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+The fv1 font format has the following characteristics:-
+
+1) Bitmap fonts (i.e. pixels are on or off)
+2) 96 DPI is assumed
+3) Glyphs from U+0020 up to a pre-defined limit are stored in the file.
+   At the time of writing this limit is U+4DFF. To change the limit
+   requires a change to xrdp/xrdp_types.h and (potentially)
+   fontutils/mkfv1.c
+4) Font format is header, plus a variable data area for each glyph.
+
+The intention (over time) is to build support for the freetype2 library
+directly into xrdp. This will allow for modern font features like
+anti-aliasing and kerning to be supported.
+
+General Info
+------------
+All numeric values are 2 octets, and stored in twos-complement
+little-endian format.
+
+Dimensions are all measured in pixels.
+
+Font header
+-----------
+
+signature     4 octets   File signature - "FNT1"
+font~name    32 octets   Null-terminated if less that 32 octets long
+point_size    2 octets   Assumes 96 DPI.
+style         2 octets   Unused. Set to 1.
+body_height   2 octets   Line spacing for font.
+min_descender 2 octets   The common lowest descender value in the font
+                         glyphs (A few glyphs may be lower than
+                         this). Used to calculate where the font baseline
+                         is in relation to the text box for the font.
+<padding>     4 octets   Set to zero.
+
+Older fonts, generated for xrdp v.0.9x and earlier, have zero values
+for the body_height and min_descender. For these fonts, the body height is
+calculated as (-baseline + 1) for the first glyph, and the glyphs are
+all offset so that a min_descender of 0 works OK.
+
+Glyph data
+----------
+The header is followed by a number of glyphs representing U+0020 upwards. The
+glyphs have a variable size. The format of each glyph is as follows:-
+
+width         2 octets   Width of character data
+height        2 octets   Height of character data
+baseline      2 octets   Offset from font baseline to 1st row of glyph data
+offset        2 octets   Space before glyph is drawn (can be -ve)
+inc_by        2 octets   Total width of glyph + spacing. The width of
+                         a string is obtained by adding up all the inc_by
+                         fields for all the glyphs
+data          <variable> Bitmap data.
+
+Bitmap data is laid out in rows from top to bottom.  Within each row the
+most significant bit of each octet is on the left.  Row data is padded
+to the nearest octet (e.g. a 14 bit width would be padded by 2 bits to
+16 bits (2 octets). The total data is padded out with between 0 and 3
+octets to end on a 4-octet boundary.
+
+Example glyph:-
+
+Glyph : U+0067
+  Width : 12
+  Height : 18
+  Baseline : -13
+  Offset : 1
+  Inc By : 15
+  Data :
+    -13: ...XXXXX..XX    1F 30
+    -12: ..XXXXXXXXXX    3F F0
+    -11: .XXX....XXXX    70 F0
+    -10: XXX......XXX    E0 70
+     -9: XX........XX    C0 30
+     -8: XX........XX    C0 30
+     -7: XX........XX    C0 30
+     -6: XX........XX    C0 30
+     -5: XX........XX    C0 30
+     -4: XXX......XXX    E0 70
+     -3: .XXX....XXXX    70 F0
+     -2: ..XXXXXXXXXX    3F F0
+     -1: ...XXXXX..XX    1F 30
+     +0: ..........XX    00 30
+     +1: .........XXX    00 70
+     +2: ..X.....XXX.    20 E0
+     +3: ..XXXXXXXX..    3F C0
+     +4: ...XXXXXX...    1F 80