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diff --git a/konsole/doc/More/vt100_scroll_region.txt b/konsole/doc/More/vt100_scroll_region.txt new file mode 100644 index 000000000..4297aaba3 --- /dev/null +++ b/konsole/doc/More/vt100_scroll_region.txt @@ -0,0 +1,124 @@ +Newsgroups: comp.terminals,comp.protocols.misc +Subject: ANSI X3.64 sequences (was Re: VT100 scrolling region) +Summary: Escape code effects +Expires: Sun, 31 Jan 1993 22:23:24 GMT +References: <18623@mindlink.bc.ca> <lj3vgrINNieu@news.bbn.com> +Sender: shuford@cs.utk.edu +Followup-To: comp.terminals +Distribution: world +Organization: University of Tennessee, Knoxville--Dept. of Computer Science +Keywords: VT100, scroll, control code, Escape, ANSI X3.64, terminal + +In article <lj3vgrINNieu@news.bbn.com> pdsmith@bbn.com (Peter D. Smith) writes: +> In article <18623@mindlink.bc.ca>, Frank@mindlink.bc.ca (Frank I. Reiter) +> writes: +> > Part of an application I am working on includes a VT100 emulator. +> > 1) Does ESC [;22r mean "scroll lines 0 through 22" or does it mean "Set +> > the bottom scrolling line to 22, leave the top line as it is set already"? +> +> It should mean 'scroll lines 1 to 22'. + +The control sequences recognized by the Digital Equipment Corporation +VT100, VT200, VT300, and VT400-family character-cell video terminals +are an extended variant of the control sequences specified by an ANSI +standard, ANSI X3.64. (ISO DP6429 is the international version.) + +The generic sequence introducer is a thing called CSI (Control +Sequence Introducer). If you are using 8-bit communication, you +can use the hexadecimal value 9B to represent this (but be sure you +understand the side effects thereof). Otherwise, use the 7-bit +equivalent: the Escape character (1Bh) followed by [ (the left +bracket character). + +The canonical form of the given scroll-region command would be + + CSI xx ; yy r + +or in 7-bit style + + Esc [ xx ; yy r + +(where xx and yy are decimal digits expressed in ASCII/IA5; you do not +actually use a space between sequence elements, this is for clarity. +Be careful with the notation here--sometimes a space character _is_ +a sequence element, as in the SR Scroll Right editing function.) + +In an X3.64 control sequence, the numeric arguments may default to an +arbitrary value specific to the device function being controlled. Do +not assume that the default always will be 0 or 1. (Or there may be +no default allowed.) For example, the numeric arguments in the GSM +(Graphic Size Modify) sequence have the default values 100, 100. + +As a private extension to X3.64, DEC defines the DECSTBM (Set Top and +Bottom Margins) command as follows: + + CSI Pt ; Pb r + + Selects top and bottom margins defining the scrolling region. + Pt is the line number of the first line in the scrolling region. + Pb is the line number of the bottom line. + If you do not select either Pt or Pb, they default to the top + and bottom respectively. Lines are counted from 1. + +(See \VT220 Programmer Pocket Guide/, part EK-VT220-HR-002, page 37.) + +> Remember that these sequences +> could be implemented in TTL without a microprocessor of any +> kind & therefore use the simplest possible implementation. + +Peter must be thinking of the much simpler DEC VT52 sequences. As far +as I know, terminals implementing X3.64 have ALWAYS used a built-in +microprocessor. The VT100 was built around an 8-bit-bus Intel 8085. + +In fact, when the X3.64 document was published (circa 1978), some +vendors, insisting on using discrete logic designs, objected that the +standard was so complex it could not be implemented. Most of these +vendors are now floating belly-up on the tide of technology. Some +credit is due to The Heath Company for a pioneering microprocessor- +based video terminal that implemented many of the X3.64 functions. + +> > 2) Should a clear screen code clear the scrolling region only, or the +> > entire screen? How about a clear to end of screen? +> +> I think this is the whole screen regardless of the scrolling region. +> Don't bet your company on it, though. + +Screen clearing should not depend on scrolling. + +Erasing parts of the display (EL and ED) in the VT100 is performed thus: + + Erase from cursor to end of line Esc [ 0 K or Esc [ K + Erase from beginning of line to cursor Esc [ 1 K + Erase line containing cursor Esc [ 2 K + Erase from cursor to end of screen Esc [ 0 J or Esc [ J + Erase from beginning of screen to cursor Esc [ 1 J + Erase entire screen Esc [ 2 J + +Some brain-damaged terminal/emulators respond to Esc [ J as if it were +Esc [ 2 J (here the default is 0), and _some_ versions of Microsoft's +MS-DOS ANSI.SYS contain a bug requiring software to send Esc [ k +(instead of the uppercase). Of course, you would never make this mistake. + +The VT200 and later terminals have the ECH control sequence: + + Esc yy X + +(where yy is a numeric parameter) + +This erases the cursor position and the next (yy-1) positions, but this +is not part of the least common denominator VT100. + + - - - - - - + +There is still various video-terminal information available for +anonymous FTP in "pub/shuford" from + + CS.UTK.EDU [128.169.94.1] + + - - - - - - + +VT, Flip Chip, DIBOL, and Rainbow are trademarks of Digital Equipment +Corporation. + + = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = + |