| <!-- |
| **************************************************************************** |
| * Copyright 2018-2019,2020 Thomas E. Dickey * |
| * Copyright 1998-2016,2017 Free Software Foundation, Inc. * |
| * * |
| * Permission is hereby granted, free of charge, to any person obtaining a * |
| * copy of this software and associated documentation files (the * |
| * "Software"), to deal in the Software without restriction, including * |
| * without limitation the rights to use, copy, modify, merge, publish, * |
| * distribute, distribute with modifications, sublicense, and/or sell * |
| * copies of the Software, and to permit persons to whom the Software is * |
| * furnished to do so, subject to the following conditions: * |
| * * |
| * The above copyright notice and this permission notice shall be included * |
| * in all copies or substantial portions of the Software. * |
| * * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * |
| * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * |
| * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * |
| * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * |
| * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * |
| * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR * |
| * THE USE OR OTHER DEALINGS IN THE SOFTWARE. * |
| * * |
| * Except as contained in this notice, the name(s) of the above copyright * |
| * holders shall not be used in advertising or otherwise to promote the * |
| * sale, use or other dealings in this Software without prior written * |
| * authorization. * |
| **************************************************************************** |
| * @Id: curs_color.3x,v 1.62 2020/02/02 23:34:34 tom Exp @ |
| --> |
| <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"> |
| <HTML> |
| <HEAD> |
| <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> |
| <meta name="generator" content="Manpage converted by man2html - see https://invisible-island.net/scripts/readme.html#others_scripts"> |
| <TITLE>curs_color 3x</TITLE> |
| <link rel="author" href="mailto:bug-ncurses@gnu.org"> |
| <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> |
| </HEAD> |
| <BODY> |
| <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> |
| <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> - <STRONG>curses</STRONG> color manipulation routines |
| |
| |
| </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>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>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> |
| |
| /* extensions */ |
| <STRONG>void</STRONG> <STRONG>reset_color_pairs(void);</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> 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 |
| <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. |
| |
| |
| </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: |
| |
| <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 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. |
| |
| 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 uses 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 attribute. |
| |
| <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 at- |
| tribute 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. |
| |
| |
| </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 |
| background color for all terminals. |
| |
| <STRONG>COLOR_BLACK</STRONG> |
| <STRONG>COLOR_RED</STRONG> |
| <STRONG>COLOR_GREEN</STRONG> |
| <STRONG>COLOR_YELLOW</STRONG> |
| <STRONG>COLOR_BLUE</STRONG> |
| <STRONG>COLOR_MAGENTA</STRONG> |
| <STRONG>COLOR_CYAN</STRONG> |
| <STRONG>COLOR_WHITE</STRONG> |
| |
| 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. |
| |
| |
| </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 |
| 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: |
| |
| <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 |
| 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_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. |
| |
| 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> 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> 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> legal color pair values are in the range <STRONG>1</STRONG> to <STRONG>COLOR_PAIRS-1</STRONG>, inclu- |
| sive. |
| |
| <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. |
| |
| |
| </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. |
| |
| |
| </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. |
| |
| |
| </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: |
| |
| <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 ad- |
| justed to allow for extra pairs which use a default color in fore- |
| ground 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. |
| |
| 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> |
| routine. |
| |
| |
| </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 exten- |
| sion <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 |
| 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 |
| index.) |
| |
| <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 |
| 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 mod- |
| ern hardware. The extension <STRONG>init_extended_color</STRONG> uses <STRONG>int</STRONG>s for the col- |
| or 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. |
| |
| <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> |
| (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 lim- |
| its 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- |
| 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>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. |
| |
| |
| </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 col- |
| ors 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> |
| <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. |
| |
| |
| </PRE><H3><a name="h3-COLOR_PAIR">COLOR_PAIR</a></H3><PRE> |
| Its inverse <STRONG>COLOR_PAIR(</STRONG><EM>n</EM><STRONG>)</STRONG> converts a color pair number to an attribute. |
| 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 functions such as <STRONG>attrset</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>ERR</STRONG>") upon successful com- |
| pletion. |
| |
| X/Open defines no error conditions. SVr4 does document some error con- |
| ditions 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 ex- |
| tension), 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_con-</STRONG> |
| <STRONG>tent</STRONG> if the pair was not initialized using <STRONG>init_pairs</STRONG> and it re- |
| turns <STRONG>ERR</STRONG> from <STRONG>color_content</STRONG> if the terminal does not support |
| changing colors. |
| |
| 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 |
| terminal description. |
| |
| <STRONG>start_color</STRONG> |
| returns an error if the color table cannot be allocated. |
| |
| |
| </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 |
| 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 |
| VGA-compatible graphics: |
| |
| <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 |
| 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 |
| blinking yellow foreground instead). |
| |
| <STRONG>o</STRONG> Color RGB values are not settable. |
| |
| |
| </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><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 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. |
| |
| 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. |
| |
| 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 |
| 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- |
| 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="curs_color.3x.html">curs_color(3x)</A></STRONG> |
| </PRE> |
| <div class="nav"> |
| <ul> |
| <li><a href="#h2-NAME">NAME</a></li> |
| <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li> |
| <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> |
| </ul> |
| </li> |
| <li><a href="#h2-CONSTANTS">CONSTANTS</a></li> |
| <li><a href="#h2-VARIABLES">VARIABLES</a> |
| <ul> |
| <li><a href="#h3-COLORS">COLORS</a></li> |
| <li><a href="#h3-COLOR_PAIRS">COLOR_PAIRS</a></li> |
| </ul> |
| </li> |
| <li><a href="#h2-FUNCTIONS">FUNCTIONS</a> |
| <ul> |
| <li><a href="#h3-start_color">start_color</a></li> |
| <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-SEE-ALSO">SEE ALSO</a></li> |
| </ul> |
| </div> |
| </BODY> |
| </HTML> |
