LPL Addons

To compile an LPL plugin, you need the 1-2-3 DOS ADK, I have a copy available here. These files were thought to be lost for many years, thanks to scenelist for recovering them from their classic BBS collection!

Types and Names

There are four types of drivers, DISPLAY, PRINTER, FILE, and LINK.

Drivers must follow a naming convention that 123 uses to determine what type of driver it is. The filename format is L13XYYYY.DLZ

              ┌→ Release 3
     Lotus ←┐ │ ┌→ Name
            ↓ ↓ ↓
            L13XYYYY.DLZ ← Platform, D (DOS) or W (Windows)
             ↑ ↑
      1-2-3 ←┘ └→ Type, D, P, F, or L

If you have a DRV file, that is from an earlier 123 release. If you have a DLD file that does not follow this naming convention, then it is an addin and not a driver. The difference is simply what APIs are exposed when loaded and what exports 123 expects to find.

Using the wrong code or trying to load a driver as an addin will cause 123 to crash, because they all use different APIs.

The purpose of DISPLAY and PRINTER drivers is obvious. FILE drivers allow i/o from new file formats, and LINK drivers allow 123 to interact with a database or other data source.

Drivers are shipped with configuration files in a binary format called a BUNDLE. A bundle contains a short header followed by a series of TLV (Tag, Length, Value) records. This allows some configuration of the driver during installation, such as fonts, colors, charset, resolution, etc.

Note: The BUNDLE related APIs use the prefix BDL.

See the description of VBD files for an example, a VBD is a Video Bundle.

Sources of information

• I have the 123R4W ADK, which includes a 123R3 compatability library for addins, but not drivers.

I converted the adk hlp file to html, if you’re interested.

• US patent US5475836 has some high-level overview of the DVLINK (Driver Link) and DBLINK (Database Link) interfaces.
• The driver for the Siemens Highprint 7400 printer has some CodeView debugging data (type NB02, meaning they used link.exe 5.20 or earlier from around 1988).

Here is the driver, and I’ve dumped the CodeView data.

• Some versions of UNARJD.DLD have CodeView debugging data (type NB09, probably using Visual C++ 1.0 from 1993 or so). Here is a sample.

• The XALERT addin for 123 on SunOS4/SPARC (wtf!) was accidentally compiled with stabs enabled, which was very detailed.

Here is the lucky addin, and I’ve dumped the stabs.

• There is an OS/2 “Tech Pack” which included some sample addins with source code. I have a copy here.

• The REXXLINK addin for OS/2 included some of the LEP (Lotus External Programming) headers. I have a copy here.

• The book “Lotus Add-in Toolkit Guide” by Robert Ainsbury, ISBN 0880225505.

• PC Magazine Volume 10, Number 7 (April 16, 1991) included a (non-technical) overview of add-in capabilities in the story “Building The Perfect Spreadsheet”.

Mirror available Here

• The IBM Developer Connection Advanced CD-ROM has some newer ADKs, but while interesting, it doesn’t have much relevance to 123R3.

I do have the R9 (I think?) ADK, it’s of no interest to me but maybe someone else wants it.

************************************
*                                  *
*         SCO Professional         *
*         ( 386 Version )          *
*                                  *
*  Portions Copyright (c) 1985-88  *
*  The Santa Cruz Operation, Inc.  *
*   Portions Copyright (c) 1985    *
*   VIP Technologies Corporation   *
*       All Rights Reserved        *
*          Version 2.0.0           *
*            sco001429             *
************************************

$ objdump -p 123.o | grep Date
Time/Date               Sat Sep  8 06:23:50 1990

Siemens Highprint 7400

The file L13PSI74.DLD is a third-party print driver presumably developed by Siemens. I found a copy on a shareware archive, and was surprised to find it had some embedded CodeView data.

It was an ancient verion that no modern tools could parse, I even tried old tools like TDUMP, CVDUMP and and SYMDEB. I did eventually find an old debugger that could dump it. Unfortunately, it was quite a challenge extracting the output - it had no way to save output to a file except “printing” your backlog, and the backlog wasn’t big enough to hold all the data!

I had to script a DOS emulator to scrape the data out a page at a time! I can’t tell you how much time I wasted getting this working, but it was worth it, it gave some valuable hints about how the DEVPRIM API worked.

