| Message ID | pull.1117.git.git.1635210227532.gitgitgadget@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | de658515ae1166577441da09fe7624769e263a3e |
| Headers | show |
| Series | color: allow colors to be prefixed with "reset" | expand |
"Robert Estelle via GitGitGadget" <gitgitgadget@gmail.com> writes: > From: Robert Estelle <robertestelle@gmail.com> > > "reset" was previously treated as a standalone special color name > representing `\e[m`. Now, it can apply to other color properties, > allowing exact specifications without implicit attribute inheritance. > > For example, "reset green" now renders `\e[;32m`, which is interpreted > as "reset everything; then set foreground to green". This means the > background and other attributes are also reset to their defaults. > > Previously, this was impossible to represent in a single color: > "reset" could be specified alone, or a color with attributes, but some > thing like clearing a background color were impossible. > > There is a separate change that introduces the "default" color name to > assist with that, but even then, the above could only to be represented > by explicitly disabling each of the attributes: > green default no-bold no-dim no-italic no-ul no-blink no-reverse no-strike > > Signed-off-by: Robert Estelle <robertestelle@gmail.com> > --- Unlike the "default" patch, I quite do not see the point of the example(s). Instead of saying "reset green", can't we already say "set bg to default, and set fg to green", thanks to the other one? Or does "default" do too little to deserve a name that implies "go back to default", e.g. by not defeating the 'blink' attribute that was set earlier?
> Unlike the "default" patch, I quite do not see the point of the example(s). Yeah. This "reset" one was developed mainly as a hedge in case there were concerns about the "default" one. You're correct that the "default" one provides a finer-grained capability, and if we had to choose, I'd go with that. However, the two are mutually compatible (no conflicts, even) and complementary. This "reset" approach seemed easier to go through since it just generalizes the treatment of the existing "reset" capability without introducing any new names or even SGR sequence numbers. (The immediate goal of was to have some way to control from a color whether to inherit or remove an existing background). > Instead of saying "reset green", can't we already say "set bg to default, and set fg to green", thanks to the other one? Yes-ish, however, "default" is just a color name: and like other colors, it doesn't imply any attribute (bold etc) resets. Like, if you turn on bold, and then change the color to red, you'll get bold red. If you then change the foreground back to default, you'll have bold whatever. Instead, with "default", to avoid inheriting you could write: green default no-bold no-dim no-italic no-ul no-blink no-reverse no-strike resulting in an ANSI sequence like: `\e[22;23;24;25;27;29;32;49m` It's just a mouthful. `reset green` results in `\e[;32m`, which does functionally the same thing. It's just the combination of "reset everything" (``\e[m` or equivalently \e[0m`) followed by a color (`\e[32m`). I considered calling "reset" something like "only" since that reads more clearly to me, but I also felt it was not worth the cuteness when "reset" already existed and was defined consistently. > Or does "default" do too little to deserve a name that implies "go back to default", e.g. by not defeating the 'blink' attribute that was set earlier? I agree that "default" feels ambiguous. Within the current positional-name format vs. e.g. "fg=green bg=default bold=on", I had a lot of trouble thinking of a name that wouldn't be. However, "default" is the same word as in the ANSI spec, used in console_codes(4) (see heading "ECMA-48 Select Graphic Rendition here: https://man7.org/linux/man-pages/man4/console_codes.4.html) and ncurses (https://man7.org/linux/man-pages/man3/default_colors.3x.html). I also explored a few terminals' settings to see if there was a better name: usually they'll just refer to it unhelpfully as "foreground" or "background", but when they're otherwise named it's usually like "DefaultForeground". Other names I'd considered had their own problems: "unset" could be confusing alongside the existing "reset", "clear" could be confusing as a foreground or in the context of translucent terms, "no-color" is usually just untrue, and "normal" is (very confusingly, IMO) already special-cased as a no-op word. Best, Robert On Tue, Oct 26, 2021 at 2:42 PM Junio C Hamano <gitster@pobox.com> wrote: > > "Robert Estelle via GitGitGadget" <gitgitgadget@gmail.com> writes: > > > From: Robert Estelle <robertestelle@gmail.com> > > > > "reset" was previously treated as a standalone special color name > > representing `\e[m`. Now, it can apply to other color properties, > > allowing exact specifications without implicit attribute inheritance. > > > > For example, "reset green" now renders `\e[;32m`, which is interpreted > > as "reset everything; then set foreground to green". This means the > > background and other attributes are also reset to their defaults. > > > > Previously, this was impossible to represent in a single color: > > "reset" could be specified alone, or a color with attributes, but some > > thing like clearing a background color were impossible. > > > > There is a separate change that introduces the "default" color name to > > assist with that, but even then, the above could only to be represented > > by explicitly disabling each of the attributes: > > green default no-bold no-dim no-italic no-ul no-blink no-reverse no-strike > > > > Signed-off-by: Robert Estelle <robertestelle@gmail.com> > > --- > > Unlike the "default" patch, I quite do not see the point of the > example(s). Instead of saying "reset green", can't we already say > "set bg to default, and set fg to green", thanks to the other one? > Or does "default" do too little to deserve a name that implies "go > back to default", e.g. by not defeating the 'blink' attribute that > was set earlier?
