Matplot++ is a C++ graphics library for data visualization that provides a MATLAB-like API for creating publication-quality plots. It supports a wide range of plot types including line, scatter, bar, histogram, surface, contour, polar, geographic, and 3D plots, as well as image display, graph visualization, and annotations. The library is designed for scientific computing and engineering applications, offering both free-standing function calls and an object-oriented interface with method chaining. It features a pluggable backend architecture with Gnuplot as the primary rendering backend (via pipe communication) and an experimental OpenGL backend. The library handles data transformation, automatic tick calculation, colormap interpolation, contour generation (adapted from Matplotlib), histogram binning with multiple algorithms, and geographic map rendering using bundled Natural Earth data. External dependencies include Gnuplot 5.2.6+ at runtime, with optional support for image processing libraries (CImg, JPEG, TIFF, PNG, OpenCV) and numerical libraries (FFTW, LAPACK, BLAS). The build system is CMake-based with comprehensive options for testing, examples, and documentation generation. Architecturally, the library is organized around a core figure-axes-object hierarchy: figure_type manages the canvas and backend, axes_type holds plot objects and axis configuration, and individual plot types (line, bars, histogram, etc.) inherit from axes_object and implement backend-specific rendering methods. Free-standing functions in freestanding/ forward calls to the current axes via a global figure registry. The backend interface abstracts rendering commands, allowing the same plot objects to work with different backends. The library includes a large set of examples (200+) that serve as both documentation and integration tests, and a documentation pipeline that auto-generates a gallery from example executables. Key entry points for users are the matplot.h header and the free-standing functions (plot, hist, surf, etc.). The library is consumed via CMake's find_package or as a subdirectory. It supports both interactive (reactive) and non-interactive (quiet) modes, and can save plots in multiple formats (SVG, EPS, PNG, PDF, etc.) through backend-specific commands.