Watermark Core Functions

create()

• Description: Creates and renders the watermark on the specified parent element
• Behavior:
  • Validates watermark uniqueness in the DOM (throws error if duplicate found)
  • Checks content validity based on contentType (text/image/rich-text)
  • Generates watermark canvas with configured styles (rotation, opacity, etc.)
  • Converts canvas to background image with proper positioning
  • Applies defensive CSS (!important flags, pointer-events: none)
  • Handles both fixed (body/html) and custom parent elements
  • Sets up MutationObserver if mutationObserve=true
  • Triggers onSuccess callback only on first creation
• Returns: Promise<void>
• Example:

  await watermark.create();

destroy()

• Description: Completely removes the watermark and cleans up observers
• Behavior:
  • Triggers onBeforeDestroy() callback
  • Disconnects all MutationObservers
  • Removes watermark DOM nodes
  • Triggers onDestroyed() callback
• Example:

  watermark.destroy();

check()

• Description: Verifies watermark DOM existence
• Returns: Promise<boolean>
  • true: Watermark exists in parentElement
  • false: Watermark not found
• Example:

  const exists = await watermark.check();

changeOptions()

• Description: Updates watermark configuration
• Parameters:
  • args: Partial<WatermarkOptions> - New configuration options
  • mode: 'overwrite'|'append' - How to merge new options
  • redraw: boolean - Whether to recreate immediately (default: true)
• Behavior:
  • Merges new options according to specified mode
  • Enables protection if monitorProtection=true
  • Recreates watermark if redraw=true
• Returns: Promise<void>
• Example:

  await watermark.changeOptions({ content: 'New Text' }, 'append');

Technical Details

• DOM Structure:

<div class="watermark" style="/* defensive CSS */">
  <div style="/* background image styles */"></div>
</div>

• Protection Mechanisms:

  • MutationObserver for DOM tampering detection
  • Automatic recreation when modified
  • CSS !important overrides

• Lifecycle Callbacks:

  • onSuccess: After successful creation
  • onBeforeDestroy: Before removal
  • onDestroyed: After removal
  • onObserveError: When MutationObserver fails