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- * @Id: curs_bkgd.3x,v 1.28 2018/12/09 00:45:05 tom Exp @
+ * @Id: curs_bkgd.3x,v 1.32 2021/06/17 21:30:22 tom Exp @
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<STRONG>void</STRONG> <STRONG>bkgdset(chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
<STRONG>void</STRONG> <STRONG>wbkgdset(WINDOW</STRONG> <STRONG>*</STRONG><EM>win,</EM> <EM>chtype</EM> <EM>ch</EM><STRONG>);</STRONG>
+
<STRONG>int</STRONG> <STRONG>bkgd(chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wbkgd(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
+
<STRONG>chtype</STRONG> <STRONG>getbkgd(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
</PRE><H3><a name="h3-bkgdset">bkgdset</a></H3><PRE>
The <STRONG>bkgdset</STRONG> and <STRONG>wbkgdset</STRONG> routines manipulate the background of the
- named window. The window background is a <STRONG>chtype</STRONG> consisting of any com-
- bination of attributes (i.e., rendition) and a character. The
+ named window. The window background is a <STRONG>chtype</STRONG> 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
characters that are written into the window with <STRONG>waddch</STRONG>. Both the
character and attribute parts of the background are combined with the
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:
+ the rendition by comparing the character, non-color attributes and
+ colors 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
<STRONG>o</STRONG> 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.
+ and color pair in the cell with those from the new background
+ character.
<STRONG>o</STRONG> 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.
+ It finishes by setting the cell to use the color from the new
+ background.
<STRONG>o</STRONG> 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.
+ attributes, first removing those which may have come from the
+ current background, and then adding attributes from the new
+ background.
+
+ 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 <STRONG>start_color</STRONG>, the new background character's color
+ attribute will be ignored.
</PRE><H3><a name="h3-getbkgd">getbkgd</a></H3><PRE>
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
These functions are described in the XSI Curses standard, Issue 4. It
- specifies that <STRONG>bkgd</STRONG> and <STRONG>wbkgd</STRONG> return <STRONG>ERR</STRONG> on failure, but gives no fail-
- ure conditions.
+ specifies that <STRONG>bkgd</STRONG> and <STRONG>wbkgd</STRONG> return <STRONG>ERR</STRONG> on failure, but gives no
+ failure conditions.
The routines <STRONG>bkgd</STRONG> and <STRONG>wbkgd</STRONG> return the integer <STRONG>OK</STRONG>, unless the library
has not been initialized.
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