* sale, use or other dealings in this Software without prior written *
* authorization. *
****************************************************************************
- * @Id: curs_color.3x,v 1.92 2023/11/25 17:36:51 tom Exp @
+ * @Id: curs_color.3x,v 1.93 2023/12/16 21:07:24 tom Exp @
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-<H1 class="no-header">curs_color 3x 2023-11-25 ncurses 6.4 Library calls</H1>
+<H1 class="no-header">curs_color 3x 2023-12-16 ncurses 6.4 Library calls</H1>
<PRE>
<STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
<STRONG>start_color</STRONG>, <STRONG>has_colors</STRONG>, <STRONG>can_change_color</STRONG>, <STRONG>init_pair</STRONG>, <STRONG>init_color</STRONG>,
<STRONG>init_extended_pair</STRONG>, <STRONG>init_extended_color</STRONG>, <STRONG>color_content</STRONG>, <STRONG>pair_content</STRONG>,
<STRONG>extended_color_content</STRONG>, <STRONG>extended_pair_content</STRONG>, <STRONG>reset_color_pairs</STRONG>,
- <STRONG>COLOR_PAIR</STRONG>, <STRONG>PAIR_NUMBER</STRONG> - manipulate terminal colors with <EM>curses</EM>
+ <STRONG>COLOR_PAIR</STRONG>, <STRONG>PAIR_NUMBER</STRONG>, <STRONG>COLORS</STRONG>, <STRONG>COLOR_PAIRS</STRONG>, <STRONG>COLOR_BLACK</STRONG>, <STRONG>COLOR_RED</STRONG>,
+ <STRONG>COLOR_GREEN</STRONG>, <STRONG>COLOR_YELLOW</STRONG>, <STRONG>COLOR_BLUE</STRONG>, <STRONG>COLOR_MAGENTA</STRONG>, <STRONG>COLOR_CYAN</STRONG>,
+ <STRONG>COLOR_WHITE</STRONG> - manipulate terminal colors with <EM>curses</EM>
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>void</STRONG> <STRONG>reset_color_pairs(void);</STRONG>
<STRONG>int</STRONG> <STRONG>COLOR_PAIR(int</STRONG> <EM>n</EM><STRONG>);</STRONG>
- <STRONG>PAIR_NUMBER(</STRONG><EM>attrs</EM><STRONG>);</STRONG>
+ <STRONG>PAIR_NUMBER(int</STRONG> <EM>attr</EM><STRONG>);</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
</PRE><H3><a name="h3-Overview">Overview</a></H3><PRE>
<EM>curses</EM> supports color attributes on terminals with that capability. 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
+ <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
background color (for the blank field on which the characters are
- displayed). A programmer initializes a color-pair with the routine
+ displayed). A programmer initializes a color pair with the routine
<STRONG>init_pair</STRONG>. After it has been initialized, <STRONG>COLOR_PAIR</STRONG>(<EM>n</EM>) can be used to
convert the pair to a video attribute.
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.
+ to find out how a given color pair is currently defined.
</PRE><H3><a name="h3-Color-Rendering">Color Rendering</a></H3><PRE>
routine right after <STRONG>initscr</STRONG>. <STRONG>start_color</STRONG> does this:
<STRONG>o</STRONG> It initializes two global variables, <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG>
- (respectively defining the maximum number of colors and color-pairs
+ (respectively defining the maximum number of colors and color pairs
the terminal can support).
<STRONG>o</STRONG> It initializes the special color pair <STRONG>0</STRONG> to the default foreground
</PRE><H3><a name="h3-init_pair">init_pair</a></H3><PRE>
- 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
+ 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:
<STRONG>o</STRONG> The second and third arguments must be valid color values.
- If the color-pair was previously initialized, the screen is refreshed
- and all occurrences of that color-pair are changed to the new
+ 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 <STRONG>0</STRONG> via the
+ As an extension, <EM>ncurses</EM> allows you to set color pair <STRONG>0</STRONG> via the
<STRONG><A HREF="default_colors.3x.html">assume_default_colors(3x)</A></STRONG> routine, or to specify the use of default
colors (color number <STRONG>-1</STRONG>) if you first invoke the <STRONG><A HREF="default_colors.3x.html">use_default_colors(3x)</A></STRONG>
routine.
