### 5.8 Point and click

Point and click lets you find notes in the input by clicking on them in the Xdvi window. This makes it easier to find input that causes some error in the sheet music.

To use it, you need the following software:

- a dvi viewer that supports src specials:
  - Xdvi, version 22.36 or newer. Available from ftp.math.berkeley.edu.

    Most TeX distributions ship with xdvik, which is always a few versions behind the official Xdvi. To find out which Xdvi you are running, try `xdvi -version` or `xdvi.bin -version`.

  - KDVI. A dvi viewer for KDE. You need KDVI from KDE 3.0 or newer. Enable option Inverse search in the menu Settings.

    Apparently, KDVI does not process PostScript specials correctly. Beams and slurs will not be visible in KDVI.

- an editor with a client/server interface (or a lightweight GUI editor):

  - Emacs. Emacs is an extensible text-editor. It is available from http://www.gnu.org/software/emacs/. You need version 21 to use column location.

  - XEmacs. XEmacs is very similar to Emacs.

  - NEdit. NEdit runs under Windows, and Unix. It is available from http://www.nedit.org.

  - GVim. GVim is a GUI variant of VIM, the popular VI clone. It is available from http://www.vim.org.

Xdvi must be configured to find the TeX fonts and music fonts. Refer to the Xdvi documentation for more information.

To use point-and-click, add one of these lines to the top of your .ly file:

         #(ly:set-point-and-click 'line)

When viewing, Control-Mousebutton 1 will take you to the originating spot in the .ly file. Control-Mousebutton 2 will show all clickable boxes.

If you correct large files with point-and-click, be sure to start correcting at the end of the file. When you start at the top, and insert one line, all following locations will be off by a line.

For using point-and-click with Emacs, add the following In your Emacs startup file (usually ~/.emacs):

         (server-start)

Make sure that the environment variable XEDITOR is set to

         emacsclient --no-wait +%l %f

If you use XEmacs instead of Emacs, you use `(gnuserve-start)` in your .emacs, and set `XEDITOR` to `gnuclient -q +%l %f`.

For using Vim, set `XEDITOR` to `gvim --remote +%l %f`, or use this argument with Xdvi's `-editor` option.

For using NEdit, set `XEDITOR` to `nc -noask +%l %f`, or use this argument with Xdvi's `-editor` option.

If can also make your editor jump to the exact location of the note you clicked. This is only supported on Emacs and VIM. Users of Emacs version 20 must apply the patch emacsclient.patch. Users of version 21 must apply server.el.patch (version 21.2 and earlier). At the top of the `ly` file, replace the `set-point-and-click` line with the following line:

         #(ly:set-point-and-click 'line-column)

and set `XEDITOR` to `emacsclient --no-wait +%l:%c %f`. Vim users can set XEDITOR to `gvim --remote +:%l:norm%c| %f`.

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