函数名: putpixel

功 能: 在指定位置画一像素

用 法: void far putpixel (int x, int y, int pixelcolor);

程序例:

#include <graphics.h>

#include <stdlib.h>

#include <stdio.h>

#include <conio.h>

#include <dos.h>

#define PIXEL_COUNT 1000

#define DELAY_TIME 100 /* in milliseconds */

int main(void)

{

/* request autodetection */

int gdriver = DETECT, gmode, errorcode;

int i, x, y, color, maxx, maxy, maxcolor, seed;

/* 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 */

}

maxx = getmaxx() + 1;

maxy = getmaxy() + 1;

maxcolor = getmaxcolor() + 1;

while (!kbhit())

{

/* seed the random number generator */

seed = random(32767);

srand(seed);

for (i=0; i<PIXEL_COUNT; i++)

{

x = random(maxx);

y = random(maxy);

color = random(maxcolor);

putpixel(x, y, color);

}

delay(DELAY_TIME);

srand(seed);

for (i=0; i<PIXEL_COUNT; i++)

{

x = random(maxx);

y = random(maxy);

color = random(maxcolor);

if (color == getpixel(x, y))

putpixel(x, y, 0);

}

}

/* clean up */

getch();

closegraph();

return 0;

}