setwritemode

raw OCR

Sets the writing mode for line drawing in graphics mode.

Defined in header <graphics.h>

Syntax

#include <graphics.h>
void far setwritemode(int mode);

Portability

DOS	UNIX	Windows	ANSI C	C++ only
■

Remarks

The following constants are defined:

COPY_PUT = 0	MOV
XOR PUT = 1 Each constant corresponds to a binary operation between each byte in the	XOR
line and the corresponding bytes onscreen. COPY_PUT language MOV instruction, overwriting with the line whatever is on the	uses the assembly
screen. XORPUT screen. Two successive XOR commands will erase the line and restore the screen to its original appearance.	uses the XOR command to combine the line with the

b^

setwritemode currently works only with line, linerel, lineto, rectangle, and drawpoly.

Return value

None.

Example

#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>

int mainO
{
   /* request autodetection */
   int gdriver = DETECT, gmode, errorcode;
   int xmax, ymax;
   /* initialize graphics and local variables  */
   initgraph(&gdriver, &gmode,  "");
   /* read result of initialization  */
   errorcode = graphresult ();
   if (errorcode  != grOk)   /* an error  occurred */
   {
      printf("Graphics error: %s\n", grapherrormsg (errorcode));
      printf("Press any key to halt:");
      getch();
      exit(l);                /* terminate with an error code */

   xmax = getmaxx ();
   ymax = getmaxy ();
   /* select XOR drawing mode  */
   setwritemode (XOR_PUT);

   /* draw a line */
   line(0, 0, xmax, ymax) ;
getchO ;
/* erase the line by drawing over  it */
line(0, 0, xmax, ymax) ;
getchO;
/* select overwrite drawing mode  */
setwritemode (COPY_PUT);
/* draw a line */
line(0, 0, xmax, ymax) ;

/* clean up */
getchO ;
closegraphO ;
return 0;

Differences from modern implementations

Nothing recorded yet.

Modern references

Microsoft C runtime (search)

These are search links, not yet checked by hand.

Stable link: /3.1/graphics.h/setwritemode/ · short form /3.1/setwritemode/