XALERT addin for SunOS

The Lotus FTP server had a few official addins still available to download after all these years, and amazingly one was mistakenly compiled with very detailed stabs data.

That addin was alert.so1, the XALERT addin for SunOS4. It’s a SPARC demand paged shared library, which is a long-obsolete format.

I was able to find an older version of GNU binutils that still supported a.out-sunos-big, and could dump it.

The structure names and enums were remarkably helpful, even though it’s for an entirely different platform.

123R4W Addin Development Kit

I sadly do not have the 123R4D or 123R3 development kits, but I do have the 123R4W kit. This includes headers, libraries and a comprehensive HLP library.

.
├── [        512 Feb 16 07:17]  BINB
│   └── [     228080 Jun 10  1993]  LRC.EXE
├── [        512 Feb 16 07:26]  HELP
│   ├── [      20928 Feb 20 18:44]  ADKREF.GID
│   ├── [     611855 Jul 26  1993]  ADKREF.HLP
│   └── [        766 Dec 27  1992]  ADKREF.ICO
├── [        512 Feb 20 22:41]  INCLUDE
│   ├── [      10788 Jul 29  1993]  GUITYPES.RC
│   ├── [      23469 Jul 29  1993]  KEYCODE.H
│   ├── [       3372 Jul 29  1993]  LCIAF.H
│   ├── [      23400 Jul 29  1993]  LCIATFNC.H
│   ├── [      11962 Jul 29  1993]  LCICELL.H
│   ├── [      10909 Jul 29  1993]  LCICOMN.H
│   ├── [      19826 Jul 29  1993]  LCIENUM.H
│   ├── [       7873 Jul 29  1993]  LCIERROR.H
│   ├── [       4487 Jul 29  1993]  LCIEVENT.H
│   ├── [      26115 Jul 29  1993]  LCIEVENT.T
│   ├── [       8956 Jul 29  1993]  LCIGUI.H
│   ├── [       3534 Jul 29  1993]  LCILD.H
│   ├── [       6465 Jul 29  1993]  LCIMATH.H
│   ├── [       8656 Jul 29  1993]  LCIMB.H
│   ├── [        902 Jul 29  1993]  LCIMBLIB.H
│   ├── [       2332 Jul 29  1993]  LCIMC.H
│   ├── [      11499 Jul 29  1993]  LCIRANGE.H
│   ├── [       5823 Jul 29  1993]  LCISHEET.H
│   ├── [       5265 Jul 29  1993]  LCIUTIL.H
│   ├── [       9116 Jul 29  1993]  LCIWFILE.H
│   ├── [      12990 Jul 29  1993]  LCIWKSPC.H
│   ├── [       1390 Jul 29  1993]  LPIMEMM.H
│   ├── [       9335 Jul 29  1993]  LPIMEMM.T
│   ├── [       9568 Jul 29  1993]  LPIPRIM.H
│   ├── [       2399 Jul 29  1993]  LPIXPORT.H
│   ├── [      44708 Jul 29  1993]  LPXATFNC.H
│   ├── [      19643 Jul 29  1993]  LPXCELL.H
│   ├── [       1781 Jul 29  1993]  LPXCOMN.H
│   ├── [      20236 Jul 29  1993]  LPXDEFS.H
│   ├── [      12832 Jul 29  1993]  LPXENUM.H
│   ├── [       7590 Jul 29  1993]  LPXERROR.H
│   ├── [       1959 Jul 29  1993]  LPXMACRO.H
│   ├── [       4966 Jul 29  1993]  LPXMATH.H
│   ├── [      23952 Jul 29  1993]  LPXRANGE.H
│   ├── [      11743 Jul 29  1993]  LPXSHEET.H
│   ├── [       2423 Jul 29  1993]  LPXUTIL.H
│   ├── [      18223 Jul 29  1993]  LPXWFILE.H
│   ├── [      17015 Jul 29  1993]  LPXWKSPC.H
│   ├── [      20055 Jul 29  1993]  LRCDEFS.H
│   ├── [       5704 Jul 29  1993]  LTSCNTRL.H
│   ├── [      21294 Jul 29  1993]  LTSDEFS.H
│   ├── [       3876 Jul 29  1993]  LTSSTRCT.H
│   └── [      47128 Jul 29  1993]  WINRESID.H
├── [        512 Feb 19 16:03]  LIB
│   ├── [      67072 Jul 29  1993]  LCI.LIB
