Background is a chtype con- sisting of any combination of attributes and a character.
Both the character and attribute parts of the background are combined with the blank char- acters. 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 routines combine the new background with every position in the window. Background is any com- bination of attributes and a character. Only the attribute part is used to set the background of non-blank characters, while both character and attributes are used for blank positions.