ch1.c

/*

ch1.c

Parameters: none

Create a 12-zone test chart with the following stripe widths (in pixels) per zone:

    10   8   9  11

     6   4   5   7

    14  12  13  16

Compile with:

    cc -o ch1 ch1.c


The 1800x1800-pixel output file, named "chart1.gray", should then be converted using
ImageMagick's "convert" command-line utility from the ".gray" bytestream format to
a more standard image format like bmp:

    convert -size 1800x1800 -depth 8 chart1.gray chart1.bmp

ImageMagick can be downloaded from: http://www.imagemagick.org/

*/

#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>

int main() {
    unsigned char
        *buf, *ptr, *ptr2;
    int i, j, fd;

    //ptr2 = ptr = buf = calloc( 648 * 600, 1 );
    buf = calloc( 1800 * 1800, 1 );

    ptr2 = buf + 1800 * 800;
    ptr = ptr2 + 260;

// 6
    for( i = 0; i < 13; i++ ) {
        for( j = 0; j < 6; j++ )
            *ptr++ = 255;
        ptr += 6;
    }
    for( j = 0; j < 6; j++ )
        *ptr++ = 255;

// 4
    for( i = 0; i < 20; i++ ) {
        ptr += 4;
        for( j = 0; j < 4; j++ )
            *ptr++ = 255;
    }

// 5
    for( i = 0; i < 16; i++ ) {
        ptr += 5;
        for( j = 0; j < 5; j++ )
            *ptr++ = 255;
    }

// 7
    for( i = 0; i < 11; i++ ) {
        ptr += 7;
        for( j = 0; j < 7; j++ )
            *ptr++ = 255;
    }

    ptr = ptr2 + 1800;
    for( i = 0; i < 199; i++ ) {
        for( j = 0; j < 1800; j++ )
            *ptr++ = *ptr2++;
    }

    ptr2 = buf + 1800 * 600;
    ptr = ptr2 + 260;

// 10
    for( i = 0; i < 8; i++ ) {
        for( j = 0; j < 10; j++ )
            *ptr++ = 255;
        ptr += 10;
    }

// 8
    for( i = 0; i < 10; i++ ) {
        for( j = 0; j < 8; j++ )
            *ptr++ = 255;
        ptr += 8;
    }

// 9
    for( i = 0; i < 9; i++ ) {
        for( j = 0; j < 9; j++ )
            *ptr++ = 255;
        ptr += 9;
    }

// 11
    for( i = 0; i < 7; i++ ) {
        for( j = 0; j < 11; j++ )
            *ptr++ = 255;
        ptr += 11;
    }
    for( j = 0; j < 11; j++ )
        *ptr++ = 255;

    ptr = ptr2 + 1800;
    for( i = 0; i < 199; i++ ) {
        for( j = 0; j < 1800; j++ )
            *ptr++ = *ptr2++;
    }

    ptr2 = buf + 1800 * 1000;
    ptr = ptr2 + 260;

// 14
    for( i = 0; i < 5; i++ ) {
        for( j = 0; j < 14; j++ )
            *ptr++ = 255;
        ptr += 14;
    }
    for( j = 0; j < 14; j++ )
        *ptr++ = 255;

// 12
    for( i = 0; i < 7; i++ ) {
        ptr += 12;
        for( j = 0; j < 12; j++ )
            *ptr++ = 255;
    }

// 13
    for( i = 0; i < 6; i++ ) {
        ptr += 13;
        for( j = 0; j < 13; j++ )
            *ptr++ = 255;
    }

// 16
    for( i = 0; i < 5; i++ ) {
        ptr += 16;
        for( j = 0; j < 16; j++ )
            *ptr++ = 255;
    }

    ptr = ptr2 + 1800;
    for( i = 0; i < 199; i++ ) {
        for( j = 0; j < 1800; j++ )
            *ptr++ = *ptr2++;
    }

    fd = open( "chart1.gray", O_WRONLY | O_CREAT | O_TRUNC, 0600 );
    write( fd, buf, 1800 * 1800 );
    close( fd );
}