BUILDS A STRING FROM THE LSB BITS OF EACH PIXEL

How to write a C Program to BUILDS A STRING FROM THE LSB BITS OF EACH PIXEL in C Programming Language ?

This C Program BUILDS A STRING FROM THE LSB BITS OF EACH PIXEL.

Solution:

// Revelation core, returns a message with the secret content of the image
// SINGLE CHANNEL (R), SINGLE BIT PER CHANNEL, NO MAGIC NUMBER.
// SIMPLY BUILDS A STRING FROM THE LSB BITS OF EACH PIXEL.
message reveal(const char *img){
int i,j;
RGBQUAD pixel;
FIBITMAP *image1= open_image(TESTIMAGE);
unsigned w,h;
int end = 0; //use as flag when found magic number, if not updated we reveal all the pixels
w = FreeImage_GetWidth(image1);
h = FreeImage_GetHeight(image1);
int len = (h*w/8);
message m; // message is struct{ char chars[]; }
m.chars= (char*)malloc(sizeof(char)*len);
char bits[h*w];
couple indexes;
unsigned char tmp;
int n = 0, b=0;
for (i=0; i<h; i++){
for (j=0; j<w; j++){
if(b%8==0)b=0;
indexes = mindex_direct(n,w,h); //returns couple (x,y) of n-th pixel in Direct order
if(readBit(image1,indexes,0))
m.chars[n/8] = set_bit(m.chars[n/8],7-b);
else
m.chars[n/8] = unset_bit(m.chars[n/8],7-b);
n++;
b++;
}
}
}

String

Bit

Pixel