X-Git-Url: https://ncurses.scripts.mit.edu/?a=blobdiff_plain;f=doc%2Fhtml%2Fman%2Fcurs_color.3x.html;h=8d0f00c6368ac4e1f5e80c8b0314d466bee0ddf1;hb=b9a2bd87a73d976d1c916815e2d370bf1090d1b2;hp=cb101f5fb89706ec22c6d89d15418d4d6af061b5;hpb=c6cfd97b8beaf0f6deafbf8aac7281cf6aa7f012;p=ncurses.git diff --git a/doc/html/man/curs_color.3x.html b/doc/html/man/curs_color.3x.html index cb101f5f..8d0f00c6 100644 --- a/doc/html/man/curs_color.3x.html +++ b/doc/html/man/curs_color.3x.html @@ -1,6 +1,6 @@ @@ -38,8 +38,7 @@
-curs_color(3x) curs_color(3x) @@ -72,8 +71,8 @@
- curses support color attributes on terminals with that ca- - pability. To use these routines start_color must be + 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 @@ -95,19 +94,88 @@ how a given color-pair is currently defined. ++
+ The curses library combines these inputs to produce the + actual foreground and background colors shown on the + screen: + + o per-character video attributes (e.g., via waddch), + + o the window attribute (e.g., by wattrset), and + + o the background character (e.g., wbkgdset). + + Per-character and window attributes are usually set by a + parameter containing video attributes including a COL- + OR_PAIR value. Some functions such as wattr_set use a + separate parameter which is the color pair number. + + The background character is a special case: it includes a + character value, 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 us- + es 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 at- + tribute. + + 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 fi- + nally the background character. + + Some curses functions such as wprintw call waddch. Those + do not combine its parameter with a color pair. Conse- + quently those calls use only the window attribute or the + background character. + +
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. + 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 COL- + OR_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_sat- + uration) capability is set). The table is initialized + first for eight basic colors (black, red, green, yel- + low, blue, magenta, cyan, and white), and after that + (if the terminal supports more than eight colors) the + components are initialized to 1000. + + start_color does not attempt to set the terminal's + color palette to match its built-in table. An appli- + cation may use init_color to alter the internal table + along with the terminal's color. These limits apply to color values and color pairs. Val- ues outside these limits are not legal, and may result in @@ -209,8 +277,9 @@
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. + the standard colors (ISO-6429). curses also assumes that + COLOR_BLACK is the default background color for all termi- + nals. COLOR_BLACK COLOR_RED @@ -224,60 +293,60 @@
- The routines can_change_color() and has_colors() return + 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 + 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 + 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_PAIRS-1. Color values used in init_color must be in - the range 0 to 1000. An error is returned from all func- - tions if the terminal has not been initialized. An error - is returned from secondary functions such as init_pair if + tension), or use color pairs outside the range 0 to COL- + OR_PAIRS-1. Color values used in init_color must be in + the range 0 to 1000. An error is returned from all func- + tions if the terminal has not been initialized. An error + is returned from secondary functions such as init_pair if start_color was not called. init_color - returns an error if the terminal does not support - this feature, e.g., if the initialize_color capa- + 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. start_color - returns an error if the color table cannot be al- + returns an error if the color table cannot be al- located.
- In the ncurses implementation, there is a separate color + 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. + 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 + 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 + 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- + Several caveats apply on 386 and 486 machines with VGA- compatible graphics: - o COLOR_YELLOW is actually brown. To get yellow, use + 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 + 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 + 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. @@ -285,20 +354,20 @@
- This implementation satisfies XSI Curses's minimum maxi- + This implementation satisfies XSI Curses's minimum maxi- mums for COLORS and COLOR_PAIRS. - 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 + 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- + The assumption that COLOR_BLACK is the default background + color for all terminals can be modified using the as- sume_default_colors extension. - This implementation checks the pointers, e.g., for the - values returned by color_content and pair_content, and + 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. @@ -318,6 +387,7 @@