Window.select_layout

layout (str | None) # – String of the layout, 'even-horizontal', 'tiled', etc. Entering None (leaving this blank) is same as select-layout with no layout. In recent tmux versions, it picks the most recently set layout. 'even-horizontal' Panes are spread out evenly from left to right across the window. 'even-vertical' Panes are spread evenly from top to bottom. 'main-horizontal' A large (main) pane is shown at the top of the window and the remaining panes are spread from left to right in the leftover space at the bottom. 'main-vertical' Similar to main-horizontal but the large pane is placed on the left and the others spread from top to bottom along the right. 'tiled' Panes are spread out as evenly as possible over the window in both rows and columns. 'custom' Custom dimensions (see tmux(1) manpages).

spread (bool | None) # – Spread panes out evenly (-E flag). added 0.56

next_layout (bool | None) # – Move to the next layout (-n flag). added 0.56

previous_layout (bool | None) # – Move to the previous layout (-p flag). added 0.56