parse_color: support 24-bit RGB values

Some terminals (like XTerm) allow full 24-bit RGB color
specifications using an extension to the regular ANSI color
scheme. Let's allow users to specify hex RGB colors,
enabling the all-important feature of hot pink ref
decorations:

  git log --format="%h%C(#ff69b4)%d%C(reset) %s"

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 9678ab6aa8ee846dabca72bb413820584aaabfe2..35b9731d49d9ff51cacd96d10ab6536c551956a5 100644 (file)
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -828,7 +828,8 @@ doesn't matter.
 +
 Colors (foreground and background) may also be given as numbers between
 0 and 255; these use ANSI 256-color mode (but note that not all
-terminals may support this).
+terminals may support this).  If your terminal supports it, you may also
+specify 24-bit RGB values as hex, like `#ff0ab3`.
 
 color.diff::
        Whether to use ANSI escape sequences to add color to patches.

diff --git a/color.c b/color.c
index 3afda9d9dc20b184f1bc1450c0a734c67fc0bfda..ae687929233a03d2601d1a2a08a55a8d192f6af1 100644 (file)
--- a/color.c
+++ b/color.c
@@ -32,10 +32,13 @@ struct color {
                COLOR_UNSPECIFIED = 0,
                COLOR_NORMAL,
                COLOR_ANSI, /* basic 0-7 ANSI colors */
-               COLOR_256
+               COLOR_256,
+               COLOR_RGB
        } type;
        /* The numeric value for ANSI and 256-color modes */
        unsigned char value;
+       /* 24-bit RGB color values */
+       unsigned char red, green, blue;
 };
 
 /*
@@ -47,6 +50,16 @@ static int match_word(const char *word, int len, const char *match)
        return !strncasecmp(word, match, len) && !match[len];
 }
 
+static int get_hex_color(const char *in, unsigned char *out)
+{
+       unsigned int val;
+       val = (hexval(in[0]) << 4) | hexval(in[1]);
+       if (val & ~0xff)
+               return -1;
+       *out = val;
+       return 0;
+}
+
 static int parse_color(struct color *out, const char *name, int len)
 {
        /* Positions in array must match ANSI color codes */
@@ -64,6 +77,16 @@ static int parse_color(struct color *out, const char *name, int len)
                return 0;
        }
 
+       /* Try a 24-bit RGB value */
+       if (len == 7 && name[0] == '#') {
+               if (!get_hex_color(name + 1, &out->red) &&
+                   !get_hex_color(name + 3, &out->green) &&
+                   !get_hex_color(name + 5, &out->blue)) {
+                       out->type = COLOR_RGB;
+                       return 0;
+               }
+       }
+
        /* Then pick from our human-readable color names... */
        for (i = 0; i < ARRAY_SIZE(color_names); i++) {
                if (match_word(name, len, color_names[i])) {
@@ -140,6 +163,10 @@ static char *color_output(char *out, const struct color *c, char type)
        case COLOR_256:
                out += sprintf(out, "%c8;5;%d", type, c->value);
                break;
+       case COLOR_RGB:
+               out += sprintf(out, "%c8;2;%d;%d;%d", type,
+                              c->red, c->green, c->blue);
+               break;
        }
        return out;
 }

diff --git a/color.h b/color.h
index f5beab1ed782549eb08ad11392ed8e6331bdd653..4ec34b448fea65f09ebbdfc0a4ae2f9e81c62550 100644 (file)
--- a/color.h
+++ b/color.h
@@ -9,14 +9,14 @@ struct strbuf;
  * The maximum length of ANSI color sequence we would generate:
  * - leading ESC '['            2
  * - attr + ';'                 2 * 8 (e.g. "1;")
- * - fg color + ';'             9 (e.g. "38;5;2xx;")
- * - fg color + ';'             9 (e.g. "48;5;2xx;")
+ * - fg color + ';'             17 (e.g. "38;2;255;255;255;")
+ * - bg color + ';'             17 (e.g. "48;2;255;255;255;")
  * - terminating 'm' NUL        2
  *
  * The above overcounts attr (we only use 5 not 8) and one semicolon
  * but it is close enough.
  */
-#define COLOR_MAXLEN 40
+#define COLOR_MAXLEN 56
 
 /*
  * IMPORTANT: Due to the way these color codes are emulated on Windows,

diff --git a/t/t4026-color.sh b/t/t4026-color.sh
index 63e423838f1025d74b830bf84629427defdb756a..65386db9168bb10dd596fca494d0170da99a03f8 100755 (executable)
--- a/t/t4026-color.sh
+++ b/t/t4026-color.sh
@@ -53,6 +53,10 @@ test_expect_success '256 colors' '
        color "254 bold 255" "[1;38;5;254;48;5;255m"
 '
 
+test_expect_success '24-bit colors' '
+       color "#ff00ff black" "[38;2;255;0;255;40m"
+'
+
 test_expect_success '"normal" yields no color at all"' '
        color "normal black" "[40m"
 '