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29 * @Id: curs_color.3x,v 1.37 2015/04/04 19:42:47 tom Exp @
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41 <H1 class="no-header">curs_color 3x</H1>
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>
49 <H2><a name="h2-NAME">NAME</a></H2><PRE>
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><a name="h2-SYNOPSIS">SYNOPSIS</a></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><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
73 <H3><a name="h3-Overview">Overview</a></H3><PRE>
74 <STRONG>curses</STRONG> support color attributes on terminals with that ca-
75 pability. To use these routines <STRONG>start_color</STRONG> must be
76 called, usually right after <STRONG>initscr</STRONG>. Colors are always
77 used in pairs (referred to as color-pairs). A color-pair
78 consists of a foreground color (for characters) and a
79 background color (for the blank field on which the charac-
80 ters are displayed). A programmer initializes a color-
81 pair with the routine <STRONG>init_pair</STRONG>. After it has been ini-
82 tialized, <STRONG>COLOR_PAIR</STRONG>(<EM>n</EM>), a macro defined in <STRONG><curses.h></STRONG>,
83 can be used as a new video attribute.
85 If a terminal is capable of redefining colors, the pro-
86 grammer can use the routine <STRONG>init_color</STRONG> to change the defi-
87 nition of a color. The routines <STRONG>has_colors</STRONG> and
88 <STRONG>can_change_color</STRONG> return <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>, depending on
89 whether the terminal has color capabilities and whether
90 the programmer can change the colors. The routine <STRONG>col-</STRONG>
91 <STRONG>or_content</STRONG> allows a programmer to extract the amounts of
92 red, green, and blue components in an initialized color.
93 The routine <STRONG>pair_content</STRONG> allows a programmer to find out
94 how a given color-pair is currently defined.
98 <H3><a name="h3-Routine-Descriptions">Routine Descriptions</a></H3><PRE>
99 The <STRONG>start_color</STRONG> routine requires no arguments. It must be
100 called if the programmer wants to use colors, and before
101 any other color manipulation routine is called. It is
102 good practice to call this routine right after <STRONG>initscr</STRONG>.
103 <STRONG>start_color</STRONG> does this:
105 <STRONG>o</STRONG> It initializes two global variables, <STRONG>COLORS</STRONG> and <STRONG>COL-</STRONG>
106 <STRONG>OR_PAIRS</STRONG> (respectively defining the maximum number of
107 colors and color-pairs the terminal can support).
109 <STRONG>o</STRONG> It initializes the special color pair <STRONG>0</STRONG> to the default
110 foreground and background colors. No other color
111 pairs are initialized.
113 <STRONG>o</STRONG> It restores the colors on the terminal to the values
114 they had when the terminal was just turned on.
116 <STRONG>o</STRONG> If the terminal supports the <STRONG>initc</STRONG> (<STRONG>initialize_color</STRONG>)
117 capability, <STRONG>start_color</STRONG> initializes its internal table
118 representing the red, green and blue components of the
121 The components depend on whether the terminal uses CGA
122 (aka "ANSI") or HLS (i.e., the <STRONG>hls</STRONG> (<STRONG>hue_lightness_sat-</STRONG>
123 <STRONG>uration</STRONG>) capability is set). The table is initialized
124 first for eight basic colors (black, red, green, yel-
125 low, blue, magenta, cyan, and white), and after that
126 (if the terminal supports more than eight colors) the
127 components are initialized to <STRONG>1000</STRONG>.
129 <STRONG>start_color</STRONG> does not attempt to set the terminal's
130 color palette to match its built-in table. An appli-
131 cation may use <STRONG>init_color</STRONG> to alter the internal table
132 along with the terminal's color.
134 These limits apply to color values and color pairs. Val-
135 ues outside these limits are not legal, and may result in
138 <STRONG>o</STRONG> <STRONG>COLORS</STRONG> corresponds to the terminal database's <STRONG>max_col-</STRONG>
139 <STRONG>ors</STRONG> capability, which is typically a signed 16-bit in-
140 teger (see <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>).
142 <STRONG>o</STRONG> color values are expected to be in the range <STRONG>0</STRONG> to <STRONG>COL-</STRONG>
143 <STRONG>ORS-1</STRONG>, inclusive (including <STRONG>0</STRONG> and <STRONG>COLORS-1</STRONG>).
145 <STRONG>o</STRONG> a special color value <STRONG>-1</STRONG> is used in certain extended
146 functions to denote the <EM>default</EM> <EM>color</EM> (see <STRONG>use_de-</STRONG>
147 <STRONG>fault_colors</STRONG>).
