowCoords.
Tree coordinates start at 0,0 for row 0 of the tree, and cover the entire
scrollable area of the tree.
Fills visible_rect with the currently-visible region of the buffer, in tree coordinates. Convert to bin_window coordinates with TreeView.convertTreeToBinWindowCoords. Tree coordinates start at 0,0 for row 0 of the tree, and cover the entire scrollable area of the tree.