*
ML family is available but not widely
used), and ‘exotic’ typescripts (ones that you cannot guarantee your
readers will have available). Other common examples are generation of
sample bitmaps, and generation for insertion into some other
application’s display — to insert equations into Microsoft
PowerPoint, or to support the enhanced-emacs setup called
preview-latex.
In the past, the commonest way of generating bitmaps was to generate a
PostScript file of the DVI and then use ghostscript to
produce the required bitmap format (possibly by way of PNM
format or something similar). This is an undesirable procedure (it is
very slow, and requires two or three steps) but it has served for a
long time.
(La)TeX users may now take advantage of two bitmap ‘drivers’. The
longer-established, dvi2bitmap, will generate XBM and
XPM formats, the long-deprecated GIF format (which is
now obsolescent, but has finally been relieved of the patent
protection of the LZW compression it uses), and also
the modern (ISO-standardised) PNG format.
Dvipng started out as a PNG renderer; from version 1.2 it can also
render to the GIF format. It is designed for speed, in environments that
generate large numbers of PNG files: the README mentions
preview-latex, LyX, and a few
web-oriented environments. Note that dvipng gives
high-quality output even though its internal operations are optimised
for speed.
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=dvi-bmp