Category : C Source Code
Archive   : WTWG12B.ZIP
Filename : WLINK.C

/* wunlink(), wlink()
* unlink the current window from the chain of windows.
* the image of the window is saved (pointer winsave).
* the screen is not changed.
* this function is used just before changing modes
* or just before wcloseall
* allows subsequent wlink to re-establish this window
* when you come back to the window's mode.
*
* RETURNS: pointer to the window if successful, NULL if error
*
*
* wlink opens the specified window, restores its image to the screen
* parameter = window pointer obtained by wunlink ()
* RETURNS: 0 if successful, -1 on error .
*
* do NOT place a text-mode window on a graphics mode screen
* or vice-versa.
*
* example: winit ('T');
* wopen (... );
* wputs ("A bunch of stuff...);
* my_textw0indow = wunlink ();
* init ('G');
* do graphics things...
* winit ('T');
* wlink ( my_textw0indow );
*
*
*/
#include "wsys.h"



/* local function to define a blank window that sits on top of
* affected area of screen
*/
static void overlay ( void );


WINDOW *wunlink (void)

{

WINDOW *oldw;
WHEAP *olds;




/* cannot unlink the only window or the fullscreen window
*/
if ( w0-> winchain == NULL || w0 == wfullscreen )
{
return (NULL);
}


oldw = w0;
olds = w0->winsave;


/* place a new window on top of the current window
* the save area of the new window will have the contents of
* the current values of the current window
*/
overlay ();


/* swap the save area pointers
* and close the old window ( will restore screen if needed )
*/

oldw->winsave = w0 -> winsave; /* contents of window to unlink */
w0 ->winsave = olds; /* screen prior to window */

wclose();

w0 = w0-> winchain; /* unlink */

return (oldw);

}




void wlink (WINDOW *neww)

{
WHEAP *news;


/* always place new window in current page */
neww-> winpage = w0->winpage;

news = neww-> winsave;



neww-> winchain = w0; /* link into chain */
w0 = neww;



overlay ();

/* swap save area pointers and restore
* screen to show new window contents
*/
neww-> winsave = w0-> winsave;
w0->winsave = news;



wclose();






return; /* wlink -- successful */
}







/* overlay()
* static fucntion to create a dummy window
* in the screen area of the window of interest.
*/
static void overlay (void)
{
int r, l, t, b, extra, extra2;


extra = ( w0->winbox ) ? 1: 0;
extra2 = 2*extra;

l = w0-> winleft - extra;
t = w0-> wintop - extra;
r = w0->winxmax + extra2;
b = w0->winymax + extra2;

wopen ( l, t, r, b, 0x07, NO_BORDER, 0x07, WSAVE2RAM );

return; /* overlay */
}



/*------------------ WLINK.C -------------------------*/