Compositor

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 — a folder's opacity dims everything inside it
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
Layer effects: Stroke, Drop Shadow, Color Overlay, Inner Shadow and Outer Glow, rendered on the GPU and editable at any time
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 the Magic tool — Wand selects by color, Object traces whatever you click (Tab switches)
Select Subject, and Expand, Contract and Feather on any selection
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, opacity and smoothing, in Paint or Erase mode (B and E), 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, ellipses and lines), which stay editable rather than being rasterized
Type tool (T): inline multiline editing in draggable, resizable paragraph boxes; font, size, color, alignment and spacing in the tool header; transform text and use it as a clipping mask
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
Rulers (⌘R), guides dragged from them, a layout grid, and Snap To for guides, grid, layers and document bounds
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, TIFF and Photoshop PSD (8-bit RGB only; not PSB or CMYK). PSD folders, masks, a subset of blend modes, and fill rectangles/ellipses stay editable; text and other vectors become pixels. A conversion report is shown before anything is applied.
Export JPEG with a live preview (⇧⌥⌘S); Copy Merged
Photoshop-style keyboard shortcuts throughout, remappable in Edit > Keyboard Shortcuts
Automatic updates, signed and notarized

Requirements

macOS 26.5 or later
Xcode 26 or later (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.