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-<H1 class="no-header">curs_color 3x</H1>
+<H1 class="no-header">curs_color 3x 2024-04-20 ncurses 6.4 Library calls</H1>
<PRE>
-<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>
Library calls <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
- <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> - <STRONG>curses</STRONG> color manipulation routines
+ <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>, <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>#include</STRONG> <STRONG><curses.h></STRONG>
+ <EM>/*</EM> <EM>variables</EM> <EM>*/</EM>
+ <STRONG>int</STRONG> <STRONG>COLOR_PAIRS;</STRONG>
+ <STRONG>int</STRONG> <STRONG>COLORS;</STRONG>
+
<STRONG>int</STRONG> <STRONG>start_color(void);</STRONG>
<STRONG>bool</STRONG> <STRONG>has_colors(void);</STRONG>
<STRONG>int</STRONG> <STRONG>init_pair(short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>f</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>b</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>init_color(short</STRONG> <EM>color</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>r</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>g</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <EM>b</EM><STRONG>);</STRONG>
- /* extensions */
+ <EM>/*</EM> <EM>extensions</EM> <EM>*/</EM>
<STRONG>int</STRONG> <STRONG>init_extended_pair(int</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>f</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>b</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>init_extended_color(int</STRONG> <EM>color</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>r</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>g</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>b</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>color_content(short</STRONG> <EM>color</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <STRONG>*</STRONG><EM>r</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <STRONG>*</STRONG><EM>g</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <STRONG>*</STRONG><EM>b</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>pair_content(short</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <STRONG>*</STRONG><EM>f</EM><STRONG>,</STRONG> <STRONG>short</STRONG> <STRONG>*</STRONG><EM>b</EM><STRONG>);</STRONG>
- /* extensions */
+ <EM>/*</EM> <EM>extensions</EM> <EM>*/</EM>
<STRONG>int</STRONG> <STRONG>extended_color_content(int</STRONG> <EM>color</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <STRONG>*</STRONG><EM>r</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <STRONG>*</STRONG><EM>g</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <STRONG>*</STRONG><EM>b</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>extended_pair_content(int</STRONG> <EM>pair</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <STRONG>*</STRONG><EM>f</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <STRONG>*</STRONG><EM>b</EM><STRONG>);</STRONG>
- /* extensions */
+ <EM>/*</EM> <EM>extension</EM> <EM>*/</EM>
<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>
- <STRONG>curses</STRONG> 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
- background color (for the blank field on which the characters are dis-
- played). 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.
+ <EM>curses</EM> supports color attributes on terminals with that capability.
+ Call <STRONG>start_color</STRONG> (typically right after <STRONG><A HREF="curs_initscr.3x.html">initscr(3x)</A></STRONG>) to enable this
+ feature. Colors are always used in pairs. A <EM>color</EM> <EM>pair</EM> couples a
+ foreground color for characters with a background color for the blank
+ field on which characters are rendered. <STRONG>init_pair</STRONG> initializes a color
+ pair. The macro <STRONG>COLOR_PAIR</STRONG>(<EM>n</EM>) can then convert the pair to a 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 rou-
- tines <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 program-
- mer can change the colors. The routine <STRONG>color_content</STRONG> allows a program-
- mer 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.
+ If a terminal has the relevant capability, <STRONG>init_color</STRONG> permits
+ (re)definition of a color. <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 capability and
+ whether the programmer can change the colors. <STRONG>color_content</STRONG> permits
+ extraction of the red, green, and blue components of an initialized
+ color. <STRONG>pair_content</STRONG> permits discovery of a color pair's current
+ definition.
-</PRE><H3><a name="h3-
Color-Rendering">Color Rendering</a></H3><PRE>
- The <STRONG>curses</STRONG> library combines these inputs to produce the actual fore-
- ground and background colors shown on the screen:
+</PRE><H3><a name="h3-
Rendering">Rendering</a></H3><PRE>
+ <EM>curses</EM> combines the following data to render a character cell. Any of
+ them can include color information.
