p_padala@yahoo.com
v1.7.1, 2002-06-25
| Revision History | ||
|---|---|---|
| Revision 1.7.1 | 2002-06-25 | Revised by: ppadala |
| Added a README file for building and instructions for building from source. | ||
| Revision 1.7 | 2002-06-25 | Revised by: ppadala |
| Added "Other formats" section and made lot of fancy changes to the programs. Inlining of programs is gone. | ||
| Revision 1.6.1 | 2002-02-24 | Revised by: ppadala |
| Removed the old Changelog section, cleaned the makefiles | ||
| Revision 1.6 | 2002-02-16 | Revised by: ppadala |
| Corrected lot of spelling mistakes, added ACS variables section | ||
| Revision 1.5 | 2002-01-05 | Revised by: ppadala |
| Changed structure to present proper TOC | ||
| Revision 1.3.1 | 2001-07-26 | Revised by: ppadala |
| Corrected maintainers paragraph, Corrected stable release number | ||
| Revision 1.3 | 2001-07-24 | Revised by: ppadala |
| Added copyright notice(LDP license) to main document, Put copyright notice (GPL) for programs as well, Corrected printw_example. | ||
| Revision 1.2 | 2001-06-05 | Revised by: ppadala |
| Incorporated ravi's changes. Mainly to introduction, menu, form, justforfun sections | ||
| Revision 1.1 | 2001-05-22 | Revised by: ppadala |
| Added "a word about window" section, Added scanw_example. | ||
This document is intended to be an "All in One" guide for programming with ncurses and its sister libraries. We graduate from a simple "Hello World" program to more complex form manipulation. No prior experience in ncurses is assumed. Latest version of the document can always be found at my web site. Send comments to this address
Suppose you wanted to print a line in color. Try typing this on your console.
echo "^[[0;31;40mIn Color" |
echo "^[[0;37;40m" |
The ncurses package was originated by Pavel Curtis. The original maintainer of this package is Zeyd Ben-Halim <zmbenhal@netcom.com>. Eric S. Raymond <esr@snark.thyrsus.com> wrote many of the new features in versions after 1.8.1. J�rgen Pfeifer wrote all of the menu and forms code as well as the Ada95 binding. Ongoing work is being done by Thomas Dickey and J�rgen Pfeifer. Florian La Roche acts as the maintainer for the Free Software Foundation, which holds the copyright on ncurses. Contact the current maintainers at bug-ncurses@gnu.org.
Ncurses can be obtained from ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz or any of the ftp sites mentioned in http://www.gnu.org/order/ftp.html. The latest stable release is 5.2 20001021.
Read the README and INSTALL files for details on to how to install it. It usually involves the following operations.
tar zxvf ncurses<version>.tar.gz # unzip and untar the archive
cd ncurses<version> # cd to the directory
./configure # configure the build according to your
# environment
make # make it
su root # become root
make install # install it |
Using the RPM
Ncurses RPM can be found and downloaded from http://rpmfind.net . The RPM can be installed with the following command after becoming root.
rpm -i <downloaded rpm> |
All the programs in the document are available in zipped form here. Unzip and untar it. The directory structure looks like this.
ncurses | |----> JustForFun -- just for fun programs |----> basics -- basic programs |----> demo -- output files go into this directory after make | | | |----> exe -- exe files of all example programs |----> forms -- programs related to form library |----> menus -- programs related to menus library |----> panels -- programs related to panels library |----> Makefile -- the top level Makefile |----> README -- the top level README file. contains instructions |----> COPYING -- copyright notice |
The individual directories contain the following files.
Description of files in each directory
--------------------------------------
JustForFun
|
|----> hanoi.c -- The Towers of Hanoi Solver
|----> life.c -- The Game of Life demo
|----> magic.c -- An Odd Order Magic Square builder
|----> queens.c -- The famous N-Queens Solver
|----> shuffle.c -- A fun game, if you have time to kill
|----> tt.c -- A very trivial typing tutor
basics
|
|----> acs_vars.c -- ACS_ variables example
|----> hello_world.c -- Simple "Hello World" Program
|----> init_func_example.c -- Initialization functions example
|----> key_code.c -- Shows the scan code of the key pressed
|----> mouse_menu.c -- A menu accessible by mouse
|----> other_border.c -- Shows usage of other border functions apa
| -- rt from box()
|----> printw_example.c -- A very simple printw() example
|----> scanw_example.c -- A very simple getstr() example
|----> simple_attr.c -- A program that can print a c file with
| -- comments in attribute
|----> simple_color.c -- A simple example demonstrating colors
|----> simple_key.c -- A menu accessible with keyboard UP, DOWN
| -- arrows
|----> temp_leave.c -- Demonstrates temporarily leaving curses mode
|----> win_border.c -- Shows Creation of windows and borders
|----> with_chgat.c -- chgat() usage example
forms
|
|----> form_attrib.c -- Usage of field attributes
|----> form_options.c -- Usage of field options
|----> form_simple.c -- A simple form example
|----> form_win.c -- Demo of windows associated with forms
menus
|
|----> menu_attrib.c -- Usage of menu attributes
|----> menu_item_data.c -- Usage of item_name() etc.. functions
|----> menu_multi_column.c -- Creates multi columnar menus
|----> menu_scroll.c -- Demonstrates scrolling capability of menus
|----> menu_simple.c -- A simple menu accessed by arrow keys
|----> menu_toggle.c -- Creates multi valued menus and explains
| -- REQ_TOGGLE_ITEM
|----> menu_userptr.c -- Usage of user pointer
|----> menu_win.c -- Demo of windows associated with menus
panels
|
|----> panel_browse.c -- Panel browsing through tab. Usage of user
| -- pointer
|----> panel_hide.c -- Hiding and Un hiding of panels
|----> panel_resize.c -- Moving and resizing of panels
|----> panel_simple.c -- A simple panel example |
There is a top level Makefile included in the main directory. It builds all the files and puts the ready-to-use exes in demo/exe directory. You can also do selective make by going into the corresponding directory. Each directory contains a README file explaining the purpose of each c file in the directory.
For every example I have given the path name for the file relative to the ncurses directory.
If you prefer you can browse individual programs at http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/
All the programs are released under GPL and you can use them for any thing you like.
If above links are broken or if you want to experiment with sgml read on.
Get both the source and the tar,gzipped programs, available at
http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/
NCURSES-HOWTO/NCURSES-Programming-HOWTO.sgml
http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/
NCURSES-HOWTO/ncurses_programs.tar.gz
Unzip ncurses_programs.tar.gz with
tar zxvf ncurses_programs.tar.gz
Use jade to create various formats. For example if you just want to create
the multiple html files, you would use
jade -t sgml -i html -d <path to docbook html stylesheet>
NCURSES-Programming-HOWTO.sgml
to get pdf, first create a single html file of the HOWTO with
jade -t sgml -i html -d <path to docbook html stylesheet> -V nochunks
NCURSES-Programming-HOWTO.sgml > NCURSES-ONE-BIG-FILE.html
then use htmldoc to get pdf file with
htmldoc --size universal -t pdf --firstpage p1 -f <output file name.pdf>
NCURSES-ONE-BIG-FILE.html
for ps, you would use
htmldoc --size universal -t ps --firstpage p1 -f <output file name.ps>
NCURSES-ONE-BIG-FILE.html |
See LDP Author guide for more details. If all else failes, mail me at p_padala@yahoo.com
I thank Sharath and Emre Akbas for helping me with few sections. The introduction was initially written by sharath. I rewrote it with few excerpts taken from his initial work. Emre helped in writing printw and scanw sections.
Then comes Ravi Parimi, my dearest friend, who has been on this project before even one line was written. He constantly bombarded me with suggestions and patiently reviewed the whole text. He also checked each program on Linux and Solaris. See his notes to check on your problems.
This is the wish list, in the order of priority. If you have a wish or you want to work on completing the wish, mail me.
Add examples to last parts of forms section. (I am working on it)
Prepare a Demo showing all the programs and allow the user to browse through description of each program. Let the user compile and see the program in action. A dialog based interface is preferred. (My friend N.N.Ashok is working on it)
Add debug info. _tracef, _tracemouse stuff.
Accessing termcap, terminfo using functions provided by ncurses package.
Working on two terminals simultaneously.
Add things in miscellaneous section.
Copyright (c) 2001 by Pradeep Padala. This document may be distributed under the terms set forth in the LDP license at linuxdoc.org/COPYRIGHT.html.
This HOWTO is free documentation; you can redistribute it and/or modify it under the terms of the LDP license. This document is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See the LDP license for more details.
#include <ncurses.h>
.
.
.
compile and link: gcc <program file> -lncurses |
Example 1. The Hello World !!! Program
#include <ncurses.h>
int main()
{
initscr(); /* Start curses mode */
printw("Hello World !!!"); /* Print Hello World */
refresh(); /* Print it on to the real screen */
getch(); /* Wait for user input */
endwin(); /* End curses mode */
return 0;
} |
Let's write a program which will clarify the usage of these functions.
Example 2. Initialization Function Usage example
#include <ncurses.h>
int main()
{ int ch;
initscr(); /* Start curses mode */
raw(); /* Line buffering disabled */
keypad(stdscr, TRUE); /* We get F1, F2 etc.. */
noecho(); /* Don't echo() while we do getch */
printw("Type any character to see it in bold\n");
ch = getch(); /* If raw() hadn't been called
* we have to press enter before it
* gets to the program */
if(ch == KEY_F(1)) /* Without keypad enabled this will */
printw("F1 Key pressed");/* not get to us either */
/* Without noecho() some ugly escape
* charachters might have been printed
* on screen */
else
{ printw("The pressed key is ");
attron(A_BOLD);
printw("%c", ch);
attroff(A_BOLD);
}
refresh(); /* Print it on to the real screen */
getch(); /* Wait for user input */
endwin(); /* End curses mode */
return 0;
} |
This program is self-explanatory. But I used functions which aren't explained yet. The function getch() is used to get a character from user. It is equivalent to normal getchar() except that we can disable the line buffering to avoid <enter> after input. Look for more about getch()and reading keys in the key management section . The functions attron and attroff are used to switch some attributes on and off respectively. In the example I used them to print the character in bold. These functions are explained in detail later.
Before we plunge into the myriad ncurses functions, let me clear few things about windows. Windows are explained in detail in following sections
A Window is an imaginary screen defined by curses system. A window does not mean a bordered window which you usually see on Win9X platforms. When curses is initialized, it creates a default window named stdscr which represents your 80x25 (or the size of window in which you are running) screen. If you are doing simple tasks like printing few strings, reading input etc., you can safely use this single window for all of your purposes. You can also create windows and call functions which explicitly work on the specified window.
For example, if you call
printw("Hi There !!!");
refresh(); |
It prints the string on stdscr at the present cursor position. Similarly the call to refresh(), works on stdscr only.
