autogenerate bg colors for the file indicator. resolves #131.

autoload/airline.vim

@@ -12,6 +12,7 @@ endfunction
 function! airline#switch_theme(name)
   let g:airline_theme = a:name
   let palette = g:airline#themes#{g:airline_theme}#palette "also lazy loads the theme
+  call airline#themes#patch(palette)
 
   let w:airline_lastmode = ''
   call airline#update_statusline()

autoload/airline/themes.vim

@@ -1,19 +1,14 @@
-" MIT license. Copyright (c) 2013 Bailey Ling.
+" MIT License. Copyright (c) 2013 Bailey Ling.
 " vim: ts=2 sts=2 sw=2 fdm=indent
 
 " generates a dictionary which defines the colors for each highlight group
 function! airline#themes#generate_color_map(section1, section2, section3, file)
-  " provide matching background colors if not provided
-  let file = copy(a:file)
-  if file[1] == '' | let file[1] = a:section3[1] | endif
-  if file[3] == '' | let file[3] = a:section3[3] | endif
-
   "                       guifg           guibg           ctermfg         ctermbg         gui/term
   return {
       \ 'airline_a':    [ a:section1[0] , a:section1[1] , a:section1[2] , a:section1[3] , get(a:section1 , 4 , 'bold') ] ,
       \ 'airline_b':    [ a:section2[0] , a:section2[1] , a:section2[2] , a:section2[3] , get(a:section2 , 4 , ''    ) ] ,
       \ 'airline_c':    [ a:section3[0] , a:section3[1] , a:section3[2] , a:section3[3] , get(a:section3 , 4 , ''    ) ] ,
-      \ 'airline_file': [ file[0]       , file[1]       , file[2]       , file[3]       , get(file      , 4, ''    ) ] ,
+      \ 'airline_file': [ a:file[0]     , a:file[1]     , a:file[2]     , a:file[3]     , get(a:file     , 4 , ''    ) ] ,
       \ }
 endfunction
 
@@ -54,3 +49,24 @@ function! airline#themes#get_highlight2(fg, bg, ...)
   return s:get_array(fg, bg, a:000)
 endfunction
 
+function! airline#themes#patch(palette)
+  " this is a pretty heavy handed, but it works...
+  " basically, look for the 'airline_file' group and copy the bg
+  " colors from 'airline_c' into it.
+  for mode in keys(a:palette)
+    let overrides = split(mode, '_')
+    if len(overrides) > 1
+      let mode_colors = a:palette[overrides[0]]
+      let file_colors = mode_colors.airline_file
+      let file_colors[1] = mode_colors.airline_c[1]
+      let file_colors[3] = mode_colors.airline_c[3]
+
+      let override_colors = a:palette[overrides[0].'_'.overrides[1]]
+      let override_colors.airline_file = copy(file_colors)
+      let override_status_colors = get(override_colors, 'airline_c', mode_colors.airline_c)
+      let override_colors.airline_file[1] = override_status_colors[1]
+      let override_colors.airline_file[3] = override_status_colors[3]
+    endif
+  endfor
+endfunction
+

autoload/airline/themes/dark.vim

@@ -23,11 +23,14 @@
 "
 " The array is in the format [ guifg, guibg, ctermfg, ctermbg, opts ].
 " The opts takes in values from ":help attr-list".
-let s:file = [ '#ff0000' , ''        , 160 , ''    , '' ]
 let s:N1   = [ '#00005f' , '#dfff00' , 17  , 190 ]
 let s:N2   = [ '#ffffff' , '#444444' , 255 , 238 ]
 let s:N3   = [ '#9cffd3' , '#202020' , 85  , 234 ]
 
+" The file array is a special case, where only the foreground colors are
+" specified.  The background colors are automatically filled.
+let s:file = [ '#ff0000' , ''        , 160 , ''  ]
+
 " vim-airline is made up of multiple sections, but for theming purposes there
 " is only 3 sections: the mode, the branch indicator, and the gutter (which
 " then get mirrored on the right side).  generate_color_map is a helper

autoload/airline/themes/jellybeans.vim

@@ -11,12 +11,7 @@ function! s:generate()
   let s:N1 = airline#themes#get_highlight('DbgCurrent', 'bold')
   let s:N2 = airline#themes#get_highlight('Folded')
   let s:N3 = airline#themes#get_highlight('NonText')
-
-  " The file indicator is a special case where if the background values are
-  " empty the generate_color_map function will extract a matching color.
   let s:file = airline#themes#get_highlight('Constant')
-  let s:file[1] = ''
-  let s:file[3] = ''
 
   let g:airline#themes#jellybeans#palette.normal = airline#themes#generate_color_map(s:N1, s:N2, s:N3, s:file)
   let g:airline#themes#jellybeans#palette.normal_modified = {

autoload/airline/themes/luna.vim

@@ -2,7 +2,7 @@
 " (https://github.com/Pychimp/vim-luna)
 
 let g:airline#themes#luna#palette = {}
-let s:file = [ '#ffffff' , '#002b2b' , 231 , 23 , '' ]
+let s:file = [ '#ffffff' , '' , 231 , '' , '' ]
 
 
 let s:N1 = [ '#ffffff' , '#005252' , 231  , 36 ]

autoload/airline/themes/molokai.vim

@@ -1,7 +1,7 @@
 let g:airline#themes#molokai#palette = {}
 
 
-let s:file = [ '#66d9ef' , '#465457' , 81 , 67 , 'bold' ]
+let s:file = [ '#66d9ef' , '' , 81 , '' , '' ]
 
 " Normal mode
 let s:N1 = [ '#080808' , '#e6db74' , 232 , 144 ] " mode

autoload/airline/themes/tomorrow.vim

@@ -2,9 +2,6 @@ let g:airline#themes#tomorrow#palette = {}
 
 function! s:generate()
   let s:file = airline#themes#get_highlight('Constant')
-  " clear out backgrounds so generate_color_map will fill them in
-  let s:file[1] = ''
-  let s:file[3] = ''
 
   let s:N1 = airline#themes#get_highlight2(['Normal', 'bg'], ['Directory', 'fg'], 'bold')
   let s:N2 = airline#themes#get_highlight('Pmenu')