- <STRONG>o</STRONG> per-character video attributes (e.g., via <STRONG>waddch</STRONG>),
+ <STRONG>o</STRONG> <EM>curses</EM> character attributes, as from <STRONG><A HREF="curs_addch.3x.html">waddch(3x)</A></STRONG> or <STRONG><A HREF="curs_add_wch.3x.html">wadd_wch(3x)</A></STRONG>
- <STRONG>o</STRONG> the window attribute (e.g., by <STRONG>wattrset</STRONG>), and
+ <STRONG>o</STRONG> window attributes, as from <STRONG><A HREF="curs_attr.3x.html">wattrset(3x)</A></STRONG> or <STRONG><A HREF="curs_attr.3x.html">wattr_set(3x)</A></STRONG>
- <STRONG>o</STRONG> the background character (e.g., <STRONG>wbkgdset</STRONG>).
+ <STRONG>o</STRONG> window background character attributes, as from <STRONG><A HREF="curs_bkgd.3x.html">wbkgdset(3x)</A></STRONG> or
+ <STRONG><A HREF="curs_bkgrnd.3x.html">wbkgrndset(3x)</A></STRONG>
- Per-character and window attributes are usually set by a parameter con-
- taining video attributes including a color pair value. Some functions
- such as <STRONG>wattr_set</STRONG> use a separate parameter which is the color pair num-
- ber.
+ Per-character and window attributes are usually set through a function
+ parameter containing attributes including a color pair value. Some
+ functions, such as <STRONG>wattr_set</STRONG>, use a separate color pair number
+ parameter.
- The background character is a special case: it includes a character
- value, just as if it were passed to <STRONG>waddch</STRONG>.
+ The background character is a special case: it includes a character
+ code, just as if it were passed to <STRONG>waddch</STRONG>.
- The <STRONG>curses</STRONG> library does the actual work of combining these color pairs
+ The <EM>curses</EM> library does the actual work of combining these color pairs
in an internal function called from <STRONG>waddch</STRONG>:
<STRONG>o</STRONG> If the parameter passed to <STRONG>waddch</STRONG> is <EM>blank</EM>, and it uses the special
color pair 0,
- <STRONG>o</STRONG> <STRONG>curses</STRONG> next checks the window attribute.
+ <STRONG>o</STRONG> <EM>curses</EM> next checks the window attribute.
- <STRONG>o</STRONG> If the window attribute does not use color pair 0, <STRONG>curses</STRONG> uses
+ <STRONG>o</STRONG> If the window attribute does not use color pair 0, <EM>curses</EM> uses
the color pair from the window attribute.
- <STRONG>o</STRONG> Otherwise, <STRONG>curses</STRONG> uses the background character.
+ <STRONG>o</STRONG> Otherwise, <EM>curses</EM> uses the background character.
- <STRONG>o</STRONG> If the parameter passed to <STRONG>waddch</STRONG> is <EM>not</EM> <EM>blank</EM>, or it does not use
- the special color pair 0, <STRONG>curses</STRONG> prefers the color pair from the
- parameter, if it is nonzero. Otherwise, it tries the window attri-
- bute next, and finally the background character.
+ <STRONG>o</STRONG> If the parameter passed to <STRONG>waddch</STRONG> is <EM>not</EM> <EM>blank</EM>, or it does not use
+ the special color pair 0, <EM>curses</EM> prefers the color pair from the
+ parameter, if it is nonzero. Otherwise, it tries the window
+ attribute next, and finally the background character.
- Some <STRONG>curses</STRONG> functions such as <STRONG>wprintw</STRONG> call <STRONG>waddch</STRONG>. Those do not com-
- bine its parameter with a color pair. Consequently those calls use on-
- ly the window attribute or the background character.
+ Some <EM>curses</EM> functions such as <STRONG>wprintw</STRONG> call <STRONG>waddch</STRONG>. Those do not
+ combine its parameter with a color pair. Consequently those calls use
+ only the window attribute or the background character.
</PRE><H2><a name="h2-CONSTANTS">CONSTANTS</a></H2><PRE>
In <STRONG><curses.h></STRONG> the following macros are defined. These are the standard
- colors (ISO-6429). <STRONG>curses</STRONG> also assumes that <STRONG>COLOR_BLACK</STRONG> is the default
+ colors (ISO-6429). <EM>curses</EM> also assumes that <STRONG>COLOR_BLACK</STRONG> is the default
background color for all terminals.
<STRONG>COLOR_BLACK</STRONG>
<STRONG>COLOR_CYAN</STRONG>
<STRONG>COLOR_WHITE</STRONG>
- Some terminals support more than the eight (8) "ANSI" colors. There
+ Some terminals support more than the eight (8) "ANSI" colors. There
are no standard names for those additional colors.
