Calculates the layout of Workspace, with additional information like the row and column
of the Workspace with index space_index.
| this |
a Screen. |
| num_workspaces |
the number of Workspace on this, or -1 to let calc_workspace_layout find this number. |
| space_index |
the index of a Workspace. |
| layout |
return location for the layout of Workspace with additional information. |