(Part 1 of 2): Creating a PGM image file in C: A step-by-step guide using `fopen` and `fprintf`”

[Rajeev Bagra]

Query: I need to create an image file with just 0 and 1 using C and Codespace account. Kindly code and help.

ChatGPT:
To create an image file with just 0 and 1 using C, you can use the PGM (Portable Graymap) format, which is a simple grayscale image format. Here’s a step-by-step guide to achieve this:

1. Set Up Your Codespace: Ensure you have a Codespace account set up and a workspace ready.

2. Write the C Program: Below is a sample C program that creates a PGM image file with a pattern of 0s and 1s.

3. Compile and Run the Program: Use the terminal in your Codespace to compile and run the program.

Here’s the complete code:

C Program to Create a PGM Image

#include <stdio.h>
#include <stdlib.h>

void generate_pgm(const char *filename, int width, int height) {
    FILE *file = fopen(filename, "wb");
    if (!file) {
        fprintf(stderr, "Could not open file for writing.\n");
        exit(1);
    }

    // Write the PGM header
    fprintf(file, "P2\n%d %d\n1\n", width, height);  // P2 means ASCII PGM, 1 means max value for pixels

    // Generate and write the pixel data
    for (int y = 0; y < height; ++y) {
        for (int x = 0; x < width; ++x) {
            int value = (x + y) % 2;  // Alternating 0 and 1
            fprintf(file, "%d ", value);
        }
        fprintf(file, "\n");
    }

    fclose(file);
}

int main() {
    const char *filename = "output.pgm";
    int width = 10;  // Change this to your desired width
    int height = 10; // Change this to your desired height

    generate_pgm(filename, width, height);

    printf("PGM image generated successfully: %s\n", filename);
    return 0;
}

Steps to Compile and Run the Program

1. Create a New File: In your Codespace, create a new file named generate_pgm.c and copy the above code into this file.

[Author]

Posts