LocoScript 1 file format

This is my best guess at the LocoScript 1 file format, based on examining a variety of documents.

LocoScript 1 saves its files on CP/M-formatted discs, and therefore uses CP/M conventions such as 8.3 filenames and 128-byte records.

A byte is 8 bits. A word is 16 bits, in little-endian format.

Header

Nearly all LocoScript files start with a 128-byte header, and the LocoScript 1 document is no exception.

Offset	Size	Description
0x00	3	Magic number: 'JOY'
0x03	word	File format version number. For LocoScript 1 this is 0x101, i.e. 1.1
0x05	90	File identity. Three lines of 30 bytes each, PCW extended ASCII.
0x5F	byte	Maximum number of layouts.
0x60	byte	Maximum number of tabs per layout.
0x61	byte	Decimal point character (usually . or , )
0x62	byte	Zero character (0x30 for slashed zero, 0x7F for unslashed)
0x63	byte	0xFF if widows and orphans are allowed, 0 if not.
0x64	byte	0xFF if paragraphs can be broken across a page, 0 if not.
0x65	byte	Bitmask of which word-processing codes to show. Bit 0: Show codes Bit 1: Show rulers Bit 2: Show blanks Bit 3: Show spaces Bit 4: Do not show effectors (paragraph / tab symbols)
0x66	3	unknown
0x69	word	page length in half-lines
0x6B	word	Number of first page in the file.
0x6D	word	Number of last page in the file.
0x6F	byte	Page numbering scheme: 0xFF: All the same 0x00: Odd / even pages differ 0x01: First page differs 0x02: Last page differs
0x70	byte	Header height, in half-lines
0x71	byte	Header start row, in half-lines
0x72	byte	Header omit flags: Bit 7 set: omit first page header Bit 0 set: omit last page header
0x73	4	Unknown
0x77	byte	Footer height, in half-lines
0x71	byte	Footer start row, in half-lines
0x72	byte	Footer omit flags: Bit 7 set: omit first page footer Bit 0 set: omit last page footer
0x7A	4	Unknown
0x7E	byte	Number of the 128-byte record containing the first chunk (see below).
0x7F	byte

Layouts

The layouts are stored immediately following the header (i.e. at offset 128). The length of each layout is 10 bytes plus the number of tab stops (header byte 0x60).

The format of a layout is:

Offset	Size	Description
0x00	byte	Character pitch. Bits 0-5 give character width in 16ths of an inch: 0x18 => 10cpi 0x14 => 12cpi 0x10 => 15cpi 0x0E => 17cpi 0x00 => proportional Bit 6 set for double width.
0x01	byte	Line pitch, in 432ths of an inch, so 0x48 for 6lpi, 0x36 for 8lpi.
0x02	byte	Line spacing, in half-lines; so 1 for half-spaced, 2 for normal-spaced, etc.
0x03	byte	Default character style: Bit 1: Word underline (underline words but not spaces) Bit 2: Underline Bit 3: Reverse video Bit 4: Doublestrike Bit 5: Italic Bit 6: ? Bit 7: Justified?
0x04	byte	Left margin position.
0x05	byte	Right margin position.
0x06	byte	Count of left tabs.
0x07	byte	Count of right tabs.
0x08	byte	Count of centre tabs.
0x09	byte	Count of decimal tabs.
0x0A	variable	Tab stops. First the positions of all the left tabs, then all the right tabs, then centre, then decimal.

The Document content

The document starts at offset 128 * byte 0x7E of the header. It consists of a number of chunks, each of which is a multiple of 128 bytes long. The format of a chunk is:

Offset	Size	Description
0x00	byte	Length, in 128-byte records.
0x01	byte	0 (high byte of length?)
0x02	byte	Flags: Bit 0 set => Last chunk of this page. Bit 7 set => First chunk of this page.
0x03	4	Unknown
0x07	byte	Number of currently- selected layout (0-based)
0x08	byte	Line alignment (details not known)
0x09	byte	Current character pitch (cf byte 0x00 of the layout). Bit 7 set if this is the default pitch.
0x0A	byte	Current line pitch (cf byte 0x01 of the layout). Bit 7 set if this is the default pitch.
0x0B	byte	Current line spacing (cf byte 0x02 of the layout). Bit 7 set if this is the default spacing.
0x0C	byte	Current character style (cf byte 0x03 of the layout).
0x0D	variable	Text and markup

In the text, characters 0x00-0x7F and 0xA0-0xFF are printable, using the PCW character set. This is the same character set used by CP/M on the Spectrum +3. Characters 0x80-0x9F are markup codes:

