WYSIWYG graphics editing

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Tip 1629 Printable Monobook Previous Next

created 2009 · complexity basic · author Michael.Eriksson · version 7.0

Why use an image editor when you can create a favicon using Vim and have WYSIWYG editing? This tip shows a Vim script to generate a portable pixmap format (PPM) text file that can be used to create an icon using a tool such as Netpbm. In addition, syntax commands are provided that highlight the source text file to give WYSIWYG editing (the screen shows how the icon will appear while the text is edited).

[edit] Procedure

As a simple example, an icon for a Swedish flag will be created. Make a file called flag.txt containing the following (the letters following "data" define the colors, other lines are ignored; B = blue and Y = yellow):

Sample data for a 16x10 flag of Sweden.

data     B B B B B Y Y B B B B B B B B B
data     B B B B B Y Y B B B B B B B B B
data     B B B B B Y Y B B B B B B B B B
data     B B B B B Y Y B B B B B B B B B
data     Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y
data     Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y
data     B B B B B Y Y B B B B B B B B B
data     B B B B B Y Y B B B B B B B B B
data     B B B B B Y Y B B B B B B B B B
data     B B B B B Y Y B B B B B B B B B

Make a file called append-colors.vim containing this Vim script:

" Basic colors from $VIMRUNTIME/rgb.txt
let colors = {
  \ 'k' : '0 0 0',
  \ 'b' : '0 0 139',
  \ 'g' : '0 100 0',
  \ 'c' : '0 139 139',
  \ 'r' : '139 0 0',
  \ 'm' : '139 0 139',
  \ 'y' : '165 42 42',
  \ 'w' : '211 211 211',
  \ 'K' : '169 169 169',
  \ 'B' : '0 0 255',
  \ 'G' : '0 255 0',
  \ 'C' : '0 255 255',
  \ 'R' : '255 0 0',
  \ 'M' : '255 0 255',
  \ 'Y' : '255 255 0',
  \ 'W' : '255 255 255'}

" Append lines to current buffer consisting of header (three lines):
"   'P3' = PPM (full color; numbers in ASCII decimal)
"   width height (two numbers)
"   color_depth  (one number)
" then lines from translating each input letter to its color triple.
" We translate only the letters that follow "data" at the start of a line.
" Width = number of letters in first data item; height = number data items.
function! AppendColors(data_file) abort
  let data = readfile(a:data_file)
  call filter(data, 'v:val=~#''^data\s''')
  call map(data, 'split(v:val)[1:]')
  let width_height = printf('%d %d', len(data[0]), len(data))
  call append(line('$'), ['P3', width_height, '255'])
  for columns in data
    call map(columns, 'g:colors[v:val]')
    call append(line('$'), columns)
command! -nargs=1 -complete=file AppendColors call AppendColors('<args>')

In Vim, enter the following commands to generate the output file:

:so append-colors.vim
:AppendColors flag.txt
:w flag.ppm

The above commands creates file flag.ppm by translating the letters in flag.txt to the color code numbers defined in the colors dictionary in the script. The script reads the file into a list called data, then filters the list, keeping only the lines that start with "data" followed by a space or a tab character. Each element in the list (a data line) is then split into a list of whitespace-separated words, but the first word ("data") is omitted. The width and height of the icon are then determined from the number of columns and rows in the data. Then the ppm output data is appended to the current buffer.

With the Netpbm tools installed, you can create an icon file (say flag.ico) using:

ppmtowinicon -output=flag.ico flag.ppm

[edit] WYSIWYG editing

Edit file flag.txt and enter the following commands:

:syntax clear
:syntax match Yellow " Y"
:syntax match Blue   " B"
:highlight Yellow guibg=#FFFF00 guifg=#FFFF00
:highlight Blue   guibg=#006FFD guifg=#006FFD

That will highlight " Y" (space then Y) in yellow, and " B" (space then B) in blue. The colors are solid (foreground = background).

An easy way to enter the commands would be to save the above lines in file flag-syntax.vim, then edit flag.txt and enter the command:

:so flag-syntax.vim

To clear the highlighting, enter:

:syntax clear

[edit] WYSIWYG editing with full-featured syntax file

An alternative to the above simple syntax commands would be to source the following syntax script while editing flag.txt:

if version < 600
  syntax clear
elseif exists('b:current_syntax')

runtime! syntax/sh.vim
unlet b:current_syntax

syn region ppmData
 \ matchgroup=ppmKeyword
 \ keepend
 \ start=/^data\>/
 \ end=/$/
 \ contains=ppmBlack,ppmDarkblue,ppmDarkgreen,ppmDarkcyan,ppmDarkred,ppmDarkmagenta,

syn match ppmBlack       /\C k/ contained
syn match ppmDarkblue    /\C b/ contained
syn match ppmDarkgreen   /\C g/ contained
syn match ppmDarkcyan    /\C c/ contained
syn match ppmDarkred     /\C r/ contained
syn match ppmDarkmagenta /\C m/ contained
syn match ppmBrown       /\C y/ contained
syn match ppmLightgrey   /\C w/ contained
syn match ppmDarkgrey    /\C K/ contained
syn match ppmBlue        /\C B/ contained
syn match ppmGreen       /\C G/ contained
syn match ppmRed         /\C R/ contained
syn match ppmMagenta     /\C M/ contained
syn match ppmYellow      /\C Y/ contained
syn match ppmWhite       /\C W/ contained

if version >= 508 || !exists('did_ppm_syntax_inits')
 if version < 508
  let did_ppm_syntax_inits = 1
  command -nargs=+ HiSet hi <args>
  command -nargs=+ HiSet hi def <args>
 HiSet ppmBlack       ctermbg=Black       ctermfg=LightGrey     guibg=black       guifg=white
 HiSet ppmDarkblue    ctermbg=DarkBlue    ctermfg=LightGrey     guibg=darkblue    guifg=white
 HiSet ppmDarkGreen   ctermbg=DarkGreen   ctermfg=LightGrey     guibg=darkgreen   guifg=white
 HiSet ppmDarkCyan    ctermbg=DarkCyan    ctermfg=LightGrey     guibg=darkcyan    guifg=white
 HiSet ppmDarkRed     ctermbg=DarkRed     ctermfg=LightGrey     guibg=darkred     guifg=white
 HiSet ppmDarkmagenta ctermbg=DarkMagenta ctermfg=LightGrey     guibg=darkmagenta guifg=white
 HiSet ppmBrown       ctermbg=Brown       ctermfg=LightGrey     guibg=brown       guifg=white
 HiSet ppmLightgrey   ctermbg=LightGrey   ctermfg=Black         guibg=lightgrey   guifg=black
 HiSet ppmDarkgrey    ctermbg=DarkGrey    ctermfg=White         guibg=darkgrey    guifg=white
 HiSet ppmBlue        ctermbg=Blue        ctermfg=White         guibg=blue        guifg=white
 HiSet ppmCyan        ctermbg=Cyan        ctermfg=DarkGrey      guibg=cyan        guifg=white
 HiSet ppmRed         ctermbg=Red         ctermfg=White         guibg=red         guifg=black
 HiSet ppmMagenta     ctermbg=Magenta     ctermfg=White         guibg=magenta     guifg=black
 HiSet ppmYellow      ctermbg=Yellow      ctermfg=DarkGrey      guibg=yellow      guifg=black
 HiSet ppmWhite       ctermbg=White       ctermfg=DarkGrey      guibg=white       guifg=black

 HiSet link ppmKeyword Keyword
 delcommand HiSet

let b:current_syntax = "ppm"

[edit] See also

[edit] Comments

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