Implement free text annotations

src/core/annotation.js

@@ -92,6 +92,9 @@ class AnnotationFactory {
       case 'Popup':
         return new PopupAnnotation(parameters);
 
+      case 'FreeText':
+        return new FreeTextAnnotation(parameters);
+
       case 'Line':
         return new LineAnnotation(parameters);
 
@@ -964,6 +967,14 @@ class PopupAnnotation extends Annotation {
   }
 }
 
+class FreeTextAnnotation extends MarkupAnnotation {
+  constructor(parameters) {
+    super(parameters);
+
+    this.data.annotationType = AnnotationType.FREETEXT;
+  }
+}
+
 class LineAnnotation extends MarkupAnnotation {
   constructor(parameters) {
     super(parameters);

src/display/annotation_layer.js

@@ -71,6 +71,9 @@ class AnnotationElementFactory {
       case AnnotationType.POPUP:
         return new PopupAnnotationElement(parameters);
 
+      case AnnotationType.FREETEXT:
+        return new FreeTextAnnotationElement(parameters);
+
       case AnnotationType.LINE:
         return new LineAnnotationElement(parameters);
 
@@ -807,6 +810,30 @@ class PopupElement {
   }
 }
 
+class FreeTextAnnotationElement extends AnnotationElement {
+  constructor(parameters) {
+    const isRenderable = !!(parameters.data.hasPopup ||
+                            parameters.data.title || parameters.data.contents);
+    super(parameters, isRenderable, /* ignoreBorder = */ true);
+  }
+
+  /**
+   * Render the free text annotation's HTML element in the empty container.
+   *
+   * @public
+   * @memberof FreeTextAnnotationElement
+   * @returns {HTMLSectionElement}
+   */
+  render() {
+    this.container.className = 'freeTextAnnotation';
+
+    if (!this.data.hasPopup) {
+      this._createPopup(this.container, null, this.data);
+    }
+    return this.container;
+  }
+}
+
 class LineAnnotationElement extends AnnotationElement {
   constructor(parameters) {
     let isRenderable = !!(parameters.data.hasPopup ||