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-<H1 class="no-header">curs_color 3x</H1>
+<H1 class="no-header">curs_color 3x 2023-10-21 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>color_content</STRONG>, <STRONG>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> - manipulate terminal colors with <EM>curses</EM>
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>bool</STRONG> <STRONG>has_colors(void);</STRONG>
<STRONG>bool</STRONG> <STRONG>can_change_color(void);</STRONG>
- <STRONG>int</STRONG> <STRONG>init_pair(short</STRONG> <STRONG>pair,</STRONG> <STRONG>short</STRONG> <STRONG>f,</STRONG> <STRONG>short</STRONG> <STRONG>b);</STRONG>
- <STRONG>int</STRONG> <STRONG>init_color(short</STRONG> <STRONG>color,</STRONG> <STRONG>short</STRONG> <STRONG>r,</STRONG> <STRONG>short</STRONG> <STRONG>g,</STRONG> <STRONG>short</STRONG> <STRONG>b);</STRONG>
- /* extensions */
- <STRONG>int</STRONG> <STRONG>init_extended_pair(int</STRONG> <STRONG>pair,</STRONG> <STRONG>int</STRONG> <STRONG>f,</STRONG> <STRONG>int</STRONG> <STRONG>b);</STRONG>
- <STRONG>int</STRONG> <STRONG>init_extended_color(int</STRONG> <STRONG>color,</STRONG> <STRONG>int</STRONG> <STRONG>r,</STRONG> <STRONG>int</STRONG> <STRONG>g,</STRONG> <STRONG>int</STRONG> <STRONG>b);</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>
+ <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> <STRONG>color,</STRONG> <STRONG>short</STRONG> <STRONG>*r,</STRONG> <STRONG>short</STRONG> <STRONG>*g,</STRONG> <STRONG>short</STRONG> <STRONG>*b);</STRONG>
- <STRONG>int</STRONG> <STRONG>pair_content(short</STRONG> <STRONG>pair,</STRONG> <STRONG>short</STRONG> <STRONG>*f,</STRONG> <STRONG>short</STRONG> <STRONG>*b);</STRONG>
- /* extensions */
- <STRONG>int</STRONG> <STRONG>extended_color_content(int</STRONG> <STRONG>color,</STRONG> <STRONG>int</STRONG> <STRONG>*r,</STRONG> <STRONG>int</STRONG> <STRONG>*g,</STRONG> <STRONG>int</STRONG> <STRONG>*b);</STRONG>
- <STRONG>int</STRONG> <STRONG>extended_pair_content(int</STRONG> <STRONG>pair,</STRONG> <STRONG>int</STRONG> <STRONG>*f,</STRONG> <STRONG>int</STRONG> <STRONG>*b);</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>
+ <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> <STRONG>n);</STRONG>
+ <STRONG>int</STRONG> <STRONG>COLOR_PAIR(int</STRONG> <EM>n</EM><STRONG>);</STRONG>
<STRONG>PAIR_NUMBER(</STRONG><EM>attrs</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
+ <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
- background color (for the blank field on which the characters are dis-
- played). A programmer initializes a color-pair with the routine
+ 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
<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.
- 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 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 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.
</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:
+ The <EM>curses</EM> library combines these inputs to produce the actual
+ foreground and background colors shown on the screen:
<STRONG>o</STRONG> per-character video attributes (e.g., via <STRONG>waddch</STRONG>),
<STRONG>o</STRONG> the background character (e.g., <STRONG>wbkgdset</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 by a parameter
+ containing video attributes including a color pair value. Some
+ functions such as <STRONG>wattr_set</STRONG> use a separate parameter which is the color
+ pair number.
- The background character is a special case: it includes a character
+ The background character is a special case: it includes a character
value, 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 at-
- tribute 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
+ is initialized by <STRONG>start_color</STRONG> to the maximum number of color pairs the
terminal can support.
</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 <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> 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
+ <STRONG>o</STRONG> It initializes the special color pair <STRONG>0</STRONG> to the default foreground
and background colors. No other color pairs are initialized.
- <STRONG>o</STRONG> It restores the colors on the terminal to the values they had when
+ <STRONG>o</STRONG> It restores the colors on the terminal to the values they had when
the terminal was just turned on.
- <STRONG>o</STRONG> If the terminal supports the <STRONG>initc</STRONG> (<STRONG>initialize_color</STRONG>) capability,
- <STRONG>start_color</STRONG> initializes its internal table representing the red,
- green and blue components of the color palette.
+ <STRONG>o</STRONG> If the terminal supports the <STRONG>initc</STRONG> (<STRONG>initialize_color</STRONG>) capability,
+ <STRONG>start_color</STRONG> initializes its internal table representing the red,
+ green, and blue components of the color palette.
The components depend on whether the terminal uses CGA (aka "ANSI")
- or HLS (i.e., the <STRONG>hls</STRONG> (<STRONG>hue_lightness_saturation</STRONG>) capability is
- set). The table is initialized first for eight basic colors
- (black, red, green, yellow, blue, magenta, cyan, and white), and
- after that (if the terminal supports more than eight colors) the
- components are initialized to <STRONG>1000</STRONG>.
