函数名: setwritemode

功 能: 设置图形方式下画线的输出模式

用 法: void far setwritemode(int mode);

程序例:

#include <graphics.h>

#include <stdlib.h>

#include <stdio.h>

#include <conio.h>

int main()

{

/* request auto detection */

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\", grapherrormsg(errorcode));

printf("Press any key to halt:");

getch();

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

}

xmax = getmaxx();

ymax = getmaxy();

/* select XOR drawing mode */

setwritemode(XOR_PUT);

/* draw a line */

line(0, 0, xmax, ymax);

getch();

/* erase the line by drawing over it */

line(0, 0, xmax, ymax);

getch();

/* select overwrite drawing mode */

setwritemode(COPY_PUT);

/* draw a line */

line(0, 0, xmax, ymax);

/* clean up */

getch();

closegraph();

return 0;

}