On Sat, Oct 24, 2009 at 07:20:28PM +0200, Nicholas Marriott wrote: > On Sat, Oct 24, 2009 at 12:49:31AM +1100, Tim Allen wrote: > > On Fri, Oct 23, 2009 at 01:24:00PM +0100, Nicholas Marriott wrote: > > > It appears screen-256color converts colours 8-15 into 90-97 which are an > > > extension designed to allow bright colours without the bold attribute > > > (bold > > > font). > > > > Looking at xterm's ctlseqs.pdf, it refers to these 90-97 and 100-107 codes > > as "aixterm" codes; I suppose before xterm invented the 88- and > > 256-color hack, IBM had their own ideas about how to extend ECMA48 > > beyond 8 colours. > > Yes, I know, but the question is why does terminfo bother itself converting > 8-15 to 90-97 when it could just pass it through and get the same result since > 90-97 are the same as 8-15 in the 256-colour palette. > > setaf/setab used to use the standard ANSI SGR sequence in xterm- and > screen-256color, the change to use the 256-colour extension is relatively > recent.
as noted in terminfo.src # 2006-06-24 ... # * improve xterm-256color by combining the ibm+16color setaf/setab # strings with SGR 48. The setf/setb strings also are cancelled here # rather than omitted so derived entries will cancel those also -Alain # Bench The improvement reduces the number of characters sent. Colors 8-15 use the aixterm SGR (which isn't "ANSI SGR"). Since aixterm 16-colors are part of the default configuration settings, it's reasonable to count on the controls being present. > Actually, in the copy with ncurses 5.7, xterm-256color and screen-256color > both > have the same setaf/setab caps (inherited from xterm+256color). Debian must be > on an older revision or have a local change. older... -- Thomas E. Dickey http://invisible-island.net ftp://invisible-island.net
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