Say you have created windows then you have to call a function with a 'w' added to the usual function.
wprintw(win, "Hi There !!!");
wrefresh(win); |
As you will see in the rest of the document, naming of functions follow the same convention. For each function there usually are three more functions.
printw(string); /* Print on stdscr at present cursor position */
mvprintw(y, x, string);/* Move to (y, x) then print string */
wprintw(win, string); /* Print on window win at present cursor position */
/* in the window */
mvwprintw(win, y, x, string); /* Move to (y, x) relative to window */
/* co-ordinates and then print */ |
Usually the w-less functions are macros which expand to corresponding w-function with stdscr as the window parameter.
There are three classes of functions which you can use to do output on screen.
These functions put a single character into the current cursor location and advance the position of the cursor. You can give the character to be printed but they usually are used to print a character with some attributes. Attributes are explained in detail in later sections of the document. If a character is associated with an attribute(bold, reverse video etc.), when curses prints the character, it is printed in that attribute.
In order to combine a character with some attributes, you have two options:
By OR'ing a single character with the desired attribute macros. These attribute macros could be found in the header file ncurses.h. For example, you want to print a character ch(of type char) bold and underlined, you would call addch() as below.
addch(ch | A_BOLD | A_UNDERLINE); |
By using functions like attrset(),attron(),attroff(). These functions are explained in the Attributes section. Briefly, they manipulate the current attributes of the given window. Once set, the character printed in the window are associated with the attributes until it is turned off.
Additionally, curses provides some special characters for character-based graphics. You can draw tables, horizontal or vertical lines, etc. You can find all avaliable characters in the header file ncurses.h. Try looking for macros beginning with ACS_ in this file.
mvaddch() is used to move the cursor to a given point, and then print. Thus, the calls:
move(row,col); /* moves the cursor to rowth row and colth column */
addch(ch); |
mvaddch(row,col,ch); |
Example 3. A Simple printw example
#include <ncurses.h> /* ncurses.h includes stdio.h */
#include <string.h>
int main()
{
char mesg[]="Just a string"; /* message to be appeared on the screen */
int row,col; /* to store the number of rows and *
* the number of colums of the screen */
initscr(); /* start the curses mode */
getmaxyx(stdscr,row,col); /* get the number of rows and columns */
mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg);
/* print the message at the center of the screen */
mvprintw(row-2,0,"This screen has %d rows and %d columns\n",row,col);
printw("Try resizing your window(if possible) and then run this program again");
refresh();
getch();
endwin();
return 0;
} |
All these functions take y co-ordinate first and then x in their arguments. A common mistake by beginners is to pass x,y in that order. If you are doing too many manipulations of (y,x) co-ordinates, think of dividing the screen into windows and manipulate each one separately. Windows are explained in the windows section.
These functions read a single character from the terminal. But there are several subtle facts to consider. For example if you don't use the function cbreak(), curses will not read your input characters contiguously but will begin read them only after a new line or an EOF is encountered. In order to avoid this, the cbreak() function must used so that characters are immediately available to your program. Another widely used function is noecho(). As the name suggests, when this function is set (used), the characters that are keyed in by the user will not show up on the screen. The two functions cbreak() and noecho() are typical examples of key management. Functions of this genre are explained in the key management section .
Example 4. A Simple scanw example
#include <ncurses.h> /* ncurses.h includes stdio.h */
#include <string.h>
int main()
{
char mesg[]="Enter a string: "; /* message to be appeared on the screen */
char str[80];
int row,col; /* to store the number of rows and *
* the number of colums of the screen */
initscr(); /* start the curses mode */
getmaxyx(stdscr,row,col); /* get the number of rows and columns */
mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg);
/* print the message at the center of the screen */
getstr(str);
mvprintw(LINES - 2, 0, "You Entered: %s", str);
getch();
endwin();
return 0;
} |
Example 5. A Simple Attributes example
#include <ncurses.h>
int main(int argc, char *argv[])
{
int ch, prev;
FILE *fp;
int goto_prev = FALSE, y, x;
if(argc != 2)
{ printf("Usage: %s <a c file name>\n", argv[0]);
exit(1);
}
fp = fopen(argv[1], "r");
if(fp == NULL)
{ perror("Cannot open input file");
exit(1);
}
initscr(); /* Start curses mode */
prev = EOF;
while((ch = fgetc(fp)) != EOF)
{ if(prev == '/' && ch == '*') /* If it is / and * then olny
* switch bold on */
{ attron(A_BOLD);
goto_prev = TRUE; /* Go to previous char / and
* print it in BOLD */
}
if(goto_prev == TRUE)
{ getyx(stdscr, y, x);
move(y, x - 1);
printw("%c%c", '/', ch); /* The actual printing is done
* here */
ch = 'a'; /* 'a' is just a dummy
* character to prevent */
// "/*/" comments.
goto_prev = FALSE; /* Set it to FALSE or every
* thing from here will be / */
} else
printw("%c", ch);
refresh();
if(prev == '*' && ch == '/')
attroff(A_BOLD); /* Switch it off once we got *
and then / */
prev = ch;
}
getch();
endwin(); /* End curses mode */
return 0;
} |
A_NORMAL Normal display (no highlight)
A_STANDOUT Best highlighting mode of the terminal.
A_UNDERLINE Underlining
A_REVERSE Reverse video
A_BLINK Blinking
A_DIM Half bright
A_BOLD Extra bright or bold
A_PROTECT Protected mode
A_INVIS Invisible or blank mode
A_ALTCHARSET Alternate character set
A_CHARTEXT Bit-mask to extract a character
COLOR_PAIR(n) Color-pair number n
|
The last one is the most colorful one :-) Colors are explained in the next sections.
We can OR(|) any number of above attributes to get a combined effect. If you wanted reverse video with blinking characters you can use
attron(A_REVERSE | A_BLINK); |
chgat(-1, A_REVERSE, 0, NULL); |
Example 6. Chgat() Usage example
#include <ncurses.h>
int main(int argc, char *argv[])
{ initscr(); /* Start curses mode */
start_color(); /* Start color functionality */
init_pair(1, COLOR_CYAN, COLOR_BLACK);
printw("A Big string which i didn't care to type fully ");
mvchgat(0, 0, -1, A_BLINK, 1, NULL);
/*
* First two parameters specify the position at which to start
* Third parameter number of characters to update. -1 means till
* end of line
* Forth parameter is the normal attribute you wanted to give
* to the charcter
* Fifth is the color index. It is the index given during init_pair()
* use 0 if you didn't want color
* Sixth one is always NULL
*/
refresh();
getch();
endwin(); /* End curses mode */
return 0;
} |
Example 7. Window Border example
#include <ncurses.h>
WINDOW *create_newwin(int height, int width, int starty, int startx);
void destroy_win(WINDOW *local_win);
int main(int argc, char *argv[])
{ WINDOW *my_win;
int startx, starty, width, height;
int ch;
initscr(); /* Start curses mode */
cbreak(); /* Line buffering disabled, Pass on
* everty thing to me */
keypad(stdscr, TRUE); /* I need that nifty F1 */
height = 3;
width = 10;
starty = (LINES - height) / 2; /* Calculating for a center placement */
startx = (COLS - width) / 2; /* of the window */
printw("Press F1 to exit");
refresh();
my_win = create_newwin(height, width, starty, startx);
while((ch = getch()) != KEY_F(1))
{ switch(ch)
{ case KEY_LEFT:
destroy_win(my_win);
my_win = create_newwin(height, width, starty,--startx);
break;
case KEY_RIGHT:
destroy_win(my_win);
my_win = create_newwin(height, width, starty,++startx);
break;
case KEY_UP:
destroy_win(my_win);
my_win = create_newwin(height, width, --starty,startx);
break;
case KEY_DOWN:
destroy_win(my_win);
my_win = create_newwin(height, width, ++starty,startx);
break;
}
}
endwin(); /* End curses mode */
return 0;
}
WINDOW *create_newwin(int height, int width, int starty, int startx)
{ WINDOW *local_win;
local_win = newwin(height, width, starty, startx);
box(local_win, 0 , 0); /* 0, 0 gives default characters
* for the vertical and horizontal
* lines */
wrefresh(local_win); /* Show that box */
return local_win;
}
void destroy_win(WINDOW *local_win)
{
/* box(local_win, ' ', ' '); : This won't produce the desired
* result of erasing the window. It will leave it's four corners
* and so an ugly remnant of window.
