Usr_06

Nvim :help pages, generated from source using the tree-sitter-vimdoc parser.


VIM USER MANUAL - by Bram Moolenaar
Using syntax highlighting
Black and white text is boring. With colors your file comes to life. This not only looks nice, it also speeds up your work. Change the colors used for the different sorts of text. Print your text, with the colors you see on the screen.
06.1 Switching it on 06.2 No or wrong colors? 06.3 Different colors 06.4 With colors or without colors 06.5 Printing with colors 06.6 Further reading
Next chapter: usr_07.txt Editing more than one file Previous chapter: usr_05.txt Set your settings Table of contents: usr_toc.txt

Switching it on

Syntax highlighting is enabled by default. Nvim will automagically detect the type of file and load the right syntax highlighting.

06.2 No or wrong colors?

There can be a number of reasons why you don't see colors:
Your terminal does not support colors. Vim will use bold, italic and underlined text, but this doesn't look very nice. You probably will want to try to get a terminal with colors.
Your terminal does support colors, but Vim doesn't know this. Make sure your $TERM setting is correct. For example, when using an xterm that supports colors:
setenv TERM xterm-color
or (depending on your shell):
TERM=xterm-color; export TERM
The terminal name must match the terminal you are using.
The file type is not recognized. Vim doesn't know all file types, and sometimes it's near to impossible to tell what language a file uses. Try this command:
:set filetype
If the result is "filetype=" then the problem is indeed that Vim doesn't know what type of file this is. You can set the type manually:
:set filetype=fortran
To see which types are available, look in the directory $VIMRUNTIME/syntax. For the GUI you can use the Syntax menu. Setting the filetype can also be done with a modeline, so that the file will be highlighted each time you edit it. For example, this line can be used in a Makefile (put it near the start or end of the file):
# vim: syntax=make
You might know how to detect the file type yourself. Often the file name extension (after the dot) can be used. See new-filetype for how to tell Vim to detect that file type.
There is no highlighting for your file type. You could try using a similar file type by manually setting it as mentioned above. If that isn't good enough, you can write your own syntax file, see mysyntaxfile.
Or the colors could be wrong:
The colored text is very hard to read. Vim guesses the background color that you are using. If it is black (or another dark color) it will use light colors for text. If it is white (or another light color) it will use dark colors for text. If Vim guessed wrong the text will be hard to read. To solve this, set the 'background' option. For a dark background:
:set background=dark
And for a light background:
:set background=light
Make sure you put this _before_ the ":syntax enable" command, otherwise the colors will already have been set. You could do ":syntax reset" after setting 'background' to make Vim set the default colors again.
The colors are wrong when scrolling bottom to top. Vim doesn't read the whole file to parse the text. It starts parsing wherever you are viewing the file. That saves a lot of time, but sometimes the colors are wrong. A simple fix is hitting CTRL-L. Or scroll back a bit and then forward again. For a real fix, see :syn-sync. Some syntax files have a way to make it look further back, see the help for the specific syntax file. For example, tex.vim for the TeX syntax.

06.3 Different colors :syn-default-override

If you don't like the default colors, you can select another color scheme. In the GUI use the Edit/Color Scheme menu. You can also type the command:
:colorscheme evening
"evening" is the name of the color scheme. There are several others you might want to try out. Look in the directory $VIMRUNTIME/colors.
When you found the color scheme that you like, add the ":colorscheme" command to your init.vim file.
You could also write your own color scheme. This is how you do it:
1. Select a color scheme that comes close. Copy this file to your own Vim directory. For Unix, this should work:
!mkdir -p ~/.config/nvim/colors
!cp $VIMRUNTIME/colors/morning.vim ~/.config/nvim/colors/mine.vim
This is done from Vim, because it knows the value of $VIMRUNTIME.
2. Edit the color scheme file. These entries are useful:
cterm attributes in a color terminal ctermfg foreground color in a color terminal ctermbg background color in a color terminal gui attributes in the GUI guifg foreground color in the GUI guibg background color in the GUI
For example, to make comments green:
:highlight Comment ctermfg=green guifg=green
Attributes you can use for "cterm" and "gui" are "bold" and "underline". If you want both, use "bold,underline". For details see the :highlight command.
3. Tell Vim to always use your color scheme. Put this line in your vimrc:
colorscheme mine
If you want to see what the most often used color combinations look like, use this command:
:runtime syntax/colortest.vim
You will see text in various color combinations. You can check which ones are readable and look nice.

06.4 With colors or without colors

Displaying text in color takes a lot of effort. If you find the displaying too slow, you might want to disable syntax highlighting for a moment:
:syntax clear
When editing another file (or the same one) the colors will come back.
If you want to stop highlighting completely use:
:syntax off
This will completely disable syntax highlighting and remove it immediately for all buffers. See :syntax-off for more details.
:syn-manual If you want syntax highlighting only for specific files, use this:
:syntax manual
This will enable the syntax highlighting, but not switch it on automatically when starting to edit a buffer. To switch highlighting on for the current buffer, set the 'syntax' option:
:set syntax=ON

06.5 Printing with colors syntax-printing

In the MS-Windows version you can print the current file with this command:
:hardcopy
You will get the usual printer dialog, where you can select the printer and a few settings. If you have a color printer, the paper output should look the same as what you see inside Vim. But when you use a dark background the colors will be adjusted to look good on white paper.
There are several options that change the way Vim prints: 'printdevice' 'printheader' 'printfont' 'printoptions'
To print only a range of lines, use Visual mode to select the lines and then type the command:
v100j:hardcopy
"v" starts Visual mode. "100j" moves a hundred lines down, they will be highlighted. Then ":hardcopy" will print those lines. You can use other commands to move in Visual mode, of course.
This also works on Unix, if you have a PostScript printer. Otherwise, you will have to do a bit more work. You need to convert the text to HTML first, and then print it from a web browser.
Convert the current file to HTML with this command:
:TOhtml
In case that doesn't work:
:source $VIMRUNTIME/syntax/2html.vim
You will see it crunching away, this can take quite a while for a large file. Some time later another window shows the HTML code. Now write this somewhere (doesn't matter where, you throw it away later):
:write main.c.html
Open this file in your favorite browser and print it from there. If all goes well, the output should look exactly as it does in Vim. See 2html.vim for details. Don't forget to delete the HTML file when you are done with it.
Instead of printing, you could also put the HTML file on a web server, and let others look at the colored text.

06.6 Further reading

usr_44.txt Your own syntax highlighted. syntax All the details.

Next chapter: usr_07.txt Editing more than one file
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