getpixel

Syntax

#include <graphics.h>

unsigned getpixel(int x, int y);

Description

getpixel gets the color of the pixel located at (x,y).

Return Value

getpixel returns the color of the given pixel.

Windows Notes

In the winbgim version, the user might set a pixel color to an RGB color. Therefore, the return value from getpixel might be an ordinary BGI color (integer from 0 to 15) or an RGB color.

See also

getimage

putpixel

Example

/* getpixel example */ 



#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\n", 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 = random(32767);  /* seed the random number generator */

      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;

}