*/
wborder(local_win, ' ', ' ', ' ',' ',' ',' ',' ',' ');
/* The parameters taken are
* 1. win: the window on which to operate
* 2. ls: character to be used for the left side of the window
* 3. rs: character to be used for the right side of the window
* 4. ts: character to be used for the top side of the window
* 5. bs: character to be used for the bottom side of the window
* 6. tl: character to be used for the top left corner of the window
* 7. tr: character to be used for the top right corner of the window
* 8. bl: character to be used for the bottom left corner of the window
* 9. br: character to be used for the bottom right corner of the window
*/
wrefresh(local_win);
delwin(local_win);
} |
wborder(win, '|', '|', '-', '-', '+', '+', '+', '+'); |
+-----------------------+
| |
| |
| |
| |
| |
| |
+-----------------------+ |
Example 8. More border functions
#include <ncurses.h>
typedef struct _win_border_struct {
chtype ls, rs, ts, bs,
tl, tr, bl, br;
}WIN_BORDER;
typedef struct _WIN_struct {
int startx, starty;
int height, width;
WIN_BORDER border;
}WIN;
void init_win_params(WIN *p_win);
void print_win_params(WIN *p_win);
void create_box(WIN *win, int bool);
int main(int argc, char *argv[])
{ WIN win;
int ch;
initscr(); /* Start curses mode */
start_color(); /* Start the color functionality */
cbreak(); /* Line buffering disabled, Pass on
* everty thing to me */
keypad(stdscr, TRUE); /* I need that nifty F1 */
noecho();
init_pair(1, COLOR_CYAN, COLOR_BLACK);
/* Initialize the window parameters */
init_win_params(&win);
print_win_params(&win);
attron(COLOR_PAIR(1));
printw("Press F1 to exit");
refresh();
attroff(COLOR_PAIR(1));
create_box(&win, TRUE);
while((ch = getch()) != KEY_F(1))
{ switch(ch)
{ case KEY_LEFT:
create_box(&win, FALSE);
--win.startx;
create_box(&win, TRUE);
break;
case KEY_RIGHT:
create_box(&win, FALSE);
++win.startx;
create_box(&win, TRUE);
break;
case KEY_UP:
create_box(&win, FALSE);
--win.starty;
create_box(&win, TRUE);
break;
case KEY_DOWN:
create_box(&win, FALSE);
++win.starty;
create_box(&win, TRUE);
break;
}
}
endwin(); /* End curses mode */
return 0;
}
void init_win_params(WIN *p_win)
{
p_win->height = 3;
p_win->width = 10;
p_win->starty = (LINES - p_win->height)/2;
p_win->startx = (COLS - p_win->width)/2;
p_win->border.ls = '|';
p_win->border.rs = '|';
p_win->border.ts = '-';
p_win->border.bs = '-';
p_win->border.tl = '+';
p_win->border.tr = '+';
p_win->border.bl = '+';
p_win->border.br = '+';
}
void print_win_params(WIN *p_win)
{
#ifdef _DEBUG
mvprintw(25, 0, "%d %d %d %d", p_win->startx, p_win->starty,
p_win->width, p_win->height);
refresh();
#endif
}
void create_box(WIN *p_win, int bool)
{ int i, j;
int x, y, w, h;
x = p_win->startx;
y = p_win->starty;
w = p_win->width;
h = p_win->height;
if(bool == TRUE)
{ mvaddch(y, x, p_win->border.tl);
mvaddch(y, x + w, p_win->border.tr);
mvaddch(y + h, x, p_win->border.bl);
mvaddch(y + h, x + w, p_win->border.br);
mvhline(y, x + 1, p_win->border.ts, w - 1);
mvhline(y + h, x + 1, p_win->border.bs, w - 1);
mvvline(y + 1, x, p_win->border.ls, h - 1);
mvvline(y + 1, x + w, p_win->border.rs, h - 1);
}
else
for(j = y; j <= y + h; ++j)
for(i = x; i <= x + w; ++i)
mvaddch(j, i, ' ');
refresh();
}
|
Example 9. A Simple Color example
#include <ncurses.h>
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string);
int main(int argc, char *argv[])
{ initscr(); /* Start curses mode */
if(has_colors() == FALSE)
{ endwin();
printf("You terminal does not support color\n");
exit(1);
}
start_color(); /* Start color */
init_pair(1, COLOR_RED, COLOR_BLACK);
attron(COLOR_PAIR(1));
print_in_middle(stdscr, LINES / 2, 0, 0, "Viola !!! In color ...");
attroff(COLOR_PAIR(1));
getch();
endwin();
}
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string)
{ int length, x, y;
float temp;
if(win == NULL)
win = stdscr;
getyx(win, y, x);
if(startx != 0)
x = startx;
if(starty != 0)
y = starty;
if(width == 0)
width = 80;
length = strlen(string);
temp = (width - length)/ 2;
x = startx + (int)temp;
mvwprintw(win, y, x, "%s", string);
refresh();
}
|
COLOR_BLACK 0
COLOR_RED 1
COLOR_GREEN 2
COLOR_YELLOW 3
COLOR_BLUE 4
COLOR_MAGENTA 5
COLOR_CYAN 6
COLOR_WHITE 7 |
init_color(COLOR_RED, 700, 0, 0);
/* param 1 : color name
* param 2, 3, 4 : rgb content min = 0, max = 1000 */ |
For example, if you call getch() like this
int ch;
ch = getch(); |
The following code piece will do that job.
if(ch == KEY_LEFT)
printw("Left arrow is pressed\n"); |
Let's write a small program which creates a menu which can be navigated by up and down arrows.
Example 10. A Simple Key Usage example
#include <stdio.h>
#include <ncurses.h>
#define WIDTH 30
#define HEIGHT 10
int startx = 0;
int starty = 0;
char *choices[] = {
"Choice 1",
"Choice 2",
"Choice 3",
"Choice 4",
"Exit",
};
int n_choices = sizeof(choices) / sizeof(char *);
void print_menu(WINDOW *menu_win, int highlight);
int main()
{ WINDOW *menu_win;
int highlight = 1;
int choice = 0;
int c;
initscr();
clear();
noecho();
cbreak(); /* Line buffering disabled. pass on everything */
startx = (80 - WIDTH) / 2;
starty = (24 - HEIGHT) / 2;
menu_win = newwin(HEIGHT, WIDTH, starty, startx);
keypad(menu_win, TRUE);
mvprintw(0, 0, "Use arrow keys to go up and down, Press enter to select a choice");
refresh();
print_menu(menu_win, highlight);
while(1)
{ c = wgetch(menu_win);
switch(c)
{ case KEY_UP:
if(highlight == 1)
highlight = n_choices;
else
--highlight;
break;
case KEY_DOWN:
if(highlight == n_choices)
highlight = 1;
else
++highlight;
break;
case 10:
choice = highlight;
break;
default:
mvprintw(24, 0, "Charcter pressed is = %3d Hopefully it can be printed as '%c'", c, c);
refresh();
break;
}
print_menu(menu_win, highlight);
if(choice != 0) /* User did a choice come out of the infinite loop */
break;
}
mvprintw(23, 0, "You chose choice %d with choice string %s\n", choice, choices[choice - 1]);
clrtoeol();
refresh();
endwin();
return 0;
}
void print_menu(WINDOW *menu_win, int highlight)
{
int x, y, i;
x = 2;
y = 2;
box(menu_win, 0, 0);
for(i = 0; i < n_choices; ++i)
{ if(highlight == i + 1) /* High light the present choice */
{ wattron(menu_win, A_REVERSE);
mvwprintw(menu_win, y, x, "%s", choices[i]);
wattroff(menu_win, A_REVERSE);
}
else
mvwprintw(menu_win, y, x, "%s", choices[i]);
++y;
}
wrefresh(menu_win);
}
|
Before you do any thing else, the events you want to receive have to be enabled with mousemask().
mousemask( mmask_t newmask, /* The events you want to listen to */
mmask_t *oldmask) /* The old events mask */ |
The following are all the event masks:
Name Description
---------------------------------------------------------------------
BUTTON1_PRESSED mouse button 1 down
BUTTON1_RELEASED mouse button 1 up
BUTTON1_CLICKED mouse button 1 clicked
