This is a mirror of http://www.vim.org/scripts/script.php?script_id=997

History:

1.0:  Initial version

1.1:  Added mapping <leader>tog to toggle the behavior of observing fixed
window heights.  If disabled, vertically split windows can be used without a
problem.  Added two functions, WindowSizesEnabled and WindowSizesMaxEnabled,
which return whether fixed sizes are observed and whether window maxing is
enabled, respectively.

Plugin to keep the vertical sizes of windows within specifications.  For
example, if you're using the Decho.vim plugin, you could force the DBG
window to always be 10 lines high and for all other windows to automatically
maximize upon entry.  Or, you could specify explicit sizes for two windows
and let all the remaining space be shared equally among the other windows.

This is a bit different from using equalalways and winheight=999 because it
will always honor the vertical height settings of individual windows, using
the maximizing or equalization only on those windows that don't have
anything set explicitly.

Caveat (and it's a big one):  No support for vertical splits.  If you have a
vertical split, the behavior is undefined (well, it's not undefined, but
it's ugly).

Usage (default mappings):

<leader>max:  Toggle whether windows without an explicit fixed size will
automatically maximize upon entry or whether all un-fixed-size windows will
simply share the vertical space left over once the fixed windows have taken
their share of the space.

<leader>fix:  If the current window has a preferred fixed vertical size,
remove it, allowing this window to expand and contract according to the
g:WindowSizes_windowMax setting.

<leader>tog:  Toggle the fixed-window-size behavior; the <leader>max
behavior is controlled separately.  If fixed-window-sizes are not being
observed, then all windows are maximized blindly upon entering (without
regard to their preferred height) if maximizing is enabled.

<s-up>:  Increases the current windows's size by the value of the
WindowSizes_increment variables (see below); using this mapping results in
fixing the window height.

<s-down>:  Decreases the current windows's size by the value of the
WindowSizes_increment variables (see below); using this mapping results in
fixing the window height.

Variables (configuration):
g:WindowSizes_windowMax:  If 1, then windows are maximized (the <leader>max
mapping merely toggles this value between 1 and 0).

b:preferredWindowSize:  If defined, the fixed vertical size of the current
window -- the window will be this size vertically (tweaked by the
<leader>fix, <s-up> and <s-down> mappings).  If not defined, a prompt is
displayed for the user to specify a fixed vertical height for the current
window where the current height is used as the default value (hit <ESC> to
get out of it).

g:WindowSizes_increment:  If defined, this is the increment by which to
increase or decrease the current window's size if using the <s-up> or
<s-down> mappings.  If not defined, 5 is used.

b:WindowSizes_increment:  If defined in a given window, this is the
increment by which to increase or decrease the current window's size when
using the <s-up> or <s-down> mappings.  If not defined, the global version
(g:WindowSizes_increment) is used (if even THAT's not defined, 5 is used).

Functions (for use in the statusline, for example):

WindowSizesEnabled:  Returns 1 if the preferred heights of windows is
currently being observed (toggle with the <leader>tog mapping).

WindowSizesMaxEnabled:  Returns 1 if the current window is going to get as
much vertical real estate as possible (taking into consideration the
WindowSizesEnabled setting and the presence of other windows).

Tips:

- Always have at least one window without a specified size so it can take
  over the remaining vertical space.

- Always make sure that the total size of the fixed windows is less than the
  actual number of lines visible on-screen!  (The behavior otherwise is
  undefined -- that is, not tested by me.)

- To restore a window to not having a preferred size, unlet
  b:preferredWindowSize (just use the <leader>fix mapping).

TODO:

- Observe the 'laststatus' value.

- Figure out how to change all the global variables to script or some such
  so they don't pollute the global variable pool.