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- * @Id: curs_color.3x,v 1.19 2002/02/16 22:38:32 tom Exp @
+ * @Id: curs_color.3x,v 1.27 2005/05/15 16:55:36 tom Exp @
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<PRE>
<!-- Manpage converted by man2html 3.0.1 -->
-<STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG> <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
+<STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
<STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
</PRE>
<H2>NAME</H2><PRE>
- <STRONG>start_color</STRONG>, <STRONG>init_pair</STRONG>, <STRONG>init_color</STRONG>, <STRONG>has_colors</STRONG>,
- <STRONG>can_change_color</STRONG>, <STRONG>color_content</STRONG>, <STRONG>pair_content</STRONG>, <STRONG>COLOR_PAIR</STRONG>
+ <STRONG>start_color</STRONG>, <STRONG>init_pair</STRONG>, <STRONG>init_color</STRONG>, <STRONG>has_colors</STRONG>,
+ <STRONG>can_change_color</STRONG>, <STRONG>color_content</STRONG>, <STRONG>pair_content</STRONG>, <STRONG>COLOR_PAIR</STRONG>
- <STRONG>curses</STRONG> color manipulation routines
</PRE>
<H2>DESCRIPTION</H2><PRE>
<STRONG>Overview</STRONG>
- <STRONG>curses</STRONG> support color attributes on terminals with that
- capability. To use these routines <STRONG>start_color</STRONG> must be
+ <STRONG>curses</STRONG> support color attributes on terminals with that ca-
+ pability. To use these routines <STRONG>start_color</STRONG> must be
called, usually right after <STRONG>initscr</STRONG>. Colors are always
used in pairs (referred to as color-pairs). A color-pair
consists of a foreground color (for characters) and a
ters are displayed). A programmer initializes a color-
pair with the routine <STRONG>init_pair</STRONG>. After it has been ini-
tialized, <STRONG>COLOR_PAIR</STRONG>(<EM>n</EM>), a macro defined in <STRONG><curses.h></STRONG>,
- can be used as a new video attribute.
-
- If a terminal is capable of redefining colors, the pro-
- grammer can use the routine <STRONG>init_color</STRONG> to change the defi-
- nition of a color. The routines <STRONG>has_colors</STRONG> and
- <STRONG>can_change_color</STRONG> return <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>, depending on
- whether the terminal has color capabilities and whether
- the programmer can change the colors. The routine
- <STRONG>color_content</STRONG> allows a programmer to extract the amounts
- of red, green, and blue components in an initialized
- color. The routine <STRONG>pair_content</STRONG> allows a programmer to
- find out how a given color-pair is currently defined.
+ can be used as a new video attribute. If a terminal is
+ capable of redefining colors, the programmer can use the
+ routine <STRONG>init_color</STRONG> to change the definition of a color.
+ The routines <STRONG>has_colors</STRONG> and <STRONG>can_change_color</STRONG> return <STRONG>TRUE</STRONG>
+ or <STRONG>FALSE</STRONG>, depending on whether the terminal has color ca-
+ pabilities and whether the programmer can change the col-
+ ors. The routine <STRONG>color_content</STRONG> allows a programmer to ex-
+ tract the amounts of red, green, and blue components in an
+ initialized color. The routine <STRONG>pair_content</STRONG> allows a pro-
+ grammer to find out how a given color-pair is currently
+ defined.
<STRONG>Routine</STRONG> <STRONG>Descriptions</STRONG>
The <STRONG>start_color</STRONG> routine requires no arguments. It must be
- called if the programmer wants to use colors, and before
- any other color manipulation routine is called. It is
- good practice to call this routine right after <STRONG>initscr</STRONG>.
- <STRONG>start_color</STRONG> initializes eight basic colors (black, red,
- green, yellow, blue, magenta, cyan, and white), and two
- global variables, <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG> (respectively
- defining the maximum number of colors and color-pairs the
+ called if the programmer wants to use colors, and before
+ any other color manipulation routine is called. It is
+ good practice to call this routine right after <STRONG>initscr</STRONG>.