BUTTON1_DOUBLE_CLICKED mouse button 1 double clicked
BUTTON1_TRIPLE_CLICKED mouse button 1 triple clicked
BUTTON2_PRESSED mouse button 2 down
BUTTON2_RELEASED mouse button 2 up
BUTTON2_CLICKED mouse button 2 clicked
BUTTON2_DOUBLE_CLICKED mouse button 2 double clicked
BUTTON2_TRIPLE_CLICKED mouse button 2 triple clicked
BUTTON3_PRESSED mouse button 3 down
BUTTON3_RELEASED mouse button 3 up
BUTTON3_CLICKED mouse button 3 clicked
BUTTON3_DOUBLE_CLICKED mouse button 3 double clicked
BUTTON3_TRIPLE_CLICKED mouse button 3 triple clicked
BUTTON4_PRESSED mouse button 4 down
BUTTON4_RELEASED mouse button 4 up
BUTTON4_CLICKED mouse button 4 clicked
BUTTON4_DOUBLE_CLICKED mouse button 4 double clicked
BUTTON4_TRIPLE_CLICKED mouse button 4 triple clicked
BUTTON_SHIFT shift was down during button state change
BUTTON_CTRL control was down during button state change
BUTTON_ALT alt was down during button state change
ALL_MOUSE_EVENTS report all button state changes
REPORT_MOUSE_POSITION report mouse movement |
The code approximately looks like this:
MEVENT event;
ch = getch();
if(ch == KEY_MOUSE)
if(getmouse(&event) == OK)
. /* Do some thing with the event */
.
. |
getmouse() returns the event into the pointer given to it. It's a structure which contains
typedef struct
{
short id; /* ID to distinguish multiple devices */
int x, y, z; /* event coordinates */
mmask_t bstate; /* button state bits */
} |
The bstate is the main variable we are interested in. It tells the button state of the mouse.
Then with a code snippet like the following, we can find out what happened.
if(event.bstate & BUTTON1_PRESSED)
printw("Left Button Pressed"); |
Example 11. Access the menu with mouse !!!
#include <ncurses.h>
#define WIDTH 30
#define HEIGHT 10
int startx = 0;
int starty = 0;
char *choices[] = { "Choice 1",
"Choice 2",
"Choice 3",
"Choice 4",
"Exit",
};
int n_choices = sizeof(choices) / sizeof(char *);
void print_menu(WINDOW *menu_win, int highlight);
void report_choice(int mouse_x, int mouse_y, int *p_choice);
int main()
{ int c, choice = 0;
WINDOW *menu_win;
MEVENT event;
/* Initialize curses */
initscr();
clear();
noecho();
cbreak(); //Line buffering disabled. pass on everything
/* Try to put the window in the middle of screen */
startx = (80 - WIDTH) / 2;
starty = (24 - HEIGHT) / 2;
attron(A_REVERSE);
mvprintw(23, 1, "Click on Exit to quit (Works best in a virtual console)");
refresh();
attroff(A_REVERSE);
/* Print the menu for the first time */
menu_win = newwin(HEIGHT, WIDTH, starty, startx);
print_menu(menu_win, 1);
/* Get all the mouse events */
mousemask(ALL_MOUSE_EVENTS, NULL);
while(1)
{ c = wgetch(menu_win);
switch(c)
{ case KEY_MOUSE:
if(getmouse(&event) == OK)
{ /* When the user clicks left mouse button */
if(event.bstate & BUTTON1_PRESSED)
{ report_choice(event.x + 1, event.y + 1, &choice);
if(choice == -1) //Exit chosen
goto end;
mvprintw(22, 1, "Choice made is : %d String Chosen is \"%10s\"", choice, choices[choice - 1]);
refresh();
}
}
print_menu(menu_win, choice);
break;
}
}
end:
endwin();
return 0;
}
void print_menu(WINDOW *menu_win, int highlight)
{
int x, y, i;
x = 2;
y = 2;
box(menu_win, 0, 0);
for(i = 0; i < n_choices; ++i)
{ if(highlight == i + 1)
{ wattron(menu_win, A_REVERSE);
mvwprintw(menu_win, y, x, "%s", choices[i]);
wattroff(menu_win, A_REVERSE);
}
else
mvwprintw(menu_win, y, x, "%s", choices[i]);
++y;
}
wrefresh(menu_win);
}
/* Report the choice according to mouse position */
void report_choice(int mouse_x, int mouse_y, int *p_choice)
{ int i,j, choice;
i = startx + 2;
j = starty + 3;
for(choice = 0; choice < n_choices; ++choice)
if(mouse_y == j + choice && mouse_x >= i && mouse_x <= i + strlen(choices[choice]))
{ if(choice == n_choices - 1)
*p_choice = -1;
else
*p_choice = choice + 1;
break;
}
} |
getyx(win, y, x);
/* win: window pointer
* y, x: y, x co-ordinates will be put into this variables
*/ |
This function can be used to make the cursor invisible. The parameter to this function should be
0 : invisible or
1 : normal or
2 : very visible. |
Example 12. Temporarily Leaving Curses Mode
#include <ncurses.h>
int main()
{
initscr(); /* Start curses mode */
printw("Hello World !!!\n"); /* Print Hello World */
refresh(); /* Print it on to the real screen */
def_prog_mode(); /* Save the tty modes */
endwin(); /* End curses mode temporarily */
system("/bin/sh"); /* Do whatever you like in cooked mode */
reset_prog_mode(); /* Return to the previous tty mode*/
/* stored by def_prog_mode() */
refresh(); /* Do refresh() to restore the */
/* Screen contents */
printw("Another String\n"); /* Back to curses use the full */
refresh(); /* capabilities of curses */
endwin(); /* End curses mode */
return 0;
} |
Example 13. ACS Variables Example
#include <ncurses.h>
int main()
{
initscr();
printw("Upper left corner "); addch(ACS_ULCORNER); printw("\n");
printw("Lower left corner "); addch(ACS_LLCORNER); printw("\n");
printw("Lower right corner "); addch(ACS_LRCORNER); printw("\n");
printw("Tee pointing right "); addch(ACS_LTEE); printw("\n");
printw("Tee pointing left "); addch(ACS_RTEE); printw("\n");
printw("Tee pointing up "); addch(ACS_BTEE); printw("\n");
printw("Tee pointing down "); addch(ACS_TTEE); printw("\n");
printw("Horizontal line "); addch(ACS_HLINE); printw("\n");
printw("Vertical line "); addch(ACS_VLINE); printw("\n");
printw("Large Plus or cross over "); addch(ACS_PLUS); printw("\n");
printw("Scan Line 1 "); addch(ACS_S1); printw("\n");
printw("Scan Line 3 "); addch(ACS_S3); printw("\n");
printw("Scan Line 7 "); addch(ACS_S7); printw("\n");
printw("Scan Line 9 "); addch(ACS_S9); printw("\n");
printw("Diamond "); addch(ACS_DIAMOND); printw("\n");
printw("Checker board (stipple) "); addch(ACS_CKBOARD); printw("\n");
printw("Degree Symbol "); addch(ACS_DEGREE); printw("\n");
printw("Plus/Minus Symbol "); addch(ACS_PLMINUS); printw("\n");
printw("Bullet "); addch(ACS_BULLET); printw("\n");
printw("Arrow Pointing Left "); addch(ACS_LARROW); printw("\n");
printw("Arrow Pointing Right "); addch(ACS_RARROW); printw("\n");
printw("Arrow Pointing Down "); addch(ACS_DARROW); printw("\n");
printw("Arrow Pointing Up "); addch(ACS_UARROW); printw("\n");
printw("Board of squares "); addch(ACS_BOARD); printw("\n");
printw("Lantern Symbol "); addch(ACS_LANTERN); printw("\n");
printw("Solid Square Block "); addch(ACS_BLOCK); printw("\n");
printw("Less/Equal sign "); addch(ACS_LEQUAL); printw("\n");
printw("Greater/Equal sign "); addch(ACS_GEQUAL); printw("\n");
printw("Pi "); addch(ACS_PI); printw("\n");
printw("Not equal "); addch(ACS_NEQUAL); printw("\n");
printw("UK pound sign "); addch(ACS_STERLING); printw("\n");
refresh();
getch();
endwin();
return 0;
} |
#include <panel.h>
.
