Guides

Overview

A watermark is a mark placed on a PDF document, usually in the form of semi-transparent text or image elements. By adding a watermark, you can highlight ownership or other relevant information without interfering with the readability of the document.

Advantages of ComPDF Watermarks

• Copyright Marking: Display document source and copyright information through watermarks to prevent screenshots or misuse.
• Branding: Customize watermark appearance to showcase your brand's logo or other preset content.
• Quick UI Integration: Easily integrate and customize watermarks using scalable UI components.

API Overview

Watermark APIs are available on CPDFDocument:

Future<bool> createWatermark(CPDFWatermark watermark);

Future<int> getWatermarkCount();

Future<CPDFWatermark?> getWatermark(
  int index, {
  bool exportImage = false,
});

Future<List<CPDFWatermark>> getWatermarks({
  bool exportImages = false,
});

Future<bool> updateWatermark(int index, CPDFWatermark watermark);

Future<bool> removeWatermark(int index);

Future<void> removeAllWatermarks();

API	Description
createWatermark	Adds a text or image watermark to the document.
getWatermarkCount	Gets the number of watermarks in the document.
getWatermark	Gets one watermark by index.
getWatermarks	Gets all watermarks in the document.
updateWatermark	Updates an existing watermark by index.
removeWatermark	Removes one watermark by index.
removeAllWatermarks	Removes all watermarks from the document.

Watermark Model

Use CPDFWatermark.text to create a text watermark and CPDFWatermark.image to create an image watermark.

CPDFWatermark.text({
  required String textContent,
  required List<int> pages,
  Color textColor = Colors.black,
  int fontSize = 24,
  double scale = 1.0,
  double rotation = 45,
  double opacity = 1,
  CPDFWatermarkVerticalAlignment verticalAlignment =
      CPDFWatermarkVerticalAlignment.center,
  CPDFWatermarkHorizontalAlignment horizontalAlignment =
      CPDFWatermarkHorizontalAlignment.center,
  double verticalOffset = 0,
  double horizontalOffset = 0,
  bool isFront = true,
  bool isTilePage = false,
  double horizontalSpacing = 0,
  double verticalSpacing = 0,
});

CPDFWatermark.image({
  required String imagePath,
  required List<int> pages,
  double scale = 1.0,
  double rotation = 45,
  double opacity = 1,
  CPDFWatermarkVerticalAlignment verticalAlignment =
      CPDFWatermarkVerticalAlignment.center,
  CPDFWatermarkHorizontalAlignment horizontalAlignment =
      CPDFWatermarkHorizontalAlignment.center,
  double verticalOffset = 0,
  double horizontalOffset = 0,
  bool isFront = true,
  bool isTilePage = false,
  double horizontalSpacing = 0,
  double verticalSpacing = 0,
});

Option	Description
pages	Zero-based page indexes where the watermark is applied.
scale	Watermark scale factor.
rotation	Watermark rotation angle in degrees.
opacity	Watermark opacity, from 0.0 to 1.0.
verticalAlignment	Vertical position: top, center, or bottom.
horizontalAlignment	Horizontal position: left, center, or right.
verticalOffset	Vertical offset from the selected alignment position.
horizontalOffset	Horizontal offset from the selected alignment position.
isFront	Whether the watermark is drawn above page content.
isTilePage	Whether the watermark is repeated across the page.
horizontalSpacing	Horizontal spacing for tiled watermarks.
verticalSpacing	Vertical spacing for tiled watermarks.

Guides

• Add Text Watermark

  Create text watermarks with custom content and appearance.

• Add Image Watermark

  Create image watermarks from custom images.

• Remove Watermark

  Remove watermarks from the PDF document.

• Get Watermarks

  Get watermark information and export image watermark content.

• Update a Watermark

  Update selected properties of an existing watermark.