# `RasterExRatatui` [๐Ÿ”—](https://github.com/mcass19/raster_ex_ratatui/blob/v0.4.0/lib/raster_ex_ratatui.ex#L1) Render [ExRatatui](https://hexdocs.pm/ex_ratatui) apps on pixel displays such as e-ink panels, with helpers for Linux framebuffers. A terminal turns cells into pixels by itself. A bare panel does not, so something has to paint every cell's glyph in its colours, and blit the bitmaps that pixel-mode widgets (`ExRatatui.Widgets.Viewport3D`, `ExRatatui.Widgets.Image`) hand to an `ExRatatui.CellSession` created with a `:font_size`. This package is that something, in three layers: โ”Œโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ” โ”‚ Surface use RasterExRatatui.Surface โ”‚ โ”‚ a process that owns a Session and calls push/2 โ”‚ โ”œโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”ค โ”‚ Session app server + cell session + raster, no process โ”‚ โ”‚ handle/2 folds renders into patches โ”‚ โ”œโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”ค โ”‚ Raster Grid (cells + regions) โ†’ [Patch] | full frame โ”‚ โ”‚ Font ร— Palette ร— PixelFormat ร— scale โ”‚ โ”œโ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”ค โ”‚ Device Framebuffer (fbdev) ยท Input.Evdev (keyboards) โ”‚ โ”‚ or the consumer's own driver (SPI, e-ink, โ€ฆ) โ”‚ โ””โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”€โ”˜ ## Where to start * `RasterExRatatui.Surface` โ€” the contract a device implements: panel geometry in `init/1`, pixels out in `push/2`, input in through `send_event/2`. Most consumers only write this module. * `RasterExRatatui.Session` โ€” the same app-on-a-raster without the process, for consumers that already own one: start it there, fold its messages with `handle/2`, write the patches. * `RasterExRatatui.Raster` โ€” the pure rasteriser underneath: payloads in, patches or a frame out. * `RasterExRatatui.Font`, `RasterExRatatui.PixelFormat` โ€” the two behaviours that make the output fit a panel: glyph bitmaps and pixel packing. * `RasterExRatatui.Framebuffer`, `RasterExRatatui.Input.Evdev` โ€” optional helpers for Linux framebuffers and evdev keyboards. * `RasterExRatatui.Telemetry` โ€” the events the surface emits. --- *Consult [api-reference.md](api-reference.md) for complete listing*