X-Git-Url: https://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=doc%2Fhtml%2Fman%2Fcurs_color.3x.html;h=c672b72a90ef586d619f9cd1c3d86f587494ea76;hp=735c6f954230ad24b66f798a627af3dda8dcdd27;hb=HEAD;hpb=17c5992a16be94247b83f2bbb9accdd9b7e7bb72 diff --git a/doc/html/man/curs_color.3x.html b/doc/html/man/curs_color.3x.html index 735c6f95..d84a5732 100644 --- a/doc/html/man/curs_color.3x.html +++ b/doc/html/man/curs_color.3x.html @@ -1,6 +1,7 @@ -
--curs_color(3x) curs_color(3x) +curs_color(3x) Library calls curs_color(3x)
- start_color, has_colors, can_change_color, init_pair, init_color, - color_content, pair_content, reset_color_pairs, COLOR_PAIR, PAIR_NUMBER - - curses color manipulation routines + start_color, has_colors, can_change_color, init_pair, init_color, + init_extended_pair, init_extended_color, color_content, pair_content, + extended_color_content, extended_pair_content, reset_color_pairs, + COLOR_PAIR, PAIR_NUMBER, COLORS, COLOR_PAIRS, COLOR_BLACK, COLOR_RED, + COLOR_GREEN, COLOR_YELLOW, COLOR_BLUE, COLOR_MAGENTA, COLOR_CYAN, + COLOR_WHITE - manipulate terminal colors with curses
#include <curses.h> + /* variables */ + int COLOR_PAIRS; + int COLORS; + int start_color(void); bool has_colors(void); bool can_change_color(void); - int init_pair(short pair, short f, short b); - int init_color(short color, short r, short g, short b); - /* extensions */ - int init_extended_pair(int pair, int f, int b); - int init_extended_color(int color, int r, int g, int b); + int init_pair(short pair, short f, short b); + int init_color(short color, short r, short g, short b); + /* extensions */ + int init_extended_pair(int pair, int f, int b); + int init_extended_color(int color, int r, int g, int b); - int color_content(short color, short *r, short *g, short *b); - int pair_content(short pair, short *f, short *b); - /* extensions */ - int extended_color_content(int color, int *r, int *g, int *b); - int extended_pair_content(int pair, int *f, int *b); + int color_content(short color, short *r, short *g, short *b); + int pair_content(short pair, short *f, short *b); + /* extensions */ + int extended_color_content(int color, int *r, int *g, int *b); + int extended_pair_content(int pair, int *f, int *b); - /* extensions */ + /* extension */ void reset_color_pairs(void); - int COLOR_PAIR(int n); - PAIR_NUMBER(attrs); + int COLOR_PAIR(int n); + PAIR_NUMBER(int attr);
- curses supports color attributes on terminals with that capability. To - use these routines start_color must be called, usually right after - initscr. 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 - init_pair. After it has been initialized, COLOR_PAIR(n) can be used to - convert the pair to a video attribute. + curses supports color attributes on terminals with that capability. + Call start_color (typically right after initscr(3x)) to enable this + feature. Colors are always used in pairs. A color pair couples a + foreground color for characters with a background color for the blank + field on which characters are rendered. init_pair initializes a color + pair. The macro COLOR_PAIR(n) can then convert the pair to a video + attribute. - If a terminal is capable of redefining colors, the programmer can use - the routine init_color to change the definition of a color. The rou- - tines has_colors and can_change_color return TRUE or FALSE, depending - on whether the terminal has color capabilities and whether the program- - mer can change the colors. The routine color_content allows a program- - mer to extract the amounts of red, green, and blue components in an - initialized color. The routine pair_content allows a programmer to - find out how a given color-pair is currently defined. + If a terminal has the relevant capability, init_color permits + (re)definition of a color. has_colors and can_change_color return TRUE + or FALSE, depending on whether the terminal has color capability and + whether the programmer can change the colors. color_content permits + extraction of the red, green, and blue components of an initialized + color. pair_content permits discovery of a color pair's current + definition. -
- The curses library combines these inputs to produce the actual fore- - ground and background colors shown on the screen: +
