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 used to 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.
Installation
Download
Get Compositor from robbietilton.com/compositor, or download the latest release directly from GitHub Releases.
Homebrew
brew install --cask robbietilton-compositor
Features
Layers
- Layers and folders, with opacity and Photoshop's full set of blend modes in its order — a folder's opacity dims everything inside it
- Layer masks: paint, fill, invert, blur and feather them anywhere on the canvas, past the layer's own pixels; 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, Grain, Black & White, Color Balance, Invert, and filter layers: Gaussian Blur, Motion Blur, Progressive Blur, Sharpen, Noise, Vignette, Bloom / Glow, RGB Split, Lens Effects and Tonal Contrast
- Layer effects: Stroke, Drop Shadow, Color Overlay, Inner Shadow, Outer Glow and Inner 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; a right-click menu in the Layers panel
- Copy and paste whole layers and folders (⌘C/⌘V with no selection), within a project or between projects, or drag them between 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
- Align and Distribute layers to each other, the selection or the canvas, from the Move tool's bar or the Layer menu
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
- Pen pressure for the Brush's size and opacity, on a graphics tablet
- 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
- Camera Raw filter: light, color, curves, color mixer, color grading, detail, optics and geometry, in a panel beside the canvas; each section resets to its defaults from its header
- Levels (with Auto), Curves, Hue/Saturation, Exposure, Gradient Map, Grain, Black & White, Color Balance and Invert
- Gaussian Blur and Motion Blur that spread past a layer's edges
- Sharpen, Add Noise, Vignette, Bloom / Glow, Dither, Scanlines, RGB Split, Lens Effects (anamorphic flare, starburst, mist, prism and bokeh in round, hexagon, oval or cat's-eye shapes), Tonal Contrast, Rim Light (up to three colored lights behind the subject, with glow that wraps it into the light), Lens Correction and Remove Background
- Live previews, limited to the selection when there is one
- Last Filter (⌃⌘F) runs the last filter again with the same settings
Canvas and files
- Multiple projects in tabs
- Search Commands (⌘F): find every menu command and tool by name, as in Raycast or Obsidian, and run it with Return
- Toggle Fullscreen (F): the canvas alone on black over the whole screen, with every panel put away; F or Esc brings them back
- Rulers (⌘R), guides dragged from them, a layout grid with adjustable spacing and subdivisions, and Snap To for guides, grid, layers and document bounds
- Crop with snapping, ratios including 3:4 and 9:16, and Option for symmetric cropping; with a selection, the crop starts at it
- Canvas Size, Image Size and Trim
- The tool bar moves into two columns when the window is too short for one
- A Navigator minimap in the canvas's corner from 300% zoom: the whole document in small with a box around the view; click or drag to move there (View › Navigator)
- Sharp high-quality downsampling when zoomed out, and a pixel grid when zoomed in
- Import JPEG, PNG, HEIC, TIFF, WebP, SVG, PDF (every page its own layer, at 300 DPI or fitted to the canvas), animated GIF (one layer whose frames show in a strip under the canvas, to play, paint on, duplicate, delete and retime), camera RAW (with a develop step first) and Photoshop PSD and PSB (8-bit RGB; not CMYK). Each Photoshop artboard opens in a tab of its own; folders, masks, blend modes, fill rectangles/ellipses, and simple horizontal text stay editable; other vectors and vertical text become pixels. A conversion report is shown before anything is applied.
- Large documents: the memory budget scales with your Mac, and a Photoshop file too big to open has its layers cropped to the canvas instead
- Export PNG (⇧⌘E), Export JPEG (⇧⌥⌘S), and Export As (⇧⌥⌘W) for PNG, JPEG, a one-page PDF at the print size or, with a GIF layer, an animated GIF, scaled if you like, with a live preview, JPEG quality and file size; Channel Pack in Export As packs layers into a PNG's red, green, blue and alpha for game textures, and RGB Split's Split to Layers turns a layer back into those four; right-click layers in the Layers panel to export each as its own PNG, trimmed to its pixels; Copy Merged
- Keep working while a project saves
- Photoshop-style keyboard shortcuts throughout, remappable in Edit > Keyboard Shortcuts
- Drag a number's label to scrub its value, as in Photoshop
- Automatic updates, signed and notarized
Works with AI agents
- AI agents and scripts can build and edit projects directly: a
.comp is a folder of PNG layers and a manifest, and an open project updates live as it's written. See Writing Compositor projects
Requirements
- macOS 26.0 or later on a Mac with Apple silicon
- Xcode 26 or later (to build from source)
Translations
Compositor is English only for now, and translation pull requests aren't being accepted. It's maintained by one person, every new string would need translating from then on, and translations in languages I don't read can't be reviewed. I'll revisit this once the app settles; until then, please don't open localization PRs.
Other platforms
Compositor is macOS only. These unofficial ports are made by others, not reviewed or supported by me, so please report issues to them:
More are listed in #23 (Windows) and #19 (Linux).
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.
