ncurses-programming-howto.html

ncurses 库 可能有用酒用 没用就算了 我觉得还可以用

</div>
<div class="SECT2">
<hr>
<h3 class="SECT2"><a name="SCANWCLASS" id="SCANWCLASS">7.2. scanw()
class of functions</a></h3>
<p>These functions are similar to <var class=
"LITERAL">scanf()</var> with the added capability of getting the
input from any location on the screen.</p>
<div class="SECT3">
<hr>
<h4 class="SECT3"><a name="SCANWMVSCANW" id="SCANWMVSCANW">7.2.1.
scanw() and mvscanw</a></h4>
<p>The usage of these functions is similar to that of <var class=
"LITERAL">sscanf()</var>, where the line to be scanned is provided
by <var class="LITERAL">wgetstr()</var> function. That is, these
functions call to <var class="LITERAL">wgetstr()</var>
function(explained below) and uses the resulting line for a
scan.</p>
</div>
<div class="SECT3">
<hr>
<h4 class="SECT3"><a name="WSCANWMVWSCANW" id=
"WSCANWMVWSCANW">7.2.2. wscanw() and mvwscanw()</a></h4>
<p>These are similar to above two functions except that they read
from a window, which is supplied as one of the arguments to these
functions.</p>
</div>
<div class="SECT3">
<hr>
<h4 class="SECT3"><a name="VWSCANW" id="VWSCANW">7.2.3.
vwscanw()</a></h4>
<p>This function is similar to <var class="LITERAL">vscanf()</var>.
This can be used when a variable number of arguments are to be
scanned.</p>
</div>
</div>
<div class="SECT2">
<hr>
<h3 class="SECT2"><a name="GETSTRCLASS" id="GETSTRCLASS">7.3.
getstr() class of functions</a></h3>
<p>These functions are used to get strings from the terminal. In
essence, this function performs the same task as would be achieved
by a series of calls to <var class="LITERAL">getch()</var> until a
newline, carriage return, or end-of-file is received. The resulting
string of characters are pointed to by <var class=
"LITERAL">str</var>, which is a character pointer provided by the
user.</p>
</div>
<div class="SECT2">
<hr>
<h3 class="SECT2"><a name="GETSTREX" id="GETSTREX">7.4. Some
examples</a></h3>
<div class="EXAMPLE"><a name="BSCEX" id="BSCEX"></a>
<p><b>Example 4. A Simple scanw example</b></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
<font color="#000000"><span class=
"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt;                   /* ncurses.h includes stdio.h */  
#include &lt;string.h&gt; 
 
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;
}</span></font>
</pre></td>
</tr>
</table>
</div>
</div>
</div>
<div class="SECT1">
<hr>
<h2 class="SECT1"><a name="ATTRIB" id="ATTRIB">8.
Attributes</a></h2>
<p>We have seen an example of how attributes can be used to print
characters with some special effects. Attributes, when set
prudently, can present information in an easy, understandable
manner. The following program takes a C file as input and prints
the file with comments in bold. Scan through the code.</p>
<div class="EXAMPLE"><a name="BSIAT" id="BSIAT"></a>
<p><b>Example 5. A Simple Attributes example</b></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
<font color="#000000"><span class=
"INLINEMEDIAOBJECT">/* pager functionality by Joseph Spainhour" &lt;[e-mail]&gt; */
#include &lt;ncurses.h&gt;
#include &lt;stdlib.h&gt;

int main(int argc, char *argv[])
{ 
  int ch, prev, row, col;
  prev = EOF;
  FILE *fp;
  int y, x;

