On Friday, 6 June 2025 05:24:21 BST G. Branden Robinson wrote: > Hi Deri, > > At 2025-06-06T00:08:38+0100, Deri wrote: > > I have been comparing HTML and X colour names, results attached as a > > pdf (and a text version which should be piped through "less -R" to see > > the colours). > > Neat! I can image the groff document you might have used to compose it, > though I wonder why tbl(1), if that's what you used, under-sized the > first column in nroff mode, causing "lightgoldenrodyellow" to overrun.
Mea culpa, I did not use tbl! Just tabs and a .ta. Problem was the first list of HTML colours garnered from the internet was incomplete and all the names "fitted", when I did a final check against the official W3C list I found some more colours, including "lightgoldenrodyellow" and did not notice it overran the tab length, and given my use of \Z to plant the text, neither did groff. > > The background colour represents the named colour. For colours marked > > "Same" the HTML and X have matched names and RGB values. If it refers > > "X=name" it means that for the same RGB value X has a different name, > > however there is nothing to stop a single RBG value having two names, > > so we could add the HTML name as such an alias. > > > > A colour marked as "Missing" means that no X colour has the particular > > RBG value, the closest nearest RBG colour is shown in the third > > column, the HTML name could be added to our list. > > > > The last group are where the names are the same but the RBG values are > > different (shown by the HTML colour in col 2, and X in col 3). There > > are 4 colours afffected. Xorg-rgb 1.0.6 addressed this by adding > > "aliases" with the suffixes "web" or "x11". > > I can imagine that a document author might prefer one color repertoire > or the other regardless of their choice of output device, so I perceive > little benefit in *tightly* coupling one to a device macro file. > > Would it make sense to offer two macro files, "color-html.tmac" and > "color-x11.tmac"? I reckon the "html" and "xhtml" devices would load > the former by default and the X11 devices the latter by default. I think you are right. It might be a good idea to add the 4 differing colours with an x11 suffix to "color-html.tmac" and with "web" suffix to color- x11.tmac. Currently the colours in html.tmac are a mish-mash! .defcolor purple rgb #8e35ef .defcolor purple1 rgb #893bff .defcolor purple2 rgb #7f38ec .defcolor purple3 rgb #6c2dc7 .defcolor purple4 rgb #461b7e The colour "purple" matches neither HTML nor X11! In fact I ran my diff program comparing the official HTML colours against the colours in html.tmac (with surprising results) practically none of them matched! See attached HTML- TmacColours.pdf (this time "X=" colours are the colours in html.tmac). So then I wondered how the html.tmac colours compared with the X11 colours in ps.tmac. The results in X-TmacColours.pdf. First column "HTML=" value from html.tmac, "X=" X11 value from ps.tmac. I will generate a color-html.tmac and color-x11.tmac for discussion. > Which should be the default for the other devices? ps and pdf would continue to use x11. Cheers Deri > Of course no matter which macro file is loaded by default, a document > can select a different one by invoking the `mso` request on the > preferred one. > > I could also extend the `defcolor` request to accept a zero-argument > form that would erase the internal dictionary of defined color names, > restoring the state of the formatter in this respect when launched with > "troff -R".[1] If one hated colors and wanted to make sure a document > didn't use them, the "-wcolor" option plus `.defcolor` at the top of a > document (or in one's "troffrc-end" file), should accomplish that. > > Regards, > Branden > > [1] It could also be extended to accept a single-argument form that > would remove only the named color from the dictionary. > > I've improved diagnostics in this development cycle. > > $ echo '.defcolor' | ~/groff-1.23.0/bin/groff -wmissing > troff:<standard input>:1: warning: missing identifier > $ echo '.defcolor red' | ~/groff-1.23.0/bin/groff -wmissing > troff:<standard input>:1: warning: missing identifier > > $ echo '.defcolor' | ~/groff-HEAD/bin/groff -wmissing > troff:<standard input>:1: warning: color definition request expects > arguments $ echo '.defcolor red' | ~/groff-HEAD/bin/groff -wmissing > troff:<standard input>:1: warning: missing color space in color > definition request
HTML-TmacColours.pdf
Description: Adobe PDF document
X-TmacColours.pdf
Description: Adobe PDF document
