Release 1.2.0 (2026-08-23) - API documentation, published at <https://ocaml.org/p/ifs-fractals> and built locally with `dune build @doc`. The library has an interface file, `lib/ifs_fractals.mli`, in which every type, function and predefined fractal carries a documentation comment, and `doc/index.mld` is the landing page of the package. The interface also settles what the library actually offers: the plumbing of the PNG writer (`output_png`, `add_chunk`, `crc_table`, `encode`, `ramp_color`) and of the Fractint reader (`words`, `group_entries`, `thresholds`, `cumulate`, ...) is no longer exported, along with `select_image`, `pixel_of_point`, `accumulate` and `viewport`. Everything the command and the documented API use is unchanged. - Fixed: `sierpinski` drew an empty window and `koch` a speck in the middle of one. Both had their coefficients written in the order of a Fractint table — `a b c d e f` for `x' = a*x + b*y + e` — rather than the order of `kf`, so neither described the fractal it was named after, and neither landed in the region its record asked to display. The transforms are reordered and both viewports now frame the attractor: `sierpinski` is the triangle on (0,0), (2,0), (1, √3), and `koch` the curve from (0,0) to (1,0). This had been the case since the first commit, in 2010. - A test suite, run with `dune test`: the affine maps and the projection, the chaos game, the framing of an attractor, the Fractint parser and the errors it reports, and the PNG writer, whose output is decoded and checked rather than counted in bytes. It needs no display and no new dependency. - The predefined fractals moved out of `lib/ifs_fractals.ml` into their own `lib/fractals.ml`, together with the `point`, `transfo` and `ifs` types, so that adding or tuning a fractal no longer touches the code that draws it. `Ifs_fractals` re-exports them, so the library API is unchanged, and so is the toplevel workflow (the loader now uses `#mod_use` for the new file). - `show fs n` draws a fractal, waits for a keypress and closes the window. Unlike `draw`, it leaves the program inside an event call, which is what lets the window manager's close button work. - Fixed: after the graphics window was closed — by `Graphics.close_graph` or by the window manager — `draw` failed with `Graphic_failure "graphic screen not opened"` instead of opening a new window. `window_open` is now a function that asks the graphics library rather than a stale flag. - Fractals can be read from Fractint `.ifs` files: `ifs-fractals -f FILE.ifs NAME` from the command line, `load_fractint` from the library. The format's plain weights are converted to cumulative thresholds (or derived from each map's determinant when the file gives none), and the viewport, which the format does not record, is fitted to the attractor by `fit`. `example/classics.ifs` collects a dozen classic systems to try it on. - Three-dimensional systems — Fractint's `(3D)` entries, twelve or thirteen numbers per transform — are read and drawn as well, projected orthographically from a direction given by `-v YAW,PITCH` in degrees (`?yaw` and `?pitch` in the library). Reading a file now returns a `system`, either `Flat of ifs` or `Solid of ifs3`; `draw_system`, `show_system` and `save_png_system` take either.