Various implementations exist for yapp, some of which are listed below. During installation one of them has been selected as your default implemention, with which all yapp-based graphics programs (a few programs, e.g. xyzview(1NEMO) ) use other graphics device drivers). Currently (2001) most used at the PGPLOT and PS implementations.
 Hopefully one of them is close enough  (or exactly) for
what you want. Note that most of them need to be linked (notable exceptions
yapp_null, yapp_ps, yapp_meta) with site dependant external libraries. For
this, the environment variable YAPPLIB needs to be defined. Most common
graphics program can then be compiled as follows: 
cc -o prog prog.c $NEMOLIB/libnemo.a $YAPPLIB -lmnormally set through the $NEMO/NEMORC.local file (see nemorc(8NEMO) ) There are some example $YAPP_XXX environment variables defined in the $NEMO/NEMORC file.
Some yapp implementations allow you to select from various devices. As we do not advertise interactive programs very much, the keyword ’yapp=’ or an environment variable YAPP will be used to select a device and it’s possible options.
Treatment of colors, in particular what the background and foreground color is, is not uniform.
PGPLOT_BACKGROUND    n/a    0 is the background color ("black" for /xs)
PGPLOT_FOREGROUND    n/a    1 is the foreground color ("white" for /xs)
PGPLOT_GIF_WIDTH    850    pixels for /gif (interchange for /vgif)
PGPLOT_GIF_HEIGHT    680    pixels for /gif (i.e. 85 dpi)
PGPLOT_PPM_WIDTH    850    pixels for /ppm (interchange for /vppm)
PGPLOT_PPM_HEIGHT    680    pixels for /ppm (i.e. 85 dpi)
PGPLOT_PS_MARKERS    n/a    use "NO" if no postscript font for markers to be used
PGPLOT_PS_COLOR        n/a    color mode
PGPLOT_PS_WIDTH        7800    width in milli-inches (these are for 8.5x11 inches)
PGPLOT_PS_HEIGHT    10500    height in milli-inches
PGPLOT_PS_HOFFSET    350    horizontal offset from bottom left
PGPLOT_PS_VOFFSET    250    vertical offset from bottom left
PGPLOT_PS_EOF        n/a    EOF marker, useful for apple laserwriters (^D)
PGPLOT_PS_BBOX        n/a    if set to "MAX", max bounding box written, else
PGPLOT_IDENT        n/a    if set, user name, date and time written in bottom right
corner
PGPLOT_PS_DRAW_BBOX
For X windows drivers (e.g. /xs and /xw) a number of X resources are used
(see xrdb(1)
), e.g. ! settings for pgplot pgxwin.Win.geometry: WIDTHxHEIGHT+X+Y pgxwin.Win.iconGeometry: +X+Yif you store them in a file ~/.Xdefaults, they can be merged into your X session as follows, after you make sure any old pgplot xwin_server has been killed:
    xkill pgxwin_server
    xrdb -merge ~/.Xdefaults
png,FILE.png PNG pdfcairo,FILE.pdf PDF (cairo) pdf,FILE.pdf PDF (Haru) svg,FILE.svg SVG xwin tk
NEMO/src/kernel/yapp various yapp_* implementations
16-aug-88 document written - some are premature! PJT 16-nov-88 yapp_suntools added PJT 26-oct-90 updated outdated documentation PJT 11-nov-94 added yapp_meta PJT 28-mar-04 added some useful PGPLOT info PJT