TIFILES(€ĒP(ĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSĘSPIX FORMAT SPECIFICATION /Copyright 1989 by Jim Reiss and Asgard Software 3Pix is a trademark of Asgard Software and Jim Reiss     HISTORY:   OThe Pix format was researched and developed by Jim Reiss under sponsorship fromAsgard Software.  ˙ JThis format was developed in response to a need for a graphics file formatLthat: (a) was portable between all systems with 9918a or compatible graphicsOprocessors, (b) provided significant compaction of picture data without complex˙Asgard Software.  ˙Ndecoding and encoding software, (c) was able to be decoded and encoded quicklyKwith a minimum amount of memory needed for buffering, (d) could serve as anLinterim format between different graphics standards native to and foreign of˙x˙Asgard Software.  ˙K9918a systems, (e) was designed more towards the needs of desktop publishngNsoftware than existing formats, and finally (f) one which was fully documented(and could be used freely by all parties.   ˙ards native to and foreign of˙x˙Asgard Software.  ˙LVirtually all file formats in widespread use today were designed to suit theIspecific needs of a particular application. As a result, data interchangeKbetween graphics applications on the TI-99/4A is fragmented at best. Widely˙n of˙x˙Asgard Software.  ˙Gused graphics formats for the TI-99/4A include GRAPHX, TI-Artist, CSGD,NJoyPaint, Picasso, Instance, TIPS, RLE, Page Pro, Calendar Maker, GIF, My-Art,OMacPaint, and many other lesser ones. Currently, users are faced with (at best)˙˙x˙Asgard Software.  ˙Igreat difficulty in moving artwork between applications. Porting graphicsNbetween file formats can sometimes take 3 or more different programs and quitea bit of time and manual labor.   ˙rrently, users are faced with (at best)˙˙x˙Asgard Software.  ˙ITI-99/4A programmers face their own problem in that no format is properlyIdesigned for use in emerging new fields of graphics applications, such asNanimation and desktop publishing. As a result, file formats can be expected to˙st)˙˙x˙Asgard Software.  ˙Nproliferate further, with commensurately less interchange of data. In order toLmaintain compatibility with existing libraries of pictures, programmers willLhave to produce more and more converters to handle conversions between other˙˙Asgard Software.  ˙Mfile formats and their own. It is plain that users and developers of graphics1files and applications need a "universal" format.   GThis format is proposed not as the native format of all existing or new˙ conversions between other˙˙Asgard Software.  ˙Japplications (since at a minimum that would require thousands of man-hoursNworth of rewriting), but as a format that facilitates data interchange betweenLgraphics applications. Pix was designed to be flexible enough to handle both˙r˙˙Asgard Software.  ˙Mcolor and monochrome pictures, and picture of every size from small "clipart"Oto full-page works many times the size of the actual screen. Pix is also usefulLas an archival format since it typically provides significant compression of˙sgard Software.  ˙Lpictures over their native formats (for instance a monochrome GRAPHX pictureOmay be reduced from 13,568 bytes to 5,376 bytes in size). Converters supportingNthis format can even decode a file from Pix to their format typically twice as˙gard Software.  ˙8fast as they could decode RLE (a popular simple format).   LApplication writers are encouraged to write converters from the file formatsMused in their programs to this format. In this way, an application author can˙ypically twice as˙gard Software.  ˙Oproduce a file format more appropriate to his or her application while ensuringNaccess to a large quantity of existing artwork for users of their application.FPix is copyrighted in an attempt to control the format and prevent the˙ce as˙gard Software.  ˙Lemergence of nonstandard versions, as happens all too easily. The author isKopen to suggestions for format extensions, but requests the right to decideLwhat is added to the official Pix definition. Authors who create derivative˙ce as˙gard Software.  ˙Eformats are asked to provide a converter to the Pix standard in their applications.     TECHNICAL SPECIFICATIONS:   OPix pictures are stored in 32 byte fixed length records. The first record is a˙s who create derivative˙ce as˙gard Software.  ˙Nheader which contains important information about the picture. The key to theOcompaction which Pix provides is that no character pattern is defined twice. AIcharacter is an 8 pixel wide by 8 pixel high block. On the TMS9918a, the˙as˙gard Software.  ˙Nscreen will have no more than 768 distinct patterns. In many cases, there areByte 3 Low byte of picture width (usually 32 decimal, 20 hex) EByte 4 High byte of picture height in characters (also usually zero)˙ :Byte 5 Low byte of picture height (usually 24, or 18 hex) AByte 6 High byte of the number of records for the Virtual Screen 8Byte 7 Low byte of number of records for Virtual Screen 7Byte 8 High byte of number of records in Pattern Table ˙ zero)˙6Byte 9 Low byte of number of records in Pattern Table -Byte 10 through byte 13 vary based on byte 1.   If byte 1 is 00:   IByte 10 The two colors in the picture. The high nybble is the foreground/ color, the low is the background color.˙˙ 2Bytes 11 through 13 are reserved and must be zero.   If byte 1 is 01:   7Byte 10 High byte of number of records for Color Screen 6Byte 11 Low byte of number of records for Color Screen 6Byte 12 High byte of number of records for Color Table ˙˙5Byte 13 Low byte of number of records for Color Table   NIn either case, bytes 14 through 31 are reserved for future expansion and mustMbe zero. For now, decoders should abort if byte 1 is anything other than oneor zero.   ˙rds for Color Table ˙˙KNote that a simple encoder for a 32x24 two color screen could merely outputNzero through 255 as bytes, then 256 through 767 as words, and then the patternOtable could be identical to how it is stored in the video RAM of the 9918a, and˙ for Color Table ˙˙Jall Pix decoders could view it. However, this gives no compaction at all.*Encoders should not allow repeat patterns.     CONTACTS:   IJim Reiss has a BSS in Computer Science from Cornell College. He has been˙f the 9918a, and˙ for Color Table ˙˙Ninvolved in programming the TI-99/4A commercially for almost 2 years, and on aNmore casual basis for many years prior to that. He is the author of TypewriterKand Tris, both available in module and disk form for the TI-99/4A and Myarc Geneve 9640.   ˙˙˙OAsgard Software is a leader in the TI-99/4A software industry with well over 70Jdifferent titles and 100 packages available for the 99/4A and Geneve 9640.NThis firm has been developing new applications since 1984, and now distributes˙Geneve 9640.   ˙˙˙Lsoftware in disk, cassette and module form, and through a subsidiary (AsgardCPublishing) publishes several books and a highly-regarded magazine.   /Any questions can be directed to the following:   Jim Reiss:   CIS TI Forum, ID # 75116,2373 ˙˙ People Link, user name JIM REISS Delphi, user name JIMREISS OBT BBS (201) 679-0549 or by US Mail at: 216 First Street West Mount Vernon, IA 52314   Asgard Software:   CIS TI Forum, ID # 72561,3241 GEnie, C.BOBBITT Delphi, ASGARD ˙˙˙By Telephone, (703)255-3085 or by US Mail at: P.O. Box 10306 Rockville, MD 20850   HSome telecommunications services aren't checked as frequently as others.  ˙oftware:   CIS TI Forum, ID # 72561,3241 GEnie, C.BOBBITT Delphi, ASGARD ˙˙˙