Adobe Photoshop costs too much and tools like GIMP don’t feel familiar enough for me to stay in flow. That’s why I built Compositor.

The goal was to create a full-featured image editor that is completely free and open source. I use Photoshop for compositing and post-processing, so Compositor is built around that workflow - with the tools needed to create a pixel-perfect final image.

Because it’s open source, you can download the Xcode project and add, remove, or modify any feature to fit your workflow.

Features

Layers

• Layers and folders, with blend modes and opacity
• Layer masks: paint, fill, invert, blur and feather them; link or unlink them to transform a mask on its own
• Clipping masks and folder masks
• Adjustment layers: Hue/Saturation, Levels, Curves, Exposure, Gradient Map and Grain
• Merge Down, Merge Layers and Merge Group (⌘E)
• Duplicate, rename inline, reorder and nest by drag and drop; Option-drag to duplicate
• Drag layers between open projects

Transform

• Non-destructive move, scale, rotate and flip — images keep their full resolution however small you make them
• Free distort (⌘-drag a handle), with Shift to lock to an axis
• Transform several layers, or a whole folder, together
• Snapping to canvas and layer edges and centers, with guides
• Exact values for position, size, scale and angle, stepped with the arrow keys
• Flip Layer and Flip Canvas, horizontal and vertical

Selections

• Rectangle and Ellipse Marquee, Freehand and Polygonal Lasso, and Magic Wand
• Add to and subtract from selections, move the outline, or move and duplicate the pixels inside
• Load a layer's pixels or a mask as a selection
• Content-Aware Fill, which can also extend an image past its edges

Painting and retouching

• Brush with size, hardness and opacity, and Shift for straight lines
• Spot Healing Brush (content-aware)
• Clone Stamp, aligned or not, sampling one layer or all of them
• Blur tool, on pixels or masks
• Gradient tool and Shape tool (rectangles, rounded rectangles and ellipses)
• Eyedropper and a full color picker

Adjustments and filters

• Levels (with Auto), Curves, Hue/Saturation, Exposure, Gradient Map, Grain and Invert
• Gaussian Blur and Motion Blur that spread past a layer's edges
• Add Noise, Lens Correction and Remove Background
• Live previews, limited to the selection when there is one

Canvas and files

• Multiple projects in tabs
• Crop with snapping, and Option for symmetric cropping
• Canvas Size and Image Size
• Sharp high-quality downsampling when zoomed out, and a pixel grid when zoomed in
• Import JPEG, PNG, HEIC and TIFF — including dropped screenshots and images from other apps
• Export JPEG with a live preview (⇧⌥⌘S); Copy Merged
• Photoshop-style keyboard shortcuts throughout

Requirements

• macOS 26
• Xcode 26 (to build from source)

Building

Open Compositor.xcodeproj and run the Compositor scheme.

Releasing

scripts/release.sh builds a Release version, signs it with Developer ID, notarizes and staples it, and packages it into dist/Compositor-<version>.dmg.

It needs, all kept outside this repository:

• a Developer ID Application certificate in the login keychain
• notarization credentials saved with xcrun notarytool store-credentials "compositor-notary" …
• create-dmg (brew install create-dmg)

License

MIT — see LICENSE.