2 ****************************************************************************
3 * Copyright (c) 1998-2015,2016 Free Software Foundation, Inc. *
5 * Permission is hereby granted, free of charge, to any person obtaining a *
6 * copy of this software and associated documentation files (the *
7 * "Software"), to deal in the Software without restriction, including *
8 * without limitation the rights to use, copy, modify, merge, publish, *
9 * distribute, distribute with modifications, sublicense, and/or sell *
10 * copies of the Software, and to permit persons to whom the Software is *
11 * furnished to do so, subject to the following conditions: *
13 * The above copyright notice and this permission notice shall be included *
14 * in all copies or substantial portions of the Software. *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
19 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
20 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
21 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
22 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
24 * Except as contained in this notice, the name(s) of the above copyright *
25 * holders shall not be used in advertising or otherwise to promote the *
26 * sale, use or other dealings in this Software without prior written *
28 ****************************************************************************
29 * @Id: curs_color.3x,v 1.42 2016/07/24 00:02:15 tom Exp @
34 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
37 <meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
38 <meta name="generator" content="Manpage converted by man2html - see http://invisible-island.net/scripts/readme.html#others_scripts">
39 <TITLE>curs_color 3x</TITLE>
40 <link rev=made href="mailto:bug-ncurses@gnu.org">
41 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
44 <H1 class="no-header">curs_color 3x</H1>
46 <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG> <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
51 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
52 <STRONG>start_color</STRONG>, <STRONG>init_pair</STRONG>, <STRONG>init_color</STRONG>, <STRONG>has_colors</STRONG>,
53 <STRONG>can_change_color</STRONG>, <STRONG>color_content</STRONG>, <STRONG>pair_content</STRONG>, <STRONG>COLOR_PAIR</STRONG>,
54 <STRONG>PAIR_NUMBER</STRONG> - <STRONG>curses</STRONG> color manipulation routines
57 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
58 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
60 <STRONG>int</STRONG> <STRONG>start_color(void);</STRONG>
61 <STRONG>int</STRONG> <STRONG>init_pair(short</STRONG> <STRONG>pair,</STRONG> <STRONG>short</STRONG> <STRONG>f,</STRONG> <STRONG>short</STRONG> <STRONG>b);</STRONG>
62 <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>
64 <STRONG>bool</STRONG> <STRONG>has_colors(void);</STRONG>
65 <STRONG>bool</STRONG> <STRONG>can_change_color(void);</STRONG>
67 <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>
69 <STRONG>int</STRONG> <STRONG>pair_content(short</STRONG> <STRONG>pair,</STRONG> <STRONG>short</STRONG> <STRONG>*f,</STRONG> <STRONG>short</STRONG> <STRONG>*b);</STRONG>
71 <STRONG>int</STRONG> <STRONG>COLOR_PAIR(int</STRONG> <STRONG>n);</STRONG>
72 <STRONG>PAIR_NUMBER(</STRONG><EM>attrs</EM><STRONG>);</STRONG>
75 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
77 </PRE><H3><a name="h3-Overview">Overview</a></H3><PRE>
78 <STRONG>curses</STRONG> supports color attributes on terminals with that
79 capability. To use these routines <STRONG>start_color</STRONG> must be
80 called, usually right after <STRONG>initscr</STRONG>. Colors are always
81 used in pairs (referred to as color-pairs). A color-pair
82 consists of a foreground color (for characters) and a
83 background color (for the blank field on which the charac-
84 ters are displayed). A programmer initializes a color-
85 pair with the routine <STRONG>init_pair</STRONG>. After it has been ini-
86 tialized, <STRONG>COLOR_PAIR</STRONG>(<EM>n</EM>) can be used to convert the pair to
89 If a terminal is capable of redefining colors, the pro-
90 grammer can use the routine <STRONG>init_color</STRONG> to change the defi-
91 nition of a color. The routines <STRONG>has_colors</STRONG> and
92 <STRONG>can_change_color</STRONG> return <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>, depending on
93 whether the terminal has color capabilities and whether
94 the programmer can change the colors. The routine <STRONG>col-</STRONG>
95 <STRONG>or_content</STRONG> allows a programmer to extract the amounts of
96 red, green, and blue components in an initialized color.
97 The routine <STRONG>pair_content</STRONG> allows a programmer to find out
98 how a given color-pair is currently defined.
101 </PRE><H3><a name="h3-Color-Rendering">Color Rendering</a></H3><PRE>
102 The <STRONG>curses</STRONG> library combines these inputs to produce the
103 actual foreground and background colors shown on the
106 <STRONG>o</STRONG> per-character video attributes (e.g., via <STRONG>waddch</STRONG>),
108 <STRONG>o</STRONG> the window attribute (e.g., by <STRONG>wattrset</STRONG>), and
110 <STRONG>o</STRONG> the background character (e.g., <STRONG>wbkgdset</STRONG>).
