a2d/APIs.md

DeskTop APIs

There are three distinct API classes that need to be used:

• MouseGraphics ToolKit - graphics primitives, windowing and events
• DeskTop Jump Table - simple JSR calls starting at $4003 MAIN, no arguments
• DeskTop API - another MLI-style interface starting at $8E00 AUX

In addition, some DeskTop data structures can be accessed directly.

MouseGraphics ToolKit

This is a complex API library written by Apple circa 1985. It consists of:

• Graphics Primitives - screen management, lines, rects, polys, text, patterns, pens
• Mouse Graphics - windows, menus, events, cursors

Entry point is fixed at $4000 AUX, called MLI-style (JSR followed by command type and address of param block).

See MGTK.md for further documentation.

DeskTop Jump Table

Call from MAIN (RAMRDOFF/RAMWRTOFF); AUX language card RAM must be banked in. Call style:

   jsr $xxxx

Some calls take parameters in registers.

NOTE: Not all of the calls have been identified. Routines marked with * are used by Desk Accessories.

JUMP_TABLE_MAIN_LOOP ($4000)

Enter DeskTop main loop

JUMP_TABLE_MGTK_RELAY ($4003)

MGTK relay call (main>aux)

JUMP_TABLE_SIZE_STRING ($4006)

Compose "nnn Blocks" string into internal buffer

JUMP_TABLE_DATE_STRING ($4009)

Compose date string into internal buffer

JUMP_TABLE_0C ($400C)

???

JUMP_TABLE_0F ($400F)

Auxload

JUMP_TABLE_EJECT ($4012)

Eject command

JUMP_TABLE_REDRAW_ALL ($4015) *

Redraws all DeskTop windows. Required after a drag or resize. Follow with DT_REDRAW_ICONS call.

JUMP_TABLE_DESKTOP_RELAY ($4018)

DESKTOP relay call (main>aux)

JUMP_TABLE_LOAD_OVL ($401B)

Load overlay routine

JUMP_TABLE_CLEAR_SEL ($401E) *

Deselect all DeskTop icons (volumes/files).

JUMP_TABLE_MLI ($4021)

ProDOS MLI call (Y=call, X,A=params addr) *

JUMP_TABLE_COPY_TO_BUF ($4024)

Copy to buffer

JUMP_TABLE_COPY_FROM_BUF:= ($4027)

Copy from buffer

JUMP_TABLE_NOOP ($402A)

No-Op command (RTS)

JUMP_TABLE_2D ($402D)

??? (Draw type/size/date in non-icon views?)

JUMP_TABLE_ALERT_0 ($4030)

Show alert 0

JUMP_TABLE_ALERT_X ($4033)

Show alert X

JUMP_TABLE_LAUNCH_FILE ($4036)

Launch file

JUMP_TABLE_CUR_POINTER ($4039) *

Changes mouse cursor to pointer.

JUMP_TABLE_CUR_WATCH ($403C)

Changes mouse cursor to watch.

JUMP_TABLE_RESTORE_OVL ($403F)

Restore from overlay routine

DeskTop API

Call from AUX (RAMRDON/RAMWRTON). Call style:

   jsr $8E00
   .byte command
   .addr params

NOTE: Only some of the calls have been identified.

Commands:

DT_ADD_ICON ($01)

Parameters: { addr icondata }

DT_HIGHLIGHT_ICON ($02)

Parameters: { byte icon }

DT_UNHIGHLIGHT_ICON ($03)

Parameters: { byte icon }

DT_CLOSE_WINDOW ($07)

Parameters: { byte window_id }

DT_FIND_ICON ($09)

Parameters: { word mousex, word mousey, (out) byte result }

DT_REDRAW_ICONS ($0C)

Parameters: none (pass $0000 as address)

Redraws the icons on the desktop (mounted volumes, trash). This call is required after destroying, moving, or resizing a window.

DT_ICON_IN_RECT ($0D)

Parameters: { byte icon, rect bounds }

DeskTop Data Structures

DeskTop's state - selection, windows, icons - is only partially accessible via APIs. Operations such as opening the selected file requires accessing internal data structures directly.

Selection

• path_index (byte) - id of active window in path_table

• selected_file_count (byte) - number of selected icons

• selected_file_list (array of bytes) - ids of selected icons

Window - representing an open directory

• path_table (array of addrs) - maps window id to window record address

Window record: 65-byte pathname buffer; it is a length-prefixed absolute path (e.g. /HD/GAMES)

Icon - representing a file (in a window) or volume (on the desktop)

• file_table (array of addrs) - maps icon id to icon record address

Icon record: 27-byte structure optimized for rendering the file/volume icon.

.byte icon      icon index
.byte ??
.byte type/window_id
                (bits 0-3 window_id)
                (bits 4,5,6)
                       000 = directory
                       001 = system
                       010 = binary
                       011 = basic
                       100 = (unused)
                       101 = text/generic
                       110 = (unused)
                       111 = trash
                (bit 7 = open flag)
.word iconx     (pixels)
.word icony     (pixels)
.addr iconbits  (addr of {mapbits, mapwidth, reserved, maprect})
.byte len       (name length + 2)
.res  17  name  (name, with a space before and after)