+ <STRONG>start_color</STRONG> initializes eight basic colors (black, red,
+ green, yellow, blue, magenta, cyan, and white), and two
+ global variables, <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG> (respectively
+ defining the maximum number of colors and color-pairs the
terminal can support). It also restores the colors on the
terminal to the values they had when the terminal was just
- turned on.
-
- The <STRONG>init_pair</STRONG> routine changes the definition of a color-
- pair. It takes three arguments: the number of the color-
- pair to be changed, the foreground color number, and the
- background color number. For portable applications:
+ turned on. The <STRONG>init_pair</STRONG> routine changes the definition
+ of a color-pair. It takes three arguments: the number of
+ the color-pair to be changed, the foreground color number,
+ and the background color number. For portable applica-
+ tions:
- The value of the first argument must be between <STRONG>1</STRONG> and
<STRONG>COLOR_PAIRS-1</STRONG>.
- The value of the second and third arguments must be
- between 0 and <STRONG>COLORS</STRONG> (the 0 color pair is wired to
- white on black and cannot be changed).
+ between 0 and <STRONG>COLORS</STRONG>. Color pair 0 is assumed to be
+ white on black, but is actually whatever the terminal
+ implements before color is initialized. It cannot be
+ modified by the application.
If the color-pair was previously initialized, the screen
is refreshed and all occurrences of that color-pair are
- changed to the new definition.
-
- As an extension, ncurses allows you to set color pair 0
- via the <STRONG>assume_default_colors</STRONG> routine, or to specify the
- use of default colors (color number <STRONG>-1</STRONG>) if you first
- invoke the <STRONG>use_default_colors</STRONG> routine.
-
- The <STRONG>init_color</STRONG> routine changes the definition of a color.
- It takes four arguments: the number of the color to be
- changed followed by three RGB values (for the amounts of
- red, green, and blue components). The value of the first
- argument must be between <STRONG>0</STRONG> and <STRONG>COLORS</STRONG>. (See the section
- <STRONG>Colors</STRONG> for the default color index.) Each of the last
- three arguments must be a value between 0 and 1000. When
- <STRONG>init_color</STRONG> is used, all occurrences of that color on the
- screen immediately change to the new definition.
-
- The <STRONG>has_colors</STRONG> routine requires no arguments. It returns
- <STRONG>TRUE</STRONG> if the terminal can manipulate colors; otherwise, it
- returns <STRONG>FALSE</STRONG>. This routine facilitates writing terminal-
+ changed to the new definition. As an extension, ncurses
+ allows you to set color pair 0 via the <STRONG>assume_default_col-</STRONG>
+ <STRONG>ors</STRONG> routine, or to specify the use of default colors (col-
+ or number <STRONG>-1</STRONG>) if you first invoke the <STRONG>use_default_colors</STRONG>
+ routine. The <STRONG>init_color</STRONG> routine changes the definition of
+ a color. It takes four arguments: the number of the color
+ to be changed followed by three RGB values (for the
+ amounts of red, green, and blue components). The value of
+ the first argument must be between <STRONG>0</STRONG> and <STRONG>COLORS</STRONG>. (See the
+ section <STRONG>Colors</STRONG> for the default color index.) Each of the
+ last three arguments must be a value between 0 and 1000.
+ When <STRONG>init_color</STRONG> is used, all occurrences of that color on
+ the screen immediately change to the new definition. The
+ <STRONG>has_colors</STRONG> routine requires no arguments. It returns <STRONG>TRUE</STRONG>
+ if the terminal can manipulate colors; otherwise, it re-
+ turns <STRONG>FALSE</STRONG>. This routine facilitates writing terminal-
independent programs. For example, a programmer can use
- it to decide whether to use color or some other video
- attribute.
-
- The <STRONG>can_change_color</STRONG> routine requires no arguments. It
- returns <STRONG>TRUE</STRONG> if the terminal supports colors and can
- change their definitions; other, it returns <STRONG>FALSE</STRONG>. This
- routine facilitates writing terminal-independent programs.