112 Per-character and window attributes are usually set by a
113 parameter containing video attributes including a color
114 pair value. Some functions such as <STRONG>wattr_set</STRONG> use a sepa-
115 rate parameter which is the color pair number.
117 The background character is a special case: it includes a
118 character value, just as if it were passed to <STRONG>waddch</STRONG>.
120 The <STRONG>curses</STRONG> library does the actual work of combining these
121 color pairs in an internal function called from <STRONG>waddch</STRONG>:
123 <STRONG>o</STRONG> If the parameter passed to <STRONG>waddch</STRONG> is <EM>blank</EM>, and it us-
124 es the special color pair 0,
126 <STRONG>o</STRONG> <STRONG>curses</STRONG> next checks the window attribute.
128 <STRONG>o</STRONG> If the window attribute does not use color pair 0,
129 <STRONG>curses</STRONG> uses the color pair from the window at-
132 <STRONG>o</STRONG> Otherwise, <STRONG>curses</STRONG> uses the background character.
134 <STRONG>o</STRONG> If the parameter passed to <STRONG>waddch</STRONG> is <EM>not</EM> <EM>blank</EM>, or it
135 does not use the special color pair 0, <STRONG>curses</STRONG> prefers
136 the color pair from the parameter, if it is nonzero.
137 Otherwise, it tries the window attribute next, and fi-
138 nally the background character.
140 Some <STRONG>curses</STRONG> functions such as <STRONG>wprintw</STRONG> call <STRONG>waddch</STRONG>. Those
141 do not combine its parameter with a color pair. Conse-
142 quently those calls use only the window attribute or the
143 background character.
146 </PRE><H3><a name="h3-Routine-Descriptions">Routine Descriptions</a></H3><PRE>
147 The <STRONG>start_color</STRONG> routine requires no arguments. It must be
148 called if the programmer wants to use colors, and before
149 any other color manipulation routine is called. It is
150 good practice to call this routine right after <STRONG>initscr</STRONG>.
151 <STRONG>start_color</STRONG> does this:
153 <STRONG>o</STRONG> It initializes two global variables, <STRONG>COLORS</STRONG> and <STRONG>COL-</STRONG>
154 <STRONG>OR_PAIRS</STRONG> (respectively defining the maximum number of
155 colors and color-pairs the terminal can support).
157 <STRONG>o</STRONG> It initializes the special color pair <STRONG>0</STRONG> to the default
158 foreground and background colors. No other color
159 pairs are initialized.
161 <STRONG>o</STRONG> It restores the colors on the terminal to the values
162 they had when the terminal was just turned on.
164 <STRONG>o</STRONG> If the terminal supports the <STRONG>initc</STRONG> (<STRONG>initialize_color</STRONG>)
165 capability, <STRONG>start_color</STRONG> initializes its internal table
166 representing the red, green and blue components of the
169 The components depend on whether the terminal uses CGA
170 (aka "ANSI") or HLS (i.e., the <STRONG>hls</STRONG> (<STRONG>hue_lightness_sat-</STRONG>
171 <STRONG>uration</STRONG>) capability is set). The table is initialized
172 first for eight basic colors (black, red, green, yel-
173 low, blue, magenta, cyan, and white), and after that
174 (if the terminal supports more than eight colors) the
175 components are initialized to <STRONG>1000</STRONG>.
177 <STRONG>start_color</STRONG> does not attempt to set the terminal's
178 color palette to match its built-in table. An appli-
179 cation may use <STRONG>init_color</STRONG> to alter the internal table
180 along with the terminal's color.
182 These limits apply to color values and color pairs. Val-
183 ues outside these limits are not legal, and may result in
186 <STRONG>o</STRONG> <STRONG>COLORS</STRONG> corresponds to the terminal database's <STRONG>max_col-</STRONG>
187 <STRONG>ors</STRONG> capability, which is typically a signed 16-bit in-
188 teger (see <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>).
190 <STRONG>o</STRONG> color values are expected to be in the range <STRONG>0</STRONG> to <STRONG>COL-</STRONG>
191 <STRONG>ORS-1</STRONG>, inclusive (including <STRONG>0</STRONG> and <STRONG>COLORS-1</STRONG>).
193 <STRONG>o</STRONG> a special color value <STRONG>-1</STRONG> is used in certain extended
194 functions to denote the <EM>default</EM> <EM>color</EM> (see <STRONG>use_de-</STRONG>
195 <STRONG>fault_colors</STRONG>).
197 <STRONG>o</STRONG> <STRONG>COLOR_PAIRS</STRONG> corresponds to the terminal database's
198 <STRONG>max_pairs</STRONG> capability, which is typically a signed
199 16-bit integer (see <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>).
