Guides

Update a Watermark

Use updateWatermark() with the watermark index and a new CPDFWatermark value. Get the original watermark first, then use copyWatermark() to change only the properties you need.

import { copyWatermark } from "@compdfkit_pdf_sdk/react_native";

const watermark = await pdfReaderRef.current?._pdfDocument.getWatermark(0);

if (watermark) {
  const success = await pdfReaderRef.current?._pdfDocument.updateWatermark(
    watermark.index,
    copyWatermark(watermark, {
      textContent: "Updated Confidential",
      textColor: "#0066FF",
      fontSize: 36,
      opacity: 0.75,
    })
  );

  console.log("Update watermark result:", success);
}

When updating an image watermark, pass a new imagePath only if you need to replace the image content. If imagePath is empty, the SDK keeps the original image and updates the other properties.

const watermark = await pdfReaderRef.current?._pdfDocument.getWatermark(0);

if (watermark?.type === "image") {
  await pdfReaderRef.current?._pdfDocument.updateWatermark(
    watermark.index,
    copyWatermark(watermark, {
      opacity: 0.65,
      scale: 0.5,
      rotation: 30,
    })
  );
}