│   ├── [       3558 Jun 10  1993]  LIBMAIN.OBJ
│   ├── [      16384 Jun 10  1993]  LMBSRVW.LIB
│   ├── [      72704 Jun 10  1993]  LPIMISC.LIB
│   └── [       3408 Jun 10  1993]  WEP.OBJ
├── [      12341 Jul 27  1993]  READ.ME
└── [        512 Feb 19 16:04]  SAMPLES
    ├── [        512 Feb 16 07:16]  ADDMENU
    │   ├── [        485 Jul 29  1993]  ADDMENU.BMK
    │   ├── [      15944 Jul 29  1993]  ADDMENU.C
    │   ├── [        568 Jul 29  1993]  ADDMENU.DEF
    │   ├── [       2237 Jul 29  1993]  ADDMENU.H
    │   ├── [       2384 Jul 29  1993]  ADDMENU.MAK
    │   ├── [       1022 Jul 29  1993]  ADDMENU.NMK
    │   └── [       1606 Jul 29  1993]  ADDMENU.RC
    ├── [        512 Feb 16 07:16]  ADNDLG
    │   ├── [        528 Jul 29  1993]  ADNDLG.BMK
    │   ├── [      12134 Jul 29  1993]  ADNDLG.C
    │   ├── [        566 Jul 29  1993]  ADNDLG.DEF
    │   ├── [       2585 Jul 29  1993]  ADNDLG.H
    │   ├── [       2439 Jul 29  1993]  ADNDLG.MAK
    │   ├── [       1161 Jul 29  1993]  ADNDLG.NMK
    │   └── [       3157 Jul 29  1993]  ADNDLG.RC
    ├── [        512 Feb 16 07:16]  ADNMDI
    │   ├── [        528 Jul 29  1993]  ADNMDI.BMK
    │   ├── [      11067 Jul 29  1993]  ADNMDI.C
    │   ├── [        578 Jul 29  1993]  ADNMDI.DEF
    │   ├── [       2451 Jul 29  1993]  ADNMDI.H
    │   ├── [       2439 Jul 29  1993]  ADNMDI.MAK
    │   ├── [       1159 Jul 29  1993]  ADNMDI.NMK
    │   └── [       3539 Jul 29  1993]  ADNMDI.RC
    ├── [        512 Feb 16 07:17]  AFHELLO
    │   ├── [        633 Jul 29  1993]  AFHELLO.BMK
    │   ├── [       4577 Jul 29  1993]  AFHELLO.C
    │   ├── [        552 Jul 29  1993]  AFHELLO.DEF
    │   ├── [       2233 Jul 29  1993]  AFHELLO.MAK
    │   └── [       1010 Jul 29  1993]  AFHELLO.NMK
    ├── [        512 Feb 16 07:17]  AMORT
    │   ├── [        607 Jul 29  1993]  AMORT.BMK
    │   ├── [      19650 Jul 29  1993]  AMORT.C
    │   ├── [        548 Jul 29  1993]  AMORT.DEF
    │   ├── [       2259 Jul 29  1993]  AMORT.MAK
    │   └── [       1004 Jul 29  1993]  AMORT.NMK
    ├── [        512 Feb 16 07:17]  COLORS
    │   ├── [        652 Jul 29  1993]  COLORS.BMK
    │   ├── [      20170 Jul 29  1993]  COLORS.C
    │   ├── [        578 Jul 29  1993]  COLORS.DEF
    │   ├── [       5049 Jul 29  1993]  COLORS.H
    │   ├── [        766 Oct  8  1991]  COLORS.ICO
    │   ├── [       2439 Jul 29  1993]  COLORS.MAK
    │   ├── [       1167 Jul 29  1993]  COLORS.NMK
    │   └── [       8030 Jul 29  1993]  COLORS.RC
    ├── [        512 Feb 16 07:17]  DEMO
    │   ├── [       5632 Jul 29  1993]  ADDMENU.ADW
    │   ├── [      37316 Jul 22  1993]  ADKDEMO.WK4
    │   ├── [       6144 Jul 29  1993]  ADNDLG.ADW
    │   ├── [       8704 Jul 29  1993]  ADNMDI.ADW
    │   ├── [       2784 Jul 29  1993]  AFHELLO.ADW
    │   ├── [       5376 Jul 29  1993]  AMORT.ADW
    │   ├── [      15360 Jul 29  1993]  COLORS.ADW
    │   ├── [       8704 Jul 29  1993]  FILEMEMO.ADW
    │   ├── [       7680 Jul 29  1993]  LMBCS.ADW
    │   ├── [       2784 Jul 29  1993]  MCHELLO.ADW
    │   ├── [       3792 Jul 29  1993]  MYSUM.ADW
