Photo Contact Sheet

Project roadmap

1. 01

   Plan the app

   ~1h

   Write README.md: the screens (a list of saved sheets, and a sheet editor with photo selection, layout settings and a preview), the settings (columns from 2 to 6, spacing, background color, and labels: none, date taken or a custom caption) and the output (a PNG or JPEG image up to a maximum size). Create a SwiftUI project. Done when: README.md describes the screens, settings and output.

2. 02

   Model sheets with SwiftData

   ~1.5h

   Create a SwiftData model ContactSheet with a title, creation date, the layout settings, and the chosen photos stored as PhotosPicker item identifiers plus small cached thumbnails. Build the list of sheets with @Query, with create and delete. Validate settings (columns within range and at least one photo before exporting). Done when: sheets are saved and listed after restarting the app.

3. 03

   Pick photos

   ~1.5h

   Use PhotosPicker with multiple selection (up to 36 photos) to choose images, load them with loadTransferable, fix their orientation, and create small thumbnails for the editor. Show a message for photos that fail to load (for example iCloud photos while offline). Allow reordering and removing photos. Done when: selected photos appear in the editor in the chosen order.

4. 04

   Lay out and render the sheet

   ~2h

   Build the sheet as a SwiftUI view: a grid (with LazyVGrid or Grid) of square-cropped photos with labels underneath, using the chosen columns, spacing and background. Render it to an image with ImageRenderer at a fixed width (for example 3,000 pixels) for good print quality. Show a preview that updates when settings change. Done when: changing settings updates the preview, and rendering produces a sharp image.

5. 05

   Save and share

   ~1.5h

   Add a ShareLink to share the rendered image and a button to save it to the photo library (asking for add-only permission with a clear explanation, and handling refusal). Show a progress indicator while rendering large sheets. Done when: the sheet can be saved to Photos and shared to other apps.

6. 06

   Test it

   ~1.5h

   Write unit tests for the layout calculations (rows needed, cell size for a given width and spacing), settings validation, and label formatting, plus a SwiftData test with an in-memory container. Test by hand with 1, 7 and 36 photos in portrait and landscape. Done when: the tests pass, and the manual checks look right.

Resources

• DocsSwiftUI tutorials (Apple)
• DocsPhotosPicker documentation
• DocsImageRenderer documentation
• DocsSwiftData documentation
• DocsShareLink documentation