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30 * @Id: curs_color.3x,v 1.36 2014/11/16 00:44:29 tom Exp @
34 <TITLE>curs_color 3x</TITLE>
35 <link rev=made href="mailto:bug-ncurses@gnu.org">
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39 <H1>curs_color 3x</H1>
42 <!-- Manpage converted by man2html 3.0.1 -->
43 <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG> <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
50 <STRONG>start_color</STRONG>, <STRONG>init_pair</STRONG>, <STRONG>init_color</STRONG>, <STRONG>has_colors</STRONG>,
51 <STRONG>can_change_color</STRONG>, <STRONG>color_content</STRONG>, <STRONG>pair_content</STRONG>, <STRONG>COLOR_PAIR</STRONG>
52 - <STRONG>curses</STRONG> color manipulation routines
56 <H2>SYNOPSIS</H2><PRE>
57 <STRONG>#</STRONG> <STRONG>include</STRONG> <STRONG><curses.h></STRONG>
59 <STRONG>int</STRONG> <STRONG>start_color(void);</STRONG>
60 <STRONG>int</STRONG> <STRONG>init_pair(short</STRONG> <STRONG>pair,</STRONG> <STRONG>short</STRONG> <STRONG>f,</STRONG> <STRONG>short</STRONG> <STRONG>b);</STRONG>
61 <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>
62 <STRONG>bool</STRONG> <STRONG>has_colors(void);</STRONG>
63 <STRONG>bool</STRONG> <STRONG>can_change_color(void);</STRONG>
64 <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>
66 <STRONG>int</STRONG> <STRONG>pair_content(short</STRONG> <STRONG>pair,</STRONG> <STRONG>short</STRONG> <STRONG>*f,</STRONG> <STRONG>short</STRONG> <STRONG>*b);</STRONG>
70 <H2>DESCRIPTION</H2><PRE>
71 <STRONG>Overview</STRONG>
72 <STRONG>curses</STRONG> support color attributes on terminals with that ca-
73 pability. To use these routines <STRONG>start_color</STRONG> must be
74 called, usually right after <STRONG>initscr</STRONG>. Colors are always
75 used in pairs (referred to as color-pairs). A color-pair
76 consists of a foreground color (for characters) and a
77 background color (for the blank field on which the charac-
78 ters are displayed). A programmer initializes a color-
79 pair with the routine <STRONG>init_pair</STRONG>. After it has been ini-
80 tialized, <STRONG>COLOR_PAIR</STRONG>(<EM>n</EM>), a macro defined in <STRONG><curses.h></STRONG>,
81 can be used as a new video attribute.
83 If a terminal is capable of redefining colors, the pro-
84 grammer can use the routine <STRONG>init_color</STRONG> to change the defi-
85 nition of a color. The routines <STRONG>has_colors</STRONG> and
86 <STRONG>can_change_color</STRONG> return <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>, depending on
87 whether the terminal has color capabilities and whether
88 the programmer can change the colors. The routine <STRONG>col-</STRONG>
89 <STRONG>or_content</STRONG> allows a programmer to extract the amounts of
90 red, green, and blue components in an initialized color.
91 The routine <STRONG>pair_content</STRONG> allows a programmer to find out
92 how a given color-pair is currently defined.
94 <STRONG>Routine</STRONG> <STRONG>Descriptions</STRONG>
95 The <STRONG>start_color</STRONG> routine requires no arguments. It must be
96 called if the programmer wants to use colors, and before
97 any other color manipulation routine is called. It is
98 good practice to call this routine right after <STRONG>initscr</STRONG>.
99 <STRONG>start_color</STRONG> initializes eight basic colors (black, red,
100 green, yellow, blue, magenta, cyan, and white), and two
101 global variables, <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG> (respectively
102 defining the maximum number of colors and color-pairs the
103 terminal can support). It also restores the colors on the
104 terminal to the values they had when the terminal was just
107 These limits apply to color values and color pairs. Val-
108 ues outside these limits are not legal, and may result in
111 <STRONG>o</STRONG> <STRONG>COLORS</STRONG> corresponds to the terminal database's <STRONG>max_col-</STRONG>
112 <STRONG>ors</STRONG> capability, which is typically a signed 16-bit in-
113 teger (see <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>).
115 <STRONG>o</STRONG> color values are expected to be in the range <STRONG>0</STRONG> to <STRONG>COL-</STRONG>
116 <STRONG>ORS-1</STRONG>, inclusive (including <STRONG>0</STRONG> and <STRONG>COLORS-1</STRONG>).
