- The <STRONG>bkgd</STRONG> and <STRONG>wbkgd</STRONG> functions set the background property
- of the current or specified window and then apply this
- setting to every character position in that window:
+ The <STRONG>bkgd</STRONG> and <STRONG>wbkgd</STRONG> 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:
+
+ <STRONG>o</STRONG> The rendition of every character on the screen is changed to the
+ new background rendition.
+
+ <STRONG>o</STRONG> 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 <STRONG>bkgd</STRONG> or
+ <STRONG>wbkgd</STRONG> is used to change the background character.
+
+ 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:
+
+ <STRONG>o</STRONG> The library first compares the <EM>character</EM>, and if it matches the
+ current character part of the background, it replaces that with the
+ new background character.