[editor] Add an Ink editor

- Approximate the drawn curve by a set of Bezier curves in using
  js code from https://github.com/soswow/fit-curves.
  The code has been slightly modified in order to make the linter
  happy.

Author: calixteman

l10n/en-US/viewer.properties

@@ -255,5 +255,7 @@ editor_none.title=Disable Annotation Editing
 editor_none_label=Disable Editing
 editor_free_text.title=Add FreeText Annotation
 editor_free_text_label=FreeText Annotation
+editor_ink.title=Add Ink Annotation
+editor_ink_label=Ink Annotation
 
 freetext_default_content=Enter some text…

src/display/editor/annotation_editor_layer.js

@@ -23,6 +23,7 @@
 import { AnnotationEditorType, Util } from "../../shared/util.js";
 import { bindEvents, KeyboardManager } from "./tools.js";
 import { FreeTextEditor } from "./freetext.js";
+import { InkEditor } from "./ink.js";
 import { PixelsPerInch } from "../display_utils.js";
 
 /**
@@ -298,6 +299,8 @@ class AnnotationEditorLayer {
     switch (this.#uiManager.getMode()) {
       case AnnotationEditorType.FREETEXT:
         return new FreeTextEditor(params);
+      case AnnotationEditorType.INK:
+        return new InkEditor(params);
     }
     return null;
   }