+ curses combines the following data to render a character cell. Any of + them can include color information. - o per-character video attributes (e.g., via waddch), + o curses character attributes, as from waddch(3x) or wadd_wch(3x) - o the window attribute (e.g., by wattrset), and + o window attributes, as from wattrset(3x) or wattr_set(3x) - o the background character (e.g., wbkgdset). + o window background character attributes, as from wbkgdset(3x) or + wbkgrndset(3x) - Per-character and window attributes are usually set by a parameter con- - taining video attributes including a color pair value. Some functions - such as wattr_set use a separate parameter which is the color pair num- - ber. + Per-character and window attributes are usually set through a function + parameter containing attributes including a color pair value. Some + functions, such as wattr_set, use a separate color pair number + parameter. The background character is a special case: it includes a character - value, just as if it were passed to waddch. + code, just as if it were passed to waddch. - The curses library does the actual work of combining these color pairs + The curses library does the actual work of combining these color pairs in an internal function called from waddch: o If the parameter passed to waddch is blank, and it uses the special color pair 0, - o curses next checks the window attribute. + o curses next checks the window attribute. - o If the window attribute does not use color pair 0, curses uses + o If the window attribute does not use color pair 0, curses uses the color pair from the window attribute. - o Otherwise, curses uses the background character. + o Otherwise, curses uses the background character. o If the parameter passed to waddch is not blank, or it does not use - the special color pair 0, curses prefers the color pair from the - parameter, if it is nonzero. Otherwise, it tries the window at- - tribute next, and finally the background character. + the special color pair 0, curses prefers the color pair from the + parameter, if it is nonzero. Otherwise, it tries the window + attribute next, and finally the background character. - Some curses functions such as wprintw call waddch. Those do not com- - bine its parameter with a color pair. Consequently those calls use on- - ly the window attribute or the background character. + Some curses functions such as wprintw call waddch. Those do not + combine its parameter with a color pair. Consequently those calls use + only the window attribute or the background character.
In <curses.h> the following macros are defined. These are the standard - colors (ISO-6429). curses also assumes that COLOR_BLACK is the default + colors (ISO-6429). curses also assumes that COLOR_BLACK is the default background color for all terminals. COLOR_BLACK @@ -162,188 +169,252 @@
- is initialized by start_color to the maximum number of colors the ter- - minal can support. + is initialized by start_color to the maximum number of colors the + terminal can support.
is initialized by start_color to the maximum number of color pairs the - terminal can support. + terminal can support. Often, its value is the product COLORS x COLORS, + but this is not always true. + + o A few terminals use the HLS color space (see start_color below), + ignoring this rule; and + + o terminals supporting a large number of colors are limited to the + number of color pairs that a signed short value can represent.
- The start_color 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 initscr. start_color does this: + The start_color 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 initscr. start_color does this: - o It initializes two global variables, COLORS and COLOR_PAIRS (re- - spectively defining the maximum number of colors and color-pairs + o It initializes two global variables, COLORS and COLOR_PAIRS + (respectively defining the maximum number of colors and color pairs the terminal can support). - o It initializes the special color pair 0 to the default foreground + o It initializes the special color pair 0 to the default foreground and background colors. No other color pairs are initialized. - o It restores the colors on the terminal to the values they had when + o It restores the colors on the terminal to the values they had when the terminal was just turned on. - o If the terminal supports the initc (initialize_color) capability, - start_color initializes its internal table representing the red, - green and blue components of the color palette. + o If the terminal supports the initc (initialize_color) capability, + start_color 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 hls (hue_lightness_saturation) capability is - set). The table is initialized first for eight basic colors - (black, red, green, yellow, blue, magenta, cyan, and white), and - after that (if the terminal supports more than eight colors) the - components are initialized to 1000. + or HLS (i.e., the hls (hue_lightness_saturation) 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 680 or 0 depending on whether the corresponding red, + green, or blue component is used or not. That permits using 1000 + 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 