README-tek 1.7 KB

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  1. These are some comments on the interface provided by GNU libplot to
  2. Tektronix emulators.
  3. The Tektronix device driver included in libplot produces output for several
  4. types of Tektronix-compatible display. This includes the Tektronix
  5. emulators built into `xterm' (the X Window System terminal emulator) and
  6. the MS-DOS version of `kermit'. They are recognized by the environment
  7. variable TERM equalling "xterm" (or "xterms" or "kterm"), and "kermit" (or
  8. "ansi.sys, "ansi.sysk", "ansisys", or "ansisysk"), respectively.
  9. Some historical comments on the Tektronix 4010/4014 follow.
  10. A Tektronix 4010 had what was effectively a 1024x780 display, as did the
  11. first Tektronix 4014 models. Effective coordinate space was
  12. [0..1023]x[0..779]. Extended resolution, available for Tektronix 4014's
  13. equipped with the Enhanced Graphics Module [EGM], yielded
  14. [0..4095]x[0..3119] as coordinate space. Actually the range of the two
  15. position registers was always [0..4095], even before the EGM was
  16. introduced. (On displays without EGM, the low two bits in each coordinate
  17. were dropped.) So the upgrade path to the 4014-with-EGM was smooth.
  18. In pre-EGM days a Tekpoint increment (display measurement unit) equalled
  19. four increments of the x or y position register. `Home cursor position'
  20. was (0,767) in terms of Tekpoints, since the character matrix was 7x9.
  21. After the introduction of the EGM, a Tekpoint increment equalled one
  22. increment of the x or y position register, not four. Home position became
  23. (0,3071).
  24. There were approximately 70 Tekpoints/inch in pre-EGM days, 280/inch with
  25. EGM. In other words, the resolution was better than that of high-end
  26. workstation displays today. Who says raster graphics is an improvement
  27. over vector graphics?