wtf is inkdiary?

InkDiary is a native iPad and iPhone app built with Swift that recreates a magic journal demo originally shown on reMarkable tablets. The idea is that you write on the screen with an Apple Pencil, either asking a question or giving an instruction like draw a dog, and after you stop writing for about two seconds your handwriting fades away and an AI reply rises up on the paper in its place, either as flowing handwritten text or a simple sketch. The personality of the diary is inspired by Tom Riddle's diary from the Harry Potter books. Under the hood, the app uses PencilKit to capture handwriting on a simulated paper surface and detects when you pause writing to trigger a submission. It sends what you wrote to a multimodal language model that can read images, so it can recognize handwriting and understand requests in whatever language you wrote in, replying in that same language, whether English, Chinese, or Japanese. If you ask for a picture, the app calls a separate image generation service called APIMart to produce a simple line sketch or a small watercolor style image, which then fades onto the page. Text replies appear letter by letter, and Chinese responses can switch between two different handwriting style fonts. The app also remembers who it is talking to across sessions, with a settings page to view or clear that memory, and it uses a paper texture with grain and shading to make the screen look like real paper. To build it you need Xcode 16 or newer and a tool called XcodeGen to generate the project file, then you can open it in Xcode and run it on a real device after selecting your developer team. Before use, you configure two things in the app's settings, a chat model that is compatible with the OpenAI API and can accept images, and the APIMart image generation service with its own API key and base URL. The project is organized into view files handling the paper interface, ink canvas, and text or sketch reveal animations, plus service files handling the language model calls, image generation, and saved conversation history. The bundled Chinese fonts are used under the OFL license, and the project overall is released under the MIT license.