| PDCurses Implementor's Guide |
| ============================ |
| |
| Version 1.3 - 200?/??/?? - notes about official ports |
| Version 1.2 - 2007/07/11 - added PDC_init_pair(), PDC_pair_content(), |
| version history; removed pdc_atrtab |
| Version 1.1 - 2007/06/06 - minor cosmetic change |
| Version 1.0 - 2007/04/01 - initial revision |
| |
| This document is for those wishing to port PDCurses to a new platform, |
| or just wanting to better understand how it works. Nothing here should |
| be needed for application programming; for that, refer to PDCurses.txt, |
| as built in doc/, or distributed as a file separate from this source |
| package. This document assumes that you've read the user-level |
| documentation and are very familiar with application-level curses |
| programming. |
| |
| If you want to submit your port for possible inclusion into the main |
| PDCurses distribution, please follow these guidelines: |
| |
| - Don't modify anything in the pdcurses directory or in other port |
| directories. Don't modify curses.h or curspriv.h unless absolutely |
| necessary. (And prefer modifying curspriv.h over curses.h.) |
| |
| - Use the same indentation style, naming and scope conventions as the |
| existing code. |
| |
| - Release all your code to the public domain -- no copyright. Code |
| under GPL, BSD, etc. will not be accepted. |
| |
| |
| DATA STRUCTURES |
| --------------- |
| |
| A port of PDCurses must provide acs_map[], a 128-element array of |
| chtypes, with values laid out based on the Alternate Character Set of |
| the VT100 (see curses.h). PDC_transform_line() must use this table; when |
| it encounters a chtype with the A_ALTCHARSET flag set, and an A_CHARTEXT |
| value in the range 0-127, it must render it using the A_CHARTEXT portion |
| of the corresponding value from this table, instead of the original |
| value. Also, values may be read from this table by apps, and passed |
| through functions such as waddch(), which does no special processing on |
| control characters (0-31 and 127) when the A_ALTCHARSET flag is set. |
| Thus, any control characters used in acs_map[] should also have the |
| A_ALTCHARSET flag set. Implementations should provide suitable values |
| for all the ACS_ macros defined in curses.h; other values in the table |
| should be filled with their own indices (e.g., acs_map['E'] == 'E'). The |
| table can be either hardwired, or filled by PDC_scr_open(). Existing |
| ports define it in pdcdisp.c, but this is not required. |
| |
| |
| FUNCTIONS |
| --------- |
| |
| A port of PDCurses must implement the following functions, with extern |
| scope. These functions are traditionally divided into several modules, |
| as indicated below; this division is not required (only the functions |
| are), but may make it easier to follow for someone familiar with the |
| existing ports. |
| |
| Any other functions you create as part of your implementation should |
| have static scope, if possible. If they can't be static, they should be |
| named with the "PDC_" prefix. This minimizes the risk of collision with |
| an application's choices. |
| |
| Current PDCurses style also uses a single leading underscore with the |
| name of any static function; and modified BSD/Allman-style indentation, |
| approximately equivalent to "indent -kr -i8 -bl -bli0", with adjustments |
| to keep every line under 80 columns. This isn't essential, but a |
| consistent style helps readability. |
| |
| |
| pdcdisp.c: |
| ---------- |
| |
| void PDC_gotoyx(int y, int x); |
| |
| Move the physical cursor (as opposed to the logical cursor affected by |
| wmove()) to the given location. This is called mainly from doupdate(). |
| In general, this function need not compare the old location with the new |
| one, and should just move the cursor unconditionally. |
| |
| void PDC_transform_line(int lineno, int x, int len, const chtype *srcp); |
| |
| The core output routine. It takes len chtype entities from srcp (a |
| pointer into curscr) and renders them to the physical screen at line |
| lineno, column x. It must also translate characters 0-127 via acs_map[], |
| if they're flagged with A_ALTCHARSET in the attribute portion of the |
| chtype. |
| |
| |
| pdcgetsc.c: |
| ----------- |
| |
| int PDC_get_columns(void); |
| |
| Returns the size of the screen in columns. It's used in resize_term() to |
| set the new value of COLS. (Some existing implementations also call it |
| internally from PDC_scr_open(), but this is not required.) |
| |
| int PDC_get_cursor_mode(void); |
| |