  if(argc != 2)
  {
    printf("Usage: %s &lt;a c file name&gt;\n", argv[0]);
    exit(1);
  }
  fp = fopen(argv[1], "r");
  if(fp == NULL)
  {
    perror("Cannot open input file");
    exit(1);
  }
  initscr();                            /* Start curses mode */
  getmaxyx(stdscr, row, col);           /* find the boundaries of the screeen */
  while((ch = fgetc(fp)) != EOF)        /* read the file till we reach the end */
  {
    getyx(stdscr, y, x);                /* get the current curser position */
    if(y == (row - 1))                  /* are we are at the end of the screen */
    {
      printw("&lt;-Press Any Key-&gt;");      /* tell the user to press a key */
      getch();
      clear();                          /* clear the screen */
      move(0, 0);                       /* start at the beginning of the screen */
    }
    if(prev == '/' &amp;&amp; ch == '*')        /* If it is / and * then only
                                         * switch bold on */    
    {
      attron(A_BOLD);                   /* cut bold on */
      getyx(stdscr, y, x);              /* get the current curser position */
      move(y, x - 1);                   /* back up one space */
      printw("%c%c", '/', ch);          /* The actual printing is done here */
    }
    else
      printw("%c", ch);
    refresh();
    if(prev == '*' &amp;&amp; ch == '/')
      attroff(A_BOLD);                  /* Switch it off once we got *
                                         * and then / */
    prev = ch;
  }
  endwin();                             /* End curses mode */
  fclose(fp);
  return 0;
}</span></font>
</pre></td>
</tr>
</table>
</div>
<p>Don't worry about all those initialization and other crap.
Concentrate on the while loop. It reads each character in the file
and searches for the pattern /*. Once it spots the pattern, it
switches the BOLD attribute on with <var class=
"LITERAL">attron()</var> . When we get the pattern */ it is
switched off by <var class="LITERAL">attroff()</var> .</p>
<p>The above program also introduces us to two useful functions
<var class="LITERAL">getyx()</var> and <var class=
"LITERAL">move()</var>. The first function gets the co-ordinates of
the present cursor into the variables y, x. Since getyx() is a
macro we don't have to pass pointers to variables. The function
<var class="LITERAL">move()</var> moves the cursor to the
co-ordinates given to it.</p>
<p>The above program is really a simple one which doesn't do much.
On these lines one could write a more useful program which reads a
C file, parses it and prints it in different colors. One could even
extend it to other languages as well.</p>
<div class="SECT2">
<hr>
<h3 class="SECT2"><a name="ATTRIBDETAILS" id="ATTRIBDETAILS">8.1.
The details</a></h3>
<p>Let's get into more details of attributes. The functions
<var class="LITERAL">attron(), attroff(), attrset()</var> , and
their sister functions <var class="LITERAL">attr_get()</var> etc..
can be used to switch attributes on/off , get attributes and
produce a colorful display.</p>
<p>The functions attron and attroff take a bit-mask of attributes
and switch them on or off, respectively. The following video
attributes, which are defined in &lt;curses.h&gt; can be passed to
these functions.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
<font color="#000000">    
    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 
    </font>
</pre></td>
</tr>
</table>
<p>The last one is the most colorful one :-) Colors are explained
in the <a href="#color" target="_top">next sections</a>.</p>
<p>We can OR(|) any number of above attributes to get a combined
effect. If you wanted reverse video with blinking characters you
can use</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
<font color="#000000">    attron(A_REVERSE | A_BLINK);</font>
</pre></td>
</tr>
</table>
</div>
<div class="SECT2">
<hr>
<h3 class="SECT2"><a name="ATTRONVSATTRSET" id=
"ATTRONVSATTRSET">8.2. attron() vs attrset()</a></h3>
<p>Then what is the difference between attron() and attrset()?
attrset sets the attributes of window whereas attron just switches
on the attribute given to it. So attrset() fully overrides whatever
attributes the window previously had and sets it to the new
attribute(s). Similarly attroff() just switches off the
attribute(s) given to it as an argument. This gives us the
flexibility of managing attributes easily.But if you use them
carelessly you may loose track of what attributes the window has
and garble the display. This is especially true while managing
menus with colors and highlighting. So decide on a consistent
policy and stick to it. You can always use <var class=
"LITERAL">standend()</var> which is equivalent to <var class=
"LITERAL">attrset(A_NORMAL)</var> which turns off all attributes
and brings you to normal mode.</p>
</div>
<div class="SECT2">
<hr>
<h3 class="SECT2"><a name="ATTR_GET" id="ATTR_GET">8.3.
attr_get()</a></h3>
<p>The function attr_get() gets the current attributes and color
pair of the window. Though we might not use this as often as the
above functions, this is useful in scanning areas of screen. Say we
wanted to do some complex update on screen and we are not sure what
attribute each character is associated with. Then this function can
be used with either attrset or attron to produce the desired
effect.</p>
</div>
<div class="SECT2">
<hr>
<h3 class="SECT2"><a name="ATTR_FUNCS" id="ATTR_FUNCS">8.4. attr_
functions</a></h3>
<p>There are series of functions like attr_set(), attr_on etc..
These are similar to above functions except that they take
parameters of type <var class="LITERAL">attr_t</var>.</p>
</div>
<div class="SECT2">
<hr>
<h3 class="SECT2"><a name="WATTRFUNCS" id="WATTRFUNCS">8.5. wattr
functions</a></h3>
<p>For each of the above functions we have a corresponding function
with 'w' which operates on a particular window. The above functions
operate on stdscr.</p>
</div>
<div class="SECT2">
<hr>
<h3 class="SECT2"><a name="CHGAT" id="CHGAT">8.6. chgat()
functions</a></h3>
<p>The function chgat() is listed in the end of the man page
curs_attr. It actually is a useful one. This function can be used
to set attributes for a group of characters without moving. I mean
it !!! without moving the cursor :-) It changes the attributes of a
given number of characters starting at the current cursor
location.</p>
<p>We can give -1 as the character count to update till end of
line. If you want to change attributes of characters from current
position to end of line, just use this.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
<font color="#000000">    chgat(-1, A_REVERSE, 0, NULL);</font>
</pre></td>
</tr>
</table>
<p>This function is useful when changing attributes for characters
that are already on the screen. Move to the character from which
you want to change and change the attribute.</p>
<p>Other functions wchgat(), mvchgat(), wchgat() behave similarly
except that the w functions operate on the particular window. The
mv functions first move the cursor then perform the work given to
them. Actually chgat is a macro which is replaced by a wchgat()
with stdscr as the window. Most of the "w-less" functions are
macros.</p>
<div class="EXAMPLE"><a name="BWICH" id="BWICH"></a>
<p><b>Example 6. Chgat() Usage example</b></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
<font color="#000000"><span class=
"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt;

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;
}</span></font>
</pre></td>
</tr>
</table>
</d