1000. + SVr4 uses a similar scheme, but uses 1000 for the components of the + initial eight colors. start_color does not attempt to set the terminal's color palette to - match its built-in table. An application may use init_color to al- - ter the internal table along with the terminal's color. + match its built-in table. An application may use init_color to + alter 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: + These limits apply to color values and color pairs. Values outside + these limits are not valid, and may result in a runtime error: - o COLORS corresponds to the terminal database's max_colors capabili- - ty, (see terminfo(5)). + o COLORS corresponds to the terminal database's max_colors + capability, (see terminfo(5)). - o color values are expected to be in the range 0 to COLORS-1, inclu- - sive (including 0 and COLORS-1). + o color values are expected to be in the range 0 to COLORS-1, + inclusive (including 0 and COLORS-1). - o a special color value -1 is used in certain extended functions to - denote the default color (see use_default_colors). + o a special color value -1 is used in certain extended functions to + denote the default color (see use_default_colors(3x)). - o COLOR_PAIRS corresponds to the terminal database's max_pairs capa- - bility, (see terminfo(5)). + o COLOR_PAIRS corresponds to the terminal database's max_pairs + capability, (see terminfo(5)). - o legal color pair values are in the range 1 to COLOR_PAIRS-1, inclu- - sive. + o valid color pair values are in the range 1 to COLOR_PAIRS-1, + inclusive. o color pair 0 is special; it denotes "no color". - Color pair 0 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. + Color pair 0 is assumed to be white on black, but is actually + whatever the terminal implements before color is initialized. It + cannot be modified by the application.
- The has_colors routine requires no arguments. It returns TRUE if the - terminal can manipulate colors; otherwise, it returns FALSE. 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. + The has_colors routine requires no arguments. It returns TRUE if the + terminal can manipulate colors; otherwise, it returns FALSE. This + routine facilitates writing terminal-independent programs. For + example, a programmer can use it to decide whether to use color or some + other video attribute.
The can_change_color routine requires no arguments. It returns TRUE if - the terminal supports colors and can change their definitions; other, - it returns FALSE. This routine facilitates writing terminal-indepen- - dent programs. + the terminal supports colors and can change their definitions; other, + it returns FALSE. This routine facilitates writing terminal- + independent programs.
- The init_pair 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: + The init_pair routine changes the definition of a color pair. It takes + three arguments: the number of the color pair to be changed, the + foreground color number, and the background color number. For portable + applications: - o The first argument must be a legal color pair value. If default - colors are used (see use_default_colors) the upper limit is adjust- - ed to allow for extra pairs which use a default color in foreground - and/or background. + o The first argument must be a valid color pair value. If default + colors are used (see use_default_colors(3x)) the upper limit is + adjusted to allow for extra pairs which use a default color in + foreground and/or background. - o The second and third arguments must be legal color values. + o The second and third arguments must be valid 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. + If the color pair was previously initialized, the screen is refreshed + and all occurrences of that color pair are changed to the new + definition. - As an extension, ncurses allows you to set color pair 0 via the as- - sume_default_colors(3x) routine, or to specify the use of default col- - ors (color number -1) if you first invoke the use_default_colors(3x) + As an extension, ncurses allows you to set color pair 0 via the + assume_default_colors(3x) routine, or to specify the use of default + colors (color number -1) if you first invoke the use_default_colors(3x) routine. - The extension reset_color_pairs tells ncurses to discard all of the - color-pair information which was set with init_pair. It also touches - the current- and standard-screens, allowing an application to switch - color palettes rapidly. + +
+ Because init_pair uses signed shorts for its parameters, that limits + color pairs and color-values to 32767 on modern hardware. The + extension init_extended_pair uses ints for the color pair and color- + value, allowing a larger number of colors to be supported.
