Create custom tools

Event handling

Tool handlers and annotation handlers process touch and gesture events from FSPDFViewCtrl. Events go to UIExtensionsManager:

• Tool handler: If a tool handler is active, UIExtensionsManager forwards the event to it and stops.
• Annotation handler: If an annotation is selected, the event goes to its annotation handler and stops.
• Selection tool handler: If neither applies, the selection tool handler receives the event.
  • Text Selection Tool: Text selection (for example adding highlight annotations).
  • Blank Selection Tool: Empty-area events (for example adding note annotations).

NOTE

• Tool and annotation handlers do not handle the same event at once.
• Tool handlers mainly create annotations (link annotations not supported yet), signatures, and text selection.
• Annotation handlers mainly edit annotations and fill forms.

Tool handler and annotation handler flow:

IToolHandler protocol

Implement IToolHandler to create custom tools (screenshot markup, custom measurement, etc.) and register them with UIExtensionsManager.

Each tool implements lifecycle and interaction methods:

Method	Description
getName	Tool name
isEnabled	Whether the tool is enabled
onActivate	Called when activated
onDeactivate	Called when deactivated
onPageViewTap:recognizer:	Tap on page
onPageViewLongPress:recognizer:	Long press on page
onPageViewPan:recognizer:	Pan on page

Example: register a custom tool

// Register
[extensionsManager registerToolHandler:myCustomTool];

// Activate
extensionsManager.currentToolHandler = myCustomTool;

// Unregister
[extensionsManager unregisterToolHandler:myCustomTool];

Custom annotation handlers

Implement IAnnotHandler to customize annotation tap, selection, and drawing:

// Register
[extensionsManager registerAnnotHandler:myAnnotHandler];

// Unregister
[extensionsManager unregisterAnnotHandler:myAnnotHandler];

API reference

See the API reference for IToolHandler and IAnnotHandler.