setgraphbufsize

Syntax

#include <graphics.h>
unsigned setgraphbufsize(unsigned bufsize);

Description

Some of the graphics routines (such as floodfill) use a memory buffer that is allocated when initgraph is called and released when closegraph is called. The default size of this buffer, allocated by _graphgetmem, is 4,096 bytes.

You might want to make this buffer smaller (to save memory space) or bigger (if, for example, a call to floodfill produces error -7: Out of flood memory).

setgraphbufsize tells initgraph how much memory to allocate for this internal graphics buffer when it calls _graphgetmem.

You must call setgraphbufsize before calling initgraph. Once initgraph has been called, all calls to setgraphbufsize are ignored until after the next call to closegraph.

Return Value

setgraphbufsize returns the previous size of the internal buffer.

Windows Notes

setgraphbufsize is not available in the winbgim implementation.

See also

closegraph

initgraph

sector

Example

/* setgraphbufsize example */ 

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

#define BUFSIZE 1000 /* internal graphics buffer size */

int main(void)
{
   /* request autodetection */
   int gdriver = DETECT, gmode, errorcode;
   int x, y, oldsize;
   char msg[80];

   /* _set size of internal graphics buffer before calling initgraph */
   oldsize = setgraphbufsize(BUFSIZE);


   /* 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(1);               /* terminate with an error code */
   }

   x = getmaxx() / 2;
   y = getmaxy() / 2;

   /* output some messages */
   sprintf(msg, "Graphics buffer size: %d", BUFSIZE);
   settextjustify(CENTER_TEXT, CENTER_TEXT);

   outtextxy(x, y, msg);
   sprintf(msg, "Old graphics buffer size: %d", oldsize);
   outtextxy(x, y+textheight("W"), msg);

   /* clean up */
   getch();
   closegraph();
   return 0;
}