NOTE: This patch has been committed.

I added the min-colors specifier to defface, and it highlighted the

fact that the tty device hadn't implemented the num-color-cells

metric.   I also added num-bit-planes since it was easy to derive.

* console-tty-impl.h (struct tty_console): Add field for number of

displayable colors.

* device-tty.c (tty_device_system_metrics): Return metrics for

num-color-cells and num-bit-planes.

* device.c: There are two required args for device-system-metric.

* redisplay-tty.c (init_tty_for_redisplay): Retrieve number of

colors from terminal description.  Default to 2 if none found.

xemacs-local source patch:

Diff command:   hg diff --git 

Files affected: src/redisplay-tty.c src/device.c src/device-tty.c src/console-tty-impl.h

diff --git a/src/console-tty-impl.h b/src/console-tty-impl.h

--- a/src/console-tty-impl.h

+++ b/src/console-tty-impl.h

@@ -63,6 +63,8 @@

   int height;

   int width;

 

+  int colors;

+

   /* The count of frame number. */

   int frame_count;

 

diff --git a/src/device-tty.c b/src/device-tty.c

--- a/src/device-tty.c

+++ b/src/device-tty.c

@@ -196,6 +196,10 @@

     case DM_size_device:

       return Fcons (make_int (CONSOLE_TTY_DATA (con)->width),

     make_int (CONSOLE_TTY_DATA (con)->height));

+    case DM_num_bit_planes:

+      return make_int (log2 (CONSOLE_TTY_DATA (con)->colors));

+    case DM_num_color_cells:

+      return make_int (CONSOLE_TTY_DATA (con)->colors);

     default: /* No such device metric property for TTY devices */

       return Qunbound;

     }

diff --git a/src/device.c b/src/device.c

--- a/src/device.c

+++ b/src/device.c

@@ -1057,8 +1057,8 @@

   return DEVICE_PRINTER_P (decode_device (device)) ? Qt : Qnil;

 }

 

-DEFUN ("device-system-metric", Fdevice_system_metric, 1, 3, 0, /*

-Get a metric for DEVICE as provided by the system.

+DEFUN ("device-system-metric", Fdevice_system_metric, 2, 3, 0, /*

+Get DEVICE METRIC as provided by the system.

 

 METRIC must be a symbol specifying requested metric.  Note that the metrics

 returned are these provided by the system internally, not read from resources,

diff --git a/src/redisplay-tty.c b/src/redisplay-tty.c

--- a/src/redisplay-tty.c

+++ b/src/redisplay-tty.c

@@ -1116,6 +1116,13 @@

   if (CONSOLE_TTY_DATA (c)->width <= 0 || CONSOLE_TTY_DATA (c)->height <= 0)

     return TTY_SIZE_UNSPECIFIED;

 

+  CONSOLE_TTY_DATA (c)->colors = tgetnum("Co");

+  if (CONSOLE_TTY_DATA (c)->colors == 0)

+    CONSOLE_TTY_DATA (c)->colors = tgetnum("colors");

+  if (CONSOLE_TTY_DATA (c)->colors == 0)

+    /* There is always foreground and background. */

+    CONSOLE_TTY_DATA (c)->colors = 2;

+

   /*

    * Initialize cursor motion information.

    */