When diffing files with vimdiff I always expect left file to appear on the left side of the diff window. So I would appreciate the help if this is possible.
There is no good way, but it can be done (in single-view layout %C %c will be used):
command! diff : if paneisat('right') && paneisat('bottom')
\ | execute '!vim -d %%C %%c'
\ | else
\ | execute '!vim -d %%c %%C'
\ | endif
Thank you very much!