201 <STRONG>o</STRONG> legal color pair values are in the range <STRONG>1</STRONG> to <STRONG>COL-</STRONG>
202 <STRONG>OR_PAIRS-1</STRONG>, inclusive.
204 <STRONG>o</STRONG> color pair <STRONG>0</STRONG> is special; it denotes "no color".
206 Color pair <STRONG>0</STRONG> is assumed to be white on black, but is
207 actually whatever the terminal implements before color
208 is initialized. It cannot be modified by the applica-
211 The <STRONG>init_pair</STRONG> routine changes the definition of a color-
212 pair. It takes three arguments: the number of the color-
213 pair to be changed, the foreground color number, and the
214 background color number. For portable applications:
216 <STRONG>o</STRONG> The first argument must be a legal color pair value.
217 If default colors are used (see <STRONG>use_default_colors</STRONG>)
218 the upper limit is adjusted to allow for extra pairs
219 which use a default color in foreground and/or back-
222 <STRONG>o</STRONG> The second and third arguments must be legal color
225 If the color-pair was previously initialized, the screen
226 is refreshed and all occurrences of that color-pair are
227 changed to the new definition.
229 As an extension, ncurses allows you to set color pair <STRONG>0</STRONG>
230 via the <STRONG>assume_default_colors</STRONG> routine, or to specify the
231 use of default colors (color number <STRONG>-1</STRONG>) if you first in-
232 voke the <STRONG>use_default_colors</STRONG> routine.
234 The <STRONG>init_color</STRONG> routine changes the definition of a color.
235 It takes four arguments: the number of the color to be
236 changed followed by three RGB values (for the amounts of
237 red, green, and blue components). The first argument must
238 be a legal color value; default colors are not allowed
239 here. (See the section <STRONG>Colors</STRONG> for the default color in-
240 dex.) Each of the last three arguments must be a value in
241 the range <STRONG>0</STRONG> through <STRONG>1000</STRONG>. When <STRONG>init_color</STRONG> is used, all
242 occurrences of that color on the screen immediately change
243 to the new definition.
245 The <STRONG>has_colors</STRONG> routine requires no arguments. It returns
246 <STRONG>TRUE</STRONG> if the terminal can manipulate colors; otherwise, it
247 returns <STRONG>FALSE</STRONG>. This routine facilitates writing terminal-
248 independent programs. For example, a programmer can use
249 it to decide whether to use color or some other video at-
252 The <STRONG>can_change_color</STRONG> routine requires no arguments. It
253 returns <STRONG>TRUE</STRONG> if the terminal supports colors and can
254 change their definitions; other, it returns <STRONG>FALSE</STRONG>. This
255 routine facilitates writing terminal-independent programs.
257 The <STRONG>color_content</STRONG> routine gives programmers a way to find
258 the intensity of the red, green, and blue (RGB) components
259 in a color. It requires four arguments: the color number,
260 and three addresses of <STRONG>short</STRONG>s for storing the information
261 about the amounts of red, green, and blue components in
262 the given color. The first argument must be a legal color
263 value, i.e., <STRONG>0</STRONG> through <STRONG>COLORS-1</STRONG>, inclusive. The values
264 that are stored at the addresses pointed to by the last
265 three arguments are in the range <STRONG>0</STRONG> (no component) through
266 <STRONG>1000</STRONG> (maximum amount of component), inclusive.
268 The <STRONG>pair_content</STRONG> routine allows programmers to find out
269 what colors a given color-pair consists of. It requires
270 three arguments: the color-pair number, and two addresses
271 of <STRONG>short</STRONG>s for storing the foreground and the background
272 color numbers. The first argument must be a legal color
273 value, i.e., in the range <STRONG>1</STRONG> through <STRONG>COLOR_PAIRS-1</STRONG>, inclu-
274 sive. The values that are stored at the addresses pointed
275 to by the second and third arguments are in the range <STRONG>0</STRONG>
276 through <STRONG>COLORS</STRONG>, inclusive.
278 <STRONG>PAIR_NUMBER(</STRONG><EM>attrs</EM>) extracts the color value from its <EM>attrs</EM>
279 parameter and returns it as a color pair number. Its in-
280 verse <STRONG>COLOR_PAIR(</STRONG><EM>n</EM><STRONG>)</STRONG> converts a color pair number to an at-
281 tribute. Attributes can hold color pairs in the range 0
282 to 255. If you need a color pair larger than that, you
283 must use functions such as <STRONG>attr_set</STRONG> (which pass the color
284 pair as a separate parameter) rather than the legacy func-
285 tions such as <STRONG>attrset</STRONG>.
