Problem1: BMPmain.c, BMPfns.c, BMPfns.h, Makefile The file \'BMPmain.c\' contain

Question

Problem1: BMPmain.c, BMPfns.c, BMPfns.h, Makefile The file 'BMPmain.c' contains a main() function which is already written for you and attached with this homework. When appropriate functions are provided, main() will create a .bmp image file. Your job is to write 'BMPfns.c' which contains the functions which main() uses to create .bmp image files. You must also write the header file 'BMPfns.h' to #include in BMPmain.c and which contains prototypes of the functions defined in BMPfns.c .

Problem2: BMPcheckerboard.c, BMPfns.c, BMPfns.h, Makefile Write a new main() in BMPcheckerboard.c which will draw a checkerboard of size 296 x 296 pixels using two attractive colors of your own choosing. You should be able to bring BMPfns.c and BMPfns.h from Problem1 over to Problem2 as-is. BMPmain.c:

//BMPmain.c 150S17 HW1 Problem1: main() of a program which builds a .bmp image // see Lancaster's "Exploring the .BMP File Format" for an accessible description of the bmp file format.

#define NROWS 252 //width in pixels of the image to be built

#define NCOLS 252 //height --"--

#include <stdio.h>

#include <stdlib.h>

#include "BMPfns.h"

int main(void) {

FILE *fp;

int row,col;

if( (fp= fopen("myBMP.bmp","wb")) == NULL ) {printf("Couldn't open 'myBMP.bmp' "); exit(0); }

//-- building a bmp header for a NROWS x NCOLS 24-bit/pixel image using Lancaster's header info

//BMP marker

fputc((int)'B',fp); fputc((int)'M',fp);

//write total length of file in bytes= (size of header + 3*number of pixels) + (number of rows * size of padding) write4LE(54 + NROWS*(3*NCOLS+padding(NCOLS)),fp);

//reserved mystery value

write4LE(0,fp);

//offset to pixel data

write4LE(54,fp);

//size of data header

write4LE(40,fp);

//width of bitmap in pixels

write4LE(NCOLS,fp);

//height of bitmap in pixels

write4LE(NROWS,fp);

//number of color planes

write2LE(1,fp);

//number of bits per pixel

write2LE(24,fp);

//compression mode

write4LE(0,fp);

//size of stored pixel data in bytes

write4LE(NROWS*(3*NCOLS),fp); //required

//width resolution in pixels/meter

write4LE(0,fp); //doesn't seem to matter

//height resolution in pixels/meter

write4LE(0,fp); //""

//height resolution in pixels/meter

write4LE(0,fp); //""

//height resolution in pixels/meter

write4LE(0,fp); //""

//--here with header built; ready to fill data //color plan is to increment red at each row increment, blue at each column increment, and keep green at 0; image starts at bottom left

for(row=0; row < NROWS; row++) {

for(col=0; col < NCOLS; col++) {

writePIXEL(row, 0, col, fp); //writePIXEL(int red, int grn, int blu, FILE *fp)

}

writePAD(padding(NCOLS),fp);

}

//here with (we hope) the bmp file built

fclose(fp);

return 0;

}

Explanation / Answer

ans of problem1:

//BMPfns.h

#ifndef BITMAP__
#define BITMAP__

#define BIT (8*sizeof(byte))
#define BITMAP_NOTFOUND -1

typedef enum{false=0, true} bool;
typedef unsigned char byte;

bool bitmapGet (byte *, int);
void bitmapSet (byte *, int);
void bitmapReset (byte *, int);
int bitmapSearch(byte *, bool, int, int);

#endif

//BMPfns.c

#include "BMPfns.h"

static bool get (byte, byte);
static void set (byte *, byte);
static void reset(byte *, byte);

bool bitmapGet(byte *bitmap, int pos) {

return get(bitmap[pos/BIT], pos%BIT);
}

void bitmapSet(byte *bitmap, int pos) {

set(&bitmap[pos/BIT], pos%BIT);
}

void bitmapReset(byte *bitmap, int pos) {

reset(&bitmap[pos/BIT], pos%BIT);
}

int bitmapSearch(byte *bitmap, bool n, int size, int start) {
int i;
  
for(i = start+1, size *= BIT; i < size; i++)
if(bitmapGet(bitmap,i) == n)
return i;
return BITMAP_NOTFOUND;
}

static bool get(byte a, byte pos) {

return (a >> pos) & 1;
}

static void set(byte *a, byte pos) {

*a |= 1 << pos;
}

static void reset(byte *a, byte pos) {

*a &= ~(1 << pos);
}

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