Show HN: Paintpot – Kid-friendly MSPaint clone for Linux

A fast, friendly, pixel-perfect paint program in the spirit of classic (XP-era) MS Paint, for Windows and Linux. It is a true pixel editor: what you draw is pixels, immediately. There are no vector objects, no layers to manage, and no antialiasing smudging your edges, so the paint bucket always does exactly what a child expects. "Paintpot" is a working name; see Naming. Features Tools (classic toolbox order): Select, Eraser / Color eraser, Fill, Pick color, Magnifier, Pencil, Brush (round/square, any size), Airbrush, Text, Line, Curve (2-bend Bezier, as in Paint), Rectangle, Polygon, Ellipse, Rounded rectangle. Left button = primary color, right button = secondary color on every tool. Shapes: outline / outline + fill / solid, line widths 1 to 12, Shift for square/circle/45°. "From center" mode for ellipses and rectangles: click the centre, drag the radius, for perfectly centred circles (odd sizes, symmetric). Alt flips the mode while dragging. Text: any installed font, size, bold/italic, transparent or opaque background. Text is aliased like everything else, so letters can be bucket-filled cleanly. Fill: 4-connected scanline flood fill, exact match by default, with an optional tolerance slider (for photos/JPEGs) and an "Everywhere" mode that replaces a color throughout the picture. Selection: move, Ctrl+drag to copy, transparent mode (secondary color is see-through), Delete, Cut/Copy/Paste through the system clipboard (pasting to/from other apps works), Crop to selection. Image: flip, rotate 90/180, invert colors, stretch (nearest-neighbour), canvas size, drag handles on the canvas edge to resize, clear image. Shrinking the canvas never destroys pixels. Pixels cut off by making the picture smaller are kept hidden; make it bigger again and they come back (shown faded while you drag). Tools, fill and saving only ever see the visible picture. Hidden pixels are frozen as they were, and are dropped by flip, rotate, stretch, crop, New and Open. Zoom from 12.5% to 3200%, pixel grid at high zoom, Ctrl+wheel zoom around the cursor, middle-drag to pan. Undo/redo (500 steps; only the changed rectangle is stored, so it's cheap). Open PNG, BMP, JPEG, GIF, TIFF, WebP, ICO; save PNG, BMP, JPEG, GIF, TIFF, WebP. Drag a file onto the window to open it, or pass it on the command line. Unsaved-changes prompt on New/Open/Exit. Design notes Why no antialiasing (and why the fill is reliable). Every primitive writes whole pixels of a single color. Lines are Bresenham (8-connected), and filled/outlined shapes are built from per-row spans whose outline is "every inside pixel that touches the outside". The flood fill is 4-connected. Together that gives a guarantee: a fill started inside a closed shape can never leak out, and it never leaves a ring of half-blended pixels behind. src/raster.rs has tests that draw thousands of ellipses, rectangles, rounded rectangles, lines and curves at every size from 1x1 to 40x40 and assert that the fill stays inside. My suggestion on antialiasing: keep the canvas aliased, always. If smooth edges are wanted later, add them as an opt-in per-shape "Smooth" toggle (off by default) and pair it with the fill tolerance slider, which already exists for exactly that case (filling a picture that came in with soft edges, e.g. a JPEG or a screenshot). Why Rust + egui (not GTK, not Python, not C). Rust compiles to a single native executable, is as fast as C, and its memory safety makes a canvas full of index arithmetic much less scary. egui/eframe draws the whole UI on the GPU and builds with nothing but cargo on both Windows and Linux. GTK4 on Windows means shipping the GTK runtime, which is painful. The UI library only displays the picture: the canvas is our own Vec of pixels, uploaded as a texture (only the changed rectangle each frame). All drawing is our own code, so it is exact and fast. Python would be too slow for flood fills on large pictures without a C extension, which is where you started. Code layout Keyboard Building You need Rust (https://rustup.rs). cargo run --release cargo test Windows: use the default MSVC toolchain (Visual Studio Build Tools with the C++ workload). The minimal x86_64-pc-windows-gnu toolchain on its own is not enough: it lacks the assembler that dlltool needs. Keep the project in a short path (e.g. C:\src\paintpot); some dependency build scripts exceed Windows' 260-character path limit otherwise. Linux (Debian/Ubuntu): sudo apt install build-essential libxkbcommon-dev libxcb-render0-dev libxcb-shape0-dev libxcb-xfixes0-dev libwayland-dev cargo run --release File dialogs use the XDG desktop portal (works on GNOME, KDE and most desktops). Arch Linux: A PKGBUILD is included in this repo. To build and install a package from source: curl -LO https://raw.githubusercontent.com/marktbaldridge/paintpot/main/PKGBUILD makepkg -si This pulls a tagged release tarball, builds it with cargo, runs the test suite, and installs paintpot via pacman. Only cargo is needed to build; everything else (libxkbcommon, Wayland/X11, Mesa, xdg-desktop-portal) is a normal runtime dependency already present on most desktop installs. No AUR package yet — this is the first step toward one. Roadmap ideas Free-form selection; moving the caret inside text being typed Stretch/skew a selection, resize selection by its handles Remember custom palette colors and window settings between runs Tiled canvas textures for pictures larger than 8192 px Optional per-shape smoothing (off by default; see design notes) Packaging: MSI/winget for Windows, Flatpak/AppImage for Linux "OpenPaint", "NeoPaint", "TuxPaint", "KolourPaint", "Pinta" and "mtPaint" are taken. Some candidates, none checked for trademarks or existing projects yet: Paintpot: friendly, says "paint" plainly, easy for kids to say Daub: short and distinctive (to daub = to smear paint) Crayonbox: instantly reads as "for kids" Splotch: playful Pixie Paint: hints at pixels, playful Doodlebox