-
- The <STRONG>color_content</STRONG> routine gives programmers a way to find
- the intensity of the red, green, and blue (RGB) components
- in a color. It requires four arguments: the color number,
- and three addresses of <STRONG>short</STRONG>s for storing the information
- about the amounts of red, green, and blue components in
- the given color. The value of the first argument must be
- between 0 and <STRONG>COLORS</STRONG>. The values that are stored at the
- addresses pointed to by the last three arguments are
- between 0 (no component) and 1000 (maximum amount of com-
- ponent).
-
- The <STRONG>pair_content</STRONG> routine allows programmers to find out
- what colors a given color-pair consists of. It requires
- three arguments: the color-pair number, and two addresses
- of <STRONG>short</STRONG>s for storing the foreground and the background
- color numbers. The value of the first argument must be
- between 1 and <STRONG>COLOR_PAIRS-1</STRONG>. The values that are stored
- at the addresses pointed to by the second and third argu-
- ments are between 0 and <STRONG>COLORS</STRONG>.
+ it to decide whether to use color or some other video at-
+ tribute. The <STRONG>can_change_color</STRONG> routine requires no argu-
+ ments. It returns <STRONG>TRUE</STRONG> if the terminal supports colors
+ and can change their definitions; other, it returns <STRONG>FALSE</STRONG>.
+ This routine facilitates writing terminal-independent pro-
+ grams. The <STRONG>color_content</STRONG> routine gives programmers a way
+ to find the intensity of the red, green, and blue (RGB)
+ components in a color. It requires four arguments: the
+ color number, and three addresses of <STRONG>short</STRONG>s for storing
+ the information about the amounts of red, green, and blue
+ components in the given color. The value of the first ar-
+ gument must be between 0 and <STRONG>COLORS</STRONG>. The values that are
+ stored at the addresses pointed to by the last three argu-
+ ments are between 0 (no component) and 1000 (maximum
+ amount of component). The <STRONG>pair_content</STRONG> routine allows
+ programmers to find out what colors a given color-pair
+ consists of. It requires three arguments: the color-pair
+ number, and two addresses of <STRONG>short</STRONG>s for storing the fore-
+ ground and the background color numbers. The value of the
+ first argument must be between 1 and <STRONG>COLOR_PAIRS-1</STRONG>. The
+ values that are stored at the addresses pointed to by the
+ second and third arguments are between 0 and <STRONG>COLORS</STRONG>.
<STRONG>Colors</STRONG>
In <STRONG><curses.h></STRONG> the following macros are defined. These are
the default colors. <STRONG>curses</STRONG> also assumes that <STRONG>COLOR_BLACK</STRONG>
is the default background color for all terminals.
-
<STRONG>COLOR_BLACK</STRONG>
<STRONG>COLOR_RED</STRONG>
<STRONG>COLOR_GREEN</STRONG>
</PRE>
<H2>RETURN VALUE</H2><PRE>
The routines <STRONG>can_change_color()</STRONG> and <STRONG>has_colors()</STRONG> return
- <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>.
-
- All other routines return the integer <STRONG>ERR</STRONG> upon failure and
- an <STRONG>OK</STRONG> (SVr4 specifies only "an integer value other than
- <STRONG>ERR</STRONG>") upon successful completion.
+ <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>. All other routines return the integer <STRONG>ERR</STRONG>
+ upon failure and an <STRONG>OK</STRONG> (SVr4 specifies only "an integer
+ value other than <STRONG>ERR</STRONG>") upon successful completion.
+
+ X/Open defines no error conditions. This implementation
+ will return <STRONG>ERR</STRONG> on attempts to use color values outside
+ the range 0 to COLORS-1 (except for the default colors ex-
+ tension), or use color pairs outside the range 0 to COL-
+ OR_PAIR-1. Color values used in <STRONG>init_color</STRONG> must be in the
+ range 0 to 1000. An error is returned from all functions
+ if the terminal has not been initialized. An error is re-
+ turned from secondary functions such as <STRONG>init_pair</STRONG> if
+ <STRONG>start_color</STRONG> was not called.
