Question

Is there a way to do this using fread/fwrite? I have the exact coordinates of the rectangle from the image I want to crop.

Answer 1

Most image files are more complex than just an array of pixels. They often contain headers with metadata and compress the image data in some way.

Editing them is often done with some sort of library, such as Magick++. These libraries contain classes and functions for

• opening image files and reading in the image data
• Modifying the image data with built-in functions, such as cropping, scaling, etc.
• Getting access to the raw image data (often exposed as an array of pixels) so the programmer can modify it in ways not provided by the library.
• saving image files