OpenEuphoria

2. Re: Font Format (.f)

• Posted by Jiri Babor <J.Babor at GNS.CRI.NZ> Jan 27, 1999
• 358 views

Chris Cox wrote:

>Would anyone here happen to have any information
>about the file format used for the .f fonts in Jiri Babor's
>(excellent) 'font.e' library? I've been hoping to try to
>make my own fonts for this, but can't seem to find the
>information needed.


It's actually quite simple and you can find it at the beginning of the
font.e include. I quote:

--  font file format
--      byte 1: ascii code of the first char
--      byte 2: ascii code of the last char
--      byte 3: width in bytes
--      byte 4: height in pixels
--      byte 5: version                           unused
--      byte 6: baseline height
--      next block of bytes: actual char widths
--      next block of bytes: simple char bitmaps, left-to-right, top-to-bottom


In other words, each file has its own six byte header. The header is
followed by a list of *actual* widths, in *pixels*, a separate byte
for each character.

Only one *contiguous* (solid, no gaps) block of characters can be
saved in the file. Individual characters are stored as bitmaps of
*fixed* dimensions: the width (in bytes) given in byte 3 and the total
(nominal) height (in pixel rows) in byte 4.

So, for example, if we have a  (common) set starting with the space
character (ascii 32) to ascii 127, the width of the fattest character
13 pixels, and the nominal font height is 16 pixels, the header would
be something like this:

    byte 1:  32
    byte 2: 127
    byte 3:   2     -- 2 bytes (=16 bits) required for 13 pixels
    byte 4:  16
    byte 5:   4     -- current version, unused
    byte 6:  12     -- height of chars *without* descenders

This would be followed by 96 (127-32+1) width bytes and that, in turn,
by 96 32 (2*16) byte blocks (bitmaps).

Caution: bitmap bytes store pixels in reverse order to that obtained
by int_to_bits() function! So instead of using int_to_bits() and
reverse() pair, fetch my own one line conversion from font.e - it's
much faster anyway.

jiri