- The init_color routine changes the definition of a color. It takes + The init_color 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). - o The first argument must be a legal color value; default colors are - not allowed here. (See the section Colors for the default color + o The first argument must be a valid color value; default colors are + not allowed here. (See the section Colors for the default color index.) - o Each of the last three arguments must be a value in the range 0 + o Each of the last three arguments must be a value in the range 0 through 1000. - When init_color is used, all occurrences of that color on the screen + When init_color is used, all occurrences of that color on the screen immediately change to the new definition. +
+ Because init_color uses signed shorts for its parameters, that limits + color-values and their red, green, and blue components to 32767 on + modern hardware. The extension init_extended_color uses ints for the + color value and for setting the red, green, and blue components, + allowing a larger number of colors to be supported. + +
The color_content 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 shorts for - storing the information about the amounts of red, green, and blue com- - ponents in the given color. + of the red, green, and blue (RGB) components in a color. It requires + four arguments: the color number, and three addresses of shorts for + storing the information about the amounts of red, green, and blue + components in the given color. - o The first argument must be a legal color value, i.e., 0 through + o The first argument must be a valid color value, i.e., 0 through COLORS-1, inclusive. - o The values that are stored at the addresses pointed to by the last - three arguments are in the range 0 (no component) through 1000 + o The values that are stored at the addresses pointed to by the last + three arguments are in the range 0 (no component) through 1000 (maximum amount of component), inclusive. +
+ Because color_content uses signed shorts for its parameters, that + limits color-values and their red, green, and blue components to 32767 + on modern hardware. The extension extended_color_content uses ints for + the color value and for returning the red, green, and blue components, + allowing a larger number of colors to be supported. + +
- The pair_content routine allows programmers to find out what colors a - given color-pair consists of. It requires three arguments: the color- + The pair_content 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 shorts for storing the foreground and the background color numbers. - o The first argument must be a legal color value, i.e., in the range + o The first argument must be a valid color value, i.e., in the range 1 through COLOR_PAIRS-1, inclusive. - o The values that are stored at the addresses pointed to by the sec- - ond and third arguments are in the range 0 through COLORS, inclu- - sive. + o The values that are stored at the addresses pointed to by the + second and third arguments are in the range 0 through COLORS, + inclusive. -
- PAIR_NUMBER(attrs) extracts the color value from its attrs parameter - and returns it as a color pair number. +
+ Because pair_content uses signed shorts for its parameters, that limits + color pair and color-values to 32767 on modern hardware. The extension + extended_pair_content uses ints for the color pair and for returning + the foreground and background colors, allowing a larger number of + colors to be supported. + + +
+ The extension reset_color_pairs tells ncurses to discard all of the + color pair information which was set with init_pair. It also touches + the current- and standard-screens, allowing an application to switch + color palettes rapidly.
- Its inverse COLOR_PAIR(n) 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 attr_set - (which pass the color pair as a separate parameter) rather than the - legacy functions such as attrset. + COLOR_PAIR(n) 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 attr_set (which pass + the color pair as a separate parameter) rather than the legacy + functions such as attrset. + + +
+ PAIR_NUMBER(attr) extracts the color information from its attr + parameter and returns it as a color pair number; it is the inverse + operation of COLOR_PAIR.
The routines can_change_color and has_colors return TRUE or FALSE. - All other routines return the integer ERR upon failure and an OK (SVr4 - specifies only "an integer value other than ERR") upon successful com- - pletion. + All other routines return the integer ERR upon failure and an OK (SVr4 + specifies only "an integer value other than ERR") upon successful + completion. + + X/Open defines no error conditions. SVr4 does document some error + conditions which apply in general: + + o This implementation will return ERR on attempts to use color values + outside the range 0 to COLORS-1 (except for the default colors + extension), or use color pairs outside the range 0 to + COLOR_PAIRS-1. + + Color values used in init_color must be in the range 0 to 1000. - X/Open defines no error conditions. This implementation will return - ERR on attempts to use color values outside the range 0 to COLORS-1 - (except for the default colors extension), or use color pairs outside - the range 0 to COLOR_PAIRS-1. Color values used in init_color must be - in the range 0 to 1000. An error is returned from all functions if the - terminal has not been initialized. An error is returned from secondary - functions such as init_pair if start_color was not called. + An error is returned from all functions if the terminal has not + been initialized. + + An error is returned from secondary functions such as init_pair if + start_color was not called. + + o SVr4 does much the same, except that it returns ERR from + pair_content if the pair was not initialized using init_pairs and + it returns ERR from color_content if the terminal does not support + changing colors. + + This implementation does not return ERR for either case. + + Specific functions make additional checks: init_color returns an error if the terminal does not support this feature, @@ -355,12 +426,12 @@
