Ticket #3145: support for True Color (16 millions colors).

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

AUTHORS

@@ -68,6 +68,7 @@ Dmitry Koterov <dmitry.koterov@gmail.com>
 
 Egmont Koblinger <egmont@gmail.com>
         Support of 256 colors
+        Support of True Color (16 millions colors)
         Support of italic text
         Support of extended mouse clicks beyond 223 column
         Support of bracketed paste mode of xterm

doc/man/mc.1.in

@@ -3654,9 +3654,9 @@ with the assignment of colors, as described in Section
 Colors\&.
 .\"Colors"
 .PP
-If your skin contains any of 256\-color definitions, you should define
-the '256colors' key set to TRUE value in [skin] section.
-
+If your skin contains any true\-color definitions, you should define
+the 'truecolors' key set to TRUE value in [skin] section. If true\-color
+is not used but 256\-color is, you should define '256colors' instead.
 .PP
 A skin\-file is searched on the following algorithm (to the first one found):
 .IP

lib/skin.h

@@ -120,6 +120,7 @@ typedef struct mc_skin_struct
     mc_config_t *config;
     GHashTable *colors;
     gboolean have_256_colors;
+    gboolean have_true_colors;
 } mc_skin_t;
 
 /*** global variables defined in .c file *********************************************************/

lib/skin/common.c

@@ -114,10 +114,12 @@ gboolean
 mc_skin_init (const gchar * skin_override, GError ** mcerror)
 {
     gboolean is_good_init = TRUE;
+    GError *error = NULL;
 
     mc_return_val_if_error (mcerror, FALSE);
 
     mc_skin__default.have_256_colors = FALSE;
+    mc_skin__default.have_true_colors = FALSE;
 
     mc_skin__default.name =
         skin_override != NULL ? g_strdup (skin_override) : mc_skin_get_default_name ();
@@ -145,6 +147,18 @@ mc_skin_init (const gchar * skin_override, GError ** mcerror)
         (void) mc_skin_ini_file_parse (&mc_skin__default);
         is_good_init = FALSE;
     }
+    if (is_good_init && !tty_use_truecolors (&error) && mc_skin__default.have_true_colors)
+    {
+        mc_propagate_error (mcerror, 0,
+                            _
+                            ("Unable to use '%s' skin with true colors support:\n%s\nDefault skin has been loaded"),
+                            mc_skin__default.name, error->message);
+        g_error_free (error);
+        mc_skin_try_to_load_default ();
+        mc_skin_colors_old_configure (&mc_skin__default);
+        (void) mc_skin_ini_file_parse (&mc_skin__default);
+        is_good_init = FALSE;
+    }
     if (is_good_init && !tty_use_256colors () && mc_skin__default.have_256_colors)
     {
         mc_propagate_error (mcerror, 0,

lib/skin/ini-file.c

@@ -187,6 +187,7 @@ mc_skin_ini_file_parse (mc_skin_t * mc_skin)
 
     mc_skin_lines_parse_ini_file (mc_skin);
     mc_skin->have_256_colors = mc_config_get_bool (mc_skin->config, "skin", "256colors", FALSE);
+    mc_skin->have_true_colors = mc_config_get_bool (mc_skin->config, "skin", "truecolors", FALSE);
 
     return TRUE;
 }

lib/tty/color-internal.c

@@ -93,11 +93,25 @@ static mc_tty_color_table_t const attributes_table[] = {
     {NULL, 0}
 };
 
+/* --------------------------------------------------------------------------------------------- */
 /*** file scope functions ************************************************************************/
 /* --------------------------------------------------------------------------------------------- */
 
+static inline int
+parse_hex_digit (char c)
+{
+    if (c >= '0' && c <= '9')
+        return c - '0';
+    c |= 0x20;
+    if (c >= 'a' && c <= 'f')
+        return c - 'a' + 10;
+    return -1;
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
 static int
-parse_256_color_name (const char *color_name)
+parse_256_or_true_color_name (const char *color_name)
 {
     int i;
     char dummy;
@@ -119,6 +133,28 @@ parse_256_color_name (const char *color_name)
     {
         return 16 + 36 * (color_name[3] - '0') + 6 * (color_name[4] - '0') + (color_name[5] - '0');
     }
+    if (color_name[0] == '#')
+    {
+        int h[6];
+
+        color_name++;
+        if (strlen (color_name) != 3 && strlen (color_name) != 6)
+            return -1;
+
+        for (i = 0; color_name[i] != '\0'; i++)
+        {
+            h[i] = parse_hex_digit (color_name[i]);
+            if (h[i] == -1)
+                return -1;
+        }
+
+        if (i == 3)
+            i = (h[0] << 20) | (h[0] << 16) | (h[1] << 12) | (h[1] << 8) | (h[2] << 4) | h[2];
+        else
+            i = (h[0] << 20) | (h[1] << 16) | (h[2] << 12) | (h[3] << 8) | (h[4] << 4) | h[5];
+        return (1 << 24) | i;
+    }
+
     return -1;
 }
 
