Add Image Watermarks to PDFs Online Add image watermark.
PDF Image Watermark
Add image watermark.
Upload PDF and Image
Select your PDF file and the image to use as watermark.
Set Position and Opacity
Configure placement and transparency of the watermark.
Download Watermarked PDF
Save or copy the result.
What Is PDF Image Watermark?
A PDF Image Watermark is a digital stamp that overlays an image on top of a PDF document to identify its origin or ownership. Graphic designers and marketers use it to protect their creative work by adding a logo or trademark as a watermark pdf with image, while also promoting their brand identity through the embedded visual element. One specific problem this tool solves is ensuring that when sharing sensitive documents like product catalogs or marketing materials, unauthorized parties cannot misuse them without being easily traceable due to the presence of the pdf watermark with logo.
What makes this tool different is its ability to embed images directly into PDFs using client-side processing, allowing users to add image watermark to pdf files without relying on server-side infrastructure. The code includes features like positioning control, where users can choose from five predefined positions - center, top-left, top-right, bottom-left, and bottom-right - to place their watermark image, as well as opacity adjustment and rotation settings for precise customization. Additionally, it supports both PNG and JPEG images for the free pdf image watermark online functionality.
The tool's implementation enables seamless integration of the selected image into the PDF document, maintaining its original layout and design while ensuring that the watermark is legible yet unobtrusive. By using it to watermark pdf with image, users can ensure their documents are professionally presented and protected against unauthorized use or distribution.
Why Use PDF Image Watermark?
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Drag-and-drop interface for PDF and image
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Client-side
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Free
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One-click copy
Common Use Cases
Development
Add watermarks to generated PDFs.
Review
Validate documents with watermarks.
Docs
Apply logos to contracts and proposals.
Learning
Try watermarking with sample files.
Technical Guide
The tool works by utilizing client-side JavaScript with React to handle file uploads and process PDF documents. It employs memoization through the `useCallback` hook to optimize performance by preventing unnecessary re-renders of components. When a user selects a PDF file, the tool uses the `arrayBuffer` method to read the file's contents and then loads it into a `PDFDocument` object using the `pdf-lib` library. This library provides an API for manipulating PDF documents, allowing the tool to embed images, adjust layout, and apply watermarks.
The watermark image is embedded into the PDF document using either the `embedPng` or `embedJpg` method of the `PDFDocument` object, depending on the image type. The image is then scaled relative to the page width using a scaling factor, which is set by the user through an input field. The scaled image dimensions are calculated while maintaining the aspect ratio to prevent distortion. The tool uses the `computePosition` function to determine the position of the watermark image based on the user's selection from five predefined positions: center, top-left, top-right, bottom-left, and bottom-right.
The `pdf-lib` library is used in conjunction with React hooks such as `useState` and `useRef` to manage state changes and handle file inputs. The tool also utilizes browser APIs like the Clipboard API to enable features such as downloading the watermarked PDF document. Additionally, it incorporates responsive UI components to ensure a seamless user experience across different devices and screen sizes. By leveraging these technologies, the tool provides an efficient and user-friendly way to add image watermarks to PDF documents directly in the browser.
When processing the PDF document, the tool iterates over each page using the `getPages` method of the `PDFDocument` object and applies the watermark image using the `drawImage` method. This method takes into account factors such as opacity, rotation, and position to ensure accurate placement of the watermark. The resulting watermarked PDF document is then saved as a blob using the `save` method of the `PDFDocument` object, which can be downloaded by the user or further processed as needed.
Error handling is also implemented throughout the tool to catch any exceptions that may occur during file loading, image embedding, or PDF processing. If an error occurs, an error message is displayed to the user, providing feedback on what went wrong and how it can be resolved. This ensures a robust and reliable experience for users when working with the tool to add watermarks to their PDF documents.
Tips & Best Practices
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1Reset input values by setting `watermarkInputRef.current.value` to an empty string
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2Compute the watermark position using the `computePosition` function with page dimensions and image size
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3Embed images as PNG or JPEG based on the `isPng` flag
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4Scale the image relative to the page width using the `scale` variable
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5Rotate the watermark by specifying degrees in the `rotation` state
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6Revoke object URLs for watermarked files when resetting with `URL.revokeObjectURL(result)`
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Frequently Asked Questions
Q Is the PDF image watermark tool free?
Q Is my data safe?
Q Can I use it offline?
Q What browsers does it support?
Q Can I use it for commercial projects?
About This Tool
PDF Image Watermark is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.