149 <STRONG>o</STRONG> <STRONG>COLOR_PAIRS</STRONG> corresponds to the terminal database's
150 <STRONG>max_pairs</STRONG> capability, which is typically a signed
151 16-bit integer (see <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>).
153 <STRONG>o</STRONG> legal color pair values are in the range <STRONG>1</STRONG> to <STRONG>COL-</STRONG>
154 <STRONG>OR_PAIRS-1</STRONG>, inclusive.
156 <STRONG>o</STRONG> color pair <STRONG>0</STRONG> is special; it denotes "no color".
158 Color pair <STRONG>0</STRONG> is assumed to be white on black, but is
159 actually whatever the terminal implements before color
160 is initialized. It cannot be modified by the applica-
163 The <STRONG>init_pair</STRONG> routine changes the definition of a color-
164 pair. It takes three arguments: the number of the color-
165 pair to be changed, the foreground color number, and the
166 background color number. For portable applications:
168 <STRONG>o</STRONG> The first argument must be a legal color pair value.
169 If default colors are used (see <STRONG>use_default_colors</STRONG>)
170 the upper limit is adjusted to allow for extra pairs
171 which use a default color in foreground and/or back-
174 <STRONG>o</STRONG> The second and third arguments must be legal color
177 If the color-pair was previously initialized, the screen
178 is refreshed and all occurrences of that color-pair are
179 changed to the new definition.
181 As an extension, ncurses allows you to set color pair <STRONG>0</STRONG>
182 via the <STRONG>assume_default_colors</STRONG> routine, or to specify the
183 use of default colors (color number <STRONG>-1</STRONG>) if you first in-
184 voke the <STRONG>use_default_colors</STRONG> routine.
186 The <STRONG>init_color</STRONG> routine changes the definition of a color.
187 It takes four arguments: the number of the color to be
188 changed followed by three RGB values (for the amounts of
189 red, green, and blue components). The first argument must
190 be a legal color value; default colors are not allowed
191 here. (See the section <STRONG>Colors</STRONG> for the default color in-
192 dex.) Each of the last three arguments must be a value in
193 the range <STRONG>0</STRONG> through <STRONG>1000</STRONG>. When <STRONG>init_color</STRONG> is used, all
194 occurrences of that color on the screen immediately change
195 to the new definition.
197 The <STRONG>has_colors</STRONG> routine requires no arguments. It returns
198 <STRONG>TRUE</STRONG> if the terminal can manipulate colors; otherwise, it
199 returns <STRONG>FALSE</STRONG>. This routine facilitates writing terminal-
200 independent programs. For example, a programmer can use
201 it to decide whether to use color or some other video at-
204 The <STRONG>can_change_color</STRONG> routine requires no arguments. It
205 returns <STRONG>TRUE</STRONG> if the terminal supports colors and can
206 change their definitions; other, it returns <STRONG>FALSE</STRONG>. This
207 routine facilitates writing terminal-independent programs.
209 The <STRONG>color_content</STRONG> routine gives programmers a way to find
210 the intensity of the red, green, and blue (RGB) components
211 in a color. It requires four arguments: the color number,
212 and three addresses of <STRONG>short</STRONG>s for storing the information
213 about the amounts of red, green, and blue components in
214 the given color. The first argument must be a legal color
215 value, i.e., <STRONG>0</STRONG> through <STRONG>COLORS-1</STRONG>, inclusive. The values
216 that are stored at the addresses pointed to by the last
217 three arguments are in the range <STRONG>0</STRONG> (no component) through
218 <STRONG>1000</STRONG> (maximum amount of component), inclusive.
220 The <STRONG>pair_content</STRONG> routine allows programmers to find out
221 what colors a given color-pair consists of. It requires
222 three arguments: the color-pair number, and two addresses
223 of <STRONG>short</STRONG>s for storing the foreground and the background
224 color numbers. The first argument must be a legal color
225 value, i.e., in the range <STRONG>1</STRONG> through <STRONG>COLOR_PAIRS-1</STRONG>, inclu-
226 sive. The values that are stored at the addresses pointed
227 to by the second and third arguments are in the range <STRONG>0</STRONG>
228 through <STRONG>COLORS</STRONG>, inclusive.
232 <H3><a name="h3-Colors">Colors</a></H3><PRE>
233 In <STRONG><curses.h></STRONG> the following macros are defined. These are
234 the default colors. <STRONG>curses</STRONG> also assumes that <STRONG>COLOR_BLACK</STRONG>
235 is the default background color for all terminals.