Code	Description
0x80	End of chunk.
0x81	Space (0x20 is used for hard spaces, i.e. those which do not permit the line to be broken).
0x82 0x00	(LastLine) code - break page after this line.
0x82 0x01	Form feed - break page now.
0x82 0x02	Hyphen (0x2D is used for hard hyphens).
0x82 0x03	Soft space.
0x82 0x04	Insert current page number,
0x82 0x05	Insert last page number.
0x82 0x06	Appears to be a combined carriage return and (-ReV). Does not appear in live documents, but is decoded as that if inserted using a binary editor.
0x82 0x07	Appears to be a combined carriage return and (+ReV). Does not appear in live documents, but is decoded as that if inserted using a binary editor.
0x82 0x08	(SiC) - the word containing this code is spelt correctly. Added some time between LocoScript 1.20 and 1.40.
0x83 0x00	(+Bold) Bold on
0x83 0x01	(+Wordul) Word underline on
0x83 0x02	(+UL) Underline on
0x83 0x03	(+ReV) Reverse video on
0x83 0x04	(+Double) Doublestrike on
0x83 0x05	(+Italic) Italic on
0x83 0x06	(+SupeR) Superscript on
0x83 0x07	(+SuB) Subscript on
0x83 0x08	(+Mail) Begin LocoMail macro. Added some time between LocoScript 1.20 and 1.40.
0x84 0x00	(-Bold) Bold off
0x84 0x01	(-Wordul) Word underline off
0x84 0x02	(-UL) Underline off
0x84 0x03	(-ReV) Reverse video off
0x84 0x04	(-Double) Doublestrike off
0x84 0x05	(-Italic) Italic off
0x84 0x06	(-SupeR) Superscript off
0x84 0x07	(-SuB) Subscript off
0x84 0x08	(-Mail) End LocoMail macro.
0x85 0x00 0x00	Soft hyphen.
0x85 0x00 0x`nn`	(0x`nn` > 0) Soft linebreak.
0x85 0x02 0x`nn`	(+LayouT) Select layout 0x`nn`
0x85 0x03 0x`nn`	(+LPitch) Set line pitch 0x`nn`. As in the layout, this is specified in 432ths of an inch. If bit 7 of the pitch is set, this is a (-LPitch) command; the value being selected is the default.
0x85 0x04 0x`nn`	(+LSpace) Set line spacing 0x`nn`. As in the layout, this is specified in half-lines. If bit 7 of the vlaue is set, this is a (-LSPace) command; the value being selected is the default.
0x85 0x05 0x`nn`	(+Pitch) Set character pitch 0x`nn`. As in the layout, this is specified in half-lines. If bit 7 of the vlaue is set, this is a (-Pitch) command; the value being selected is the default.
0x85 0x06 0x`nn`	(+Keep) Keep the following 0x`nn` lines together.
0x85 0x07 0x`nn`	(-Keep) Keep the previous 0x`nn` lines together.
0x86 0x`nn` 0x`mm`	Start of line. The two following bytes are a little-endian Z80 word, giving the distance of the right-hand end of the line from the right margin, in 240ths (?) of an inch.
0x88 0x`nn`	End of line. `nn` is: 0x01 => soft end-of-line (normal wrapping) 0x02 => hard end-of-line (paragraph) 0x03 => Unit 0x04 => Tab } These 4 not found in live documents, 0x05 => Indent tab } but LS1 interprets them thus if they're 0x06 => Centre } inserted manually 0x07 => Right align } 0x08 => Carriage return? Seems to be used at the start of some pages.
0x89 0x`aa` 0x`bb` 0x`cc` 0x`dd`	Change horizontal position. `aa` is the code that caused realignment: 0x00 => Layout change causes left margin to move 0x01 => soft end-of-line (normal wrapping) 0x02 => hard end-of-line (paragraph) 0x03 => Unit 0x04 => Tab. 0x05 => Indent tab 0x06 => Centre. 0x07 => Right align. `bb` is the new X position in characters. `cc` and `dd` is the new position in 240ths of an inch (not sure where it's measured from).
0x8A 0x`aa` 0x`bb` 0x`cc` 0x`dd` 0x`ee`	Justified text. The first byte is: 0x01 => End-of-line (caused by text wrapping). If there are no packing spaces to be inserted, the standard 0x88 0x01 end-of-line is used. 0x02 => Start justified paragraph. 0x08 => A justified version of the 0x88 0x08 carriage return code? Other bytes unknown.
0x89 0x`aa` 0x`bb` 0x`cc` 0x`dd` 0x`ee` 0x`ff` 0x`gg`	Justified version of the 0x89 code. The first 5 bytes are the same as this code. Other bytes unknown.
0x8C-0x9F	Do not appear to be used.