| Returns the size/shape of the cursor. The format of the result is |
| unspecified, except that it must be returned as an int. This function is |
| called from initscr(), and the result is stored in SP->orig_cursor, |
| which is used by PDC_curs_set() to determine the size/shape of the |
| cursor in normal visibility mode (curs_set(1)). |
| |
| int PDC_get_rows(void); |
| |
| Returns the size of the screen in rows. It's used in resize_term() to |
| set the new value of LINES. (Some existing implementations also call it |
| internally from PDC_scr_open(), but this is not required.) |
| |
| |
| pdckbd.c: |
| --------- |
| |
| bool PDC_check_key(void); |
| |
| Keyboard/mouse event check, called from wgetch(). Returns TRUE if |
| there's an event ready to process. This function must be non-blocking. |
| |
| void PDC_flushinp(void); |
| |
| This is the core of flushinp(). It discards any pending key or mouse |
| events, removing them from any internal queue and from the OS queue, if |
| applicable. |
| |
| int PDC_get_key(void); |
| |
| Get the next available key, or mouse event (indicated by a return of |
| KEY_MOUSE), and remove it from the OS' input queue, if applicable. This |
| function is called from wgetch(). This function may be blocking, and |
| traditionally is; but it need not be. If a valid key or mouse event |
| cannot be returned, for any reason, this function returns -1. Valid keys |
| are those that fall within the appropriate character set, or are in the |
| list of special keys found in curses.h (KEY_MIN through KEY_MAX). When |
| returning a special key code, this routine must also set SP->key_code to |
| TRUE; otherwise it must set it to FALSE. If SP->return_key_modifiers is |
| TRUE, this function may return modifier keys (shift, control, alt), |
| pressed alone, as special key codes; if SP->return_key_modifiers is |
| FALSE, it must not. If modifier keys are returned, it should only happen |
| if no other keys were pressed in the meantime; i.e., the return should |
| happen on key up. But if this is not possible, it may return the |
| modifier keys on key down (if and only if SP->return_key_modifiers is |
| TRUE). |
| |
| int PDC_modifiers_set(void); |
| |
| Called from PDC_return_key_modifiers(). If your platform needs to do |
| anything in response to a change in SP->return_key_modifiers, do it |
| here. Returns OK or ERR, which is passed on by the caller. |
| |
| int PDC_mouse_set(void); |
| |
| Called by mouse_set(), mouse_on(), and mouse_off() -- all the functions |
| that modify SP->_trap_mbe. If your platform needs to do anything in |
| response to a change in SP->_trap_mbe (for example, turning the mouse |
| cursor on or off), do it here. Returns OK or ERR, which is passed on by |
| the caller. |
| |
| void PDC_set_keyboard_binary(bool on); |
| |
| Set keyboard input to "binary" mode. If you need to do something to keep |
| the OS from processing ^C, etc. on your platform, do it here. TRUE turns |
| the mode on; FALSE reverts it. This function is called from raw() and |
| noraw(). |
| |
| |
| pdcscrn.c: |
| ---------- |
| |
| bool PDC_can_change_color(void); |
| |
| Returns TRUE if init_color() and color_content() give meaningful |
| results, FALSE otherwise. Called from can_change_color(). |
| |
| int PDC_color_content(short color, short *red, short *green, short *blue); |
| |
| The core of color_content(). This does all the work of that function, |
| except checking for values out of range and null pointers. |
| |
| int PDC_init_color(short color, short red, short green, short blue); |
| |
| The core of init_color(). This does all the work of that function, |
| except checking for values out of range. |
| |
| void PDC_init_pair(short pair, short fg, short bg); |
| |
| The core of init_pair(). This does all the work of that function, except |
| checking for values out of range. The values passed to this function |
| should be returned by a call to PDC_pair_content() with the same pair |
| number. PDC_transform_line() should use the specified colors when |
| rendering a chtype with the given pair number. |
| |
| int PDC_pair_content(short pair, short *fg, short *bg); |
| |
| The core of pair_content(). This does all the work of that function, |
| except checking for values out of range and null pointers. |
| |
| void PDC_reset_prog_mode(void); |
| |
| The non-portable functionality of reset_prog_mode() is handled here -- |
| whatever's not done in _restore_mode(). In current ports: In OS/2, this |
| sets the keyboard to binary mode; in Win32, it enables or disables the |