</PRE><H2><a name="h2-VARIABLES">VARIABLES</a></H2><PRE>
</PRE><H3><a name="h3-COLORS">COLORS</a></H3><PRE>
- is initialized by <STRONG>start_color</STRONG> to the maximum number of colors the ter-
- minal can support.
+ is initialized by <STRONG>start_color</STRONG> to the maximum number of colors the
+ terminal can support.
</PRE><H3><a name="h3-COLOR_PAIRS">COLOR_PAIRS</a></H3><PRE>
- is initialized by <STRONG>start_color</STRONG> to the maximum number of color pairs the
- terminal can support.
+ is initialized by <STRONG>start_color</STRONG> to the maximum number of color pairs the
+ terminal can support. Often, its value is the product <STRONG>COLORS</STRONG> x <STRONG>COLORS</STRONG>,
+ but this is not always true.
+
+ <STRONG>o</STRONG> A few terminals use the HLS color space (see <STRONG>start_color</STRONG> below),
+ ignoring this rule; and
+
+ <STRONG>o</STRONG> terminals supporting a large number of colors are limited to the
+ number of color pairs that a <EM>signed</EM> <EM>short</EM> value can represent.
</PRE><H2><a name="h2-FUNCTIONS">FUNCTIONS</a></H2><PRE>
</PRE><H3><a name="h3-start_color">start_color</a></H3><PRE>
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 manipu-
- lation routine is called. It is good practice to call this routine
- right after <STRONG>initscr</STRONG>. <STRONG>start_color</STRONG> does this:
+ 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> does this:
- <STRONG>o</STRONG> It initializes two global variables, <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG> (re-
- spectively defining the maximum number of colors and color-pairs
+ <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
the terminal can support).
<STRONG>o</STRONG> It initializes the special color pair <STRONG>0</STRONG> to the default foreground
initial eight colors.
<STRONG>start_color</STRONG> does not attempt to set the terminal's color palette to
- match its built-in table. An application may use <STRONG>init_color</STRONG> to al-
- ter the internal table along with the terminal's color.
+ match its built-in table. An application may use <STRONG>init_color</STRONG> to
+ alter the internal table along with the terminal's color.
These limits apply to color values and color pairs. Values outside
- these limits are not legal, and may result in a runtime error:
+ these limits are not valid, and may result in a runtime error:
- <STRONG>o</STRONG> <STRONG>COLORS</STRONG> corresponds to the terminal database's <STRONG>max_colors</STRONG> capabili-
- ty, (see <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>).
+ <STRONG>o</STRONG> <STRONG>COLORS</STRONG> corresponds to the terminal database's <STRONG>max_colors</STRONG>
+
capability, (see <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>).
- <STRONG>o</STRONG> color values are expected to be in the range <STRONG>0</STRONG> to <STRONG>COLORS-1</STRONG>, inclu-
- sive (including <STRONG>0</STRONG> and <STRONG>COLORS-1</STRONG>).
+ <STRONG>o</STRONG> color values are expected to be in the range <STRONG>0</STRONG> to <STRONG>COLORS-1</STRONG>,
+ inclusive (including <STRONG>0</STRONG> and <STRONG>COLORS-1</STRONG>).
<STRONG>o</STRONG> a special color value <STRONG>-1</STRONG> is used in certain extended functions to
denote the <EM>default</EM> <EM>color</EM> (see <STRONG><A HREF="default_colors.3x.html">use_default_colors(3x)</A></STRONG>).
- <STRONG>o</STRONG> <STRONG>COLOR_PAIRS</STRONG> corresponds to the terminal database's <STRONG>max_pairs</STRONG> capa-
- bility, (see <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>).
+ <STRONG>o</STRONG> <STRONG>COLOR_PAIRS</STRONG> corresponds to the terminal database's <STRONG>max_pairs</STRONG>
+
capability, (see <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>).
- <STRONG>o</STRONG> legal color pair values are in the range <STRONG>1</STRONG> to <STRONG>COLOR_PAIRS-1</STRONG>, inclu-
- sive.
+ <STRONG>o</STRONG> valid color pair values are in the range <STRONG>1</STRONG> to <STRONG>COLOR_PAIRS-1</STRONG>,
+ inclusive.
