On Sunday, 17 December 2023 20:53:52 GMT G. Branden Robinson wrote: > Hi Deri, > > At 2023-12-10T18:43:42+0000, Deri wrote: > > On Saturday, 9 December 2023 19:25:27 GMT G. Branden Robinson wrote: > > > When a line of output is "finished" and sent to the device > > > (device-independent output is prepared for it), the vertical > > > position advances by one vee, and, (in groff, if vertical position > > > traps are not disabled,) any visible vertical position traps planted > > > between the previous text baseline and the new one are sprung.[1] > > > If one of these traps is what I term "the implicit page trap"[2], > > > then the page is ejected and a new one started. > > > > Is this the problem? It does not make sense to start a new page until > > groff "knows" there will be further output. > > Changing that is a deeper, more intrusive change than I am proposing. > It would affect approximately all page transitions processed by the > formatter. > > Not saying that it's wrong or a bad idea, but it's significantly more > ambitious than what I proposed. > > > So if the implicit page trap is triggered it should set a flag to > > trigger the new page code if further output, other than "x trailer", > > is output. This is an example of troff output:- > > > > x T pdf > > x res 72000 1 1 > > x init > > p1 > > x font 5 TR > > f5 > > s10000 > > V12000 > > H72000 > > mr 0 0 0 > > DFd > > tline > > n12000 0 > > V792000 > > H72000 > > tline > > n12000 0 > > V792000 > > p2 > > x trailer > > V792000 > > x stop > > > > The V792000 and p2 are unnecessary unless there is further output. > > That's true, but my hunch is that most *roff users over the years to > want to write within 1v of the page bottom use "local" vertical motions > from a safe distance to do so. > > Hmmm, I was going to show you an exhibit involving `\V` but managed to > surprise myself. > > Here's a counterexample. > > $ cat ATTIC/kiss-foot.tr > .\" U.S. letter paper assumed > .sp 65v > Hello! > > This produces a ONE page PostScript document with "Hello!"'s text > baseline sitting at the very boundary of the paper. And there is no > blank second page. I had predicted one, so obviously there is more for > me to understand here. (And another trip back to groff.texi with my > text editor after that.) > > Obviously when the formatter performed a break and pushed the output > line, it recognized that there was no more input, and didn't break the > page as well. > > Here's the grout: > > $ groff -Z ATTIC/kiss-foot.tr > x T ps > x res 72000 1 1 > x init > p1 > x font 5 TR > f5 > s10000 > V792000 > H72000 > md > DFd > tHello! > n12000 0 > x trailer > V792000 > x stop > > (It even _SAYS_ there's a break after the text, with the 'n12000 0' > documentary command.) > > I challenge you to explain! :D > > Regards, > Branden
Add .fl after Hello. :-) Cheers Deri