| mouse pointer to match the saved mode; in others it does nothing. |
| |
| void PDC_reset_shell_mode(void); |
| |
| The same thing, for reset_shell_mode(). In OS/2 and Win32, it restores |
| the default console mode; in others it does nothing. |
| |
| int PDC_resize_screen(int nlines, int ncols); |
| |
| This does the main work of resize_term(). It may respond to non-zero |
| parameters, by setting the screen to the specified size; to zero |
| parameters, by setting the screen to a size chosen by the user at |
| runtime, in an unspecified way (e.g., by dragging the edges of the |
| window); or both. It may also do nothing, if there's no appropriate |
| action for the platform. |
| |
| void PDC_restore_screen_mode(int i); |
| |
| Called from _restore_mode() in kernel.c, this function does the actual |
| mode changing, if applicable. Currently used only in DOS and OS/2. |
| |
| void PDC_save_screen_mode(int i); |
| |
| Called from _save_mode() in kernel.c, this function saves the actual |
| screen mode, if applicable. Currently used only in DOS and OS/2. |
| |
| void PDC_scr_close(void); |
| |
| The platform-specific part of endwin(). It may restore the image of the |
| original screen saved by PDC_scr_open(), if the PDC_RESTORE_SCREEN |
| environment variable is set; either way, if using an existing terminal, |
| this function should restore it to the mode it had at startup, and move |
| the cursor to the lower left corner. (The X11 port does nothing.) |
| |
| void PDC_scr_free(void); |
| |
| Frees the memory for SP allocated by PDC_scr_open(). Called by |
| delscreen(). |
| |
| int PDC_scr_open(int argc, char **argv); |
| |
| The platform-specific part of initscr(). It's actually called from |
| Xinitscr(); the arguments, if present, correspond to those used with |
| main(), and may be used to set the title of the terminal window, or for |
| other, platform-specific purposes. (The arguments are currently used |
| only in X11.) PDC_scr_open() must allocate memory for SP, and must |
| initialize acs_map[] (unless it's preset) and several members of SP, |
| including lines, cols, mouse_wait, orig_attr (and if orig_attr is TRUE, |
| orig_fore and orig_back), mono, _restore and _preserve. (Although SP is |
| used the same way in all ports, it's allocated here in order to allow |
| the X11 port to map it to a block of shared memory.) If using an |
| existing terminal, and the environment variable PDC_RESTORE_SCREEN is |
| set, this function may also store the existing screen image for later |
| restoration by PDC_scr_close(). |
| |
| |
| pdcsetsc.c: |
| ----------- |
| |
| int PDC_curs_set(int visibility); |
| |
| Called from curs_set(). Changes the appearance of the cursor -- 0 turns |
| it off, 1 is normal (the terminal's default, if applicable, as |
| determined by SP->orig_cursor), and 2 is high visibility. The exact |
| appearance of these modes is not specified. |
| |
| |
| pdcutil.c: |
| ---------- |
| |
| void PDC_beep(void); |
| |
| Emits a short audible beep. If this is not possible on your platform, |
| you must set SP->audible to FALSE during initialization (i.e., from |
| PDC_scr_open() -- not here); otherwise, set it to TRUE. This function is |
| called from beep(). |
| |
| void PDC_napms(int ms); |
| |
| This is the core delay routine, called by napms(). It pauses for about |
| (the X/Open spec says "at least") ms milliseconds, then returns. High |
| degrees of accuracy and precision are not expected (though desirable, if |
| you can achieve them). More important is that this function gives back |
| the process' time slice to the OS, so that PDCurses idles at low CPU |
| usage. |
| |
| const char *PDC_sysname(void); |
| |
| Returns a short string describing the platform, such as "DOS" or "X11". |
| This is used by longname(). It must be no more than 100 characters; it |
| should be much, much shorter (existing platforms use no more than 5). |
| |
| -------------------------------------------------------------------------- |
| |
| The following functions are implemented in the platform directories, but |
| are accessed directly by apps. Refer to the user documentation for their |
| descriptions: |
| |
| |
| pdcclip.c: |
| ---------- |
| |
| int PDC_clearclipboard(void); |
| int PDC_freeclipboard(char *contents); |
| int PDC_getclipboard(char **contents, long *length); |
| int PDC_setclipboard(const char *contents, long length); |
| |
| |
| pdckbd.c: |
| --------- |
| |
| unsigned long PDC_get_input_fd(void); |
| |
| |
| pdcsetsc.c: |
| ----------- |
| |
| int PDC_set_blink(bool blinkon); |
| void PDC_set_title(const char *title); |