Smart region detection
Vision-based segmentation into paint regions.
iOS · iPad · Creative utility
Paint by Code
Turn photos into paint-by-numbers canvases. Color in the app or export and print at home.
The idea
A classic hobby, from your photos
Paint by numbers is a classic hobby: a picture broken into numbered regions, each matched to a color on a legend. Fill the numbers and the image appears. The idea took off in the early 1950s and has stayed popular for about seventy-five years as a calm way to paint without starting from a blank canvas.
Paint by Code makes that old craft new again. Upload a photo, and the app turns it into a paint-by-numbers drawing: numbered regions plus a color legend. Paint in-app with Apple Pencil, or export for print sizes like A4 and Letter. No cloud required for the conversion.
Capabilities
What you can do
From photo to numbered canvas, without sending your images to a server.
Create
Numbered canvas
Canvas and color legend generated from the photo.
Paint mode
Color in-app with PencilKit-friendly input.
Pencil matching
Match the legend to brands like Faber-Castell, Prismacolor, Bruynzeel, and Ohuhu.
Finish
Export and print
A4, Letter, and square export options for home printing.
Color & detail
Tune color count, detail level, and canvas format before you paint.
Share sheet
Send exports to Files, AirDrop, or print from the iOS share sheet.
On device
Local processing and saves. No account, no cloud dependency.
From photo to craft
Making a creative hobby technical
Paint by numbers is tactile. Paper still wins when you want a finished piece on the wall. The iPad wins when you want to undo a stroke, zoom into a tight region, try colors before you commit, and keep every canvas in one place without wasting sheets.
Paint by Code keeps both paths open: paint in-app with Apple Pencil, or export and print for A4, Letter, and square. When you print, the color legend can match real colored-pencil brands such as Faber-Castell Polychromos and Prismacolor Premier, so the numbers map to pencils you already own. The conversion stays on device, so the hobby can stay offline and personal either way.
On iPad
From photo to numbered canvas
Three steps on the big screen: pick a photo, dial in detail, then paint or print.
Built with
Tech stack
On-device image pipelines with Vision, Core Image, and PencilKit.
SwiftUI
Native iOS and iPadOS interface for picking photos, painting, and exporting canvases.
PencilKit
In-app painting with Apple Pencil support, undo, and zoom-friendly strokes.
Vision
On-device region detection that turns a photo into paint-by-numbers areas.
Core Image
Image processing for palette extraction and canvas generation from your photo.
PhotosUI
System photo picker so canvases start from images already on your device.
Core Graphics
Numbered regions, legends, and print-ready layouts drawn on device.
PDFKit
Export for A4, Letter, and square prints without leaving the app stack.
ShareSheet
Hand exports to Files, AirDrop, or print through the iOS share sheet.
On-device
Conversion stays local. No cloud account required for the photo-to-canvas pipeline.
Updates
Changelog
Another big step for Paint by Code: a real app home, full Dutch, gallery power tools, and a smoother Paint Studio.
Added
- Tab bar — Create, Canvases, and Settings as first-class homes (Paint Studio / result stay fullscreen)
- Language — System / English / Nederlands, with a full Dutch string catalog across Create, Customize, Processing, Gallery, Settings, Paint Studio, and export
- Look presets on Customize — Poster, Soft watercolor, Bold comic (one-tap colors, smoothing, region size, and line style)
- Before ↔ After compare slider on Your Canvas — drag to compare quantized photo vs painted result
- Stats — quiet paint-time tracking (today, this week, active days, average, busiest day, week chart, library counts); no streaks or badges
- App Settings — default pencil brand, Paint Studio defaults, new-canvas defaults, Resume tile, haptics, keep screen awake, preferred look, Rate, Send feedback
- Firebase feedback — Settings → Send feedback writes to your Paint by Code Firestore project
- Gallery folders — create, rename, delete folders; filter chips; move canvases into folders
- Gallery multi-select — select many canvases, then Move or Delete
- Gallery swipe-to-delete with confirmation
- Clear selected photo on Create — dismiss preview and return to pick Library / Camera
- Resume last canvas on Create — shows last opened (relative time) under the wizard
- Collapsible Settings sections with live summaries when closed
- About & how it works as one Settings row (was separate Create toolbar actions)
Changed
- Create wizard redesigned — cleaner step flow, richer Library/Camera rows, look chips after photo pick, clearer Continue to Customize; iPad side-by-side layout
- Create copy emphasizes digital coloring (not only print)
- Create tab label in Dutch: Nieuw (instead of “Maken”)
- Customize: step 3 of 3 header; photo preview removed so controls use full width
- Paint Studio: pinch to zoom while drawing (1 finger / Pencil draws; pinch zooms; 2 fingers pan) — Zoom mode optional for one-finger pan
- Gallery list layout — wider thumbnails, denser rows, horizontal header
- Opening a saved canvas no longer freezes the UI (background load + “Opening canvas…”)
- Export options sheet opens larger by default
- Settings collapse animation stays inside its own card
- Localization uses the active in-app language reliably (status tips, gallery counts, export titles, resume dates)
Fixed
- Language switch no longer remounts the whole app (avoids SIGKILL / jetsam on device)
- Dutch UI still showing English in Settings summaries, Create copy, resume dates, and Paint Studio status
- Rate / review button: clearer behavior in Simulator vs live App Store review link
- Canvas open felt stuck — heavy decode work moved off the main thread; gallery no longer decodes huge segmentation JSON just to list items
Removed
- Example / teaser canvas on Create (tabs replace the old home chrome)
- Separate Create toolbar for About / How it works
- Tip strip under Create after Resume moved into the wizard flow
- Draw / Zoom modes and expanded brushes
- Layer lock, opacity, visibility, and reorder
- Tap-to-fill by number and reference fade
- Timelapse, print kit PDF, and paper guides
- More reliable stroke saving and eraser
- First release: photo to paint-by-numbers
- Paint Studio with Apple Pencil support
- My Canvases gallery
- Line art PNG/PDF export with color legend