I have no problems with the horizontal resizing but can't identify what is the problem in my code with the vertical resizing. Any help would be much appreciated.
/**
* Copies a BMP piece by piece, just because.
*/
#include <stdio.h>
#include <stdlib.h>
#include "bmp.h"
int main(int argc, char *argv[])
{
// ensure proper usage
if (argc != 4)
{
fprintf(stderr, "Usage: ./copy infile outfile\n");
return 1;
}
//Conversion of string(command line argument) to int//
int n = atoi(argv[1]);
//Ensuring that value of n is from 0 to 100//
if(n<0 || n>100)
{
printf("try again!\n");
return 1;
}
// remember filenames
char *infile = argv[2];
char *outfile = argv[3];
// open input file
FILE *inptr = fopen(infile, "r");
if (inptr == NULL)
{
fprintf(stderr, "Could not open %s.\n", infile);
return 2;
}
// open output file
FILE *outptr = fopen(outfile, "w");
if (outptr == NULL)
{
fclose(inptr);
fprintf(stderr, "Could not create %s.\n", outfile);
return 3;
}
// read infile's BITMAPFILEHEADER
BITMAPFILEHEADER bf;
fread(&bf, sizeof(BITMAPFILEHEADER), 1, inptr);
// read infile's BITMAPINFOHEADER
BITMAPINFOHEADER bi;
fread(&bi, sizeof(BITMAPINFOHEADER), 1, inptr);
//change in new header info//
BITMAPFILEHEADER bfo = bf;
BITMAPINFOHEADER bio = bi;
bio.biWidth = bi.biWidth*n;
bio.biHeight = bi.biHeight*n;
// ensure infile is (likely) a 24-bit uncompressed BMP 4.0
if (bf.bfType != 0x4d42 || bf.bfOffBits != 54 || bi.biSize != 40 ||
bi.biBitCount != 24 || bi.biCompression != 0)
{
fclose(outptr);
fclose(inptr);
fprintf(stderr, "Unsupported file format.\n");
return 4;
}
// determine padding for scanlines
int oldPadding = (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;
int newPadding = (4 - (bio.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;
//change of file size//
bfo.bfSize = 54 + (bio.biWidth * sizeof(RGBTRIPLE) + newPadding) * abs(bio.biHeight);
bio.biSizeImage = bfo.bfSize - 54;
// write outfile's BITMAPFILEHEADER
fwrite(&bfo, sizeof(BITMAPFILEHEADER), 1, outptr);
// write outfile's BITMAPINFOHEADER
fwrite(&bio, sizeof(BITMAPINFOHEADER), 1, outptr);
// iterate over infile's scanlines
for (int i = 0, biHeight = abs(bio.biHeight); i < biHeight; i++)
{
for(int m = 0; m < n; m++)
{
// iterate over pixels in scanline
for (int j = 0; j < bio.biWidth; j++)
{
// temporary storage
RGBTRIPLE triple;
// read RGB triple from infile
fread(&triple, sizeof(RGBTRIPLE), 1, inptr);
for(int k = 0; k < n; k++)
{
// write RGB triple to outfile
fwrite(&triple, sizeof(RGBTRIPLE), 1, outptr);
}
//return to previous scanline and repeat same process//
}
// then add it back (to demonstrate how)
for (int k = 0; k < newPadding; k++)
{
fputc(0x00, outptr);
}
if(m == (n-1))
{
// skip over padding, if any
fseek(inptr, oldPadding, SEEK_CUR);
}
else
{
fseek(inptr, -(bi.biWidth*sizeof(RGBTRIPLE)), SEEK_CUR);
}
}
}
// close infile
fclose(inptr);
// close outfile
fclose(outptr);
// success
return 0;
}