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web/draw_layer_builder.js

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+/* Copyright 2022 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { DrawLayer } from "pdfjs-lib";
+
+/**
+ * @typedef {Object} DrawLayerBuilderOptions
+ * @property {number} pageIndex
+ */
+
+/**
+ * @typedef {Object} DrawLayerBuilderRenderOptions
+ * @property {string} [intent] - The default value is "display".
+ */
+
+class DrawLayerBuilder {
+  #drawLayer = null;
+
+  /**
+   * @param {DrawLayerBuilderOptions} options
+   */
+  constructor(options) {
+    this.pageIndex = options.pageIndex;
+  }
+
+  /**
+   * @param {DrawLayerBuilderRenderOptions} options
+   * @returns {Promise<void>}
+   */
+  async render({ intent = "display" }) {
+    if (intent !== "display" || this.#drawLayer || this._cancelled) {
+      return;
+    }
+    this.#drawLayer = new DrawLayer({
+      pageIndex: this.pageIndex,
+    });
+  }
+
+  cancel() {
+    this._cancelled = true;
+
+    if (!this.#drawLayer) {
+      return;
+    }
+    this.#drawLayer.destroy();
+    this.#drawLayer = null;
+  }
+
+  setParent(parent) {
+    this.#drawLayer?.setParent(parent);
+  }
+
+  getDrawLayer() {
+    return this.#drawLayer;
+  }
+}
+
+export { DrawLayerBuilder };