.
.
compile and link: gcc <program file> -lpanel -lncurses |
Example 14. Panel basics
#include <panel.h>
int main()
{ WINDOW *my_wins[3];
PANEL *my_panels[3];
int lines = 10, cols = 40, y = 2, x = 4, i;
initscr();
cbreak();
noecho();
/* Create windows for the panels */
my_wins[0] = newwin(lines, cols, y, x);
my_wins[1] = newwin(lines, cols, y + 1, x + 5);
my_wins[2] = newwin(lines, cols, y + 2, x + 10);
/*
* Create borders around the windows so that you can see the effect
* of panels
*/
for(i = 0; i < 3; +++i)
box(my_wins[i], 0, 0);
/* Attach a panel to each window */ /* Order is bottom up */
my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
/* Update the stacking order. 2nd panel will be on top */
update_panels();
/* Show it on the screen */
doupdate();
getch();
endwin();
}
|
Example 15. Panel Window Browsing Example
#include <panel.h>
#define NLINES 10
#define NCOLS 40
void init_wins(WINDOW **wins, int n);
void win_show(WINDOW *win, char *label, int label_color);
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
int main()
{ WINDOW *my_wins[3];
PANEL *my_panels[3];
PANEL *top;
int ch;
/* Initialize curses */
initscr();
start_color();
cbreak();
noecho();
keypad(stdscr, TRUE);
/* Initialize all the colors */
init_pair(1, COLOR_RED, COLOR_BLACK);
init_pair(2, COLOR_GREEN, COLOR_BLACK);
init_pair(3, COLOR_BLUE, COLOR_BLACK);
init_pair(4, COLOR_CYAN, COLOR_BLACK);
init_wins(my_wins, 3);
/* Attach a panel to each window */ /* Order is bottom up */
my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
/* Set up the user pointers to the next panel */
set_panel_userptr(my_panels[0], my_panels[1]);
set_panel_userptr(my_panels[1], my_panels[2]);
set_panel_userptr(my_panels[2], my_panels[0]);
/* Update the stacking order. 2nd panel will be on top */
update_panels();
/* Show it on the screen */
attron(COLOR_PAIR(4));
mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)");
attroff(COLOR_PAIR(4));
doupdate();
top = my_panels[2];
while((ch = getch()) != KEY_F(1))
{ switch(ch)
{ case 9:
top = (PANEL *)panel_userptr(top);
top_panel(top);
break;
}
update_panels();
doupdate();
}
endwin();
return 0;
}
/* Put all the windows */
void init_wins(WINDOW **wins, int n)
{ int x, y, i;
char label[80];
y = 2;
x = 10;
for(i = 0; i < n; ++i)
{ wins[i] = newwin(NLINES, NCOLS, y, x);
sprintf(label, "Window Number %d", i + 1);
win_show(wins[i], label, i + 1);
y += 3;
x += 7;
}
}
/* Show the window with a border and a label */
void win_show(WINDOW *win, char *label, int label_color)
{ int startx, starty, height, width;
getbegyx(win, starty, startx);
getmaxyx(win, height, width);
box(win, 0, 0);
mvwaddch(win, 2, 0, ACS_LTEE);
mvwhline(win, 2, 1, ACS_HLINE, width - 2);
mvwaddch(win, 2, width - 1, ACS_RTEE);
print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color));
}
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
{ int length, x, y;
float temp;
if(win == NULL)
win = stdscr;
getyx(win, y, x);
if(startx != 0)
x = startx;
if(starty != 0)
y = starty;
if(width == 0)
width = 80;
length = strlen(string);
temp = (width - length)/ 2;
x = startx + (int)temp;
wattron(win, color);
mvwprintw(win, y, x, "%s", string);
wattroff(win, color);
refresh();
} |
Example 16. Panel Moving and Resizing example
#include <panel.h>
typedef struct _PANEL_DATA {
int x, y, w, h;
char label[80];
int label_color;
PANEL *next;
}PANEL_DATA;
#define NLINES 10
#define NCOLS 40
void init_wins(WINDOW **wins, int n);
void win_show(WINDOW *win, char *label, int label_color);
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
void set_user_ptrs(PANEL **panels, int n);
int main()
{ WINDOW *my_wins[3];
PANEL *my_panels[3];
PANEL_DATA *top;
PANEL *stack_top;
WINDOW *temp_win, *old_win;
int ch;
int newx, newy, neww, newh;
int size = FALSE, move = FALSE;
/* Initialize curses */
initscr();
start_color();
cbreak();
noecho();
keypad(stdscr, TRUE);
/* Initialize all the colors */
init_pair(1, COLOR_RED, COLOR_BLACK);
init_pair(2, COLOR_GREEN, COLOR_BLACK);
init_pair(3, COLOR_BLUE, COLOR_BLACK);
init_pair(4, COLOR_CYAN, COLOR_BLACK);
init_wins(my_wins, 3);
/* Attach a panel to each window */ /* Order is bottom up */
my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
set_user_ptrs(my_panels, 3);
/* Update the stacking order. 2nd panel will be on top */
update_panels();
/* Show it on the screen */
attron(COLOR_PAIR(4));
mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing");
mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)");
attroff(COLOR_PAIR(4));
doupdate();
stack_top = my_panels[2];
top = (PANEL_DATA *)panel_userptr(stack_top);
newx = top->x;
newy = top->y;
neww = top->w;
newh = top->h;
while((ch = getch()) != KEY_F(1))
{ switch(ch)
{ case 9: /* Tab */
top = (PANEL_DATA *)panel_userptr(stack_top);
top_panel(top->next);
stack_top = top->next;
top = (PANEL_DATA *)panel_userptr(stack_top);
newx = top->x;
newy = top->y;
neww = top->w;
newh = top->h;
break;
case 'r': /* Re-Size*/
size = TRUE;
attron(COLOR_PAIR(4));
mvprintw(LINES - 4, 0, "Entered Resizing :Use Arrow Keys to resize and press <ENTER> to end resizing");
refresh();
attroff(COLOR_PAIR(4));
break;
case 'm': /* Move */
attron(COLOR_PAIR(4));
mvprintw(LINES - 4, 0, "Entered Moving: Use Arrow Keys to Move and press <ENTER> to end moving");
refresh();
attroff(COLOR_PAIR(4));
move = TRUE;
break;
case KEY_LEFT:
if(size == TRUE)
{ --newx;
++neww;
}
if(move == TRUE)
--newx;
break;
case KEY_RIGHT:
if(size == TRUE)
{ ++newx;
--neww;
}
if(move == TRUE)
++newx;
break;
case KEY_UP:
if(size == TRUE)
{ --newy;
++newh;
}
if(move == TRUE)
--newy;
break;
case KEY_DOWN:
if(size == TRUE)
{ ++newy;
--newh;
}
if(move == TRUE)
++newy;
break;
case 10: /* Enter */
move(LINES - 4, 0);
clrtoeol();
refresh();
if(size == TRUE)
{ old_win = panel_window(stack_top);
temp_win = newwin(newh, neww, newy, newx);
replace_panel(stack_top, temp_win);
win_show(temp_win, top->label, top->label_color);
delwin(old_win);
size = FALSE;
}
if(move == TRUE)
{ move_panel(stack_top, newy, newx);
move = FALSE;
}
break;
}
attron(COLOR_PAIR(4));
mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing");
mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)");
attroff(COLOR_PAIR(4));
refresh();
update_panels();
doupdate();
}
endwin();
return 0;
}
/* Put all the windows */
void init_wins(WINDOW **wins, int n)
{ int x, y, i;
char label[80];
y = 2;
x = 10;
for(i = 0; i < n; ++i)
{ wins[i] = newwin(NLINES, NCOLS, y, x);
sprintf(label, "Window Number %d", i + 1);
win_show(wins[i], label, i + 1);
y += 3;
x += 7;
}
}
/* Set the PANEL_DATA structures for individual panels */
void set_user_ptrs(PANEL **panels, int n)
{ PANEL_DATA *ptrs;
WINDOW *win;
int x, y, w, h, i;
char temp[80];
ptrs = (PANEL_DATA *)calloc(n, sizeof(PANEL_DATA));
for(i = 0;i < n; ++i)
{ win = panel_window(panels[i]);
getbegyx(win, y, x);
getmaxyx(win, h, w);
ptrs[i].x = x;
ptrs[i].y = y;
ptrs[i].w = w;
ptrs[i].h = h;
sprintf(temp, "Window Number %d", i + 1);
strcpy(ptrs[i].label, temp);
ptrs[i].label_color = i + 1;
if(i + 1 == n)
ptrs[i].next = panels[0];
else
ptrs[i].next = panels[i + 1];
set_panel_userptr(panels[i], &ptrs[i]);
}
}
/* Show the window with a border and a label */
void win_show(WINDOW *win, char *label, int label_color)
{ int startx, starty, height, width;
getbegyx(win, starty, startx);
getmaxyx(win, height, width);
box(win, 0, 0);
mvwaddch(win, 2, 0, ACS_LTEE);
mvwhline(win, 2, 1, ACS_HLINE, width - 2);
mvwaddch(win, 2, width - 1, ACS_RTEE);
print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color));
}
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
{ int length, x, y;
float temp;
if(win == NULL)
win = stdscr;
getyx(win, y, x);
if(startx != 0)
x = startx;
if(starty != 0)
y = starty;
if(width == 0)
width = 80;
length = strlen(string);
temp = (width - length)/ 2;
x = startx + (int)temp;
wattron(win, color);
mvwprintw(win, y, x, "%s", string);
wattroff(win, color);
refresh();
} |
The following program shows the hiding of panels. Press 'a' or 'b' or 'c' to show or hide first, second and third windows respectively. It uses a user data with a small variable hide, which keeps track of whether the window is hidden or not. For some reason the function panel_hidden() which tells whether a panel is hidden or not is not working. A bug report was also presented by Michael Andres here
Example 17. Panel Hiding and Showing example
#include <panel.h>
typedef struct _PANEL_DATA {
int hide; /* TRUE if panel is hidden */
}PANEL_DATA;
#define NLINES 10
#define NCOLS 40
void init_wins(WINDOW **wins, int n);
void win_show(WINDOW *win, char *label, int label_color);
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
int main()
{ WINDOW *my_wins[3];
PANEL *my_panels[3];
PANEL_DATA panel_datas[3];
PANEL_DATA *temp;
int ch;
/* Initialize curses */
initscr();
start_color();
cbreak();
noecho();
keypad(stdscr, TRUE);
/* Initialize all the colors */
init_pair(1, COLOR_RED, COLOR_BLACK);
init_pair(2, COLOR_GREEN, COLOR_BLACK);
init_pair(3, COLOR_BLUE, COLOR_BLACK);
init_pair(4, COLOR_CYAN, COLOR_BLACK);
init_wins(my_wins, 3);
/* Attach a panel to each window */ /* Order is bottom up */
my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
/* Initialize panel datas saying that nothing is hidden */
panel_datas[0].hide = FALSE;
panel_datas[1].hide = FALSE;
panel_datas[2].hide = FALSE;
set_panel_userptr(my_panels[0], &panel_datas[0]);
set_panel_userptr(my_panels[1], &panel_datas[1]);
set_panel_userptr(my_panels[2], &panel_datas[2]);
/* Update the stacking order. 2nd panel will be on top */
update_panels();
/* Show it on the screen */
attron(COLOR_PAIR(4));
mvprintw(LINES - 3, 0, "Show or Hide a window with 'a'(first window) 'b'(Second Window) 'c'(Third Window)");
mvprintw(LINES - 2, 0, "F1 to Exit");
attroff(COLOR_PAIR(4));
doupdate();
while((ch = getch()) != KEY_F(1))
{ switch(ch)
{ case 'a':
temp = (PANEL_DATA *)panel_userptr(my_panels[0]);
if(temp->hide == FALSE)
{ hide_panel(my_panels[0]);
temp->hide = TRUE;
}
else
{ show_panel(my_panels[0]);
temp->hide = FALSE;
}
break;
case 'b':
temp = (PANEL_DATA *)panel_userptr(my_panels[1]);
if(temp->hide == FALSE)
{ hide_panel(my_panels[1]);
temp->hide = TRUE;
}
else
{ show_panel(my_panels[1]);
temp->hide = FALSE;
}
break;
case 'c':
temp = (PANEL_DATA *)panel_userptr(my_panels[2]);
if(temp->hide == FALSE)
{ hide_panel(my_panels[2]);
temp->hide = TRUE;
}
else
{ show_panel(my_panels[2]);
temp->hide = FALSE;
}
break;
}
update_panels();
doupdate();
}
endwin();
return 0;
}
/* Put all the windows */
void init_wins(WINDOW **wins, int n)
{ int x, y, i;
char label[80];
y = 2;
x = 10;
for(i = 0; i < n; ++i)
{ wins[i] = newwin(NLINES, NCOLS, y, x);
sprintf(label, "Window Number %d", i + 1);
win_show(wins[i], label, i + 1);
y += 3;
x += 7;
}
}
/* Show the window with a border and a label */
void win_show(WINDOW *win, char *label, int label_color)
{ int startx, starty, height, width;
getbegyx(win, starty, startx);
getmaxyx(win, height, width);
box(win, 0, 0);
mvwaddch(win, 2, 0, ACS_LTEE);
mvwhline(win, 2, 1, ACS_HLINE, width - 2);
mvwaddch(win, 2, width - 1, ACS_RTEE);
print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color));
}
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
{ int length, x, y;
float temp;
if(win == NULL)
win = stdscr;
getyx(win, y, x);
if(startx != 0)
x = startx;
if(starty != 0)
y = starty;
if(width == 0)
width = 80;
length = strlen(string);
temp = (width - length)/ 2;
x = startx + (int)temp;
wattron(win, color);
mvwprintw(win, y, x, "%s", string);
wattroff(win, color);
refresh();
} |
The general flow of control of a menu program looks like this.
#include <menu.h>
.
.
.
compile and link: gcc <program file> -lmenu -lncurses |
Example 18. Menu Basics
#include <curses.h>
#include <menu.h>
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
#define CTRLD 4
char *choices[] = {
"Choice 1",
"Choice 2",
"Choice 3",
"Choice 4",
"Exit",
};
int main()
{ ITEM **my_items;
int c;
MENU *my_menu;
int n_choices, i;
ITEM *cur_item;
initscr();
cbreak();
noecho();
keypad(stdscr, TRUE);
n_choices = ARRAY_SIZE(choices);
my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
for(i = 0; i < n_choices; ++i)
my_items[i] = new_item(choices[i], choices[i]);
my_items[n_choices] = (ITEM *)NULL;
my_menu = new_menu((ITEM **)my_items);
mvprintw(LINES - 2, 0, "F1 to Exit");
post_menu(my_menu);
refresh();
while((c = getch()) != KEY_F(1))
{ switch(c)
{ case KEY_DOWN:
menu_driver(my_menu, REQ_DOWN_ITEM);
break;
case KEY_UP:
menu_driver(my_menu, REQ_UP_ITEM);
break;
}
}
free_item(my_items[0]);
free_item(my_items[1]);
free_menu(my_menu);
endwin();
}
|
The menu_driver accepts following navigational requests.
REQ_LEFT_ITEM Move left to an item.
REQ_RIGHT_ITEM Move right to an item.
REQ_UP_ITEM Move up to an item.
REQ_DOWN_ITEM Move down to an item.
REQ_SCR_ULINE Scroll up a line.
REQ_SCR_DLINE Scroll down a line.
REQ_SCR_DPAGE Scroll down a page.
REQ_SCR_UPAGE Scroll up a page.
REQ_FIRST_ITEM Move to the first item.
REQ_LAST_ITEM Move to the last item.
REQ_NEXT_ITEM Move to the next item.
REQ_PREV_ITEM Move to the previous item.
REQ_TOGGLE_ITEM Select/deselect an item.
REQ_CLEAR_PATTERN Clear the menu pattern buffer.
REQ_BACK_PATTERN Delete the previous character from the pattern buffer.
REQ_NEXT_MATCH Move to the next item matching the pattern match.
REQ_PREV_MATCH Move to the previous item matching the pattern match.
