12 KiB
PDCurses User's Guide
Curses Overview
The X/Open Curses Interface Definition describes a set of C-Language functions that provide screen-handling and updating, which are collectively known as the curses library.
The curses library permits manipulation of data structures called windows which may be thought of as two-dimensional arrays of characters representing all or part of a terminal's screen. The windows are manipulated using a procedural interface described elsewhere. The curses package maintains a record of what characters are on the screen. At the most basic level, manipulation is done with the routines move() and addch() which are used to "move" the curses around and add characters to the default window, stdscr, which represents the whole screen.
An application may use these routines to add data to the window in any convenient order. Once all data have been added, the routine refresh() is called. The package then determines what changes have been made which affect the screen. The screen contents are then changed to reflect those characters now in the window, using a sequence of operations optimized for the type of terminal in use.
At a higher level routines combining the actions of move() and addch() are defined, as are routines to add whole strings and to perform format conversions in the manner of printf().
Interfaces are also defined to erase the entire window and to specify the attributes of individual characters in the window. Attributes such as inverse video, underline and blink can be used on a per-character basis.
New windows can be created by allowing the application to build several images of the screen and display the appropriate one very quickly. New windows are created using the routine newwin(). For each routine that manipulates the default window, stdscr, there is a corresponding routine prefixed with w to manipulate the contents of a specified window; for example, move() and wmove(). In fact, move(...) is functionally equivalent to wmove( stdscr, ...). This is similar to the interface offered by printf(...) and fprintf(stdout, ...).
Windows do not have to correspond to the entire screen. It is possible to create smaller windows, and also to indicate that the window is only partially visible on the screen. Furthermore, large windows or pads, which are bigger than the actual screen size, may be created.
Interfaces are also defined to allow input character manipulation and to disable and enable many input attributes: character echo, single character input with or without signal processing (cbreak or raw modes), carriage returns mapping to newlines, screen scrolling, etc.
Data Types and the <curses.h> Header
The data types supported by curses are described in this section.
As the library supports a procedural interface to the data types, actual structure contents are not described. All curses data are manipulated using the routines provided.
The <curses.h> Header
The <curses.h> header defines various constants and declares the data types that are available to the application.
Data Types
The following data types are declared:
WINDOW * pointer to screen representation
SCREEN * pointer to terminal descriptor
bool boolean data type
chtype representation of a character in a window
cchar_t the wide-character equivalent of chtype
attr_t for WA_-style attributes
The actual WINDOW and SCREEN objects used to store information are created by the corresponding routines and a pointer to them is provided. All manipulation is through that pointer.
Variables
The following variables are defined:
LINES number of lines on terminal screen
COLS number of columns on terminal screen
stdscr pointer to the default screen window
curscr pointer to the current screen image
SP pointer to the current SCREEN struct
Mouse_status status of the mouse
COLORS number of colors available
COLOR_PAIRS number of color pairs available
TABSIZE size of one TAB block
acs_map[] alternate character set map
ttytype[] terminal name/description
Constants
The following constants are defined:
General
FALSE boolean false value
TRUE boolean true value
NULL zero pointer value
ERR value returned on error condition
OK value returned on successful completion
Video Attributes
Normally, attributes are a property of the character.
For chtype:
A_ALTCHARSET use the alternate character set
A_BLINK bright background or blinking
A_BOLD bright foreground or bold
A_DIM half bright -- no effect in PDCurses
A_INVIS invisible -- no effect in PDCurses
A_ITALIC italic
A_LEFT line along the left edge
A_PROTECT protected -- no effect in PDCurses
A_REVERSE reverse video
A_RIGHT line along the right edge
A_STANDOUT terminal's best highlighting mode
A_UNDERLINE underline
A_ATTRIBUTES bit-mask to extract attributes
A_CHARTEXT bit-mask to extract a character
A_COLOR bit-mask to extract a color-pair
Not all attributes will work on all terminals. A_ITALIC is not standard, but is shared with ncurses.
For attr_t:
WA_ALTCHARSET same as A_ALTCHARSET
WA_BLINK same as A_BLINK
WA_BOLD same as A_BOLD
WA_DIM same as A_DIM
WA_INVIS same as A_INVIS
WA_ITALIC same as A_ITALIC
WA_LEFT same as A_LEFT
WA_PROTECT same as A_PROTECT
WA_REVERSE same as A_REVERSE
WA_RIGHT same as A_RIGHT
WA_STANDOUT same as A_STANDOUT
WA_UNDERLINE same as A_UNDERLINE
The following are also defined, for compatibility, but currently have no effect in PDCurses: A_HORIZONTAL, A_LOW, A_TOP, A_VERTICAL and their WA_* equivalents.
The Alternate Character Set
For use in chtypes and with related functions. These are a portable way to represent graphics characters on different terminals.
