Intermediate Emacs Hacking

Emacs, as usual, offers you a lot of flexibility for printing. You can print by sending the raw contents of the buffer to the printer. This is quick and easy, but it may not give you exactly what you wanted. You have far more control over PostScript printing, so that may be the way to go. For one thing, font-locked (colorized) buffers print in color on color printers and in gray scale on monochrome printers, where Ghostscript supports those features.

Probably the most common change to Emacs in the printing area is changing the name of Emacs' default printer. This can be nil, which tells Emacs to use the default printer, lp in Linux or UNIX. Or, it can be a printer name such that the lp dæmon recognizes it as a printer name. If you have Red Hat's printtool or similar, you can get printer names from it. Failing that, look in /var/spool/lpd/ for the names of your printers. Emacs can use any printer for which you can define a local queue, including remote printers.

Two variables are set to indicate the printer, one for PostScript printing and one for non-PostScript printing. The code below shows how I set up Emacs under Linux and Windows. The Windows definition uses a remote printer on the computer charlesc. Setting both printers to the same computer works only because the server is a Linux box. The printcap detects PostScript and runs it through Ghostscript before printing it:

;; Begin setup for printing on Win32
(if (and  (>= sams-Gnu-Emacs-p 20)
	   (memq window-system '(win32 w32)))
    (progn (setq printer-name "//charlesc/lp")
	   (setq ps-printer-name "//charlesc/lp"))
  )
;; End setup for printing on Win32

;; Begin setup for printing on Linux
(if (and  (>= sams-Gnu-Emacs-p 20)
	  (string-equal system-name "charlesc.localdomain"))
    (progn (setq printer-name "lp")
	   (setq ps-printer-name "lp"))
  )
;; End setup for printing on Linux

Emacs' PostScript printing is very powerful. By default, it prints a gray box at the top of each page with the buffer's name, the data, a page number and a count.

You can set a text string and other characterstics of a watermark on each page or on selected pages. For example, a watermark of Preliminary or Draft is a good idea for code reviews; see the variable ps-print-background-text. You also can use an EPS image, such as a picture of Tux or the Free Software Foundation's GNU logo, for a watermark.

We geriatric cases who don't like 8.5 point type can change the value of ps-font-size. The value contans two numbers, the first for landscape and the second for portrait printing. Whether to print landscape or portrait is controlled by the variable ps-landscape-mode.

You can modify the default PostScript header and add a footer as well. For two-sided printing, you may specify left and right headers and footers. And if you want to save trees, look at ps-n-up-printing. It lets you print multiple pages on a sheet of paper.

Emacs supports multiple frames or windows. You can launch another frame with Ctrl-X 5 2, or remove one with Ctrl-X 5 0. The initial frame created when Emacs is launched has a number of graphics characteristics defined by the variable initial-frame-alist. Subsequent frames are governed by default-frame-alist. Use these two variables identically. Each variable is a list of sub-variables and their values, rather like a hash in Perl. For example, to set the initial position of the first frame on the screen, use:

(setq initial-frame-alist
    '((top . 40) (left . -15)
      (width . 96) (height . 40)
      (background-color . "Gray94")
      (foreground-color . "Black")
      (cursor-color	. "red3")
      (user-position t)
      ))

This definition sets the Emacs initial frame 40 pixels from the top of the screen, 15 pixels from the right (hence the negative number for left), with a width of 96 characters and a height of 40 lines. It sets the default background and foreground text colors and then sets the cursor color.

This definition is also where you set your font, if you don't like the default. The program xfontsel comes with XFree86, and you can use it to find a suitable font (Figure 3). Press Select as an option, and xfontsel puts it into the clipboard. Add another pair of parentheses to the definition of initial-frame-alist, insert the phrase font . and insert a pair of quote marks. Then recover the font definition between the quotes with Ctrl-Y, like any other clipboard entry:

(font . "-adobe-courier-*-r-*-*-*-140-*-*-*-*-*-*")

Figure 3. Selecting a Font with X's Utility Program xfontsel

If you are wondering how I get the colors in my screenshots, that's how I do it.

If you have problems with these settings, look in your .Xresources file for any Emacs settings. Any settings in .Xresources overrides these definitions. To get rid of the overrides, comment them out of the .Xresources file and restart X.

Until recently, Emacs had no support for variable-width fonts, and fixed-width fonts are fine for most purposes. But with support for proportional fonts and non-English character sets included in recent versions, you now can define your own sets of fonts within Emacs. Fontsets allow word-processor ease of control over fonts. For examples, take a look at the headers in Emacs' Info and the Customize menus; see also Emacs' info nodes on fontsets.

For more information on fonts under X, see Emacs' info node on Font Specification Options.