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Version: 4

Text and Image-based Watermarks – Gravity PDF Development

Introduction​

A watermark is a semi-transparent element overlaid on each page of your PDF. Both text and image watermarks are supported, and you have full control over the transparency.

Example of text watermark

Two unique HTML tags are used to output watermarks (one for text watermarks and one for images):

  • <watermarktext content [ alpha ] />
  • <watermarkimage src [ alpha ] [ size ] [ position ] />

Watermarks cannot be used when setting the PDF format to PDF/A-1b or PDF/X-1a.

Text Watermarks​

<watermarktext content [ alpha ] />

Text watermarks can be enabled by including the following HTML in your PDF template:

<watermarktext content="PRIVATE" />

content : The text you want watermarked on the PDF. This is a required attribute. : If content is set to blank it will disable watermarking in the document from that page onwards. : The content attribute must have special characters encoded correctly. This includes the <, >, ', " and & symbols. To prevent unexpected behaviour use the PHP function htmlspecialchars.

<watermarktext content="<?php echo htmlspecialchars( '<CONFIDENTIAL>', ENT_QUOTES ); ?>" />

alpha : Controls the text transparency and should be a number between 0-1. This field is optional.

<watermarktext content="PRIVATE" alpha="0.3" />

Image Watermarks​

<watermarkimage src [ alpha ] [ size ] [ position ] />

The image watermark only requires the src attribute. The alpha, size and position attributes are all optional.

src : The URL or path to the image. We recommend using the path as it has better support across a range of hosting environments.

alpha : Controls the image transparency and should be a number between 0-1

size : Controls the image size that your watermark should be displayed at. By default the image will display at its original size (depending on the PDF DPI settings) : Values: D – Display at original image size (default) P – Resize image to fit the full page F – Resize to fit the PDF print area, respecting page margins width,height – Two comma-separated numbers specifying the width and height of the image in millimetres

position : Specifies where the image should be positioned on the page : Values: P – Vertically and horizontally centred on the page F – Vertically and horizontally centred on the print area with respect to page margins width,height – Specify the x and y position (in millimetres) of where the image should be placed

<!-- Basic Image Watermark -->
<watermarkimage src="<?php echo PDF_PLUGIN_DIR; ?>resources/images/gravityformspdfextended.jpg" />

<pagebreak>

<!-- Image watermark with 50% transparency -->
<watermarkimage src="<?php echo PDF_PLUGIN_DIR; ?>resources/images/gravityformspdfextended.jpg" alpha="0.5" />

<pagebreak>

<!-- Image watermark resized to fit the full page -->
<watermarkimage src="<?php echo PDF_PLUGIN_DIR; ?>resources/images/gravityformspdfextended.jpg" size="P" />

<pagebreak>

<!-- Image watermark with default size positioned 10mm x 10mm from the top left corner -->
<watermarkimage src="<?php echo PDF_PLUGIN_DIR; ?>resources/images/gravityformspdfextended.jpg" position="10,10" />

<pagebreak>

<!-- Image watermark resized to 50x50mm image -->
<watermarkimage src="<?php echo PDF_PLUGIN_DIR; ?>resources/images/gravityformspdfextended.jpg" size="50,50" />

Example​

We’ve put together a sample showing off the text and image watermark capabilities in Gravity PDF.

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