118 <STRONG>o</STRONG> a special color value <STRONG>-1</STRONG> is used in certain extended
119 functions to denote the <EM>default</EM> <EM>color</EM> (see <STRONG>use_de-</STRONG>
120 <STRONG>fault_colors</STRONG>).
122 <STRONG>o</STRONG> <STRONG>COLOR_PAIRS</STRONG> corresponds to the terminal database's
123 <STRONG>max_pairs</STRONG> capability, which is typically a signed
124 16-bit integer (see <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>).
126 <STRONG>o</STRONG> legal color pair values are in the range <STRONG>1</STRONG> to <STRONG>COL-</STRONG>
127 <STRONG>OR_PAIRS-1</STRONG>, inclusive.
129 <STRONG>o</STRONG> color pair <STRONG>0</STRONG> is special; it denotes "no color".
131 Color pair <STRONG>0</STRONG> is assumed to be white on black, but is
132 actually whatever the terminal implements before color
133 is initialized. It cannot be modified by the applica-
136 The <STRONG>init_pair</STRONG> routine changes the definition of a color-
137 pair. It takes three arguments: the number of the color-
138 pair to be changed, the foreground color number, and the
139 background color number. For portable applications:
141 <STRONG>o</STRONG> The first argument must be a legal color pair value.
142 If default colors are used (see <STRONG>use_default_colors</STRONG>)
143 the upper limit is adjusted to allow for extra pairs
144 which use a default color in foreground and/or back-
147 <STRONG>o</STRONG> The second and third arguments must be legal color
150 If the color-pair was previously initialized, the screen
151 is refreshed and all occurrences of that color-pair are
152 changed to the new definition.
154 As an extension, ncurses allows you to set color pair <STRONG>0</STRONG>
155 via the <STRONG>assume_default_colors</STRONG> routine, or to specify the
156 use of default colors (color number <STRONG>-1</STRONG>) if you first in-
157 voke the <STRONG>use_default_colors</STRONG> routine.
159 The <STRONG>init_color</STRONG> routine changes the definition of a color.
160 It takes four arguments: the number of the color to be
161 changed followed by three RGB values (for the amounts of
162 red, green, and blue components). The first argument must
163 be a legal color value; default colors are not allowed
164 here. (See the section <STRONG>Colors</STRONG> for the default color in-
165 dex.) Each of the last three arguments must be a value in
166 the range <STRONG>0</STRONG> through <STRONG>1000</STRONG>. When <STRONG>init_color</STRONG> is used, all
167 occurrences of that color on the screen immediately change
168 to the new definition.
170 The <STRONG>has_colors</STRONG> routine requires no arguments. It returns
171 <STRONG>TRUE</STRONG> if the terminal can manipulate colors; otherwise, it
172 returns <STRONG>FALSE</STRONG>. This routine facilitates writing terminal-
173 independent programs. For example, a programmer can use
174 it to decide whether to use color or some other video at-
177 The <STRONG>can_change_color</STRONG> routine requires no arguments. It
178 returns <STRONG>TRUE</STRONG> if the terminal supports colors and can
179 change their definitions; other, it returns <STRONG>FALSE</STRONG>. This
180 routine facilitates writing terminal-independent programs.
182 The <STRONG>color_content</STRONG> routine gives programmers a way to find
183 the intensity of the red, green, and blue (RGB) components
184 in a color. It requires four arguments: the color number,
185 and three addresses of <STRONG>short</STRONG>s for storing the information
186 about the amounts of red, green, and blue components in
187 the given color. The first argument must be a legal color
188 value, i.e., <STRONG>0</STRONG> through <STRONG>COLORS-1</STRONG>, inclusive. The values
189 that are stored at the addresses pointed to by the last
190 three arguments are in the range <STRONG>0</STRONG> (no component) through
191 <STRONG>1000</STRONG> (maximum amount of component), inclusive.
193 The <STRONG>pair_content</STRONG> routine allows programmers to find out
194 what colors a given color-pair consists of. It requires
195 three arguments: the color-pair number, and two addresses
196 of <STRONG>short</STRONG>s for storing the foreground and the background
197 color numbers. The first argument must be a legal color
198 value, i.e., in the range <STRONG>1</STRONG> through <STRONG>COLOR_PAIRS-1</STRONG>, inclu-
199 sive. The values that are stored at the addresses pointed
200 to by the second and third arguments are in the range <STRONG>0</STRONG>
201 through <STRONG>COLORS</STRONG>, inclusive.
203 <STRONG>Colors</STRONG>
204 In <STRONG><curses.h></STRONG> the following macros are defined. These are
205 the default colors. <STRONG>curses</STRONG> also assumes that <STRONG>COLOR_BLACK</STRONG>
206 is the default background color for all terminals.
