- The use_default_colors() and assume_default_colors() func-
+ The use_default_colors() and assume_default_colors() func-
tions are extensions to the curses library. They are used
with terminals that support ISO 6429 color, or equivalent.
These terminals allow the application to reset color to an
@@ -29,103 +72,104 @@
whole screen do not take advantage of SGR 39 and SGR 49.
Some applications are designed to work with the default
background, using colors only for text. For example,
- there are several implementations of the ls program which
+ there are several implementations of the ls program which
use colors to denote different file types or permissions.
These "color ls" programs do not necessarily modify the
- background color, typically using only the setaf terminfo
+ background color, typically using only the setaf terminfo
capability to set the foreground color. Full-screen
applications that use default colors can achieve similar
visual effects.
- The first function, use_default_colors() tells the curses
+ The first function, use_default_colors() tells the curses
library to assign terminal default foreground/background
colors to color number -1. So init_pair(x,COLOR_RED,-1)
will initialize pair x as red on default background and
init_pair(x,-1,COLOR_BLUE) will initialize pair x as
default foreground on blue.
- The other, assume_default_colors() is a refinement which
+ The other, assume_default_colors() is a refinement which
tells which colors to paint for color pair 0. This func-
tion recognizes a special color number -1, which denotes
the default terminal color.
The following are equivalent:
- use_default_colors();
- assume_default_colors(-1,-1);
+ use_default_colors();
+ assume_default_colors(-1,-1);
These are ncurses extensions. For other curses implemen-
tations, color number -1 does not mean anything, just as
- for ncurses before a successful call of use_default_col-
- ors() or assume_default_colors().
+ for ncurses before a successful call of use_default_col-
+ ors() or assume_default_colors().
Other curses implementations do not allow an application
to modify color pair 0. They assume that the background
is COLOR_BLACK, but do not ensure that the color pair 0 is
painted to match the assumption. If your application does
- not use either use_default_colors() or assume_default_col-
- ors() ncurses will paint a white foreground (text) with
+ not use either use_default_colors() or assume_default_col-
+ ors() ncurses will paint a white foreground (text) with
black background for color pair 0.
RETURN VALUE
- These functions return the integer ERR upon failure and OK
+ These functions return the integer ERR upon failure and OK
on success. They will fail if either the terminal does
- not support the orig_pair or orig_colors capability. If
- the initialize_pair capability is found, this causes an
+ not support the orig_pair or orig_colors capability. If
+ the initialize_pair capability is found, this causes an
error as well.
NOTES
- Associated with this extension, the init_pair(3x) function
+ Associated with this extension, the init_pair(3x) function
accepts negative arguments to specify default foreground
or background colors.
+ The use_default_colors() function was added to support
+ ded. This is a full-screen application which uses curses
+ to manage only part of the screen. The bottom portion of
+ the screen, which is of adjustable size, is left uncolored
+ to display the results from shell commands. The top por-
+ tion of the screen colors filenames using a scheme like
+ the "color ls" programs. Attempting to manage the back-
+ ground color of the screen for this application would give
+ unsatisfactory results for a variety of reasons. This
+ extension was devised after noting that color xterm (and
+ similar programs) provides a background color which does
+ not necessarily correspond to any of the ANSI colors.
+ While a special terminfo entry could be constructed using
+ nine colors, there was no mechanism provided within curses
+ to account for the related orig_pair and back_color_erase
+ capabilities.
+
+ The assume_default_colors() function was added to solve a
+ different problem: support for applications which would
+ use environment variables and other configuration to
+ bypass curses' notion of the terminal's default colors,
+ setting specific values.
+
PORTABILITY
- These routines are specific to ncurses. They were not
- supported on Version 7, BSD or System V implementations.
- It is recommended that any code depending on them be con-
+ These routines are specific to ncurses. They were not
+ supported on Version 7, BSD or System V implementations.
+ It is recommended that any code depending on them be con-
ditioned using NCURSES_VERSION.
- Thomas Dickey (from an analysis of the requirements for
+ Thomas Dickey (from an analysis of the requirements for
color xterm for XFree86 3.1.2C, February 1996).
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+ default_colors(3x)