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Magnifier Architecture

Overview​

The Magnifier architecture is designed to provide high-precision visual feedback during interactive alignment and inspection workflows. It is implemented as a viewer-level subsystem that integrates rendering, user interaction, and markup logic while remaining modular and extensible.

The architecture separates core coordination, visual rendering, and event handling, allowing the Magnifier to be reused and extended without tight coupling to viewer internals.

Architectural Goals​

The Magnifier is designed with the following goals:

  • Pixel-accurate magnification of document content
  • Smooth integration with viewer rendering and input events
  • Clear separation between logic and presentation
  • Minimal intrusion into existing viewer and markup systems
  • Extensible callback and method interfaces

Magnifier Object​

The Magnifier object acts as the central coordinator. It:

  • Manages the lifecycle of the magnification workflow
  • Tracks current alignment state and active points
  • Delegates rendering responsibilities to the magnify panel
  • Emits callbacks to notify host applications of user actions

This object is the primary integration point for external consumers.

Magnify Panel​

The Magnify Panel is a visual component responsible for rendering the magnified content. It:

  • Displays a zoomed-in view of the underlying document
  • Synchronizes its position with cursor or alignment points
  • Renders visual guides such as crosshairs or focus indicators
  • Updates in real time as user interaction occurs

The panel is intentionally isolated from business logic to keep rendering concerns separate from workflow control.

Overlay and Visual Guides​

Overlay elements provide visual context during alignment operations. These include:

  • Crosshairs
  • Alignment markers
  • Optional helper guides

Overlay rendering is coordinated by the Magnifier object but executed by the visual layer, ensuring consistency without direct coupling.

Event and Callback Flow​

The Magnifier exposes a set of callbacks that notify consumers about key moments in the alignment lifecycle, such as:

  • Start of an alignment interaction
  • Movement or update of alignment points
  • Completion or cancellation of an alignment step

Callbacks are emitted by the Magnifier object and are observer-style, meaning they do not influence internal state directly.

Detailed callback documentation is provided in the Magnifier Callbacks section.

Integration with Viewer and Markup Systems​

The Magnifier integrates with:

  • Viewer rendering pipeline – to sample and magnify document content
  • Input handling – to track pointer movement and user actions
  • Markup annotations – to align magnified views with annotation data

This integration is intentionally indirect, allowing the Magnifier to remain decoupled from specific viewer implementations.

Extensibility Considerations​

The architecture supports extension by:

  • Adding new visual guides without modifying core logic
  • Introducing additional callbacks for new workflow stages
  • Replacing or enhancing the magnify panel implementation
  • Supporting different alignment strategies through configuration

This design ensures the Magnifier can evolve alongside viewer and annotation features without requiring architectural changes.