imginj

README

This Golang code is about a program that manipulates PNG images, allowing users to view metadata, inject data into images, and encode/decode payloads.

1. The program starts by importing necessary packages, including some custom ones for handling PNG images and utilities.

2. It sets up command-line flags that users can use to control the program's behavior. These flags include:

   • Input and output file paths
   • Options to view metadata
   • Options to inject data at a specific location in the image
   • Options to encode or decode data using a key

3. The init() function sets up these flags and does some basic error checking. For example, it makes sure required flags are provided and that certain flags aren't used together when they shouldn't be.

4. The usage() function provides examples of how to use the program.

5. The main() function opens the input file, prepares it for processing, and then processes the image based on the options provided.

To write this code, the developer likely followed these steps:

1. Decide on the features needed (viewing metadata, injecting data, encoding/decoding).
2. Choose appropriate libraries to help with PNG manipulation and command-line parsing.
3. Set up the command-line interface using the pflag package.
4. Implement error checking to ensure the program is used correctly.
5. Create the main logic for processing the image based on the provided options.
6. Test the program with various inputs and options to ensure it works as expected.

The thought process involves breaking down the problem into smaller parts (parsing command-line options, reading PNG files, manipulating image data) and then implementing each part step by step. The developer also had to consider different use cases and potential errors to make the program robust and user-friendly.