What is Ruwa

Ruwa is a raster painting app and a layer-based image editor in the same window. It runs on 64-bit Windows 10 and Windows 11, it's free, and the source is open. Accretion builds it.

Philosophy

Painting and editing in one project

Painting apps give you brushes and a canvas. Image editors give you layers, masks, and precise adjustments. Most finished illustrations need both, so you end up exporting out of one program and importing into another every time the work changes gear.

Ruwa points both toolsets at the same .rwf project. A sketch, a painted pass, a Liquify correction, a stack of adjustment layers — all of it is one file that stays editable the whole way through.

Non-destructive editing

Masks, clipping, blend modes, adjustment layers, smart layers, and layer effects change how a layer is composited. The pixels underneath stay untouched. Layer transforms keep their source resolution, and text and smart layers stay editable until you rasterize them yourself.

You get this from the first second, too: a new project opens with an empty Draw here layer sitting above Background, so your first stroke has somewhere to land that isn't the background.

A workspace you actually arrange

Every panel around the canvas can be shown, hidden, docked, floated, or resized, and Ruwa remembers where you left things. Named layouts save a whole arrangement — panels, Canvas widgets, the lot — and export to .json if you want the same setup on another machine.

Ruwa starts you on the built-in Base layout. The Canvas widgets are there for setups where the keyboard isn't in reach: the Joystick puts panning, rotation, and zoom on the canvas itself, and Brush Control keeps size and opacity next to your hand.

Free and open source

No subscription, no paid edition. The source code is on GitHub, development happens in the open, and you can build the app from it if you'd rather not run someone else's binary.

A narrow scope

Ruwa is a raster painting and editing app for Windows, and the work goes into making that set of things good rather than piling on more. Parts of it are unfinished. The list below is what's actually in there today.

What Ruwa includes

Canvas — Classic canvases with fixed dimensions or an infinite canvas, at 8-bit, 16-bit, or 32-bit float color depth. Several projects can stay open at once as tabs.
Brushes — Four brush packs with 15 brushes, a Brush Editor, custom input curves for many parameters, Photoshop .abr import, and Ruwa .rbf import and export.
Color — A color wheel, HSV and hexadecimal input, recently used colors, and a spectral pigment model that wet brushes mix with.
Layers — Paint layers, groups, masks, clipping, blend modes, text layers, smart layers, adjustment layers, and non-destructive layer effects.
Tools — Brush, Eraser, Lasso and Lasso Fill, Blur, Smudge, Liquify, Canvas Resize, and the Hand, Zoom, Rotate View, and Move navigation tools.
Files — .rwf projects, legacy .uwa projects, image import from PNG, JPEG, BMP, GIF, WebP, TIFF, and TGA, and export to PNG, JPEG, and WebP.

Documentation coverage

Brushes, layers, color, tools, and file handling all work in the app but have no pages here yet. Ask in the Ruwa Discord server if you need one of them before it's written.

When to use Ruwa

Taking a painting from sketch to export

This is the path the default workspace and the default layer setup are built around. Your first painting walks it end to end: create a project, paint, keep the .rwf, export an image.

Working on a pen display or tablet

The Joystick handles panning, rotation, and zoom on the canvas itself. Brush Control keeps size, opacity, brush selection, and your starred settings within reach of the pen. Both widgets move anywhere and save per layout, so a tablet arrangement and a desktop arrangement can live side by side.