Guides

Page Text Extraction

ComPDF React Native SDK provides page text APIs for extracting text content from a PDF page. You can get all text from a page, extract text inside a rectangle, retrieve text lines, and get the text content for a specific line.

Get All Text From a Page

Use getAllText() to extract all text from the current page.

const page = pdfReaderRef.current?._pdfDocument.pageAtIndex(0);
const text = await page?.getAllText();

console.log("Page text:", text);

If the page has no text layer, such as a scanned image-only PDF, the result is usually an empty string.

Get Text Inside a Rectangle

Use getTextInRect(rect) to extract text inside a rectangle on the current page.

const page = pdfReaderRef.current?._pdfDocument.pageAtIndex(0);

const text = await page?.getTextInRect({
  left: 40,
  top: 120,
  right: 300,
  bottom: 180,
});

console.log("Text in rectangle:", text);

The rect parameter uses the CPDFRectF structure. The values are page coordinates:

type CPDFRectF = {
  left: number;
  top: number;
  right: number;
  bottom: number;
};

Get Text Lines From a Page

Use getTextLines() to retrieve all text lines from the current page.

const page = pdfReaderRef.current?._pdfDocument.pageAtIndex(0);
const lines = await page?.getTextLines();

console.log("Line count:", lines?.length ?? 0);

Each text line is represented by CPDFTextLine:

type CPDFTextLine = {
  pageIndex: number;
  lineIndex: number;
  location: number;
  length: number;
  rect: CPDFRectF;
};

Field description:

Field	Description
pageIndex	The zero-based page index where the line is located
lineIndex	The zero-based line index in the page line collection
location	The start character position of the line in the page text
length	The character length of the line
rect	The line bounding rectangle in page coordinates

Get Text From a Specific Line

Use getTextByLine(line) to get the actual text content for a text line.

const page = pdfReaderRef.current?._pdfDocument.pageAtIndex(0);
const lines = await page?.getTextLines();

if (page && lines && lines.length > 0) {
  const firstLineText = await page.getTextByLine(lines[0]);
  console.log("First line:", firstLineText);
}

The line should come from getTextLines() on the same page. Passing a line from another page to the current page returns an error.

Complete Example

The following example extracts all page text, text inside a rectangle, the page line count, and the text of the first line.

import { useRef } from "react";
import { Button } from "react-native";
import { CPDFReaderView } from "@compdfkit_pdf_sdk/react_native";

export default function PageTextExample() {
  const pdfReaderRef = useRef<CPDFReaderView>(null);

  const extractPageText = async () => {
    const page = pdfReaderRef.current?._pdfDocument.pageAtIndex(0);
    if (!page) {
      return;
    }

    const allText = await page.getAllText();

    const rectText = await page.getTextInRect({
      left: 40,
      top: 120,
      right: 300,
      bottom: 180,
    });

    const lines = await page.getTextLines();
    const firstLineText =
      lines.length > 0 ? await page.getTextByLine(lines[0]) : "";

    console.log("All text length:", allText.length);
    console.log("Rectangle text:", rectText);
    console.log("Line count:", lines.length);
    console.log("First line:", firstLineText);
  };

  return (
    <>
      <CPDFReaderView
        ref={pdfReaderRef}
        document="file:///path/to/sample.pdf"
        style={{ flex: 1 }}
      />
      <Button title="Extract Text" onPress={extractPageText} />
    </>
  );
}

Notes

• The page text APIs require a mounted CPDFReaderView. Call them after the document has loaded.
• Scanned PDFs or PDFs without a text layer may return an empty string or an empty array.
• getTextInRect(rect) and CPDFTextLine.rect use page coordinates, not screen coordinates.
• getTextByLine(line) should use a line returned by getTextLines() from the same page.
• If you need keyword search, continue using the existing CPDFTextSearcher.