X-Git-Url: https://ncurses.scripts.mit.edu/?a=blobdiff_plain;ds=inline;f=doc%2Fhtml%2Fman%2Fcurs_bkgd.3x.html;h=4c772ccd14126586822c6325140ee1b47af7ab2c;hb=9193d076200365eeb5ff932acdbbdcc5e452292c;hp=bcd5712ce079100d585bfbc379a8c9843ca1c75a;hpb=f9d358b4f3cf9b44727a0ee5c08f8ca6ae4e3821;p=ncurses.git diff --git a/doc/html/man/curs_bkgd.3x.html b/doc/html/man/curs_bkgd.3x.html index bcd5712c..4c772ccd 100644 --- a/doc/html/man/curs_bkgd.3x.html +++ b/doc/html/man/curs_bkgd.3x.html @@ -1,7 +1,6 @@ - +
+ +- -curs_bkgd(3x) curs_bkgd(3x) +curs_bkgd(3x) curs_bkgd(3x) --
- bkgdset, wbkgdset, bkgd, wbkgd, getbkgd - curses window - background manipulation routines +
+ bkgdset, wbkgdset, bkgd, wbkgd, getbkgd - curses window background + manipulation routines --
+
#include <curses.h> - void bkgdset(chtype ch); - void wbkgdset(WINDOW *win, chtype ch); - int bkgd(chtype ch); - int wbkgd(WINDOW *win, chtype ch); - chtype getbkgd(WINDOW *win); + void bkgdset(chtype ch); + void wbkgdset(WINDOW *win, chtype ch); + int bkgd(chtype ch); + int wbkgd(WINDOW *win, chtype ch); + chtype getbkgd(WINDOW *win); --
- The bkgdset and wbkgdset routines manipulate the back- - ground of the named window. The window background is a - chtype consisting of any combination of attributes (i.e., - rendition) and a character. The attribute part of the - background is combined (OR'ed) with all non-blank charac- - ters that are written into the window with waddch. Both - the character and attribute parts of the background are - combined with the blank characters. The background - becomes a property of the character and moves with the - character through any scrolling and insert/delete +
+ +
+ The bkgdset and wbkgdset routines manipulate the background of the + named window. The window background is a chtype consisting of any com- + bination of attributes (i.e., rendition) and a character. The + attribute part of the background is combined (OR'ed) with all non-blank + characters that are written into the window with waddch. Both the + character and attribute parts of the background are combined with the + blank characters. The background becomes a property of the character + and moves with the character through any scrolling and insert/delete line/character operations. - To the extent possible on a particular terminal, the - attribute part of the background is displayed as the - graphic rendition of the character put on the screen. + To the extent possible on a particular terminal, the attribute part of + the background is displayed as the graphic rendition of the character + put on the screen. - The bkgd and wbkgd functions set the background property - of the current or specified window and then apply this - setting to every character position in that window: - The rendition of every character on the screen is - changed to the new background rendition. +
+ The bkgd and wbkgd functions set the background property of the current + or specified window and then apply this setting to every character + position in that window. According to X/Open Curses, it should do + this: - Wherever the former background character appears, - it is changed to the new background character. + o The rendition of every character on the screen is changed to the + new background rendition. - The getbkgd function returns the given window's current - background character/attribute pair. + o Wherever the former background character appears, it is changed to + the new background character. + Neither X/Open Curses nor the SVr4 manual pages give details about the + way the rendition of characters on the screen is updated when bkgd or + wbkgd is used to change the background character. --
- The routines bkgd and wbkgd return the integer OK. The - SVr4.0 manual says "or a non-negative integer if immedok - is set", but this appears to be an error. + This implementation, like SVr4 curses, does not store the background + and window attribute contributions to each cell separately. It updates + the rendition by comparing the character, non-color attributes and col- + ors contained in the background. For each cell in the window, whether + or not it is blank: + o The library first compares the character, and if it matches the + current character part of the background, it replaces that with the + new background character. --
+ o The library then checks if the cell uses color, i.e., its color + pair value is nonzero. If not, it simply replaces the attributes + and color pair in the cell with those from the new background char- + acter. + + o If the cell uses color, and that matches the color in the current + background, the library removes attributes which may have come from + the current background and adds attributes from the new background. + It finishes by setting the cell to use the color from the new back- + ground. + + o If the cell uses color, and that does not match the color in the + current background, the library updates only the non-color + attributes, first removing those which may have come from the cur- + rent background, and then adding attributes from the new back- + ground. + + If the background's character value is zero, a space is assumed. + + If the terminal does not support color, or if color has not been + started with start_color, the new background character's color + attribute will be ignored. + + +
+ The getbkgd function returns the given window's current background + character/attribute pair. + + +
+ These functions are described in the XSI Curses standard, Issue 4. It + specifies that bkgd and wbkgd return ERR on failure, but gives no fail- + ure conditions. + + The routines bkgd and wbkgd return the integer OK, unless the library + has not been initialized. + + In contrast, the SVr4.0 manual says bkgd and wbkgd may return OK "or a + non-negative integer if immedok is set", which refers to the return + value from wrefresh (used to implement the immediate repainting). The + SVr4 curses wrefresh returns the number of characters written to the + screen during the refresh. This implementation does not do that. + + +
Note that bkgdset and bkgd may be macros. + X/Open Curses mentions that the character part of the background must + be a single-byte value. This implementation, like SVr4, checks to + ensure that, and will reuse the old background character if the check + fails. --
- These functions are described in the XSI Curses standard, - Issue 4. It specifies that bkgd and wbkgd return ERR on - failure, but gives no failure conditions. +
+ These functions are described in the XSI Curses standard, Issue 4 + (X/Open Curses). --
- curses(3x), curs_addch(3x), curs_attr(3x), curs_out- - opts(3x) + +
+ curses(3x), curs_addch(3x), curs_attr(3x), curs_outopts(3x) - curs_bkgd(3x) + curs_bkgd(3x)-