    │   ├── [       2768 Jul 29  1993]  NAVIGATE.ADW
    │   ├── [       3536 Jul 29  1993]  UNDOEX.ADW
    │   ├── [      12800 Jul 29  1993]  WECYCLE.ADW
    │   └── [       2752 Jul 29  1993]  WIDTHX2.ADW
    ├── [        512 Feb 16 07:17]  FILEMEMO
    │   ├── [        686 Jul 29  1993]  FILEMEMO.BMK
    │   ├── [      26423 Jul 29  1993]  FILEMEMO.C
    │   ├── [        626 Jul 29  1993]  FILEMEMO.DEF
    │   ├── [       1308 Jul 29  1993]  FILEMEMO.H
    │   ├── [       2850 Jul 29  1993]  FILEMEMO.MAK
    │   ├── [       1177 Jul 29  1993]  FILEMEMO.NMK
    │   └── [       3029 Jul 29  1993]  FILEMEMO.RC
    ├── [       1696 Jul 29  1993]  LIBMAIN.C
    ├── [        512 Feb 16 07:17]  LMBCS
    │   ├── [        511 Jul 29  1993]  LMBCS.BMK
    │   ├── [      12274 Jul 29  1993]  LMBCS.C
    │   ├── [        597 Jul 29  1993]  LMBCS.DEF
    │   ├── [       4279 Jul 29  1993]  LMBCS.H
    │   ├── [       2406 Jul 29  1993]  LMBCS.MAK
    │   ├── [       1154 Jul 29  1993]  LMBCS.NMK
    │   └── [       4237 Jul 29  1993]  LMBCS.RC
    ├── [        512 Feb 16 07:17]  MCHELLO
    │   ├── [        633 Jul 29  1993]  MCHELLO.BMK
    │   ├── [       5933 Jul 29  1993]  MCHELLO.C
    │   ├── [        552 Jul 29  1993]  MCHELLO.DEF
    │   ├── [       2228 Jul 29  1993]  MCHELLO.MAK
    │   └── [       1010 Jul 29  1993]  MCHELLO.NMK
    ├── [        512 Feb 16 07:17]  MYSUM
    │   ├── [        607 Jul 29  1993]  MYSUM.BMK
    │   ├── [      10805 Jul 29  1993]  MYSUM.C
    │   ├── [        548 Jul 29  1993]  MYSUM.DEF
    │   ├── [       2445 Jul 29  1993]  MYSUM.MAK
    │   └── [       1004 Jul 29  1993]  MYSUM.NMK
    ├── [        512 Feb 16 07:17]  NAVIGATE
    │   ├── [        646 Jul 29  1993]  NAVIGATE.BMK
    │   ├── [       3804 Jul 29  1993]  NAVIGATE.C
    │   ├── [        552 Jul 29  1993]  NAVIGATE.DEF
    │   ├── [       2240 Jul 29  1993]  NAVIGATE.MAK
    │   └── [       1013 Jul 29  1993]  NAVIGATE.NMK
    ├── [        512 Feb 16 07:17]  UNDOEX
    │   ├── [        620 Jul 29  1993]  UNDOEX.BMK
    │   ├── [       6751 Jul 29  1993]  UNDOEX.C
    │   ├── [        560 Jul 29  1993]  UNDOEX.DEF
    │   ├── [       2115 Jul 29  1993]  UNDOEX.MAK
    │   └── [       1007 Jul 29  1993]  UNDOEX.NMK
    ├── [        512 Feb 16 07:17]  WECYCLE
    │   ├── [        370 Jul 21  1993]  TRUCK.BMP
    │   ├── [        766 Sep  2  1991]  TRUCK.ICO
    │   ├── [        691 Jul 29  1993]  WECYCLE.BMK
    │   ├── [      19406 Jul 29  1993]  WECYCLE.C
    │   ├── [        584 Jul 29  1993]  WECYCLE.DEF
    │   ├── [       2066 Jul 29  1993]  WECYCLE.H
    │   ├── [       2984 Jul 29  1993]  WECYCLE.MAK
    │   ├── [       1180 Jul 29  1993]  WECYCLE.NMK
    │   └── [      13859 Jul 29  1993]  WECYCLE.RC
    ├── [       1545 Jul 29  1993]  WEP.C
    └── [        512 Feb 16 07:17]  WIDTHX2
        ├── [        633 Jul 29  1993]  WIDTHX2.BMK
        ├── [       4050 Jul 29  1993]  WIDTHX2.C
        ├── [        529 Jul 29  1993]  WIDTHX2.DEF
        ├── [       1969 Jul 29  1993]  WIDTHX2.MAK
        └── [       1010 Jul 29  1993]  WIDTHX2.NMK

