设置图形方式下画线的输出模式

[c]代码库

#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\n", 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; 
}