|
REQ_FIRST_ITEM, REQ_LAST_ITEM, REQ_NEXT_ITEM and REQ_PREV_ITEM
If the second argument is the KEY_MOUSE special key, the
associated mouse event is translated into one of the above
pre-defined requests. Currently only clicks in the user
window (e.g. inside the menu display area or the decora�
tion window) are handled. If you click above the display
region of the menu, a REQ_SCR_ULINE is generated, if you
doubleclick a REQ_SCR_UPAGE is generated and if you
tripleclick a REQ_FIRST_ITEM is generated. If you click
below the display region of the menu, a REQ_SCR_DLINE is
generated, if you doubleclick a REQ_SCR_DPAGE is generated
and if you tripleclick a REQ_LAST_ITEM is generated. If
you click at an item inside the display area of the menu,
the menu cursor is positioned to that item. |
Example 19. Menu Windows Usage example
#include <menu.h>
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
#define CTRLD 4
char *choices[] = {
"Choice 1",
"Choice 2",
"Choice 3",
"Choice 4",
"Exit",
(char *)NULL,
};
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
int main()
{ ITEM **my_items;
int c;
MENU *my_menu;
WINDOW *my_menu_win;
int n_choices, i;
/* Initialize curses */
initscr();
start_color();
cbreak();
noecho();
keypad(stdscr, TRUE);
init_pair(1, COLOR_RED, COLOR_BLACK);
/* Create items */
n_choices = ARRAY_SIZE(choices);
my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *));
for(i = 0; i < n_choices; ++i)
my_items[i] = new_item(choices[i], choices[i]);
/* Crate menu */
my_menu = new_menu((ITEM **)my_items);
/* Create the window to be associated with the menu */
my_menu_win = newwin(10, 40, 4, 4);
keypad(my_menu_win, TRUE);
/* Set main window and sub window */
set_menu_win(my_menu, my_menu_win);
set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1));
/* Set menu mark to the string " * " */
set_menu_mark(my_menu, " * ");
/* Print a border around the main window and print a title */
box(my_menu_win, 0, 0);
print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1));
mvwaddch(my_menu_win, 2, 0, ACS_LTEE);
mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38);
mvwaddch(my_menu_win, 2, 39, ACS_RTEE);
mvprintw(LINES - 2, 0, "F1 to exit");
refresh();
/* Post the menu */
post_menu(my_menu);
wrefresh(my_menu_win);
while((c = wgetch(my_menu_win)) != KEY_F(1))
{ switch(c)
{ case KEY_DOWN:
menu_driver(my_menu, REQ_DOWN_ITEM);
break;
case KEY_UP:
menu_driver(my_menu, REQ_UP_ITEM);
break;
}
wrefresh(my_menu_win);
}
/* Unpost and free all the memory taken up */
unpost_menu(my_menu);
free_menu(my_menu);
for(i = 0; i < n_choices; ++i)
free_item(my_items[i]);
endwin();
}
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
{ int length, x, y;
float temp;
if(win == NULL)
win = stdscr;
getyx(win, y, x);
if(startx != 0)
x = startx;
if(starty != 0)
y = starty;
if(width == 0)
width = 80;
length = strlen(string);
temp = (width - length)/ 2;
x = startx + (int)temp;
wattron(win, color);
mvwprintw(win, y, x, "%s", string);
wattroff(win, color);
refresh();
} |
Example 20. Scrolling Menus example
#include <curses.h>
#include <menu.h>
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
#define CTRLD 4
char *choices[] = {
"Choice 1",
"Choice 2",
"Choice 3",
"Choice 4",
"Choice 5",
"Choice 6",
"Choice 7",
"Choice 8",
"Choice 9",
"Choice 10",
"Exit",
(char *)NULL,
};
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
int main()
{ ITEM **my_items;
int c;
MENU *my_menu;
WINDOW *my_menu_win;
int n_choices, i;
/* Initialize curses */
initscr();
start_color();
cbreak();
noecho();
keypad(stdscr, TRUE);
init_pair(1, COLOR_RED, COLOR_BLACK);
init_pair(2, COLOR_CYAN, COLOR_BLACK);
/* Create items */
n_choices = ARRAY_SIZE(choices);
my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *));
for(i = 0; i < n_choices; ++i)
my_items[i] = new_item(choices[i], choices[i]);
/* Crate menu */
my_menu = new_menu((ITEM **)my_items);
/* Create the window to be associated with the menu */
my_menu_win = newwin(10, 40, 4, 4);
keypad(my_menu_win, TRUE);
/* Set main window and sub window */
set_menu_win(my_menu, my_menu_win);
set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1));
set_menu_format(my_menu, 5, 1);
/* Set menu mark to the string " * " */
set_menu_mark(my_menu, " * ");
/* Print a border around the main window and print a title */
box(my_menu_win, 0, 0);
print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1));
mvwaddch(my_menu_win, 2, 0, ACS_LTEE);
mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38);
mvwaddch(my_menu_win, 2, 39, ACS_RTEE);
/* Post the menu */
post_menu(my_menu);
wrefresh(my_menu_win);
attron(COLOR_PAIR(2));
mvprintw(LINES - 2, 0, "Use PageUp and PageDown to scoll down or up a page of items");
mvprintw(LINES - 1, 0, "Arrow Keys to navigate (F1 to Exit)");
attroff(COLOR_PAIR(2));
refresh();
while((c = wgetch(my_menu_win)) != KEY_F(1))
{ switch(c)
{ case KEY_DOWN:
menu_driver(my_menu, REQ_DOWN_ITEM);
break;
case KEY_UP:
menu_driver(my_menu, REQ_UP_ITEM);
break;
case KEY_NPAGE:
menu_driver(my_menu, REQ_SCR_DPAGE);
break;
case KEY_PPAGE:
menu_driver(my_menu, REQ_SCR_UPAGE);
break;
}
wrefresh(my_menu_win);
}
/* Unpost and free all the memory taken up */
unpost_menu(my_menu);
free_menu(my_menu);
for(i = 0; i < n_choices; ++i)
free_item(my_items[i]);
endwin();
}
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
{ int length, x, y;
float temp;
if(win == NULL)
win = stdscr;
getyx(win, y, x);
if(startx != 0)
x = startx;
if(starty != 0)
y = starty;
if(width == 0)
width = 80;
length = strlen(string);
temp = (width - length)/ 2;
x = startx + (int)temp;
wattron(win, color);
mvwprintw(win, y, x, "%s", string);
wattroff(win, color);
refresh();
} |
Example 21. Milt Columnar Menus Example
#include <curses.h>
#include <menu.h>
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
#define CTRLD 4
char *choices[] = {
"Choice 1", "Choice 2", "Choice 3", "Choice 4", "Choice 5",
"Choice 6", "Choice 7", "Choice 8", "Choice 9", "Choice 10",
"Choice 11", "Choice 12", "Choice 13", "Choice 14", "Choice 15",
"Choice 16", "Choice 17", "Choice 18", "Choice 19", "Choice 20",
"Exit",
(char *)NULL,
};
int main()
{ ITEM **my_items;
int c;
MENU *my_menu;
WINDOW *my_menu_win;
int n_choices, i;
/* Initialize curses */
initscr();
start_color();
cbreak();
noecho();
keypad(stdscr, TRUE);
init_pair(1, COLOR_RED, COLOR_BLACK);
init_pair(2, COLOR_CYAN, COLOR_BLACK);
/* Create items */
n_choices = ARRAY_SIZE(choices);
my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *));
for(i = 0; i < n_choices; ++i)
my_items[i] = new_item(choices[i], choices[i]);
/* Crate menu */
my_menu = new_menu((ITEM **)my_items);
/* Set menu option not to show the description */
menu_opts_off(my_menu, O_SHOWDESC);
/* Create the window to be associated with the menu */
my_menu_win = newwin(10, 70, 4, 4);
keypad(my_menu_win, TRUE);
/* Set main window and sub window */
set_menu_win(my_menu, my_menu_win);
set_menu_sub(my_menu, derwin(my_menu_win, 6, 68, 3, 1));
set_menu_format(my_menu, 5, 3);
set_menu_mark(my_menu, " * ");
/* Print a border around the main window and print a title */
box(my_menu_win, 0, 0);
attron(COLOR_PAIR(2));
mvprintw(LINES - 3, 0, "Use PageUp and PageDown to scroll");
mvprintw(LINES - 2, 0, "Use Arrow Keys to navigate (F1 to Exit)");
attroff(COLOR_PAIR(2));
refresh();
/* Post the menu */
post_menu(my_menu);
wrefresh(my_menu_win);
while((c = wgetch(my_menu_win)) != KEY_F(1))
{ switch(c)
{ case KEY_DOWN:
menu_driver(my_menu, REQ_DOWN_ITEM);
break;
case KEY_UP:
menu_driver(my_menu, REQ_UP_ITEM);
break;
case KEY_LEFT:
menu_driver(my_menu, REQ_LEFT_ITEM);
break;
case KEY_RIGHT:
menu_driver(my_menu, REQ_RIGHT_ITEM);
break;
case KEY_NPAGE:
menu_driver(my_menu, REQ_SCR_DPAGE);
break;
case KEY_PPAGE:
menu_driver(my_menu, REQ_SCR_UPAGE);
break;
}
wrefresh(my_menu_win);
}
/* Unpost and free all the memory taken up */
unpost_menu(my_menu);
free_menu(my_menu);
for(i = 0; i < n_choices; ++i)
free_item(my_items[i]);
endwin();
} |
O_ONEVALUE
Only one item can be selected for this menu.
O_SHOWDESC
Display the item descriptions when the menu is
posted.
O_ROWMAJOR
Display the menu in row-major order.
O_IGNORECASE
Ignore the case when pattern-matching.
O_SHOWMATCH
Move the cursor to within the item name while pat�
tern-matching.
O_NONCYCLIC
Don't wrap around next-item and previous-item,
requests to the other end of the menu. |
Example 22. Multi Valued Menus example
#include <curses.h>
#include <menu.h>
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
#define CTRLD 4
char *choices[] = {
"Choice 1",
"Choice 2",
"Choice 3",
"Choice 4",
"Choice 5",
"Choice 6",
"Choice 7",
"Exit",
};
int main()
{ ITEM **my_items;
int c;
MENU *my_menu;
int n_choices, i;
ITEM *cur_item;
/* Initialize curses */
initscr();
cbreak();
noecho();
keypad(stdscr, TRUE);
/* Initialize items */
n_choices = ARRAY_SIZE(choices);
my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
for(i = 0; i < n_choices; ++i)
my_items[i] = new_item(choices[i], choices[i]);
my_items[n_choices] = (ITEM *)NULL;
my_menu = new_menu((ITEM **)my_items);
/* Make the menu multi valued */
menu_opts_off(my_menu, O_ONEVALUE);
mvprintw(LINES - 3, 0, "Use <SPACE> to select or unselect an item.");
mvprintw(LINES - 2, 0, "<ENTER> to see presently selected items(F1 to Exit)");
post_menu(my_menu);
refresh();
while((c = getch()) != KEY_F(1))
{ switch(c)
{ case KEY_DOWN:
menu_driver(my_menu, REQ_DOWN_ITEM);
break;
case KEY_UP:
menu_driver(my_menu, REQ_UP_ITEM);
break;
case ' ':
menu_driver(my_menu, REQ_TOGGLE_ITEM);
break;
case 10: /* Enter */
{ char temp[200];
ITEM **items;
items = menu_items(my_menu);
temp[0] = '\0';
for(i = 0; i < item_count(my_menu); ++i)
if(item_value(items[i]) == TRUE)
{ strcat(temp, item_name(items[i]));
strcat(temp, " ");
}
move(20, 0);
clrtoeol();
mvprintw(20, 0, temp);
refresh();
}
break;
}
}
free_item(my_items[0]);
free_item(my_items[1]);
free_menu(my_menu);
endwin();
}
|
Well, by this time you must be itching for some difference in your menu, with lots of functionality. I know. You want Colors !!!. You want to create nice menus similar to those text mode dos games. The functions set_menu_fore() and set_menu_back() can be used to change the attribute of the selected item and unselected item. The names are misleading. They don't change menu's foreground or background which would have been useless.