<STRONG>o</STRONG> color pair <STRONG>0</STRONG> is special; it denotes "no color".
- Color pair <STRONG>0</STRONG> is assumed to be white on black, but is actually what-
- ever the terminal implements before color is initialized. It can-
- not be modified by the application.
+ Color pair <STRONG>0</STRONG> 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.
</PRE><H3><a name="h3-has_colors">has_colors</a></H3><PRE>
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 rou-
- tine facilitates writing terminal-independent programs. For example, a
- programmer can use it to decide whether to use color or some other
- video attribute.
+ terminal can manipulate colors; otherwise, it returns <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.
</PRE><H3><a name="h3-can_change_color">can_change_color</a></H3><PRE>
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-indepen-
- dent programs.
+ it returns <STRONG>FALSE</STRONG>. This routine facilitates writing terminal-
+ independent programs.
</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 fore-
- ground color number, and the background color number. For portable ap-
- plications:
+ 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 first argument must be a legal color pair value. If default
- colors are used (see <STRONG><A HREF="default_colors.3x.html">use_default_colors(3x)</A></STRONG>) the upper limit is ad-
- justed to allow for extra pairs which use a default color in fore-
- ground and/or background.
+ <STRONG>o</STRONG> The first argument must be a valid color pair value. If default
+ colors are used (see <STRONG><A HREF="default_colors.3x.html">use_default_colors(3x)</A></STRONG>) the upper limit is
+ adjusted to allow for extra pairs which use a default color in
+ foreground and/or background.
- <STRONG>o</STRONG> The second and third arguments must be legal color values.
+ <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 defini-
- tion.
+ 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 <STRONG>as-</STRONG>
- <STRONG><A HREF="assume_default_colors.3x.html">sume_default_colors(3x)</A></STRONG> routine, or to specify the use of default col-
-
ors (color number <STRONG>-1</STRONG>) if you first invoke the <STRONG><A HREF="default_colors.3x.html">use_default_colors(3x)</A></STRONG>
+ 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 exten-
- sion <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.
+ 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-init_color">init_color</a></H3><PRE>
four arguments: the number of the color to be changed followed by three
RGB values (for the amounts of red, green, and blue components).
- <STRONG>o</STRONG> The first argument must be a legal color value; default colors are
+ <STRONG>o</STRONG> The first argument must be a valid color value; default colors are
not allowed here. (See the section <STRONG>Colors</STRONG> for the default color
index.)
</PRE><H3><a name="h3-init_extended_color">init_extended_color</a></H3><PRE>
Because <STRONG>init_color</STRONG> uses signed <STRONG>short</STRONG>s for its parameters, that limits
- color-values and their red, green, and blue components to 32767 on mod-
- ern hardware. The extension <STRONG>init_extended_color</STRONG> uses <STRONG>int</STRONG>s for the col-
- or value and for setting the red, green, and blue components, allowing
- a larger number of colors to be supported.
+ color-values and their red, green, and blue components to 32767 on
+ modern hardware. The extension <STRONG>init_extended_color</STRONG> uses <STRONG>int</STRONG>s for the
+ color value and for setting the red, green, and blue components,
+ allowing a larger number of colors to be supported.
</PRE><H3><a name="h3-color_content">color_content</a></H3><PRE>
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 com-
- ponents in the given color.
+ storing the information about the amounts of red, green, and blue
+ components in the given color.
- <STRONG>o</STRONG> The first argument must be a legal color value, i.e., <STRONG>0</STRONG> through
+ <STRONG>o</STRONG> The first argument must be a valid color value, i.e., <STRONG>0</STRONG> through
<STRONG>COLORS-1</STRONG>, inclusive.
<STRONG>o</STRONG> The values that are stored at the addresses pointed to by the last
</PRE><H3><a name="h3-extended_color_content">extended_color_content</a></H3><PRE>
- Because <STRONG>color_content</STRONG> uses signed <STRONG>short</STRONG>s for its parameters, that lim-
- its color-values and their red, green, and blue components to 32767 on
- modern hardware. The extension <STRONG>extended_color_content</STRONG> uses <STRONG>int</STRONG>s for
+ Because <STRONG>color_content</STRONG> uses signed <STRONG>short</STRONG>s for its parameters, that
+ limits color-values and their red, green, and blue components to 32767
+ on modern hardware. The extension <STRONG>extended_color_content</STRONG> uses <STRONG>int</STRONG>s for
the color value and for returning the red, green, and blue components,
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.