</PRE><H3><a name="h3-init_extended_pair">init_extended_pair</a></H3><PRE>
Because <STRONG>init_pair</STRONG> uses signed <STRONG>short</STRONG>s for its parameters, that limits
- color-pairs and color-values to 32767 on modern hardware. The
- extension <STRONG>init_extended_pair</STRONG> uses <STRONG>int</STRONG>s for the color-pair and color-
+ color pairs and color-values to 32767 on modern hardware. The
+ extension <STRONG>init_extended_pair</STRONG> uses <STRONG>int</STRONG>s for the color pair and color-
value, allowing a larger number of colors to be supported.
</PRE><H3><a name="h3-pair_content">pair_content</a></H3><PRE>
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-
+ 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.
</PRE><H3><a name="h3-extended_pair_content">extended_pair_content</a></H3><PRE>
Because <STRONG>pair_content</STRONG> uses signed <STRONG>short</STRONG>s for its parameters, that limits
- color-pair and color-values to 32767 on modern hardware. The extension
+ color pair and color-values to 32767 on modern hardware. The extension
<STRONG>extended_pair_content</STRONG> uses <STRONG>int</STRONG>s for the color pair and for returning
the foreground and background colors, allowing a larger number of
colors to be supported.
</PRE><H3><a name="h3-reset_color_pairs">reset_color_pairs</a></H3><PRE>
- The extension <STRONG>reset_color_pairs</STRONG> tells ncurses to discard all of the
- color-pair information which was set with <STRONG>init_pair</STRONG>. It also touches
+ The extension <STRONG>reset_color_pairs</STRONG> tells <EM>ncurses</EM> to discard all of the
+ color pair information which was set with <STRONG>init_pair</STRONG>. It also touches
the current- and standard-screens, allowing an application to switch
color palettes rapidly.
-</PRE><H3><a name="h3-PAIR_NUMBER">PAIR_NUMBER</a></H3><PRE>
- <STRONG>PAIR_NUMBER(</STRONG><EM>attrs</EM>) extracts the color value from its <EM>attrs</EM> parameter
- and returns it as a color pair number.
+</PRE><H3><a name="h3-COLOR_PAIR">COLOR_PAIR</a></H3><PRE>
+ <STRONG>COLOR_PAIR(</STRONG><EM>n</EM><STRONG>)</STRONG> converts a color pair number to an attribute. Attributes
+ can hold color pairs in the range 0 to 255. If you need a color pair
+ larger than that, you must use functions such as <STRONG>attr_set</STRONG> (which pass
+ the color pair as a separate parameter) rather than the legacy
+ functions such as <STRONG>attrset</STRONG>.
-</PRE><H3><a name="h3-COLOR_PAIR">COLOR_PAIR</a></H3><PRE>
- Its inverse <STRONG>COLOR_PAIR(</STRONG><EM>n</EM><STRONG>)</STRONG> converts a color pair number to an attribute.
- Attributes can hold color pairs in the range 0 to 255. If you need a
- color pair larger than that, you must use functions such as <STRONG>attr_set</STRONG>
- (which pass the color pair as a separate parameter) rather than the
- legacy functions such as <STRONG>attrset</STRONG>.
+</PRE><H3><a name="h3-PAIR_NUMBER">PAIR_NUMBER</a></H3><PRE>
+ <STRONG>PAIR_NUMBER(</STRONG><EM>attr</EM>) extracts the color information from its <EM>attr</EM>
+ parameter and returns it as a color pair number; it is the inverse
+ operation of <STRONG>COLOR_PAIR</STRONG>.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></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
+ 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. SVr4 does document some error
+ X/Open defines no error conditions. SVr4 does document some error
conditions which apply in general:
<STRONG>o</STRONG> This implementation will return <STRONG>ERR</STRONG> on attempts to use color values
- outside the range <STRONG>0</STRONG> to <STRONG>COLORS</STRONG>-1 (except for the default colors
- extension), or use color pairs outside the range <STRONG>0</STRONG> to
+ outside the range <STRONG>0</STRONG> to <STRONG>COLORS</STRONG>-1 (except for the default colors
+ extension), or use color pairs outside the range <STRONG>0</STRONG> to
<STRONG>COLOR_PAIRS-1</STRONG>.
Color values used in <STRONG>init_color</STRONG> must be in the range <STRONG>0</STRONG> to <STRONG>1000</STRONG>.