20 directories, 158 files

1. GetDisplayInfo

This function simply copies a struct DISPLAYINFO into the far pointer provided. 123 uses this to learn the display charateristics. The DISPLAYINFO struct is given below.

Note: DriverInit() is called before GetDisplayInfo(), even though it’s declared first.

struct DISPLAYINFO_ { /* size 24 id 107 */
  short unsigned int num_text_cols; /* bitsize 16, bitpos 0 */
  short unsigned int num_text_rows; /* bitsize 16, bitpos 16 */
  short int graphics; /* bitsize 16, bitpos 32 */
  short int full_screen_graph; /* bitsize 16, bitpos 48 */
  short unsigned int hpu_per_col; /* bitsize 16, bitpos 64 */
  short unsigned int graph_cols; /* bitsize 16, bitpos 80 */
  short unsigned int graph_rows; /* bitsize 16, bitpos 96 */
  short unsigned int graph_col_res; /* bitsize 16, bitpos 112 */
  short unsigned int graph_row_res; /* bitsize 16, bitpos 128 */
  short unsigned int view_set_size; /* bitsize 16, bitpos 144 */
  short int iscolor; /* bitsize 16, bitpos 160 */
};

The prototype is:

void __pascal __far GetDisplayInfo(struct DISPLAYINFO far *dspinfo);

2. DriverInit

This function is called as soon as the device is loaded, you can use this function to initalize any data structure you want, parse configuration data, etc.

The prototype is something like:

int __pascal DriverInit(void far *drvapi,
                        struct BDLHDR far *vbdptr,
                        const char far *cfgname,
                        char deflmbcsgrp);

Return 0 if you successfully initialized, or 1 if there was an error.

The vbdptr is a BDLHDR, followed by a sequence of BDLRECHDRs.

struct BDLHDR
{
  int bdllen;
  int bdlver;
  int driver_id;
  int bundle_id;
};

struct BDLRECHDR
{
  int bdltype;
  int reclen;
};

Before this routine completes, you should use RegisterDevData to report device capabilities and graphics callbacks to 123.

struct DEVDATA
{
  int ShowMeFlag;
  int RasterHeight;
  int AspectX;
  int AspectY;
  int RHmusPerTHmu;
  int RHmuPerGHmus;
  int RVmusPerTVmu;
  int RVmuPerGVmus;
  PATT FillPatts[12];
  unsigned char ColorMap[16];
  int SrcPatD[8];
  int SrcPatS[8];
  int FIndexCnt;
  void far *FontIndex;
  int FNamesCnt;
  void far *FontNames;
  DEVPRIM DevFuncs;
};

struct DEVPRIM
{
  void (__pascal __far *scan_linx)(int, int, int, int);
  void (__pascal __far *fill_rect)(int, int, int, int, int);
  void (__pascal __far *thin_diag_line)(int, int, int, int, int);
  void (__pascal __far *thin_vert_line)(int, int, int, int);
  void (__pascal __far *shade_rect)(int, int, int, int, void far *, int);
  void (__pascal __far *fill_scan_list)();
};

struct POINT
{
  int pty;
  int ptx;
};

struct PATT
{
  POINT pattsize;
  POINT patthotSpot;
  void far *pattptr;
  POINT pattSecOffset;
};

3. DriverTerminate

This function is called when you are being unloaded, you can use it to cleanup.

int __pascal DriverTerminate();

4. ResetDisplay

This function is called when 1-2-3 exits graphics mode (e.g after the user closes a graph).

