bitmap-plus-plus

https://github.com/ruby-rice/BitmapPlusPlus-ruby

BitmapPlusPlus is a Ruby gem that provides bindings to the BitmapPlusPlus C++ library for creating and manipulating 24-bit BMP images. Features include drawing primitives (lines, rectangles, triangles, circles), pixel manipulation, image transformations (flip, rotate), and file I/O. Uses Rice for C++ to Ruby bindings.