Linux console termcap and line drawing errors
John Hardin asked why Linux curses applications drew the tabs and spaces before a line-drawing character in the alternate character set, and whether termcap, the libraries or the console driver was at fault. He then found the application itself was at fault: it switched to graphics mode before moving the cursor. T.E.Dickey added that ncurses apps handle this correctly. Solved.
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Several curses applications compiled under Linux (most notably menuing programs) don't draw line graphics properly - if the application attempts to display a line of text, followed by whitespace (tabs & spaces), followed by a line drawing character, the tabs and spaces are drawn in the alternate character set. Does anybody know whether this is a problem with the termcap entry, or a problem in the termcap or curses libraries, or a problem in the kernel console driver? How can I fix this? Thanks. -- John Hardin Internal Systems Administrator Apropos Retail Management Systems, Inc. <johnh@aproposretail.com>
John Hardin wrote: > > Several curses applications compiled under Linux (most notably menuing > programs) don't draw line graphics properly - if the application > attempts to display a line of text, followed by whitespace (tabs & > spaces), followed by a line drawing character, the tabs and spaces are > drawn in the alternate character set. Oops. It turns out that the application was at fault. It was switching to graphics mode *before* moving the cursor, and was moving the cursor by displaying spaces instead of using a cursor-addressing escape sequence. Nevermind. {sulks off in embarrassment} -- John Hardin Internal Systems Administrator Apropos Retail Management Systems, Inc. <johnh@aproposretail.com>
In comp.os.linux.development.apps John Hardin <johnh@aproposretail.com> wrote: > Several curses applications compiled under Linux (most notably menuing > programs) don't draw line graphics properly - if the application > attempts to display a line of text, followed by whitespace (tabs & > spaces), followed by a line drawing character, the tabs and spaces are > drawn in the alternate character set. > Does anybody know whether this is a problem with the termcap entry, or a > problem in the termcap or curses libraries, or a problem in the kernel > console driver? If you are using 'screen', it has problems with alternate character set; otherwise ncurses applications has no problem dealing with this. (curses apps on Linux that use the alternate character set are not likely to use termcap, rather terminfo is the place to look). -- Thomas E. Dickey dickey@clark.net http://www.clark.net/pub/dickey
In comp.os.linux.development.apps John Hardin <johnh@aproposretail.com> wrote: > John Hardin wrote: >> >> Several curses applications compiled under Linux (most notably menuing >> programs) don't draw line graphics properly - if the application >> attempts to display a line of text, followed by whitespace (tabs & >> spaces), followed by a line drawing character, the tabs and spaces are >> drawn in the alternate character set. > Oops. It turns out that the application was at fault. It was switching > to graphics mode *before* moving the cursor, and was moving the cursor > by displaying spaces instead of using a cursor-addressing escape > sequence. then it probably wasn't an ncurses app (ncurses checks that) -- Thomas E. Dickey dickey@clark.net http://www.clark.net/pub/dickey