imagesize

Syntax

#include <graphics.h>

unsigned imagesize(int left, int top, int right, int bottom);

Description

imagesize determines the size of the memory area required to store a bit image. If the size required for the selected image is greater than or equal to 64K - 1 bytes, imagesize returns 0xFFFF (-1).

Return Value

imagesize returns the size of the required memory area in bytes.

See also

getimage

putimage

Example

/* imagesize example */ 



#include <graphics.h>

#include <stdlib.h>

#include <stdio.h>

#include <conio.h>



#define ARROW_SIZE 10



void draw_arrow(int x, int y);



int main(void)

{

   /* request autodetection */

   int gdriver = DETECT, gmode, errorcode;

   void *arrow;

   int x, y, maxx;

   unsigned int size;



   /* 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();

   x = 0;

   y = getmaxy() / 2;



   /* draw the image to be grabbed */

   draw_arrow(x, y);



   /* calculate the size of the image */

   size = imagesize(x, y-ARROW_SIZE, x+(4*ARROW_SIZE), y+ARROW_SIZE);



   /* allocate memory to hold the image */

   arrow = malloc(size);





   /* grab the image */

   getimage(x, y-ARROW_SIZE, x+(4*ARROW_SIZE), y+ARROW_SIZE, arrow);



   /* repeat until a key is pressed */

   while (!kbhit()) {

      /* erase old image */

      putimage(x, y-ARROW_SIZE, arrow, XOR_PUT);

      x += ARROW_SIZE;

      if (x >= maxx)

          x = 0;



      /* plot new image */

      putimage(x, y-ARROW_SIZE, arrow, XOR_PUT);

   }



   /* clean up */

   free(arrow);

   closegraph();

   return 0;

}



void draw_arrow(int x, int y)



{

   /* draw an arrow on the screen */

   moveto(x, y);

   linerel(4*ARROW_SIZE, 0);

   linerel(-2*ARROW_SIZE, -1*ARROW_SIZE);

   linerel(0, 2*ARROW_SIZE);

   linerel(2*ARROW_SIZE, -1*ARROW_SIZE);

}