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
    A_ITALIC      italic
    A_LEFTLINE    line along the left edge
    A_PROTECT     protected (?) -- PDCurses renders this as a 
                  combination of the *LINE attributes
    A_REVERSE     reverse video
    A_RIGHTLINE   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_RIGHTLINE, A_LEFTLINE
and A_ITALIC are specific to PDCurses. A_INVIS and A_ITALIC are given
the same value in PDCurses.

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_LEFT       same as A_LEFTLINE
    WA_PROTECT    same as A_PROTECT
    WA_REVERSE    same as A_REVERSE
    WA_RIGHT      same as A_RIGHTLINE
    WA_STANDOUT   same as A_STANDOUT
    WA_UNDERLINE  same as A_UNDERLINE

Note that while A_LEFTLINE and A_RIGHTLINE are PDCurses-specific,
WA_LEFT and WA_RIGHT are standard. The following are also defined, for
compatibility, but currently have no effect in PDCurses: WA_HORIZONTAL,
WA_LOW, WA_TOP, WA_VERTICAL.

### 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.

--------------------------------------------------------------------------
