pdf_signature/docs/meta-arch.md

meta archietecture

• MVVM

Package structure

The repo structure follows official Package structure with slight modifications.

• put each <FEATURE NAME>/s in features/ sub-directory under ui/.
• test/features/ contains BDD unit tests for each feature. It focuses on pure logic, therefore will not access View but ViewModel and Model.
• test/widget/ contains UI widget(component) tests which focus on View from MVVM of each component.
• integration_test/ for integration tests. They should be volatile to follow UI layout changes.

Abstraction

terminology

• signature asset
  • image file of a signature, stored in the device or cloud storage
    • can drawing from canvas
• signature card
  • template of signature placement
  • It will include modifications such as brightness, contrast, background removal, rotation of the signature asset.
• signature placement
  • placed modified signature asset from signature card on a specific position on a specific page of a specific PDF document
• document
  • PDF document to be signed

key dependencies

• pdfrx
  • packages/pdfrx/example/viewer/lib/main.dart
  • When using pdfrx, developers should control view function e.g. zoom, scroll... by component of pdfrx e.g. PdfViewer, rather than introduce additional view.
    • PdfViewer could not be scrollable when nested inside SingleChildScrollView #27
    • How to zoom in PdfPageView #244
  • So does overlay some widgets, they should be placed using the provided overlay builder.
    • Viewer Customization using Widget Overlay
    • Per-page Customization using Widget Overlay
      • pageOverlaysBuilder