following the pseudocode to resize vertically - can you tell me if I'm on the right lines? Looks like too many nested for loops.
// horizontal resize
// for each row
for (int i = 0; i < bio.biHeight; i++){
// for each pixel in row
for (int j = 0; j < bio.biWidth; j++){
write to outfile n times......
// write outfile padding
fwrite(&triple,sizeof(RGBTRIPLE),1,outptr);
// skip over infile padding
fseek(inptr, padding, SEEK_CUR);
}
I havent implemented writing to outfile n times because I don't want to add another for loop.
UPDATED CODE:
/**
* copy.c
*
* Computer Science 50
* Problem Set 4
*
* 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)
{
printf("Usage: ./copy infile outfile\n");
return 1;
}
if (atoi(argv[1]) > 100){
printf("Please enter number smaller than 100...");
return 1;
}
int n = atoi(argv[1]);
// remember filenames
char* infile = argv[2];
char* outfile = argv[3];
// open input file
FILE* inptr = fopen(infile, "r");
if (inptr == NULL)
{
printf("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);
// copy these file headers so they can be written to output file
BITMAPFILEHEADER bfo = bf;
BITMAPINFOHEADER bio = bi;
// new height and width
bio.biHeight = bi.biHeight * n;
bio.biWidth = bi.biWidth * n;
// old padding
int padding = (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;
// new padding
int newpadding = (4-bio.biWidth * sizeof(RGBTRIPLE) % 4) % 4;
bio.biSizeImage = ((bio.biWidth) * sizeof(RGBTRIPLE) + (newpadding)) * abs(bio.biHeight);
bfo.bfSize = (bio.biSizeImage) + 54;
// 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;
}
// write outfile's BITMAPFILEHEADER
fwrite(&bfo, sizeof(BITMAPFILEHEADER), 1, outptr);
// write outfile's BITMAPINFOHEADER
fwrite(&bio, sizeof(BITMAPINFOHEADER), 1, outptr);
// determine padding for scanlines
// iterate over infile's scanlines
for (int i = 0, biHeight = abs(bi.biHeight); i < biHeight; i++)
{
// iterate over pixels in scanline
for (int j = 0; j < bi.biWidth; j++)
{
// temporary storage
RGBTRIPLE triple;
// read RGB triple from infile
fread(&triple, sizeof(RGBTRIPLE), 1, inptr);
for (int a = 0; a < n; a++){
for (int b = 0; b < n; b++){
fread(&triple, sizeof(RGBTRIPLE), 1, inptr);
{
for (int c = 0; c < n; c++){
fwrite(&triple, sizeof(RGBTRIPLE), 1, outptr);
}
fseek(inptr, padding, SEEK_CUR);
}
}
}
}
// then add it back (to demonstrate how)
for (int k = 0; k < padding; k++)
{
fputc(0x00, outptr);
}
}
// close infile
fclose(inptr);
// close outfile
fclose(outptr);
// that's all folks
return 0;
}