- <STRONG>o</STRONG> The first argument must be a legal color value, i.e., in the range
+ <STRONG>o</STRONG> The first argument must be a valid color value, i.e., in the range
<STRONG>1</STRONG> through <STRONG>COLOR_PAIRS-1</STRONG>, inclusive.
- <STRONG>o</STRONG> The values that are stored at the addresses pointed to by the sec-
- ond and third arguments are in the range <STRONG>0</STRONG> through <STRONG>COLORS</STRONG>, inclu-
- sive.
+ <STRONG>o</STRONG> The values that are stored at the addresses pointed to by the
+ second and third arguments are in the range <STRONG>0</STRONG> through <STRONG>COLORS</STRONG>,
+ inclusive.
</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 col-
- ors to be supported.
+ 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 com-
- pletion.
+ 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 con-
- ditions which apply in general:
+ 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 ex-
- tension), or use color pairs outside the range <STRONG>0</STRONG> to <STRONG>COLOR_PAIRS-1</STRONG>.
+ 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 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_con-</STRONG>
- <STRONG>tent</STRONG> if the pair was not initialized using <STRONG>init_pairs</STRONG> and it re-
- turns <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.
</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
- In the <STRONG>ncurses</STRONG> implementation, there is a separate color activation
- flag, color palette, color pairs table, and associated <STRONG>COLORS</STRONG> and <STRONG>COL-</STRONG>
- <STRONG>OR_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.
+ 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.
<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 <EM>curses</EM>, 4.4BSD <EM>curses</EM>, or any other previous
+ curses implementation.
+
+
+</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+ Applications employing <EM>ncurses</EM> extensions should condition their use on
+ the visibility of the <STRONG>NCURSES_VERSION</STRONG> preprocessor macro.
+
+ This implementation satisfies X/Open 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
+ 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>
+ 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.
+
+ 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
+ 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-
+ numbers.
+
+ 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
- state from <STRONG>SP</STRONG> (the <STRONG>SCREEN</STRONG> structure) to <STRONG>cur_term</STRONG> (the <STRONG>TERMINAL</STRONG> struc-
- ture), but provided the same set of library functions.
+ state from <STRONG>SP</STRONG> (the <EM>SCREEN</EM> structure) to <STRONG>cur_term</STRONG> (the <EM>TERMINAL</EM>
+ 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
<STRONG>o</STRONG> PCCurses (1987-1990) provided for only eight (8) colors.
- <STRONG>o</STRONG> PDCurses (1992-present) inherited the 8-color limitation from PC-
- Curses, but changed this to 256 in version 2.5 (2001), along with
+ <STRONG>o</STRONG> PDCurses (1992-present) inherited the 8-color limitation from
+ PCCurses, but changed this to 256 in version 2.5 (2001), along with
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> val-
- ues.
+ <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.
-
- 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 us-
- ing <STRONG>chtype</STRONG> values.
+ color pairs as part of the attributes-field.
- <STRONG>o</STRONG> NetBSD curses used 6 bits from 2000 (when colors were first sup-
- ported) 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 the size of the
- bitfield.
+ 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.
-
-</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
- 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 back-
- ground 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> exten-
- sion.
-
- 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 pa-
- rameters when null.
-
- 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
- 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-
- numbers.
-
- The <STRONG>reset_color_pairs</STRONG> function is an extension of ncurses.
+ <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_initscr.3x.html">curs_initscr(3x)</A></STRONG>, <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG>de-</STRONG>
- <STRONG><A HREF="default_colors.3x.html">fault_colors(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>
-
<STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
+
ncurses 6.4 2024-04-20 <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-Overview">Overview</a></li>
-<li><a href="#h3-Color-Rendering">Color Rendering</a></li>
+<li><a href="#h3-Rendering">Rendering</a></li>
</ul>
</li>
<li><a href="#h2-CONSTANTS">CONSTANTS</a></li>
<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>
<li><a href="#h2-NOTES">NOTES</a></li>
-<li><a href="#h2-HISTORY">HISTORY</a></li>
+<li><a href="#h2-EXTENSIONS">EXTENSIONS</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
+<li><a href="#h2-HISTORY">HISTORY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
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