These functions are an extension to the curses library. They permit an
- application to dynamically allocate a color pair using the fore-
- ground/background colors rather than assign a fixed color pair number,
- and return an unused pair to the pool.
+ application to dynamically allocate a color pair using the
+ foreground/background colors rather than assign a fixed color pair
+ number, and return an unused pair to the pool.
The number of colors may be related to the number of possible color
pairs for a given terminal, or it may not:
- o While almost all terminals allow setting the color attributes inde-
- pendently, it is unlikely that your terminal allows you to modify
- the attributes of a given character cell without rewriting it.
- That is, the foreground and background colors are applied as a
+ o While almost all terminals allow setting the color attributes
+ independently, it is unlikely that your terminal allows you to
+ modify the attributes of a given character cell without rewriting
+ it. That is, the foreground and background colors are applied as a
pair.
- o Color pairs are the curses library's way of managing a color pal-
- ette on a terminal. If the library does not keep track of the com-
- binations of colors which are displayed, it will be inefficient.
+ o Color pairs are the curses library's way of managing a color
+ palette on a terminal. If the library does not keep track of the
+ combinations of colors which are displayed, it will be inefficient.
- o For simple terminal emulators with only a few dozen color combina-
- tions, it is convenient to use the maximum number of combinations
- as the limit on color pairs:
+ o For simple terminal emulators with only a few dozen color
+ combinations, it is convenient to use the maximum number of
+ combinations as the limit on color pairs:
- COLORS*COLORS
+ COLORS*COLORS
- o Terminals which support defaultcolors distinct from "ANSI colors"
+ o Terminals which support defaultcolors distinct from "ANSI colors"
add to the possible combinations, producing this total:
- (COLORS+1)*(COLORS+1)
+ (COLORS+1)*(COLORS+1)
- o An application might use up to a few dozen color pairs to implement
+ o An application might use up to a few dozen color pairs to implement
a predefined color scheme.
Beyond that lies in the realm of programs using the foreground and
- background colors for "ASCII art" (or some other non-textual appli-
- cation).
+ background colors for "ASCII art" (or some other non-textual
+ application).
Also beyond those few dozen pairs, the required size for a table to
represent the combinations grows rapidly with an increasing number
@@ -105,31 +105,31 @@
- The alloc_pair function accepts parameters for foreground and back-
- ground color, and checks if that color combination is already associ-
- ated with a color pair.
+ The alloc_pair function accepts parameters for foreground and
+ background color, and checks if that color combination is already
+ associated with a color pair.
- o If the combination already exists, alloc_pair returns the existing
+ o If the combination already exists, alloc_pair returns the existing
pair.
- o If the combination does not exist, alloc_pair allocates a new color
+ o If the combination does not exist, alloc_pair allocates a new color
pair and returns that.
- o If the table fills up, alloc_pair discards the least-recently allo-
- cated entry using free_pair and allocates a new color pair.
+ o If the table fills up, alloc_pair discards the least-recently
+ allocated entry using free_pair and allocates a new color pair.
All of the color pairs are allocated from a table of possible color
- pairs. The size of the table is determined by the terminfo pairs capa-
- bility. The table is shared with init_pair; in fact alloc_pair calls
- init_pair after updating the ncurses library's fast index to the colors
- versus color pairs.
+ pairs. The size of the table is determined by the terminfo pairs
+ capability. The table is shared with init_pair; in fact alloc_pair
+ calls init_pair after updating the ncurses library's fast index to the
+ colors versus color pairs.
- The find_pair function accepts parameters for foreground and background
+ The find_pair function accepts parameters for foreground and background
color, and checks if that color combination is already associated with
- a color pair, returning the pair number if it has been allocated. Oth-
- erwise it returns -1.
+ a color pair, returning the pair number if it has been allocated.
+ Otherwise it returns -1.
- The alloc_pair function returns a color pair number in the range 1
- through COLOR_PAIRS-1, unless it encounters an error updating its fast
+ The alloc_pair function returns a color pair number in the range 1
+ through COLOR_PAIRS-1, unless it encounters an error updating its fast
index to the color pair values, preventing it from allocating a color
pair. In that case, it returns -1.
- The find_pair function returns a color pair number if the given color
+ The find_pair function returns a color pair number if the given color
combination has been associated with a color pair, or -1 if not.
- Likewise, free_pair returns OK unless it encounters an error updating
+ Likewise, free_pair returns OK unless it encounters an error updating
the fast index or if no such color pair is in use.
@@ -156,7 +156,7 @@