@@ -136,21 +172,17 @@ tty_color_get_name_by_index (int idx)
     for (i = 0; color_table[i].name != NULL; i++)
         if (idx == color_table[i].value)
             return color_table[i].name;
-    /* Create and return the strings "color16" to "color255". */
-    if (idx >= 16 && idx < 256)
-    {
-        static char **color_N_names = NULL;
 
-        if (color_N_names == NULL)
-        {
-            color_N_names = g_try_malloc0 (240 * sizeof (char *));
-        }
-        if (color_N_names[idx - 16] == NULL)
-        {
-            color_N_names[idx - 16] = g_try_malloc (9);
-            sprintf (color_N_names[idx - 16], "color%d", idx);
-        }
-        return color_N_names[idx - 16];
+    /* Create and return the strings in "colorNNN" or "#rrggbb" format. */
+    if ((idx >= 16 && idx < 256) || (idx & (1 << 24)) != 0)
+    {
+        char name[9];
+
+        if (idx < 256)
+            sprintf (name, "color%d", idx);
+        else
+            sprintf (name, "#%06X", idx & 0xFFFFFF);
+        return g_intern_string (name);
     }
     return "default";
 }
@@ -167,7 +199,7 @@ tty_color_get_index_by_name (const char *color_name)
         for (i = 0; color_table[i].name != NULL; i++)
             if (strcmp (color_name, color_table[i].name) == 0)
                 return color_table[i].value;
-        return parse_256_color_name (color_name);
+        return parse_256_or_true_color_name (color_name);
     }
     return -1;
 }

lib/tty/color-ncurses.c

@@ -180,8 +180,8 @@ tty_color_try_alloc_pair_lib (tty_color_pair_t * mc_color_pair)
         ibg = mc_color_pair->ibg;
         attr = mc_color_pair->attr;
 
-        /* In non-256 color mode, change bright colors into bold */
-        if (!tty_use_256colors ())
+        /* In legacy color mode, change bright colors into bold */
+        if (!tty_use_256colors () && !tty_use_truecolors (NULL))
         {
             if (ifg >= 8 && ifg < 16)
             {
@@ -234,3 +234,13 @@ tty_use_256colors (void)
 }
 
 /* --------------------------------------------------------------------------------------------- */
+
+gboolean
+tty_use_truecolors (GError ** error)
+{
+    /* Not yet supported in ncurses */
+    g_set_error (error, MC_ERROR, -1, _("True color not supported with ncurses."));
+    return FALSE;
+}
+
+/* --------------------------------------------------------------------------------------------- */

lib/tty/color-slang.c

@@ -215,3 +215,42 @@ tty_use_256colors (void)
 }
 
 /* --------------------------------------------------------------------------------------------- */
+
+gboolean
+tty_use_truecolors (GError ** error)
+{
+    char *colorterm;
+
+    /* True color is supported since slang-2.3.1 on 64-bit machines,
+       and expected to be supported from slang-3 on 32-bit machines:
+       http://lists.jedsoft.org/lists/slang-users/2016/0000014.html.
+       Check for sizeof (long) being 8, exactly as slang does. */
+    if (SLang_Version < 20301 || (sizeof (long) != 8 && SLang_Version < 30000))
+    {
+        g_set_error (error, MC_ERROR, -1, _("True color not supported in this slang version."));
+        return FALSE;
+    }
+
+    /* Sanity check that at least 256 colors are supported. */
+    if (!tty_use_256colors ())
+    {
+        g_set_error (error, MC_ERROR, -1,
+                     _("Your terminal doesn't even seem to support 256 colors."));
+        return FALSE;
+    }
+
+    /* Duplicate slang's check so that we can pop up an error message
+       rather than silently use wrong colors. */
+    colorterm = getenv ("COLORTERM");
+    if (colorterm == NULL
+        || (strcmp (colorterm, "truecolor") != 0 && strcmp (colorterm, "24bit") != 0))
+    {
+        g_set_error (error, MC_ERROR, -1,
+                     _("Set COLORTERM=truecolor if your terminal really supports true colors."));
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+/* --------------------------------------------------------------------------------------------- */

lib/tty/color.h

@@ -48,6 +48,7 @@ void tty_set_normal_attrs (void);
 void tty_color_set_defaults (const char *, const char *, const char *);
 
 extern gboolean tty_use_256colors (void);
+extern gboolean tty_use_truecolors (GError **);
 
 /*** inline functions ****************************************************************************/
 #endif /* MC_COLOR_H */

lib/tty/tty-slang.c

@@ -316,7 +316,7 @@ tty_init (gboolean mouse_enable, gboolean is_xterm)
     tty_reset_prog_mode ();
     load_terminfo_keys ();
 
-    SLtt_Blink_Mode = tty_use_256colors ()? 1 : 0;
+    SLtt_Blink_Mode = (tty_use_256colors () || tty_use_truecolors (NULL)) ? 1 : 0;
 
     tty_start_interrupt_key ();