208 <STRONG>COLOR_BLACK</STRONG>
209 <STRONG>COLOR_RED</STRONG>
210 <STRONG>COLOR_GREEN</STRONG>
211 <STRONG>COLOR_YELLOW</STRONG>
212 <STRONG>COLOR_BLUE</STRONG>
213 <STRONG>COLOR_MAGENTA</STRONG>
214 <STRONG>COLOR_CYAN</STRONG>
215 <STRONG>COLOR_WHITE</STRONG>
219 <H2>RETURN VALUE</H2><PRE>
220 The routines <STRONG>can_change_color()</STRONG> and <STRONG>has_colors()</STRONG> return
221 <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>.
223 All other routines return the integer <STRONG>ERR</STRONG> upon failure and
224 an <STRONG>OK</STRONG> (SVr4 specifies only "an integer value other than
225 <STRONG>ERR</STRONG>") upon successful completion.
227 X/Open defines no error conditions. This implementation
228 will return <STRONG>ERR</STRONG> on attempts to use color values outside
229 the range <STRONG>0</STRONG> to COLORS-1 (except for the default colors ex-
230 tension), or use color pairs outside the range <STRONG>0</STRONG> to <STRONG>COL-</STRONG>
231 <STRONG>OR_PAIRS-1</STRONG>. Color values used in <STRONG>init_color</STRONG> must be in
232 the range <STRONG>0</STRONG> to <STRONG>1000</STRONG>. An error is returned from all func-
233 tions if the terminal has not been initialized. An error
234 is returned from secondary functions such as <STRONG>init_pair</STRONG> if
235 <STRONG>start_color</STRONG> was not called.
237 <STRONG>init_color</STRONG>
238 returns an error if the terminal does not support
239 this feature, e.g., if the <EM>initialize</EM><STRONG>_</STRONG><EM>color</EM> capa-
240 bility is absent from the terminal description.
242 <STRONG>start_color</STRONG>
243 returns an error if the color table cannot be al-
249 In the <EM>ncurses</EM> implementation, there is a separate color
250 activation flag, color palette, color pairs table, and as-
251 sociated COLORS and COLOR_PAIRS counts for each screen;
252 the <STRONG>start_color</STRONG> function only affects the current screen.
253 The SVr4/XSI interface is not really designed with this in
254 mind, and historical implementations may use a single
255 shared color palette.
257 Note that setting an implicit background color via a color
258 pair affects only character cells that a character write
259 operation explicitly touches. To change the background
260 color used when parts of a window are blanked by erasing
261 or scrolling operations, see <STRONG><A HREF="curs_bkgd.3x.html">curs_bkgd(3x)</A></STRONG>.
263 Several caveats apply on 386 and 486 machines with VGA-
266 <STRONG>o</STRONG> COLOR_YELLOW is actually brown. To get yellow, use
267 COLOR_YELLOW combined with the <STRONG>A_BOLD</STRONG> attribute.
269 <STRONG>o</STRONG> The A_BLINK attribute should in theory cause the back-
270 ground to go bright. This often fails to work, and
271 even some cards for which it mostly works (such as the
272 Paradise and compatibles) do the wrong thing when you
273 try to set a bright "yellow" background (you get a
274 blinking yellow foreground instead).
276 <STRONG>o</STRONG> Color RGB values are not settable.
280 <H2>PORTABILITY</H2><PRE>
281 This implementation satisfies XSI Curses's minimum maxi-
282 mums for <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG>.
284 The <STRONG>init_pair</STRONG> routine accepts negative values of fore-
285 ground and background color to support the <STRONG>use_de-</STRONG>
286 <STRONG>fault_colors</STRONG> extension, but only if that routine has been
289 The assumption that <STRONG>COLOR_BLACK</STRONG> is the default background
290 color for all terminals can be modified using the <STRONG>as-</STRONG>
291 <STRONG>sume_default_colors</STRONG> extension.
293 This implementation checks the pointers, e.g., for the
294 values returned by <STRONG>color_content</STRONG> and <STRONG>pair_content</STRONG>, and
295 will treat those as optional parameters when null.
299 <H2>SEE ALSO</H2><PRE>
300 <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>
301 <STRONG><A HREF="curs_variables.3x.html">ables(3x)</A></STRONG>, <STRONG><A HREF="default_colors.3x.html">default_colors(3x)</A></STRONG>
305 <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
308 Man(1) output converted with <a href="http://invisible-island.net/scripts/readme.html#others_scripts">man2html</a>