- An error is returned from all functions if the terminal has not
+ An error is returned from all functions if the terminal has not
been initialized.
- An error is returned from secondary functions such as <STRONG>init_pair</STRONG> if
+ An error is returned from secondary functions such as <STRONG>init_pair</STRONG> if
<STRONG>start_color</STRONG> was not called.
- <STRONG>o</STRONG> SVr4 does much the same, except that it returns <STRONG>ERR</STRONG> from
- <STRONG>pair_content</STRONG> if the pair was not initialized using <STRONG>init_pairs</STRONG> and
- it returns <STRONG>ERR</STRONG> from <STRONG>color_content</STRONG> if the terminal does not support
+ <STRONG>o</STRONG> SVr4 does much the same, except that it returns <STRONG>ERR</STRONG> from
+ <STRONG>pair_content</STRONG> if the pair was not initialized using <STRONG>init_pairs</STRONG> and
+ it returns <STRONG>ERR</STRONG> from <STRONG>color_content</STRONG> if the terminal does not support
changing colors.
This implementation does not return <STRONG>ERR</STRONG> for either case.
<STRONG>init_color</STRONG>
returns an error if the terminal does not support this feature,
- e.g., if the <STRONG>initialize_color</STRONG> capability is absent from the
+ e.g., if the <STRONG>initialize_color</STRONG> capability is absent from the
terminal description.
<STRONG>start_color</STRONG>
</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
- In the <EM>ncurses</EM> implementation, there is a separate color activation
- flag, color palette, color pairs table, and associated <STRONG>COLORS</STRONG> and
- <STRONG>COLOR_PAIRS</STRONG> 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
+ In the <EM>ncurses</EM> implementation, there is a separate color activation
+ flag, color palette, color pairs table, and associated <STRONG>COLORS</STRONG> and
+ <STRONG>COLOR_PAIRS</STRONG> 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.
- 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
+ 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 older x86 machines (e.g., i386, i486) with
+ Several caveats apply on older x86 machines (e.g., i386, i486) with
VGA-compatible graphics:
- <STRONG>o</STRONG> COLOR_YELLOW is actually brown. To get yellow, use COLOR_YELLOW
+ <STRONG>o</STRONG> COLOR_YELLOW is actually brown. To get yellow, use COLOR_YELLOW
combined with the <STRONG>A_BOLD</STRONG> attribute.
- <STRONG>o</STRONG> The A_BLINK attribute should in theory cause the background to go
+ <STRONG>o</STRONG> 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
+ 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).
<STRONG>o</STRONG> Color RGB values are not settable.
</PRE><H2><a name="h2-EXTENSIONS">EXTENSIONS</a></H2><PRE>
- The functions marked as extensions were designed for <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>, and
- are not found in SVr4 curses, 4.4BSD curses, or any other previous
+ The functions marked as extensions were designed for <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>, and
+ are not found in SVr4 curses, 4.4BSD curses, or any other previous
version of curses.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
- This implementation satisfies XSI Curses's minimum maximums for <STRONG>COLORS</STRONG>
+ This implementation satisfies XSI Curses's minimum maximums for <STRONG>COLORS</STRONG>
and <STRONG>COLOR_PAIRS</STRONG>.
The <STRONG>init_pair</STRONG> routine accepts negative values of foreground and
- background color to support the <STRONG><A HREF="default_colors.3x.html">use_default_colors(3x)</A></STRONG> extension, but
+ background color to support the <STRONG><A HREF="default_colors.3x.html">use_default_colors(3x)</A></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><A HREF="default_colors.3x.html">assume_default_colors(3x)</A></STRONG>
+ terminals
can be modified using the <STRONG><A HREF="default_colors.3x.html">assume_default_colors(3x)</A></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
+ 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.
- X/Open Curses does not specify a limit for the number of colors and
+ X/Open Curses does not specify a limit for the number of colors and
color pairs which a terminal can support. However, in its use of <STRONG>short</STRONG>
- for the parameters, it carries over SVr4's implementation detail for
+ for the parameters, it carries over SVr4's implementation detail for
the compiled terminfo database, which uses signed 16-bit numbers. This
- implementation provides extended versions of those functions which use
- <STRONG>short</STRONG> parameters, allowing applications to use larger color- and pair-
+ implementation provides extended versions of those functions which use
+ <STRONG>short</STRONG> parameters, allowing applications to use larger color- and pair-
numbers.