- In the ncurses implementation, there is a separate color activation - flag, color palette, color pairs table, and associated COLORS and COL- - OR_PAIRS counts for each screen; the start_color 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. + In the ncurses implementation, there is a separate color activation + flag, color palette, color pairs table, and associated COLORS and + COLOR_PAIRS counts for each screen; the start_color 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. @@ -382,40 +453,93 @@ o Color RGB values are not settable. +
+ The functions marked as extensions were designed for ncurses(3x), and + are not found in SVr4 curses, 4.4BSD curses, or any other previous + curses implementation. + +
- This implementation satisfies XSI Curses's minimum maximums for COLORS - and COLOR_PAIRS. + Applications employing ncurses extensions should condition their use on + the visibility of the NCURSES_VERSION preprocessor macro. - The init_pair routine accepts negative values of foreground and back- - ground color to support the use_default_colors(3x) extension, but only - if that routine has been first invoked. + This implementation satisfies X/Open Curses's minimum maximums for + COLORS and COLOR_PAIRS. + + The init_pair routine accepts negative values of foreground and + background color to support the use_default_colors(3x) extension, but + only if that routine has been first invoked. The assumption that COLOR_BLACK is the default background color for all - terminals can be modified using the assume_default_colors(3x) exten- - sion. + terminals can be modified using the assume_default_colors(3x) + extension. - This implementation checks the pointers, e.g., for the values returned - by color_content and pair_content, and will treat those as optional pa- - rameters when null. + This implementation checks the pointers, e.g., for the values returned + by color_content and pair_content, and will treat those as optional + parameters when null. - X/Open Curses does not specify a limit for the number of colors and + 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 short - for the parameters, it carries over SVr4's implementation detail for + 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 - short parameters, allowing applications to use larger color- and pair- + implementation provides extended versions of those functions which use + short parameters, allowing applications to use larger color- and pair- numbers. - The reset_color_pairs function is an extension of ncurses. + The reset_color_pairs function is an extension of ncurses. + + +
+ SVr3.2 introduced color support to curses in 1987. + + SVr4 made internal changes, e.g., moving the storage for the color + state from SP (the SCREEN structure) to cur_term (the TERMINAL + structure), but provided the same set of library functions. + + SVr4 curses limits the number of color pairs to 64, reserving color + pair zero (0) as the terminal's initial uncolored state. This limit + arises because the color pair information is a bitfield in the chtype + data type (denoted by A_COLOR). + + Other implementations of curses had different limits: + + o PCCurses (1987-1990) provided for only eight (8) colors. + + o PDCurses (1992-present) inherited the 8-color limitation from + PCCurses, but changed this to 256 in version 2.5 (2001), along with + changing chtype from 16-bits to 32-bits. + + o X/Open Curses (1992-present) added a new structure cchar_t to store + the character, attributes and color pair values, allowing increased + range of color pairs. Both color pairs and color-values used a + signed short, limiting values to 15 bits. + + o ncurses (1992-present) uses eight bits for A_COLOR in chtype + values. + + Version 5.3 provided a wide-character interface (2002), but left + color pairs as part of the attributes-field. + + Since version 6 (2015), ncurses uses a separate int for color pairs + in the cchar_t values. When those color pair values fit in 8 bits, + ncurses allows color pairs to be manipulated via the functions + using chtype values. + + o NetBSD curses used 6 bits from 2000 (when colors were first + supported) until 2004. At that point, NetBSD changed to use 10 + bits. As of 2021, that size is unchanged. Like ncurses before + version 6, the NetBSD color pair information is stored in the + attributes field of cchar_t, limiting the number of color pairs by + the size of the bitfield.
- curses(3x), curs_initscr(3x), curs_attr(3x), curs_variables(3x), de- - fault_colors(3x) + curses(3x), curs_attr(3x), curs_initscr(3x), curs_variables(3x), + default_colors(3x) - curs_color(3x) +ncurses 6.5 2024-04-20 curs_color(3x)