Update Fontrix font converter

We now allow the conversion to be a sample string or a glyph grid,
using the same approach as the IIgs bitmap font converter.

FileConv/Gfx/Fontrix-notes.md

@@ -1,51 +1,69 @@
 # Fontrix Fonts #
 
 File types:
-
-- BIN / $6400: Fontrix Font File
+ - BIN / $6400: Fontrix Font File
 
 Primary references:
+ - Reverse engineering
+
+Font filenames generally start with "SET.".
+
+## General ##
 
-- Reverse engineering
+Fontrix was a desktop publishing application for the Apple II.  Developed by Data Transforms, Inc.,
+it could generate large, detailed graphics ("16 times larger than the Apple screen"), combining
+graphics with text rendered in custom fonts.
 
-## Fonts ##
+A series of "fontpaks" were released, each of which had ten fonts.  At one point the company
+was offering $100 for original font designs.
+
+## Font File Structure ##
 
 Each font contains between 1 and 94 characters.
 
 Character data is stored one bit per pixel, where 0 indicated background and 1 is foreground. Data
-for each glyph is stored in byte order from left to right, top to bottom,  with the left-most pixel
+for each glyph is stored in byte order from left to right, top to bottom, with the left-most pixel
 of each byte stored in the LSB.  Glyph data is referenced by a pointer into the file for each
-character.  Fonts need not contain all characters; there are values identifying  the first character
+character.  Fonts need not contain all characters; there are values identifying the first character
 and number of characters included in the file.  Regardless of how many characters are included,
 there are always 96 data pointers, representing ASCII values 32 through 127, although the first and
-last characters are never defined nor used by Fontrix. Although the is not necessarily glyph data
-provided for it, the offset for character 127 always points to the first byte beyond the  glyph data
+last characters are never defined nor used by Fontrix. Although there is not necessarily glyph data
+provided for it, the offset for character 127 always points to the first byte beyond the glyph data
 for character 126.
 
-The glyph data is always mapped sequentially
-and the width in bytes of a character can be determined by the difference between its data offset
-and that of the following character, divided by the given glyph height.
+The glyph data is always mapped sequentially, and the width in bytes of a character can be
+determined by the difference between its data offset and that of the following character,
+divided by the given glyph height.
 
 Offsets $0E2-$141 appear to potentially be the individual character widths for proportional fonts,
 although further research needs to be done to confirm this.
 
-The file format is:
+The Fontrix font editor allows glyph cells to be 1-32 pixels wide, and 1-32 pixels high, inclusive.
 
+The file format is:
+```
++$000 /  1: Unknown byte (usually $02)
++$001 / 15: Font Name, encoded in low ASCII, padded with spaces
++$010 /  1: Number of characters in file
++$011 /  1: ASCII value of first encoded character
++$012 /  1: Proportional flag.  0 = Non-proportional, 1 = Proportional
++$013 /  1: Non-Proportional font glyph width. For proportional fonts this seems to be an average.
++$014 /  1: Font height
++$015 /  1: Unknown byte
++$016 /  2: Font file size. This is little-endian encoded.
++$018 /  3: Identifier bytes.  All Fontrix fonts have a fixed sequence of $90/$F7/$B2 here.
++$01B /  5: Unknown bytes
++$020 /192: Character data offsets. 96 little-endian offsets from start of file. There are offsets
+            for characters 32 (space) and 127 (del) although they are not used in Fontrix.
++$0E2 / 96: Unknown bytes.  These may be width or spacing data for proportional fonts.
++$142 / 62: Unknown bytes.  Usually 0 filled.
++$180 / nn: Character glyph data.
 ```
-+$000/001: - Unknown byte
-+$001/015: - Font Name, encoded in low ASCII
-+$010/001: - Number of characters in file
-+$011/001: - ASCII value of first encoded character
-+$012/001: - Proportional flag.  0 = Non-proportional/1 = Proportional
-+$013/001: - Non-Proportional font glyph width. For proportional fonts this seems to be an average
-+$014/001: - Font height
-+$015/001: - Unknown byte
-+$016/002: - Font file size. This is little-endian encoded. 
-+$018/003: - Identifier bytes.  All Fontrix fonts have a fixed sequence of $90/$F7/$B2 here.
-+$01B/005: - Unknown bytes
-+$020/192: - Character data offsets. 96 little-endian offsets from start of file. There are offsets
-             for characters 32 (space) and 127 (del) although they are not used in Fontrix.
-+$0E2/096: - Unknown bytes.  These may be width or spacing data for proportional fonts.
-+$142/062: - Unknown bytes.  Usually 0 filled.
-+$180/nnn: - Character glyph data.  
-```
+
+## Rendering Notes ##
+
+When creating a "GRAFFILE" with Fontrix, the space between glyphs is configurable, with a default
+of one pixel.  Space characters aren't stored explicitly; rather, they're determined by "the size
+of the last character accessed plus the size of the space between characters."  For a
+non-proportional font that makes perfect sense, for a proportional font that can cause some
+variability.