- The <STRONG>reset_color_pairs</STRONG> function is an extension of ncurses.
+ The <STRONG>reset_color_pairs</STRONG> function is an extension of <EM>ncurses</EM>.
</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
SVr3.2 introduced color support to curses in 1987.
- SVr4 made internal changes, e.g., moving the storage for the color
+ SVr4 made internal changes, e.g., moving the storage for the color
state from <STRONG>SP</STRONG> (the <STRONG>SCREEN</STRONG> structure) to <STRONG>cur_term</STRONG> (the <STRONG>TERMINAL</STRONG>
structure), but provided the same set of library functions.
- SVr4 curses limits the number of color pairs to 64, reserving color
- pair zero (0) as the terminal's initial uncolored state. This limit
- arises because the color pair information is a bitfield in the <STRONG>chtype</STRONG>
+ SVr4 curses limits the number of color pairs to 64, reserving color
+ pair zero (0) as the terminal's initial uncolored state. This limit
+ arises because the color pair information is a bitfield in the <STRONG>chtype</STRONG>
data type (denoted by <STRONG>A_COLOR</STRONG>).
Other implementations of curses had different limits:
changing <STRONG>chtype</STRONG> from 16-bits to 32-bits.
<STRONG>o</STRONG> X/Open Curses (1992-present) added a new structure <STRONG>cchar_t</STRONG> to store
- the character, attributes and color-pair values, allowing increased
- range of color-pairs. Both color-pairs and color-values used a
+ the character, attributes and color pair values, allowing increased
+ range of color pairs. Both color pairs and color-values used a
signed <STRONG>short</STRONG>, limiting values to 15 bits.
- <STRONG>o</STRONG> ncurses (1992-present) uses eight bits for <STRONG>A_COLOR</STRONG> in <STRONG>chtype</STRONG>
+ <STRONG>o</STRONG> <EM>ncurses</EM> (1992-present) uses eight bits for <STRONG>A_COLOR</STRONG> in <STRONG>chtype</STRONG>
values.
- Version 5.3 provided a wide-character interface (2002), but left
- color-pairs as part of the attributes-field.
+ Version 5.3 provided a wide-character interface (2002), but left
+ color pairs as part of the attributes-field.
- Since version 6 (2015), ncurses uses a separate <STRONG>int</STRONG> for color-pairs
- in the <STRONG>cchar_t</STRONG> values. When those color-pair values fit in 8 bits,
- ncurses allows color-pairs to be manipulated via the functions
+ Since version 6 (2015), ncurses uses a separate <STRONG>int</STRONG> for color pairs
+ in the <STRONG>cchar_t</STRONG> values. When those color pair values fit in 8 bits,
+ ncurses allows color pairs to be manipulated via the functions
using <STRONG>chtype</STRONG> values.
- <STRONG>o</STRONG> NetBSD curses used 6 bits from 2000 (when colors were first
- supported) until 2004. At that point, NetBSD changed to use 10
- bits. As of 2021, that size is unchanged. Like ncurses before
- version 6, the NetBSD color-pair information is stored in the
- attributes field of <STRONG>cchar_t</STRONG>, limiting the number of color-pairs by
+ <STRONG>o</STRONG> NetBSD curses used 6 bits from 2000 (when colors were first
+ supported) until 2004. At that point, NetBSD changed to use 10
+ bits. As of 2021, that size is unchanged. Like <EM>ncurses</EM> before
+ version 6, the NetBSD color pair information is stored in the
+ attributes field of <STRONG>cchar_t</STRONG>, limiting the number of color pairs by
the size of the bitfield.
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
- <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>,
<STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>,
+ <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>,
<STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>,
<STRONG><A HREF="default_colors.3x.html">default_colors(3x)</A></STRONG>
-ncurses 6.4 2023-1
1-25 <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
+ncurses 6.4 2023-1
2-16 <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h3-pair_content">pair_content</a></li>
<li><a href="#h3-extended_pair_content">extended_pair_content</a></li>
<li><a href="#h3-reset_color_pairs">reset_color_pairs</a></li>
-<li><a href="#h3-PAIR_NUMBER">PAIR_NUMBER</a></li>
<li><a href="#h3-COLOR_PAIR">COLOR_PAIR</a></li>
+<li><a href="#h3-PAIR_NUMBER">PAIR_NUMBER</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
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