Function selectAnnotation

examples/pdf-server/src/mcp-app.ts:1259–1341

* Select annotation(s). Pass null to deselect all. * If additive is true, toggle the given id without clearing existing selection.

(id: string | null, additive = false)

 * If additive is true, toggle the given id without clearing existing selection.
 */
function selectAnnotation(id: string | null, additive = false): void {
  if (!additive) {
    // Clear all existing selection visuals
    for (const prevId of selectedAnnotationIds) {
      const tracked = annotationMap.get(prevId);
      if (tracked) {
        for (const el of tracked.elements) {
          el.classList.remove("annotation-selected");
        }
      }
    }
    // Remove handles
    for (const h of annotationLayerEl.querySelectorAll(
      ".annotation-handle, .annotation-handle-rotate",
    )) {
      h.remove();
    }
    selectedAnnotationIds.clear();
  }

  if (id) {
    if (additive && selectedAnnotationIds.has(id)) {
      // Toggle off
      selectedAnnotationIds.delete(id);
      const tracked = annotationMap.get(id);
      if (tracked) {
        for (const el of tracked.elements) {
          el.classList.remove("annotation-selected");
        }
      }
    } else {
      selectedAnnotationIds.add(id);
    }
  }

  // Apply selection visuals + handles on all selected
  // Only show handles when exactly one annotation is selected
  for (const selId of selectedAnnotationIds) {
    const tracked = annotationMap.get(selId);
    if (tracked) {
      for (const el of tracked.elements) {
        el.classList.add("annotation-selected");
      }
      if (selectedAnnotationIds.size === 1) {
        showHandles(tracked);
      }
    }
  }

  // Auto-expand the accordion section for the selected annotation's page
  if (id) {
    const tracked = annotationMap.get(id);
    if (tracked) {
      panelState.openAccordionSection = `page-${tracked.def.page}`;
    }
  }

  // Re-render the panel so accordion sections open/close to match selection