an opinionated terminal multiplexer in C with programmable pane chrome https://git.sl0p.foo/slosh.git/atom/src/png.c?h=docs-new 2026-08-15T17:14:59Z 2026-08-15T17:14:59Z user user@clank 2026-08-15T17:14:59Z urn:sha1:2f0b3426d0f40d2cf53740cb597495af2c45bc2e Kitty graphics were green in the suite and a real program still drew nothing. libghostty-vt ships no image codec: built as a library it sets its `sys.decode_png` hook to null, and a null hook rejects every `f=100` transmission outright -- no image stored, so no placement exists, so the re-emission layer this project is mostly *about* is never reached. The program gets no error and no picture. Raw RGB worked throughout, which is why it looked done: every test here sent raw pixels, because that is what is easy to write in a test. It is the same lesson the last kitty graphics bug taught -- write the test the way a program actually behaves -- and a program with a picture on disk has a PNG. Found because ida-tui's startup logo never appeared, and its detection probe answers `OK` first, so it fails silently rather than falling back to its block art. PNG is the whole of the gap and cannot grow: the protocol has exactly three formats (`f=24`, `f=32`, `f=100`), the first two are raw pixels lib-vt already handles, and `decode_png` is the only codec hook it has. Decoding only, never encoding. The decoder is the stb_image lib-vt already vendors and we already commit -- upstream compiles that same header with the same `STBI_ONLY_PNG` for this same purpose, it is just not in the `-Demit-lib-vt` build. So nothing new is pulled in; a file we already ship is finally compiled. src/png.c is the hook, a header pre-check and a copy: dimensions are read before decoding because the buffer we return is allocated through lib-vt's limited allocator but stb's own working allocation is plain malloc and answers to nothing. Tests cover a PNG placed at the size it asked for (RGB and RGBA sources, both normalised to RGBA), the client being handed `f=32` rather than the png it was given, and a malformed png placing nothing without taking the pane with it. They fail on the previous binary.