diff --git a/Documentation/config.txt b/Documentation/config.txt index bf82766a6a2..b1423b6ce8b 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -280,6 +280,11 @@ The position of any attributes with respect to the colors be turned off by prefixing them with `no` or `no-` (e.g., `noreverse`, `no-ul`, etc). + +The pseudo-attribute `reset` resets all colors and attributes before +applying the specified coloring. For example, `reset green` will result +in a green foreground and default background without any active +attributes. ++ An empty color string produces no color effect at all. This can be used to avoid coloring specific elements without disabling color entirely. + diff --git a/color.c b/color.c index 64f52a4f93a..29ac83b2d6e 100644 --- a/color.c +++ b/color.c @@ -234,6 +234,7 @@ int color_parse_mem(const char *value, int value_len, char *dst) const char *ptr = value; int len = value_len; char *end = dst + COLOR_MAXLEN; + unsigned int has_reset = 0; unsigned int attr = 0; struct color fg = { COLOR_UNSPECIFIED }; struct color bg = { COLOR_UNSPECIFIED }; @@ -248,12 +249,7 @@ int color_parse_mem(const char *value, int value_len, char *dst) return 0; } - if (!strncasecmp(ptr, "reset", len)) { - xsnprintf(dst, end - dst, GIT_COLOR_RESET); - return 0; - } - - /* [fg [bg]] [attr]... */ + /* [reset] [fg [bg]] [attr]... */ while (len > 0) { const char *word = ptr; struct color c = { COLOR_UNSPECIFIED }; @@ -270,6 +266,11 @@ int color_parse_mem(const char *value, int value_len, char *dst) len--; } + if (match_word(word, wordlen, "reset")) { + has_reset = 1; + continue; + } + if (!parse_color(&c, word, wordlen)) { if (fg.type == COLOR_UNSPECIFIED) { fg = c; @@ -295,13 +296,16 @@ int color_parse_mem(const char *value, int value_len, char *dst) *dst++ = (x); \ } while(0) - if (attr || !color_empty(&fg) || !color_empty(&bg)) { + if (has_reset || attr || !color_empty(&fg) || !color_empty(&bg)) { int sep = 0; int i; OUT('\033'); OUT('['); + if (has_reset) + sep++; + for (i = 0; attr; i++) { unsigned bit = (1 << i); if (!(attr & bit)) diff --git a/color.h b/color.h index 98894d6a175..684dbd3bceb 100644 --- a/color.h +++ b/color.h @@ -6,6 +6,7 @@ struct strbuf; /* * The maximum length of ANSI color sequence we would generate: * - leading ESC '[' 2 + * - reset ';' .................1 * - attr + ';' 2 * num_attr (e.g. "1;") * - no-attr + ';' 3 * num_attr (e.g. "22;") * - fg color + ';' 17 (e.g. "38;2;255;255;255;") diff --git a/t/t4026-color.sh b/t/t4026-color.sh index c0b642c1ab0..5ef2ff28c48 100755 --- a/t/t4026-color.sh +++ b/t/t4026-color.sh @@ -58,6 +58,10 @@ test_expect_success 'fg bg attr...' ' color "blue bold dim ul blink reverse" "[1;2;4;5;7;34m" ' +test_expect_success 'reset fg bg attr...' ' + color "reset blue bold dim ul blink reverse" "[;1;2;4;5;7;34m" +' + # note that nobold and nodim are the same code (22) test_expect_success 'attr negation' ' color "nobold nodim noul noblink noreverse" "[22;24;25;27m"