Raster driver

This driver is intended to create various raster formats, at the moment there is support for binary PPM (portable pixmap) and PNG.

The driver creates the output file(s) specified with the -o switch. The parameter is used as a format string for sprintf(), if you specify '%d' in the output file, files with a sequence number will be created.

The output file is first created with a '.tmp' extension, this temporary file will be written and closed, and finally (atomically) renamed. This way you can be shure that you will always get a complete file, but its contents changes every 'tick' milliseconds.

The driver needs/supports the following entries in lcd4linux.conf:

Display: must be either “PPM” or “PNG” \

size: columnsxrows, e.g. “20×4” \

font: xrexxyres, at the moment only “5×8” and “6×8” supported. \

pixel: pixelsize+pixelgap, e.g. “5+1” \

gap: gapxgap, e.g. “3×3” \

border: border width \

foreground: color of an active LCD Pixel, must be #rrggbb \

halfground: color of an inactive LCD Pixel, must be #rrggbb \

background: backlight color, must be #rrggbb \

This may look weird, but it is weird. It's explained in detail on the X11 driver page.

To display this png file continuosly in a web page, follow these instructions:

  • Copy the sample png.html to an appropriate place under your htdocs.
  • Copy the sample nph-png perl script into your cgi-bin directory, and adjust png.html to contain this directory.
  • Adjust nph-png to contain the path/filename of the outputfile (s -o above).
  • Start lcd4linux -o path/filename.png.
  • If you are on a slow connection to your webserver you might also adjust the $DELAY in nph-png or in lcd4linux.conf.

Note: depending on your webervers configuration, you must rename nph-png to nph-png.pl or npg-png.cgi.

  • raster_09.txt
  • Last modified: 2020/07/17 18:33
  • (external edit)