The function set_menu_grey() can be used to set the display attribute for the non-selectable items in the menu. This brings us to the interesting option for an item the one and only O_SELECTABLE. We can turn it off by the function item_opts_off() and after that that item is not selectable. It's like a grayed item in those fancy windows menus. Let's put these concepts in practice with this example
Example 23. Menu Options example
#include <menu.h>
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
#define CTRLD 4
char *choices[] = {
"Choice 1",
"Choice 2",
"Choice 3",
"Choice 4",
"Choice 5",
"Choice 6",
"Choice 7",
"Exit",
};
int main()
{ ITEM **my_items;
int c;
MENU *my_menu;
int n_choices, i;
ITEM *cur_item;
/* Initialize curses */
initscr();
start_color();
cbreak();
noecho();
keypad(stdscr, TRUE);
init_pair(1, COLOR_RED, COLOR_BLACK);
init_pair(2, COLOR_GREEN, COLOR_BLACK);
init_pair(3, COLOR_MAGENTA, COLOR_BLACK);
/* Initialize items */
n_choices = ARRAY_SIZE(choices);
my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
for(i = 0; i < n_choices; ++i)
my_items[i] = new_item(choices[i], choices[i]);
my_items[n_choices] = (ITEM *)NULL;
item_opts_off(my_items[3], O_SELECTABLE);
item_opts_off(my_items[6], O_SELECTABLE);
/* Create menu */
my_menu = new_menu((ITEM **)my_items);
/* Set fore ground and back ground of the menu */
set_menu_fore(my_menu, COLOR_PAIR(1) | A_REVERSE);
set_menu_back(my_menu, COLOR_PAIR(2));
set_menu_grey(my_menu, COLOR_PAIR(3));
/* Post the menu */
mvprintw(LINES - 3, 0, "Press <ENTER> to see the option selected");
mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)");
post_menu(my_menu);
refresh();
while((c = getch()) != KEY_F(1))
{ switch(c)
{ case KEY_DOWN:
menu_driver(my_menu, REQ_DOWN_ITEM);
break;
case KEY_UP:
menu_driver(my_menu, REQ_UP_ITEM);
break;
case 10: /* Enter */
move(20, 0);
clrtoeol();
mvprintw(20, 0, "Item selected is : %s",
item_name(current_item(my_menu)));
pos_menu_cursor(my_menu);
break;
}
}
unpost_menu(my_menu);
for(i = 0; i < n_choices; ++i)
free_item(my_items[i]);
free_menu(my_menu);
endwin();
}
|
Example 24. Menu User Pointer Usage
#include <curses.h>
#include <menu.h>
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
#define CTRLD 4
char *choices[] = {
"Choice 1",
"Choice 2",
"Choice 3",
"Choice 4",
"Choice 5",
"Choice 6",
"Choice 7",
"Exit",
};
void func(char *name);
int main()
{ ITEM **my_items;
int c;
MENU *my_menu;
int n_choices, i;
ITEM *cur_item;
/* Initialize curses */
initscr();
start_color();
cbreak();
noecho();
keypad(stdscr, TRUE);
init_pair(1, COLOR_RED, COLOR_BLACK);
init_pair(2, COLOR_GREEN, COLOR_BLACK);
init_pair(3, COLOR_MAGENTA, COLOR_BLACK);
/* Initialize items */
n_choices = ARRAY_SIZE(choices);
my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
for(i = 0; i < n_choices; ++i)
{ my_items[i] = new_item(choices[i], choices[i]);
/* Set the user pointer */
set_item_userptr(my_items[i], func);
}
my_items[n_choices] = (ITEM *)NULL;
/* Create menu */
my_menu = new_menu((ITEM **)my_items);
/* Post the menu */
mvprintw(LINES - 3, 0, "Press <ENTER> to see the option selected");
mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)");
post_menu(my_menu);
refresh();
while((c = getch()) != KEY_F(1))
{ switch(c)
{ case KEY_DOWN:
menu_driver(my_menu, REQ_DOWN_ITEM);
break;
case KEY_UP:
menu_driver(my_menu, REQ_UP_ITEM);
break;
case 10: /* Enter */
{ ITEM *cur;
void (*p)(char *);
cur = current_item(my_menu);
p = item_userptr(cur);
p((char *)item_name(cur));
pos_menu_cursor(my_menu);
break;
}
break;
}
}
unpost_menu(my_menu);
for(i = 0; i < n_choices; ++i)
free_item(my_items[i]);
free_menu(my_menu);
endwin();
}
void func(char *name)
{ move(20, 0);
clrtoeol();
mvprintw(20, 0, "Item selected is : %s", name);
} |
The general flow of control of a forms program looks like this.
#include <form.h>
.
.
.
compile and link: gcc <program file> -lform -lncurses |
Example 25. Forms Basics
#include <form.h>
int main()
{ FIELD *field[3];
FORM *my_form;
int ch;
/* Initialize curses */
initscr();
cbreak();
noecho();
keypad(stdscr, TRUE);
/* Initialize the fields */
field[0] = new_field(1, 10, 4, 18, 0, 0);
field[1] = new_field(1, 10, 6, 18, 0, 0);
field[2] = NULL;
/* Set field options */
set_field_back(field[0], A_UNDERLINE); /* Print a line for the option */
field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */
/* Field is filled up */
set_field_back(field[1], A_UNDERLINE);
field_opts_off(field[1], O_AUTOSKIP);
/* Create the form and post it */
my_form = new_form(field);
post_form(my_form);
refresh();
mvprintw(4, 10, "Value 1:");
mvprintw(6, 10, "Value 2:");
refresh();
/* Loop through to get user requests */
while((ch = getch()) != KEY_F(1))
{ switch(ch)
{ case KEY_DOWN:
/* Go to next field */
form_driver(my_form, REQ_NEXT_FIELD);
/* Go to the end of the present buffer */
/* Leaves nicely at the last character */
form_driver(my_form, REQ_END_LINE);
break;
case KEY_UP:
/* Go to previous field */
form_driver(my_form, REQ_PREV_FIELD);
form_driver(my_form, REQ_END_LINE);
break;
default:
/* If this is a normal character, it gets */
/* Printed */
form_driver(my_form, ch);
break;
}
}
/* Un post form and free the memory */
unpost_form(my_form);
free_form(my_form);
free_field(field[0]);
free_field(field[1]);
endwin();
return 0;
} |
int field_info( FIELD *field, /* field from which to fetch */
int *height, *int width, /* field size */
int *top, int *left, /* upper left corner */
int *offscreen, /* number of offscreen rows */
int *nbuf); /* number of working buffers */ |
The location of the field can be moved to a different position with move_field().
int move_field( FIELD *field, /* field to alter */
int top, int left); /* new upper-left corner */ |
As usual, the changed position can be queried with field_infor().
The justification to be done for the field can be fixed using the function set_field_just().
int set_field_just(FIELD *field, /* field to alter */
int justmode); /* mode to set */
int field_just(FIELD *field); /* fetch justify mode of field */ |
int set_field_fore(FIELD *field, /* field to alter */
chtype attr); /* attribute to set */
chtype field_fore(FIELD *field); /* field to query */
/* returns foreground attribute */
int set_field_back(FIELD *field, /* field to alter */
chtype attr); /* attribute to set */
chtype field_back(FIELD *field); /* field to query */
/* returns background attribute */
int set_field_pad(FIELD *field, /* field to alter */
int pad); /* pad character to set */
chtype field_pad(FIELD *field); /* field to query */
/* returns present pad character */
|
Example 26. Form Attributes example
#include <form.h>
int main()
{ FIELD *field[3];
FORM *my_form;
int ch;
/* Initialize curses */
initscr();
start_color();
cbreak();
noecho();
keypad(stdscr, TRUE);
/* Initialize few color pairs */
init_pair(1, COLOR_WHITE, COLOR_BLUE);
init_pair(2, COLOR_WHITE, COLOR_BLUE);
/* Initialize the fields */
field[0] = new_field(1, 10, 4, 18, 0, 0);
field[1] = new_field(1, 10, 6, 18, 0, 0);
field[2] = NULL;
/* Set field options */
set_field_fore(field[0], COLOR_PAIR(1));/* Put the field with blue background */
set_field_back(field[0], COLOR_PAIR(2));/* and white foreground (characters */
/* are printed in white */
field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */
/* Field is filled up */
set_field_back(field[1], A_UNDERLINE);
field_opts_off(field[1], O_AUTOSKIP);
/* Create the form and post it */
my_form = new_form(field);
post_form(my_form);
refresh();
set_current_field(my_form, field[0]); /* Set focus to the colored field */
mvprintw(4, 10, "Value 1:");
mvprintw(6, 10, "Value 2:");
mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields");
refresh();
/* Loop through to get user requests */
while((ch = getch()) != KEY_F(1))
{ switch(ch)
{ case KEY_DOWN:
/* Go to next field */
form_driver(my_form, REQ_NEXT_FIELD);
/* Go to the end of the present buffer */
/* Leaves nicely at the last character */
form_driver(my_form, REQ_END_LINE);
break;
case KEY_UP:
/* Go to previous field */
form_driver(my_form, REQ_PREV_FIELD);
form_driver(my_form, REQ_END_LINE);
break;
default:
/* If this is a normal character, it gets */
/* Printed */
form_driver(my_form, ch);
break;
}
}
/* Un post form and free the memory */
unpost_form(my_form);
free_form(my_form);
free_field(field[0]);
free_field(field[1]);
endwin();
return 0;
} |
int set_field_opts(FIELD *field, /* field to alter */
int attr); /* attribute to set */
int field_opts_on(FIELD *field, /* field to alter */
int attr); /* attributes to turn on */
int field_opts_off(FIELD *field, /* field to alter */
int attr); /* attributes to turn off */
int field_opts(FIELD *field); /* field to query */ |
Example 27. Field Options Usage example
#include <form.h>
#define STARTX 15
#define STARTY 4
#define WIDTH 25
#define N_FIELDS 3
int main()
{ FIELD *field[N_FIELDS];
FORM *my_form;
int ch, i;
/* Initialize curses */
initscr();
cbreak();
noecho();
keypad(stdscr, TRUE);
/* Initialize the fields */
for(i = 0; i < N_FIELDS - 1; ++i)
field[i] = new_field(1, WIDTH, STARTY + i * 2, STARTX, 0, 0);
field[N_FIELDS - 1] = NULL;
/* Set field options */
set_field_back(field[1], A_UNDERLINE); /* Print a line for the option */
field_opts_off(field[0], O_ACTIVE); /* This field is a static label */
field_opts_off(field[1], O_PUBLIC); /* This filed is like a password field*/
field_opts_off(field[1], O_AUTOSKIP); /* To avoid entering the same field */
/* after last character is entered */
/* Create the form and post it */
my_form = new_form(field);
post_form(my_form);
refresh();
set_field_just(field[0], JUSTIFY_CENTER); /* Center Justification */
set_field_buffer(field[0], 0, "This is a static Field");
/* Initialize the field */
mvprintw(STARTY, STARTX - 10, "Field 1:");
mvprintw(STARTY + 2, STARTX - 10, "Field 2:");
refresh();
/* Loop through to get user requests */
while((ch = getch()) != KEY_F(1))
{ switch(ch)
{ case KEY_DOWN:
/* Go to next field */
form_driver(my_form, REQ_NEXT_FIELD);
/* Go to the end of the present buffer */
/* Leaves nicely at the last character */
form_driver(my_form, REQ_END_LINE);
break;
case KEY_UP:
/* Go to previous field */
form_driver(my_form, REQ_PREV_FIELD);
form_driver(my_form, REQ_END_LINE);
break;
default:
/* If this is a normal character, it gets */
/* Printed */
form_driver(my_form, ch);
break;
}
}
/* Un post form and free the memory */
unpost_form(my_form);
free_form(my_form);
free_field(field[0]);
free_field(field[1]);
endwin();
return 0;
} |
int set_field_status(FIELD *field, /* field to alter */
int status); /* status to set */
int field_status(FIELD *field); /* fetch status of field */ |
int set_field_userptr(FIELD *field,
char *userptr); /* the user pointer you wish to associate */
/* with the field */
char *field_userptr(FIELD *field); /* fetch user pointer of the field */ |
field_opts_off(field_pointer, O_STATIC); |
int set_max_field(FIELD *field, /* Field on which to operate */
int max_growth); /* maximum growth allowed for the field */ |
The field info for a dynamically growable field can be retrieved by
int dynamic_field_info( FIELD *field, /* Field on which to operate */
int *prows, /* number of rows will be filled in this */
int *pcols, /* number of columns will be filled in this*/
int *pmax) /* maximum allowable growth will be filled */
/* in this */ |
Example 28. Form Windows Example
#include <form.h>
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
