chrome/browser/resources/lens/overlay/text_rendering.ts

// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import type {BrowserProxy} from './browser_proxy.js';
import {CenterRotatedBox_CoordinateType} from './geometry.mojom-webui.js';
import {UserAction} from './lens.mojom-webui.js';
import {INVOCATION_SOURCE} from './lens_overlay_app.js';
import {recordLensOverlayInteraction} from './metrics_utils.js';
import type {Line, Paragraph, Word} from './text.mojom-webui.js';

// A struct representing a text response from the server. Used instead of the
// mojo Text struct so text can be easily extracted using common functions that
// also apply to the regular text layer.
export interface TextResponse {
  // The content language received from OnTextReceived.
  contentLanguage: string;
  // The words received.
  receivedWords: Word[];
  // An array that corresponds 1:1 to receivedWords, where paragraphNumbers[i]
  // is the paragraph number for receivedWords[i]. In addition, the index at
  // paragraphNumbers[i] corresponds to the Paragraph in paragraphs[i] that the
  // word belongs in.
  paragraphNumbers: number[];
  // An array that corresponds 1:1 to receivedWords, where lineNumbers[i] is the
  // line number for receivedWords[i]. In addition, the index at lineNumbers[i]
  // corresponds to the Line in lines[i] that the word belongs in.
  lineNumbers: number[];
  // The lines received from OnTextReceived.
  lines: Line[];
  // The paragraphs received from OnTextReceived.
  paragraphs: Paragraph[];
}

// Returns true if the word has a valid bounding box and is renderable by the
// TextLayer.
export function isWordRenderable(word: Word): boolean {
  // For a word to be renderable, it must have a bounding box with normalized
  // coordinates.
  // TODO(crbug.com/330183480): Add rendering for IMAGE CoordinateType
  const wordBoundingBox = word.geometry?.boundingBox;
  if (!wordBoundingBox) {
    return false;
  }

  return wordBoundingBox.coordinateType ===
      CenterRotatedBox_CoordinateType.kNormalized;
}

// Return the text separator if there is one, else returns a space.
export function getTextSeparator(word: Word): string {
  return (word.textSeparator !== null && word.textSeparator !== undefined) ?
      word.textSeparator :
      ' ';
}

// Sends the words to the browser to be translated.
export function translateWords(
    highlightedText: string, contentLanguage: string, startIndex: number,
    endIndex: number, browserProxy: BrowserProxy) {
  browserProxy.handler.issueTranslateSelectionRequest(
      highlightedText.replaceAll('\r\n', ' '), contentLanguage, startIndex,
      endIndex);
  recordLensOverlayInteraction(INVOCATION_SOURCE, UserAction.kTranslateText);
}