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- * @Id: curs_color.3x,v 1.36 2014/11/16 00:44:29 tom Exp @
+ * @Id: curs_color.3x,v 1.45 2016/10/15 17:10:19 tom Exp @
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-<H1>curs_color 3x</H1>
-<HR>
+<H1 class="no-header">curs_color 3x</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>
-</PRE>
-<H2><a name="h2-NAME">NAME</a></H2><PRE>
+</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
<STRONG>start_color</STRONG>, <STRONG>init_pair</STRONG>, <STRONG>init_color</STRONG>, <STRONG>has_colors</STRONG>,
- <STRONG>can_change_color</STRONG>, <STRONG>color_content</STRONG>, <STRONG>pair_content</STRONG>, <STRONG>COLOR_PAIR</STRONG>
- - <STRONG>curses</STRONG> color manipulation routines
+ <STRONG>can_change_color</STRONG>, <STRONG>color_content</STRONG>, <STRONG>pair_content</STRONG>, <STRONG>COLOR_PAIR</STRONG>,
+ <STRONG>PAIR_NUMBER</STRONG> - <STRONG>curses</STRONG> color manipulation routines
-</PRE>
-<H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
- <STRONG>#</STRONG> <STRONG>include</STRONG> <STRONG><curses.h></STRONG>
+</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
+ <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
<STRONG>int</STRONG> <STRONG>start_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>
+
<STRONG>bool</STRONG> <STRONG>has_colors(void);</STRONG>
<STRONG>bool</STRONG> <STRONG>can_change_color(void);</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>
+ <STRONG>int</STRONG> <STRONG>COLOR_PAIR(int</STRONG> <STRONG>n);</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> support color attributes on terminals with that ca-
- pability. To use these routines <STRONG>start_color</STRONG> must be
+</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 charac-
ters are displayed). A programmer initializes a color-
pair with the routine <STRONG>init_pair</STRONG>. After it has been ini-
- tialized, <STRONG>COLOR_PAIR</STRONG>(<EM>n</EM>), a macro defined in <STRONG><curses.h></STRONG>,
- can be used as a new video attribute.
+ tialized, <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 pro-
grammer can use the routine <STRONG>init_color</STRONG> to change the defi-
how a given color-pair is currently defined.
-</PRE>
-<H3><a name="h3-Routine-Descriptions">Routine Descriptions</a></H3><PRE>
+</PRE><H3><a name="h3-Color-Rendering">Color Rendering</a></H3><PRE>
+ The <STRONG>curses</STRONG> 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 window attribute (e.g., by <STRONG>wattrset</STRONG>), and
+
+ <STRONG>o</STRONG> the background character (e.g., <STRONG>wbkgdset</STRONG>).
+
+ 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 sepa-
+ rate parameter which is the color pair number.
+
+ 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 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 us-
+ es the special color pair 0,
+
+ <STRONG>o</STRONG> <STRONG>curses</STRONG> next checks the window attribute.
+
+ <STRONG>o</STRONG> If the window attribute does not use color pair 0,
+ <STRONG>curses</STRONG> uses the color pair from the window at-
+ tribute.
+
+ <STRONG>o</STRONG> Otherwise, <STRONG>curses</STRONG> 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 attribute next, and fi-
+ nally the background character.
+
+ Some <STRONG>curses</STRONG> functions such as <STRONG>wprintw</STRONG> call <STRONG>waddch</STRONG>. Those
+ do not combine its parameter with a color pair. Conse-
+ quently those calls use only the window attribute or the
+ background character.
+
+
+</PRE><H3><a name="h3-Routine-Descriptions">Routine Descriptions</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 manipulation routine is called. It is
- good practice to call this routine right after <STRONG>initscr</STRONG>.
- <STRONG>start_color</STRONG> initializes eight basic colors (black, red,
- green, yellow, blue, magenta, cyan, and white), and two
- global variables, <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG> (respectively
- defining the maximum number of colors and color-pairs the
- terminal can support). It also restores the colors on the
- terminal to the values they had when the terminal was just
- turned on.
+ 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>COL-</STRONG>
+ <STRONG>OR_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 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 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.
+
+ The components depend on whether the terminal uses CGA
+ (aka "ANSI") or HLS (i.e., the <STRONG>hls</STRONG> (<STRONG>hue_lightness_sat-</STRONG>
+ <STRONG>uration</STRONG>) capability is set). The table is initialized
+ first for eight basic colors (black, red, green, yel-
+ low, blue, magenta, cyan, and white), and after that
+ (if the terminal supports more than eight colors) the
+ components are initialized to <STRONG>1000</STRONG>.
+
+ <STRONG>start_color</STRONG> does not attempt to set the terminal's
+ color palette to match its built-in table. An appli-
+ cation 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. Val-
ues outside these limits are not legal, and may result in
to by the second and third arguments are in the range <STRONG>0</STRONG>
through <STRONG>COLORS</STRONG>, inclusive.
+ <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. Its in-
+ verse <STRONG>COLOR_PAIR(</STRONG><EM>n</EM><STRONG>)</STRONG> converts a color pair number to an at-
+ tribute. 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 func-
+ tions such as <STRONG>attrset</STRONG>.
-</PRE>
-<H3><a name="h3-Colors">Colors</a></H3><PRE>
+
+<
/PRE><H3><a name="h3-Colors">Colors</a></H3><PRE>
In <STRONG><curses.h></STRONG> the following macros are defined. These are
- the default colors. <STRONG>curses</STRONG> also assumes that <STRONG>COLOR_BLACK</STRONG>
- is the default background color for all terminals.
+ the standard colors (ISO-6429). <STRONG>curses</STRONG> also assumes that
+ <STRONG>COLOR_BLACK</STRONG> is the default background color for all termi-
+ nals.
<STRONG>COLOR_BLACK</STRONG>
<STRONG>COLOR_RED</STRONG>
<STRONG>COLOR_WHITE</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>.
+</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>init_color</STRONG>
returns an error if the terminal does not support
- this feature, e.g., if the <EM>initialize</EM><STRONG>_</STRONG><EM>color</EM> capa-
+ this feature, e.g., if the <STRONG>initialize_color</STRONG> capa-
bility is absent from the terminal description.
<STRONG>start_color</STRONG>
located.
-</PRE>
-<H2><a name="h2-NOTES">NOTES</a></H2><PRE>
+</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 as-
sociated COLORS and COLOR_PAIRS counts for each screen;
<STRONG>o</STRONG> Color RGB values are not settable.
-</PRE>
-<H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
This implementation satisfies XSI Curses's minimum maxi-
mums for <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG>.
will treat those as optional parameters when null.
-</PRE>
-<H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
+</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>curs_vari-</STRONG>
<STRONG><A HREF="curs_variables.3x.html">ables(3x)</A></STRONG>, <STRONG><A HREF="default_colors.3x.html">default_colors(3x)</A></STRONG>
<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-Routine-Descriptions">Routine Descriptions</a></li>
<li><a href="#h3-Colors">Colors</a></li>
</ul>
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