int main()
{
FIELD *field[3];
FORM *my_form;
WINDOW *my_form_win;
int ch, rows, cols;
/* Initialize curses */
initscr();
start_color();
cbreak();
noecho();
keypad(stdscr, TRUE);
/* Initialize few color pairs */
init_pair(1, COLOR_RED, COLOR_BLACK);
/* Initialize the fields */
field[0] = new_field(1, 10, 6, 1, 0, 0);
field[1] = new_field(1, 10, 8, 1, 0, 0);
field[2] = NULL;
/* Set field options */
set_field_back(field[0], A_UNDERLINE);
field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */
/* Field is filled up */
set_field_back(field[1], A_UNDERLINE);
field_opts_off(field[1], O_AUTOSKIP);
/* Create the form and post it */
my_form = new_form(field);
/* Calculate the area required for the form */
scale_form(my_form, &rows, &cols);
/* Create the window to be associated with the form */
my_form_win = newwin(rows + 4, cols + 4, 4, 4);
keypad(my_form_win, TRUE);
/* Set main window and sub window */
set_form_win(my_form, my_form_win);
set_form_sub(my_form, derwin(my_form_win, rows, cols, 2, 2));
/* Print a border around the main window and print a title */
box(my_form_win, 0, 0);
print_in_middle(my_form_win, 1, 0, cols + 4, "My Form", COLOR_PAIR(1));
post_form(my_form);
wrefresh(my_form_win);
mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields");
refresh();
/* Loop through to get user requests */
while((ch = wgetch(my_form_win)) != KEY_F(1))
{ switch(ch)
{ case KEY_DOWN:
/* Go to next field */
form_driver(my_form, REQ_NEXT_FIELD);
/* Go to the end of the present buffer */
/* Leaves nicely at the last character */
form_driver(my_form, REQ_END_LINE);
break;
case KEY_UP:
/* Go to previous field */
form_driver(my_form, REQ_PREV_FIELD);
form_driver(my_form, REQ_END_LINE);
break;
default:
/* If this is a normal character, it gets */
/* Printed */
form_driver(my_form, ch);
break;
}
}
/* Un post form and free the memory */
unpost_form(my_form);
free_form(my_form);
free_field(field[0]);
free_field(field[1]);
endwin();
return 0;
}
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
{ int length, x, y;
float temp;
if(win == NULL)
win = stdscr;
getyx(win, y, x);
if(startx != 0)
x = startx;
if(starty != 0)
y = starty;
if(width == 0)
width = 80;
length = strlen(string);
temp = (width - length)/ 2;
x = startx + (int)temp;
wattron(win, color);
mvwprintw(win, y, x, "%s", string);
wattroff(win, color);
refresh();
} |
Validation can be attached to a field with the following function.
int set_field_type(FIELD *field, /* field to alter */
FIELDTYPE *ftype, /* type to associate */
...); /* additional arguments*/ |
FIELDTYPE *field_type(FIELD *field); /* field to query */ |
the application program changes the field value by calling set_field_buffer.
linked field values are changed indirectly -- by changing the field to which they are linked
int set_field_type(FIELD *field, /* field to alter */
TYPE_ALPHA, /* type to associate */
int width); /* maximum width of field */ |
int set_field_type(FIELD *field, /* field to alter */
TYPE_ALNUM, /* type to associate */
int width); /* maximum width of field */ |
int set_field_type(FIELD *field, /* field to alter */
TYPE_ENUM, /* type to associate */
char **valuelist; /* list of possible values */
int checkcase; /* case-sensitive? */
int checkunique); /* must specify uniquely? */ |
The REQ_NEXT_CHOICE and REQ_PREV_CHOICE input requests can be particularly useful with these fields.
This field type accepts an integer. It is set up as follows:
int set_field_type(FIELD *field, /* field to alter */
TYPE_INTEGER, /* type to associate */
int padding, /* # places to zero-pad to */
int vmin, int vmax); /* valid range */ |
A TYPE_INTEGER value buffer can conveniently be interpreted with the C library function atoi(3).
This field type accepts a decimal number. It is set up as follows:
int set_field_type(FIELD *field, /* field to alter */
TYPE_NUMERIC, /* type to associate */
int padding, /* # places of precision */
int vmin, int vmax); /* valid range */ |
A TYPE_NUMERIC value buffer can conveniently be interpreted with the C library function atof(3).
This field type accepts data matching a regular expression. It is set up as follows:
int set_field_type(FIELD *field, /* field to alter */
TYPE_REGEXP, /* type to associate */
char *regexp); /* expression to match */ |
int form_driver(FORM *form, /* form on which to operate */
int request) /* form request code */ |
int set_new_page(FIELD *field,/* Field at which page break to be set or unset */
bool new_page_flag); /* should be TRUE to put a break */ |
The following requests allow you to move to different pages
These requests handle navigation between fields on the same page.
These requests drive movement of the edit cursor within the currently selected field.
REQ_SCR_HBLINE Scroll horizontally one field width backward.
REQ_SCR_HFHALF Scroll horizontally one half field width forward.
REQ_SCR_HBHALF Scroll horizontally one half field width backward.
For scrolling purposes, a page of a field is the height of its visible part.
The following requests support editing the field and changing the edit mode:
First, we consider REQ_NEW_LINE:
Now, let us consider REQ_DEL_PREV:
However, REQ_DEL_PREV at the beginning of a field is instead treated as a REQ_PREV_FIELD.
The kit provides some useful widgets, which can be used in your programs directly. It's pretty well written and the documentation is very good. The examples in the examples directory can be a good place to start for beginners. The CDK can be downloaded from http://www.vexus.ca/release/cdk.tar.gz . Follow the instructions in README file to install it.
The following is the list of widgets provided with cdk and their description.
Widget Type Quick Description
===========================================================================
Alphalist Allows a user to select from a list of words, with
the ability to narrow the search list by typing in a
few characters of the desired word.
Buttonbox This creates a multiple button widget.
Calendar Creates a little simple calendar widget.
Dialog Prompts the user with a message, and the user
can pick an answer from the buttons provided.
Entry Allows the user to enter various types of information.
File Selector A file selector built from Cdk base widgets. This
example shows how to create more complicated widgets
using the Cdk widget library.
Graph Draws a graph.
Histogram Draws a histogram.
Item List Creates a pop up field which allows the user to select
one of several choices in a small field. Very useful
for things like days of the week or month names.
Label Displays messages in a pop up box, or the label can be
considered part of the screen.
Marquee Displays a message in a scrolling marquee.
Matrix Creates a complex matrix with lots of options.
Menu Creates a pull-down menu interface.
Multiple Line Entry A multiple line entry field. Very useful
for long fields. (like a description
field)
Radio List Creates a radio button list.
Scale Creates a numeric scale. Used for allowing a user to
pick a numeric value and restrict them to a range of
values.
Scrolling List Creates a scrolling list/menu list.
Scrolling Window Creates a scrolling log file viewer. Can add
information into the window while its running.
A good widget for displaying the progress of
something. (akin to a console window)
Selection List Creates a multiple option selection list.
Slider Akin to the scale widget, this widget provides a
visual slide bar to represent the numeric value.
Template Creates a entry field with character sensitive
positions. Used for pre-formatted fields like
dates and phone numbers.
Viewer This is a file/information viewer. Very useful
when you need to display loads of information.
=========================================================================== |
"</B/1>This line should have a yellow foreground and a blue background.<!1>" |
Long long ago, in September 1994, when few people knew linux, Jeff Tranter wrote an article on dialog in Linux Journal. He starts the article with these words..
Linux is based on the Unix operating system, but also features a number of unique and useful kernel features and application programs that often go beyond what is available under Unix. One little-known gem is "dialog", a utility for creating professional-looking dialog boxes from within shell scripts. This article presents a tutorial introduction to the dialog utility, and shows examples of how and where it can be used
As he explains, dialog is a real gem in making professional-looking dialog boxes with ease. It creates a variety of dialog boxes, menus, check lists etc.. It is usually installed by default. If not, you can find it at ibiblio linux archive.
The above-mentioned article gives a very good overview of its uses and capabilites. The man page has more details. It can be used in variety of situations. One good example is building of linux kernel in text mode. Linux kernel uses a modified version of dialog tailored for its needs.
dialog was initially designed to be used with shell scripts. If you want to use its functionality in a c program, then you can use libdialog. The documentation regarding this is sparse. Definitive reference is the dialog.h header file which comes with the library. You may need to hack here and there to get the required output. The source is easily customizable. I have used it on a number of occasions by modifying the code.
The perl module Curses, Curses::Form and Curses::Widgets give access to curses from perl. If you have curses and basic perl is installed, you can get these modules from CPAN All Modules page. Get the three zipped modules in the Curses category. Once installed you can use these modules from perl scripts like any other module. For more information on perl modules see perlmod man page. The above modules come with good documentation and they have some demo scripts to test the functionality. Though the widgets provided are very rudimentary, these modules provide good access to curses library from perl.
For more information see man pages Curses(3) , Curses::Form(3) and Curses::Widgets(3). These pages are installed only when the above modules are acquired and installed.
This section contains few programs written by me just for fun. They don't signify a better programming practice or the best way of using ncurses. They are provided here so as to allow beginners to get ideas and add more programs to this section. If you have written a couple of nice, simple programs in curses and want them to included here, contact me.
Game of life is a wonder of math. In Paul Callahan's words
The Game of Life (or simply Life) is not a game in the conventional sense. There are no players, and no winning or losing. Once the "pieces" are placed in the starting position, the rules determine everything that happens later. Nevertheless, Life is full of surprises! In most cases, it is impossible to look at a starting position (or pattern) and see what will happen in the future. The only way to find out is to follow the rules of the game. |
This program starts with a simple inverted U pattern and shows how wonderful life works. There is a lot of room for improvement in the program. You can let the user enter pattern of his choice or even take input from a file. You can also change rules and play with a lot of variations. Search on google for interesting information on game of life.
File Path: JustForFun/life.c