+ or HLS (i.e., the <STRONG>hls</STRONG> (<STRONG>hue_lightness_saturation</STRONG>) capability is
+ set). The table is initialized first for eight basic colors
+ (black, red, green, yellow, blue, magenta, cyan, and white), using
+ weights that depend upon the CGA/HLS choice. For "ANSI" colors the
+ weights are <STRONG>680</STRONG> or <STRONG>0</STRONG> depending on whether the corresponding red,
+ green, or blue component is used or not. That permits using <STRONG>1000</STRONG>
+ to represent bold/bright colors. After the initial eight colors
+ (if the terminal supports more than eight colors) the components
+ are initialized using the same pattern, but with weights of <STRONG>1000</STRONG>.
+ SVr4 uses a similar scheme, but uses <STRONG>1000</STRONG> for the components of the
+ 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 apply to color values and color pairs. Values outside
these limits are not legal, 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>use_default_colors</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> legal 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.
+ 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-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.
+ the terminal supports colors and can change their definitions; other,
+ 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:
+ 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>use_default_colors</STRONG>) the upper limit is adjust-
- ed to allow for extra pairs which use a default color in foreground
- and/or background.
+ <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
+ 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.
- 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, ncurses 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.
- 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 current- and standard-screens, allowing an application to switch
- color palettes rapidly.
+
+</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-
+ value, allowing a larger number of colors to be supported.
</PRE><H3><a name="h3-init_color">init_color</a></H3><PRE>
- The <STRONG>init_color</STRONG> routine changes the definition of a color. It takes
+ 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).
- <STRONG>o</STRONG> The first argument must be a legal color value; default colors are
- not allowed here. (See the section <STRONG>Colors</STRONG> for the default color
+ <STRONG>o</STRONG> The first argument must be a legal color value; default colors are
+ not allowed here. (See the section <STRONG>Colors</STRONG> for the default color
index.)
- <STRONG>o</STRONG> Each of the last three arguments must be a value in the range <STRONG>0</STRONG>
+ <STRONG>o</STRONG> Each of the last three arguments must be a value in the range <STRONG>0</STRONG>
through <STRONG>1000</STRONG>.
- When <STRONG>init_color</STRONG> is used, all occurrences of that color on the screen
+ When <STRONG>init_color</STRONG> is used, all occurrences of that color on the screen
immediately change to the new definition.
+</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
+ 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.
+ 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.
- <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 legal 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
- three arguments are in the range <STRONG>0</STRONG> (no component) through <STRONG>1000</STRONG>
+ <STRONG>o</STRONG> The values that are stored at the addresses pointed to by the last
+ three arguments are in the range <STRONG>0</STRONG> (no component) through <STRONG>1000</STRONG>
(maximum amount of component), inclusive.
+</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
+ 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-
+ 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.
- <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 legal 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
+ <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 current- and standard-screens, allowing an application to switch
+ color palettes rapidly.
</PRE><H3><a name="h3-PAIR_NUMBER">PAIR_NUMBER</a></H3><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.
+ specifies only "an integer value other than <STRONG>ERR</STRONG>") upon successful
+ completion.
+
+ 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
+ <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
+ been initialized.
+
+ 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
+ changing colors.
- X/Open defines no error conditions. 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 <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 been initialized. An error is returned from secondary
- functions such as <STRONG>init_pair</STRONG> if <STRONG>start_color</STRONG> was not called.
+ This implementation does not return <STRONG>ERR</STRONG> for either case.
+
+ Specific functions make additional checks:
<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 <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.
-
- 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
+ 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
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-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>
+ 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>
+ data type (denoted by <STRONG>A_COLOR</STRONG>).
+
+ Other implementations of curses had different limits:
+
+ <STRONG>o</STRONG> PCCurses (1987-1990) provided for only eight (8) colors.
+
+ <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
+ 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>
+ 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
+ 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
+ the size of the bitfield.
+
+
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
- This implementation satisfies XSI Curses's minimum maximums for <STRONG>COLORS</STRONG>
+
+</PRE><H3><a name="h3-Extensions">Extensions</a></H3><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
+ version of curses.
+
+
+</PRE><H3><a name="h3-Standards">Standards</a></H3><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 <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> exten-
- sion.
+ 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 pa-
- rameters when null.
+ 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.
</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_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><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 2023-10-21 <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h3-has_colors">has_colors</a></li>
<li><a href="#h3-can_change_color">can_change_color</a></li>
<li><a href="#h3-init_pair">init_pair</a></li>
+<li><a href="#h3-init_extended_pair">init_extended_pair</a></li>
<li><a href="#h3-init_color">init_color</a></li>
+<li><a href="#h3-init_extended_color">init_extended_color</a></li>
<li><a href="#h3-color_content">color_content</a></li>
+<li><a href="#h3-extended_color_content">extended_color_content</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>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
-<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
+<li><a href="#h2-HISTORY">HISTORY</a></li>
+<li><a href="#h2-PORTABILITY">PORTABILITY</a>
+<ul>
+<li><a href="#h3-Extensions">Extensions</a></li>
+<li><a href="#h3-Standards">Standards</a></li>
+</ul>
+</li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
projects / ncurses.git / blobdiff