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=9aa1b1f0af58b7513f7c0f05b0ee4d760d5584e0;hb=HEAD;hpb=cef50b3afcd58166f3541b701c97bce538844c76 diff --git a/doc/html/man/curs_color.3x.html b/doc/html/man/curs_color.3x.html index 9aa1b1f0..d84a5732 100644 --- a/doc/html/man/curs_color.3x.html +++ b/doc/html/man/curs_color.3x.html @@ -1,7 +1,7 @@ - - +
-- -curs_color(3x) curs_color(3x) +curs_color(3x) Library calls curs_color(3x) --
- start_color, init_pair, init_color, has_colors, - can_change_color, color_content, pair_content, COLOR_PAIR - - 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> +
+ #include <curses.h> + + /* variables */ + int COLOR_PAIRS; + int COLORS; int start_color(void); - int init_pair(short pair, short f, short b); - int init_color(short color, short r, short g, short b); + bool has_colors(void); bool can_change_color(void); - int color_content(short color, short *r, short *g, short - *b); - int pair_content(short pair, short *f, short *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); --
- Overview - curses support color attributes on terminals with that ca- - pability. 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 charac- - ters are displayed). A programmer initializes a color- - pair with the routine init_pair. After it has been ini- - tialized, COLOR_PAIR(n), a macro defined in <curses.h>, - can be used as a new video attribute. - - If a terminal is capable of redefining colors, the pro- - grammer can use the routine init_color to change the defi- - nition of a color. The routines has_colors and - can_change_color return TRUE or FALSE, depending on - whether the terminal has color capabilities and whether - the programmer can change the colors. The routine col- - or_content allows a programmer 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. - - Routine Descriptions - 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 initializes eight basic colors (black, red, - green, yellow, blue, magenta, cyan, and white), and two - global variables, COLORS and COLOR_PAIRS (respectively - defining the maximum number of colors and color-pairs the - terminal can support). It also restores the colors on the - terminal to the values they had when the terminal was just - turned on. - - 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 value of the first argument must be between 1 and - COLOR_PAIRS-1, except that if default colors are used - (see use_default_colors) the upper limit is adjusted - to allow for extra pairs which use a default color in - foreground and/or background. + 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); + + /* extension */ + void reset_color_pairs(void); + + int COLOR_PAIR(int n); + PAIR_NUMBER(int attr); + + +
+ +
+ 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 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. + + +
+ curses combines the following data to render a character cell. Any of + them can include color information. + + o curses character attributes, as from waddch(3x) or wadd_wch(3x) - o The value of the second and third arguments must be - between 0 and COLORS. 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. - - 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 assume_default_colors routine, or to specify the - use of default colors (color number -1) if you first in- - voke the use_default_colors routine. - - 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). The value of the first - argument must be between 0 and COLORS. (See the section - Colors for the default color index.) Each of the last - three arguments must be a value between 0 and 1000. When - init_color is used, all occurrences of that color on the - screen immediately change to the new definition. - - 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 at- - tribute. - - 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-independent programs. - - 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 components in - the given color. The value of the first argument must be - between 0 and COLORS. The values that are stored at the - addresses pointed to by the last three arguments are be- - tween 0 (no component) and 1000 (maximum amount of compo- - nent). - - 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. The value of the first argument must be - between 1 and COLOR_PAIRS-1. The values that are stored - at the addresses pointed to by the second and third argu- - ments are between 0 and COLORS. - - Colors - In <curses.h> the following macros are defined. These are - the default colors. curses also assumes that COLOR_BLACK - is the default background color for all terminals. + o window attributes, as from wattrset(3x) or wattr_set(3x) + + o window background character attributes, as from wbkgdset(3x) or + wbkgrndset(3x) + + 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 + code, just as if it were passed to waddch. + + 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 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 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 + attribute next, and finally 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 + background color for all terminals. COLOR_BLACK COLOR_RED @@ -186,100 +162,427 @@ COLOR_CYAN COLOR_WHITE + Some terminals support more than the eight (8) "ANSI" colors. There + are no standard names for those additional colors. --
- 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 completion. - - 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 ex- - tension), or use color pairs outside the range 0 to COL- - OR_PAIR-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 re- - turned from secondary functions such as init_pair if - start_color was not called. + +
+ +
+ 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. 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 + 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 + (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 + and background colors. No other color pairs are initialized. + + 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. + + 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), 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 + 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 valid, and may result in a runtime error: + + 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, + 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(3x)). + + o COLOR_PAIRS corresponds to the terminal database's max_pairs + capability, (see terminfo(5)). + + 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 + 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 + 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- + 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 + foreground color number, and the background color number. For portable + applications: + + 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 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 + definition. + + 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. + + +
+ 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 + 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 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 + through 1000. + + 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 + components in the given color. + + 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 + (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 + pair number, and two addresses of shorts for storing the foreground and + the background color numbers. + + 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 + second and third arguments are in the range 0 through COLORS, + inclusive. + + +
+ 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. + + +
+ 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 + 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. + + 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, e.g., if the initialize_color capa- - bility is absent from the terminal description. + returns an error if the terminal does not support this feature, + e.g., if the initialize_color capability is absent from the + terminal description. start_color - returns an error if the color table cannot be al- - located. + returns an error if the color table cannot be allocated. --
- In the ncurses implementation, there is a separate color - activation flag, color palette, color pairs table, and as- - sociated 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. - - Note that 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 curs_bkgd(3x). - - Several caveats apply on 386 and 486 machines with VGA- - compatible graphics: - - o COLOR_YELLOW is actually brown. To get yellow, use - COLOR_YELLOW combined with the A_BOLD attribute. - - o The A_BLINK attribute should in theory cause the back- - ground 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 +
+ 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. + To change the background color used when parts of a window are blanked + by erasing or scrolling operations, see curs_bkgd(3x). + + Several caveats apply on older x86 machines (e.g., i386, i486) with + VGA-compatible graphics: + + o COLOR_YELLOW is actually brown. To get yellow, use COLOR_YELLOW + combined with the A_BOLD attribute. + + o 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). o Color RGB values are not settable. --
- This implementation satisfies XSI Curses's minimum maxi- - mums for COLORS and COLOR_PAIRS. +
+ 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. - The init_pair routine accepts negative values of fore- - ground and background color to support the use_de- - fault_colors 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 as- - sume_default_colors extension. +
+ Applications employing ncurses extensions should condition their use on + the visibility of the NCURSES_VERSION preprocessor macro. - 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. + 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. --
- curses(3x), curs_initscr(3x), curs_attr(3x), curs_vari- - ables(3x), default_colors(3x) + The assumption that COLOR_BLACK is the default background color for all + 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 + parameters 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 short + 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- + numbers. + + 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_attr(3x), curs_initscr(3x), curs_variables(3x), + default_colors(3x) - curs_color(3x) +ncurses 6.5 2024-04-20 curs_color(3x)-