You would typically use it to switch back to text mode. The screen should be blank, ready to write text, and the cursor should be at 0,0 when complete.

int __pascal ResetDisplay();

5. SetGraphicsMode

Prepare the screen for graphics, e.g. when the user presses F10.

The screen should be blank and ready to accept drawing commands (e.g. fill_rect, thin_line, etc) when this returns.

int __pascal SetGraphicsMode();

6. MoveCursor

Move the internal cursor to the specified position, you do not have to adjust the position of the visible cursor - only where the next screen write will occur.

void __pascal MoveCursor(int col, int line);

7. WriteLmbcsStringWithAttributes

A pointer to an LMBCS string is specified with color attributes, it should be translated to the users current charset, and printed to the current cursor location.

int __pascal WriteLmbcsStringWithAttributes(unsigned byteslen,
                                            unsigned char far *lmbcsptr,
                                            unsigned char attrs);

8. WritePaddedLmbcsStringWithAttributes

This is similar to WriteLmbcsStringWithAttributes, but you can specify padding to apply to either side of the string. The attributes specified are applied to the padding and the string.

Using SPC characters for padding is fine.

int __pascal WritePaddedLmbcsStringWithAttributes(unsigned byteslen,
                                                  char far *lmbcsptr,
                                                  unsigned char attrs,
                                                  unsigned startpad,
                                                  unsigned endpad);

9. SetRegionBgAttributes

Change the bg attributes of a screen region, leaving the contents intact. The region starts at the current cursor.

For example, this might be used to change the background color.

Note that the text and fg attributes are unchanged.

void __pascal SetRegionBgAttributes(unsigned cols,
                                    unsigned lines,
                                    char attrs);

As far as I can tell, 123 will never request an invalid column or line number, i.e. you are not expected to handle line wrap or off-screen drawing.

10. ClearRegionForeground

Remove the foreground content (i.e. write blanks over it and clear fg attributes). New background attributes can be specified.

void __pascal ClearRegionForeground(unsigned cols,
                                    unsigned lines,
                                    unsigned char attrs);

11. ClearRegionForegroundKeepBg

The same as ClearRegionForeground, but the existing bg attributes are retained.

void __pascal ClearRegionForegroundKeepBg(unsigned cols, unsigned lines);

12. BlockRegionCopy

Copy a rectangular, including attributes, from one screen area to another.

The regions may overlap, and you’re expected to handle that.

void __pascal BlockRegionCopy(int width, int height, int dstx, int dsty);

13. CalcSizeTranslatedString

You should translate the passed LMBCS string into the current character set, and then return the length. You don’t have to display anything.

int __pascal CalcSizeTranslatedString(int argstrlen, char far *argstr);

14. FitTranslatedString

Lotus has maxlen columns to display an LMBCS string, so you should translate it and truncate it (if necessary) to fit.

int __pascal FitTranslatedString(int strarglen,
                                 char far *strarg,
                                 int ncols,
                                 int far *bytesneeded)

15. SetCursorInvisible

The screen cursor should no longer be visible to the user, perhaps because they are navigating a menu.

void __pascal SetCursorInvisible();

16. SetCursorVisible

The user is entering data so the screen cursor should be visible. The position should match the internal cursor, as set by MoveCursor.

void __pascal SetCursorVisible();

17. LockCursorAttributes

Not really sure why this is useful, or what the intention is. I believe it ignores changes to cursor attributes until turned off.

void __pascal LockCursorAttributes(int, int);

18. Unknown

This is called before entering graphics mode, and appears to be related to querying resolution data.

int __pascal QQCalledBeforeGraphicsMode(void far *m)

19. DrawString

This appears to be related to setting graph legends in graphics mode.

int __pascal DrawString(int strarglen, void far *strarg);

20. MoveCursor2

This appears to be identical to MoveCursor().

void __pascal MoveCursor2(int col, int line);

21. IsGraphicsModeReady

When entering graphics mode, this function is called repeatedly until it returns 1. Perhaps the intention is to query if the hardware is ready to display graphics.

int __pascal __far IsGraphicsModeReady(void far *ptr)

Printer Driver API

The display driver API is quite complicated, the printer driver API is simple in comparison. Even better, it’s essentially just a tiny subset of the DISPLAY API (the DEVPRIM part).