288 </PRE><H3><a name="h3-Colors">Colors</a></H3><PRE>
289 In <STRONG><curses.h></STRONG> the following macros are defined. These are
290 the standard colors (ISO-6429). <STRONG>curses</STRONG> also assumes that
291 <STRONG>COLOR_BLACK</STRONG> is the default background color for all termi-
294 <STRONG>COLOR_BLACK</STRONG>
295 <STRONG>COLOR_RED</STRONG>
296 <STRONG>COLOR_GREEN</STRONG>
297 <STRONG>COLOR_YELLOW</STRONG>
298 <STRONG>COLOR_BLUE</STRONG>
299 <STRONG>COLOR_MAGENTA</STRONG>
300 <STRONG>COLOR_CYAN</STRONG>
301 <STRONG>COLOR_WHITE</STRONG>
304 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
305 The routines <STRONG>can_change_color()</STRONG> and <STRONG>has_colors()</STRONG> return
306 <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>.
308 All other routines return the integer <STRONG>ERR</STRONG> upon failure and
309 an <STRONG>OK</STRONG> (SVr4 specifies only "an integer value other than
310 <STRONG>ERR</STRONG>") upon successful completion.
312 X/Open defines no error conditions. This implementation
313 will return <STRONG>ERR</STRONG> on attempts to use color values outside
314 the range <STRONG>0</STRONG> to COLORS-1 (except for the default colors ex-
315 tension), or use color pairs outside the range <STRONG>0</STRONG> to <STRONG>COL-</STRONG>
316 <STRONG>OR_PAIRS-1</STRONG>. Color values used in <STRONG>init_color</STRONG> must be in
317 the range <STRONG>0</STRONG> to <STRONG>1000</STRONG>. An error is returned from all func-
318 tions if the terminal has not been initialized. An error
319 is returned from secondary functions such as <STRONG>init_pair</STRONG> if
320 <STRONG>start_color</STRONG> was not called.
322 <STRONG>init_color</STRONG>
323 returns an error if the terminal does not support
324 this feature, e.g., if the <EM>initialize</EM><STRONG>_</STRONG><EM>color</EM> capa-
325 bility is absent from the terminal description.
327 <STRONG>start_color</STRONG>
328 returns an error if the color table cannot be al-
332 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
333 In the <EM>ncurses</EM> implementation, there is a separate color
334 activation flag, color palette, color pairs table, and as-
335 sociated COLORS and COLOR_PAIRS counts for each screen;
336 the <STRONG>start_color</STRONG> function only affects the current screen.
337 The SVr4/XSI interface is not really designed with this in
338 mind, and historical implementations may use a single
339 shared color palette.
341 Note that setting an implicit background color via a color
342 pair affects only character cells that a character write
343 operation explicitly touches. To change the background
344 color used when parts of a window are blanked by erasing
345 or scrolling operations, see <STRONG><A HREF="curs_bkgd.3x.html">curs_bkgd(3x)</A></STRONG>.
347 Several caveats apply on 386 and 486 machines with VGA-
350 <STRONG>o</STRONG> COLOR_YELLOW is actually brown. To get yellow, use
351 COLOR_YELLOW combined with the <STRONG>A_BOLD</STRONG> attribute.
353 <STRONG>o</STRONG> The A_BLINK attribute should in theory cause the back-
354 ground to go bright. This often fails to work, and
355 even some cards for which it mostly works (such as the
356 Paradise and compatibles) do the wrong thing when you
357 try to set a bright "yellow" background (you get a
358 blinking yellow foreground instead).
360 <STRONG>o</STRONG> Color RGB values are not settable.
363 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
364 This implementation satisfies XSI Curses's minimum maxi-
365 mums for <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG>.
367 The <STRONG>init_pair</STRONG> routine accepts negative values of fore-
368 ground and background color to support the <STRONG>use_de-</STRONG>
369 <STRONG>fault_colors</STRONG> extension, but only if that routine has been
372 The assumption that <STRONG>COLOR_BLACK</STRONG> is the default background
373 color for all terminals can be modified using the <STRONG>as-</STRONG>
374 <STRONG>sume_default_colors</STRONG> extension.
376 This implementation checks the pointers, e.g., for the
377 values returned by <STRONG>color_content</STRONG> and <STRONG>pair_content</STRONG>, and
378 will treat those as optional parameters when null.
381 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
382 <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>
383 <STRONG><A HREF="curs_variables.3x.html">ables(3x)</A></STRONG>, <STRONG><A HREF="default_colors.3x.html">default_colors(3x)</A></STRONG>
387 <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
391 <li><a href="#h2-NAME">NAME</a></li>
392 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
393 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
395 <li><a href="#h3-Overview">Overview</a></li>
396 <li><a href="#h3-Color-Rendering">Color Rendering</a></li>
397 <li><a href="#h3-Routine-Descriptions">Routine Descriptions</a></li>
398 <li><a href="#h3-Colors">Colors</a></li>
401 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
402 <li><a href="#h2-NOTES">NOTES</a></li>
403 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
404 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>