237 <STRONG>COLOR_BLACK</STRONG>
238 <STRONG>COLOR_RED</STRONG>
239 <STRONG>COLOR_GREEN</STRONG>
240 <STRONG>COLOR_YELLOW</STRONG>
241 <STRONG>COLOR_BLUE</STRONG>
242 <STRONG>COLOR_MAGENTA</STRONG>
243 <STRONG>COLOR_CYAN</STRONG>
244 <STRONG>COLOR_WHITE</STRONG>
248 <H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
249 The routines <STRONG>can_change_color()</STRONG> and <STRONG>has_colors()</STRONG> return
250 <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>.
252 All other routines return the integer <STRONG>ERR</STRONG> upon failure and
253 an <STRONG>OK</STRONG> (SVr4 specifies only "an integer value other than
254 <STRONG>ERR</STRONG>") upon successful completion.
256 X/Open defines no error conditions. This implementation
257 will return <STRONG>ERR</STRONG> on attempts to use color values outside
258 the range <STRONG>0</STRONG> to COLORS-1 (except for the default colors ex-
259 tension), or use color pairs outside the range <STRONG>0</STRONG> to <STRONG>COL-</STRONG>
260 <STRONG>OR_PAIRS-1</STRONG>. Color values used in <STRONG>init_color</STRONG> must be in
261 the range <STRONG>0</STRONG> to <STRONG>1000</STRONG>. An error is returned from all func-
262 tions if the terminal has not been initialized. An error
263 is returned from secondary functions such as <STRONG>init_pair</STRONG> if
264 <STRONG>start_color</STRONG> was not called.
266 <STRONG>init_color</STRONG>
267 returns an error if the terminal does not support
268 this feature, e.g., if the <EM>initialize</EM><STRONG>_</STRONG><EM>color</EM> capa-
269 bility is absent from the terminal description.
271 <STRONG>start_color</STRONG>
272 returns an error if the color table cannot be al-
277 <H2><a name="h2-NOTES">NOTES</a></H2><PRE>
278 In the <EM>ncurses</EM> implementation, there is a separate color
279 activation flag, color palette, color pairs table, and as-
280 sociated COLORS and COLOR_PAIRS counts for each screen;
281 the <STRONG>start_color</STRONG> function only affects the current screen.
282 The SVr4/XSI interface is not really designed with this in
283 mind, and historical implementations may use a single
284 shared color palette.
286 Note that setting an implicit background color via a color
287 pair affects only character cells that a character write
288 operation explicitly touches. To change the background
289 color used when parts of a window are blanked by erasing
290 or scrolling operations, see <STRONG><A HREF="curs_bkgd.3x.html">curs_bkgd(3x)</A></STRONG>.
292 Several caveats apply on 386 and 486 machines with VGA-
295 <STRONG>o</STRONG> COLOR_YELLOW is actually brown. To get yellow, use
296 COLOR_YELLOW combined with the <STRONG>A_BOLD</STRONG> attribute.
298 <STRONG>o</STRONG> The A_BLINK attribute should in theory cause the back-
299 ground to go bright. This often fails to work, and
300 even some cards for which it mostly works (such as the
301 Paradise and compatibles) do the wrong thing when you
302 try to set a bright "yellow" background (you get a
303 blinking yellow foreground instead).
305 <STRONG>o</STRONG> Color RGB values are not settable.
309 <H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
310 This implementation satisfies XSI Curses's minimum maxi-
311 mums for <STRONG>COLORS</STRONG> and <STRONG>COLOR_PAIRS</STRONG>.
313 The <STRONG>init_pair</STRONG> routine accepts negative values of fore-
314 ground and background color to support the <STRONG>use_de-</STRONG>
315 <STRONG>fault_colors</STRONG> extension, but only if that routine has been
318 The assumption that <STRONG>COLOR_BLACK</STRONG> is the default background
319 color for all terminals can be modified using the <STRONG>as-</STRONG>
320 <STRONG>sume_default_colors</STRONG> extension.
322 This implementation checks the pointers, e.g., for the
323 values returned by <STRONG>color_content</STRONG> and <STRONG>pair_content</STRONG>, and
324 will treat those as optional parameters when null.
328 <H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
329 <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>
330 <STRONG><A HREF="curs_variables.3x.html">ables(3x)</A></STRONG>, <STRONG><A HREF="default_colors.3x.html">default_colors(3x)</A></STRONG>
334 <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
338 <li><a href="#h2-NAME">NAME</a></li>
339 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
340 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
342 <li><a href="#h3-Overview">Overview</a></li>
343 <li><a href="#h3-Routine-Descriptions">Routine Descriptions</a></li>
344 <li><a href="#h3-Colors">Colors</a></li>
347 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
348 <li><a href="#h2-NOTES">NOTES</a></li>
349 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
350 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>