ItsPaint

MS Paint for the Mac. Paste a screenshot, number the steps, drag it out.

Preview markup has no step badges, no pixelate and no drag-out.

3.46 MB · free on the App Store · MIT · no network entitlement, so the kernel refuses a socket

brew install --cask joshlin2201/itspaint/itspaint

Download the disk image · Mac App Store · macOS 14+, universal

What makes it different

• 3.46 MB, and a window on screen in half a second. Krita is a gigabyte and built for painters. CleanShot X is $29 plus a cloud subscription. Preview is already on your Mac and will not number a step or pixelate a token.
• No network entitlement. com.apple.security.network.client is not requested, so the kernel will not open a socket for it. Three commands to check that yourself.
• Background removal with no ML model and nothing to download. Four corner-seeded flood selections, unioned. Thirty lines of code.
• The drawing engine has no UI. Packages/PaintKit imports Foundation, CoreGraphics, ImageIO, CoreText and UniformTypeIdentifiers, and nothing else, so swift test verifies most changes with no Xcode. It is also a package you can depend on.
• Free, MIT, and it stays that way. There is no account and no telemetry.

Paste the screenshot, number the steps, crop it, drag it out, close the window. Nothing lands on your Desktop.

PaintKit as a dependency

The engine is its own SwiftPM product, so you can draw, key out a background or encode a PNG with none of the app around it. No AppKit, no third-party dependency, macOS 12 and up.

.package(url: "https://github.com/joshlin2201/itspaint", from: "0.19.0")

Those two are served from the Swift Package Index's own API rather than written here, so they report what it built, on a machine that is not mine, and they go red without anybody having to notice. The same page records zero data-race-safety errors — every target in both manifests is swiftLanguageMode(.v6), so strict concurrency is on and nothing is waived.

The macOS 12 is deliberate. The app needs macOS 14; the engine does not and no longer says it does. It had the app's number by inheritance rather than by need, and a floor is not a warning a consumer can ignore — SwiftPM refuses to resolve at all when a dependency's deployment target is above yours.

PaintKit gets you a product shot off its page in four lines, on device, with no model and no network:

import PaintKit

let engine = PaintEngine(canvas: try ImageCodec.decode(contentsOf: input))
guard engine.removeBackground() else { fatalError("no background to remove") }
try ImageCodec.encode(engine.canvas, as: .png).write(to: output)

Those four lines are compiled on every push, by a CI job that builds them from a package outside this repository — the one that declares macOS 12, so the floor above cannot quietly rise. And the result is checked by counting transparent pixels rather than by whether the program exited quietly: on a 60px mark centred on a 400×400 page the count goes from 0 to 156,400, which is 160,000 minus the 3,600 pixels of subject, asserted for six subject sizes.

If you do depend on it: it ships often while it is in beta, and until 1.0 a minor version may still carry a breaking change to the document format — CHANGELOG.md says so at the top. Watch ▸ Custom ▸ Releases is the notification for that one thing. Watching the repository outright also mails you every issue and every comment, which is why most people do not.

What it does

Marking up

Getting things in and out

Remove a background with no model and no network

One command. It floods from all four corners and makes the union transparent. If the page is not actually separable it says so and changes nothing.

It knows what a page is, not what a subject is, so it works on logos, product shots and scanned diagrams. It is useless on hair.

How it works, in thirty lines of code →

Painting

Thirteen tools, fifteen shapes, and a transparent canvas. The window above is ItsPaint painting, not marking up.

Install

brew install --cask joshlin2201/itspaint/itspaint

Or take the disk image, open it and drag ItsPaint to Applications. It is also free on the Mac App Store.

It ships often while it is in beta. Watch ▸ Custom ▸ Releases is the quietest way to hear about a new build.

shasum -a 256 -c checksums.txt
xcrun stapler validate ItsPaint-*.dmg

If macOS asks you to confirm the first launch, open System Settings ▸ Privacy & Security and click Open Anyway. Why that happens.

No network. Three commands to prove it

This is a property the kernel enforces, not a promise anyone is making. The first two commands run against the copy in /Applications, the third greps this repository:

codesign -d --entitlements - --xml /Applications/ItsPaint.app | plutil -p -
otool -L /Applications/ItsPaint.app/Contents/MacOS/ItsPaint
grep -rniE 'URLSession|NWConnection|import Network|CFSocket' App Packages

The entitlements check goes first because it is the one that holds even if the developer is lying to you. It reports what the kernel will permit.

Why that order, and how to make the same claim falsifiable in your own app →

Contributing, and the engine needs no Xcode

Because PaintKit has no UI, most changes to how ItsPaint draws can be made and checked with a text editor and a terminal. No simulator, no GUI session, no Xcode project:

git clone https://github.com/joshlin2201/itspaint.git
cd itspaint
swift test          # the whole engine suite, in a fresh clone

Seven issues are open and labelled good first issue, each naming the file and the line to start at. They sit in three different parts of the app so you can pick whichever suits you:

View layer, AppKit drawing, no engine knowledge needed

• #11 A loupe that follows the pointer

Engine, pure functions over pixels, no Xcode needed

• #12 Brightness, contrast and saturation
• #5 Arrowheads as a line style, not a separate shape

Selection arithmetic, also engine-only

• #3 Grow and shrink a selection by a pixel amount
• #4 Make a selection from the alpha channel
• #6 Flip and rotate the selection, not the whole image
• #7 Add to and subtract from a selection

CONTRIBUTING.md covers the structure, the design constraints, and what a change has to prove before it lands.

Packages/PaintKit/   UI-free drawing engine, raster operations, undo, and codecs
App/                 AppKit document lifecycle, canvas, and SwiftUI interface

shasum -a 256 -c checksums.txt
codesign --verify --deep --strict --verbose=2 /Volumes/ItsPaint*/ItsPaint.app
spctl -a -vvv -t exec /Volumes/ItsPaint*/ItsPaint.app   # expect: accepted