.XPM File Format – XPM 1 and XPM 2

Telling them apart

libXpm looks at the first words of the file:

More exactly, libXpm skips the first word and reads the second: XPM means XPM 3, and XPM2 means XPM 2, with the third word naming the syntax (none for plain, C or Lisp). Anything else that does not start with #define is not an XPM file.

XPM 2

XPM 2 has the same four parts as XPM 3, in the same order and with the same contents: a values line, ncolors colour lines with the keys c, g, g4, m and s, height pixel lines, and optional extensions ending XPMENDEXT. In the plain syntax each part is one line of the file, with no quotes and no commas, and a line starting with ! is a comment.

! XPM2
4 3 2 1
. c None
# c #000000
.##.
####
.##.

A colour line’s first cpp characters are its pixel code, whatever they are, exactly as in XPM 3. The C and Lisp syntaxes put each line in double quotes, C separating them with commas and Lisp with new lines inside (setq name '( … )).

XPM 1

An XPM 1 file starts with a define whose name ends in _format, then four more defines, in any order, each exactly once:

Then come two arrays of strings. In the colours array each colour is two strings: its pixel code, then its colour as a name or # RGB value. There are no keys; the colour is used as the c colour. The pixels array has one string per row, as in XPM 3. XPM 1 has no hotspot and no extensions.

#define dot_format 1
#define dot_width 4
#define dot_height 3
#define dot_ncolors 2
#define dot_chars_per_pixel 1
static char *dot_colors[] = {
   ".", "white",
   "#", "black"
};
static char *dot_pixels[] = {
".##.",
"####",
".##."
};