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added 20 characters in body

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edited Feb 11, 2016 at 17:01

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#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; }

#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 (argv[1] < 0 || argv[1] > 101)
{
    printf("Enter a resize amount between 1 and 100!\n");
    return 1;
}

// remember filenames
char* infile = argv[2];
char* outfile = argv[3];

int n = atoi(argv[1]);

// 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);

bi.biHeight *= n;
bi.biWidth *= n;
int padding =  (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;
bi.biSizeImage = abs(bi.biWidth) * (bi.biWidth + padding);
bf.bfSize = bi.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(&bf, sizeof(BITMAPFILEHEADER), 1, outptr);


// write outfile's BITMAPINFOHEADER
fwrite(&bi, 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);

        // write RGB triple to outfile
       
        for (a = 0; a < n; a++)
        {
            fwrite(&triple, sizeof(RGBTRIPLE), 1, outptr);
        }
    }

    // skip over padding, if any
    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;

#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 (argv[1] < 0 || argv[1] > 101)
{
    printf("Enter a resize amount between 1 and 100!\n");
    return 1;
}

// remember filenames
char* infile = argv[2];
char* outfile = argv[3];

int n = atoi(argv[1]);

// 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);

bi.biHeight *= n;
bi.biWidth *= n;
int padding =  (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;
bi.biSizeImage = abs(bi.biWidth) * (bi.biWidth + padding);
bf.bfSize = bi.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(&bf, sizeof(BITMAPFILEHEADER), 1, outptr);


// write outfile's BITMAPINFOHEADER
fwrite(&bi, 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);

        // write RGB triple to outfile
       
        for (a = 0; a < n; a++)
        {
            fwrite(&triple, sizeof(RGBTRIPLE), 1, outptr);
        }
    }

    // skip over padding, if any
    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;

#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 (argv[1] < 0 || argv[1] > 101)
{
    printf("Enter a resize amount between 1 and 100!\n");
    return 1;
}

// remember filenames
char* infile = argv[2];
char* outfile = argv[3];

int n = atoi(argv[1]);

// 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);

bi.biHeight *= n;
bi.biWidth *= n;
int padding =  (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;
bi.biSizeImage = abs(bi.biWidth) * (bi.biWidth + padding);
bf.bfSize = bi.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(&bf, sizeof(BITMAPFILEHEADER), 1, outptr);


// write outfile's BITMAPINFOHEADER
fwrite(&bi, 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);

        // write RGB triple to outfile
       
        for (a = 0; a < n; a++)
        {
            fwrite(&triple, sizeof(RGBTRIPLE), 1, outptr);
        }
    }

    // skip over padding, if any
    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;

Source Link

asked Feb 11, 2016 at 9:14

Sun Zumwalt

pset4 Resize adding padding... and resize in general (HELP ME!)

I'm having a really hard time grasping pset4, I think I've changed the header files correctly but I'm not sure.. I feel like this pset is WAAAY harder than the last. I still barely understand a lot of it even after going through all of the videos at least twice each and writing most of it down. Anyway.. I've managed to get the image to resize but it comes out black and multi colored. I know I haven't done the padding yet but I don't even know where to start ): I'm getting pretty discouraged with cs and programming because I know it's only going to get tougher. So if anyone can give me some tips on where to get started with the padding or anything that's already wrong with my code it would be greatly appreciated.

#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 (argv[1] < 0 || argv[1] > 101)
{
    printf("Enter a resize amount between 1 and 100!\n");
    return 1;
}

// remember filenames
char* infile = argv[2];
char* outfile = argv[3];

int n = atoi(argv[1]);

// 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);

bi.biHeight *= n;
bi.biWidth *= n;
int padding =  (4 - (bi.biWidth * sizeof(RGBTRIPLE)) % 4) % 4;
bi.biSizeImage = abs(bi.biWidth) * (bi.biWidth + padding);
bf.bfSize = bi.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(&bf, sizeof(BITMAPFILEHEADER), 1, outptr);


// write outfile's BITMAPINFOHEADER
fwrite(&bi, 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);

        // write RGB triple to outfile
       
        for (a = 0; a < n; a++)
        {
            fwrite(&triple, sizeof(RGBTRIPLE), 1, outptr);
        }
    }

    // skip over padding, if any
    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;