VT100-compatible symbols -- box characters:
ACS_ULCORNER upper left box corner
ACS_LLCORNER lower left box corner
ACS_URCORNER upper right box corner
ACS_LRCORNER lower right box corner
ACS_RTEE right "T"
ACS_LTEE left "T"
ACS_BTEE bottom "T"
ACS_TTEE top "T"
ACS_HLINE horizontal line
ACS_VLINE vertical line
ACS_PLUS plus sign, cross, or four-corner piece
VT100-compatible symbols -- other:
ACS_S1 scan line 1
ACS_S9 scan line 9
ACS_DIAMOND diamond
ACS_CKBOARD checkerboard -- 50% grey
ACS_DEGREE degree symbol
ACS_PLMINUS plus/minus sign
ACS_BULLET bullet
Teletype 5410v1 symbols -- these are defined in SysV curses, but are not well-supported by most terminals. Stick to VT100 characters for optimum portability:
ACS_LARROW left arrow
ACS_RARROW right arrow
ACS_DARROW down arrow
ACS_UARROW up arrow
ACS_BOARD checkerboard -- lighter (less dense) than
ACS_CKBOARD
ACS_LANTERN lantern symbol
ACS_BLOCK solid block
That goes double for these -- undocumented SysV symbols. Don't use them:
ACS_S3 scan line 3
ACS_S7 scan line 7
ACS_LEQUAL less than or equal
ACS_GEQUAL greater than or equal
ACS_PI pi
ACS_NEQUAL not equal
ACS_STERLING pounds sterling symbol
Box character aliases:
ACS_BSSB same as ACS_ULCORNER
ACS_SSBB same as ACS_LLCORNER
ACS_BBSS same as ACS_URCORNER
ACS_SBBS same as ACS_LRCORNER
ACS_SBSS same as ACS_RTEE
ACS_SSSB same as ACS_LTEE
ACS_SSBS same as ACS_BTEE
ACS_BSSS same as ACS_TTEE
ACS_BSBS same as ACS_HLINE
ACS_SBSB same as ACS_VLINE
ACS_SSSS same as ACS_PLUS
For cchar_t and wide-character functions, WACS_ equivalents are also defined.
Colors
For use with init_pair(), color_set(), etc.:
COLOR_BLACK
COLOR_BLUE
COLOR_GREEN
COLOR_CYAN
COLOR_RED
COLOR_MAGENTA
COLOR_YELLOW
COLOR_WHITE
Use these instead of numeric values. The definition of the colors depends on the implementation of curses.
Input Values
The following constants might be returned by getch() if keypad() has been enabled. Note that not all of these may be supported on a particular terminal:
KEY_BREAK break key
KEY_DOWN the four arrow keys
KEY_UP
KEY_LEFT
KEY_RIGHT
KEY_HOME home key (upward+left arrow)
KEY_BACKSPACE backspace
KEY_F0 function keys; space for 64 keys is reserved
KEY_F(n) (KEY_F0+(n))
KEY_DL delete line
KEY_IL insert line
KEY_DC delete character
KEY_IC insert character
KEY_EIC exit insert character mode
KEY_CLEAR clear screen
KEY_EOS clear to end of screen
KEY_EOL clear to end of line
KEY_SF scroll 1 line forwards
KEY_SR scroll 1 line backwards (reverse)
KEY_NPAGE next page
KEY_PPAGE previous page
KEY_STAB set tab
KEY_CTAB clear tab
KEY_CATAB clear all tabs
KEY_ENTER enter or send
KEY_SRESET soft (partial) reset
KEY_RESET reset or hard reset
KEY_PRINT print or copy
KEY_LL home down or bottom (lower left)
KEY_A1 upper left of virtual keypad
KEY_A3 upper right of virtual keypad
KEY_B2 center of virtual keypad
KEY_C1 lower left of virtual keypad
KEY_C3 lower right of virtual keypad
KEY_BTAB Back tab key
KEY_BEG Beginning key
KEY_CANCEL Cancel key
KEY_CLOSE Close key
KEY_COMMAND Cmd (command) key
KEY_COPY Copy key
KEY_CREATE Create key
KEY_END End key
KEY_EXIT Exit key
KEY_FIND Find key
KEY_HELP Help key
KEY_MARK Mark key
KEY_MESSAGE Message key
KEY_MOVE Move key
KEY_NEXT Next object key
KEY_OPEN Open key
KEY_OPTIONS Options key
KEY_PREVIOUS Previous object key
KEY_REDO Redo key
KEY_REFERENCE Reference key
KEY_REFRESH Refresh key
KEY_REPLACE Replace key
KEY_RESTART Restart key
KEY_RESUME Resume key
KEY_SAVE Save key
KEY_SBEG Shifted beginning key
KEY_SCANCEL Shifted cancel key
KEY_SCOMMAND Shifted command key
KEY_SCOPY Shifted copy key
KEY_SCREATE Shifted create key
KEY_SDC Shifted delete char key
KEY_SDL Shifted delete line key
KEY_SELECT Select key
KEY_SEND Shifted end key
KEY_SEOL Shifted clear line key
KEY_SEXIT Shifted exit key
KEY_SFIND Shifted find key
KEY_SHELP Shifted help key
KEY_SHOME Shifted home key
KEY_SIC Shifted input key
KEY_SLEFT Shifted left arrow key
KEY_SMESSAGE Shifted message key
KEY_SMOVE Shifted move key
KEY_SNEXT Shifted next key
KEY_SOPTIONS Shifted options key
KEY_SPREVIOUS Shifted prev key
KEY_SPRINT Shifted print key
KEY_SREDO Shifted redo key
KEY_SREPLACE Shifted replace key
KEY_SRIGHT Shifted right arrow
KEY_SRSUME Shifted resume key
KEY_SSAVE Shifted save key
KEY_SSUSPEND Shifted suspend key
KEY_SUNDO Shifted undo key
KEY_SUSPEND Suspend key
KEY_UNDO Undo key
The virtual keypad is arranged like this:
A1 up A3
left B2 right
C1 down C3
This list is incomplete -- see curses.h for the full list, and use the testcurs demo to see what values are actually returned. The above are just the keys required by X/Open. In particular, PDCurses defines many CTL_ and ALT_ combinations; these are not portable.