+
+ <STRONG>init_color</STRONG>
+ returns an error if the terminal does not sup-
+ port this feature, e.g., if the <EM>initial-</EM>
+ <EM>ize</EM><STRONG>_</STRONG><EM>color</EM> capability is absent from the termi-
+ nal description.
+
+ <STRONG>start_color</STRONG>
+ returns an error If the color table cannot be
+ allocated.
</PRE>
<H2>NOTES</H2><PRE>
In the <EM>ncurses</EM> implementation, there is a separate color
- activation flag, color palette, color pairs table, and
- associated COLORS and COLOR_PAIRS counts for each screen;
+ activation flag, color palette, color pairs table, and as-
+ sociated COLORS and COLOR_PAIRS counts for each screen;
the <STRONG>start_color</STRONG> function only affects the current screen.
The SVr4/XSI interface is not really designed with this in
mind, and historical implementations may use a single
- shared color palette.
-
- Note that setting an implicit background color via a color
- pair affects only character cells that a character write
- operation explicitly touches. To change the background
- color used when parts of a window are blanked by erasing
- or scrolling operations, see <STRONG><A HREF="curs_bkgd.3x.html">curs_bkgd(3x)</A></STRONG>.
-
- Several caveats apply on 386 and 486 machines with VGA-
- compatible graphics:
-
- - COLOR_YELLOW is actually brown. To get yellow, use
+ shared color palette. Note that setting an implicit back-
+ ground color via a color pair affects only character cells
+ that a character write operation explicitly touches. To
+ change the background color used when parts of a window
+ are blanked by erasing or scrolling operations, see
+ <STRONG><A HREF="curs_bkgd.3x.html">curs_bkgd(3x)</A></STRONG>. Several caveats apply on 386 and 486 ma-
+ chines with VGA-compatible graphics:
+
+ - COLOR_YELLOW is actually brown. To get yellow, use
COLOR_YELLOW combined with the <STRONG>A_BOLD</STRONG> attribute.
- - The A_BLINK attribute should in theory cause the
- background to go bright. This often fails to work,
- and even some cards for which it mostly works (such
- as the Paradise and compatibles) do the wrong thing
+ - The A_BLINK attribute should in theory cause the
+ background to go bright. This often fails to work,
+ and even some cards for which it mostly works (such
+ as the Paradise and compatibles) do the wrong thing
when you try to set a bright "yellow" background (you
get a blinking yellow foreground instead).
</PRE>
<H2>PORTABILITY</H2><PRE>
- This implementation satisfies XSI Curses's minimum maxi-
+ This implementation satisfies XSI Curses's minimum maxi-
mums for <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG>.
- The <STRONG>init_pair</STRONG> routine accepts negative values of fore-
- ground and background color to support the
- <STRONG>use_default_colors</STRONG> extension, but only if that routine has
- been first invoked.
+ The <STRONG>init_pair</STRONG> routine accepts negative values of fore-
+ ground and background color to support the <STRONG>use_de-</STRONG>
+ <STRONG>fault_colors</STRONG> extension, but only if that routine has been
+ first invoked.
- The assumption that <STRONG>COLOR_BLACK</STRONG> is the default background
- color for all terminals can be modified using the
- <STRONG>assume_default_colors</STRONG> extension,
+ The assumption that <STRONG>COLOR_BLACK</STRONG> is the default background
+ color for all terminals can be modified using the <STRONG>as-</STRONG>
+ <STRONG>sume_default_colors</STRONG> extension.
+ This implementation checks the pointers, e.g., for the
+ values returned by <STRONG>color_content</STRONG> and <STRONG>pair_content</STRONG>, and
+ will treat those as optional parameters when null.
</PRE>
<H2>SEE ALSO</H2><PRE>
- <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>, <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, <STRONG>default_col-</STRONG>
+ <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>, <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, <STRONG>default_col-</STRONG>
<STRONG><A HREF="default_colors.3x.html">ors(3x)</A></STRONG>
- <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
+
<STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
</PRE>
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