Adding text watermarks Leave feedback

Utilizing text watermarks is a savvy strategy to safeguard the integrity of document content. By overlaying sensitive documents with watermarks such as “Confidential” or “Draft,” organizations can deter unauthorized distribution and reinforce data security protocols. This visual cue serves as a constant reminder of the document’s restricted nature, prompting individuals to handle it with appropriate care.

The following code snippet shows how to add text watermark to a document.

// Specify an absolute or relative path to your document. Ex: @"C:\Docs\sample.pdf"
using (Watermarker watermarker = new Watermarker("sample.pdf"))
{
    // Initialize the font to be used for watermark
    Font font = new Font("Arial", 19, FontStyle.Bold | FontStyle.Italic);

    // Create the watermark object
    TextWatermark watermark = new TextWatermark("Test watermark", font);

    // Set watermark properties
    watermark.ForegroundColor = Color.Red;
    watermark.BackgroundColor = Color.Blue;
    watermark.TextAlignment = TextAlignment.Right;
    watermark.Opacity = 0.5;

    // Add watermark
    watermarker.Add(watermark);
    watermarker.Save("output.pdf");
}

If the document consists of multiple parts (pages, worksheets, slides, frames, etc.), the watermark will be added to each of them. You can configure this behaivior through the PageSetup property:


var pages = new System.Collections.Generic.List<int>() { 1, 3 };

watermark.PagesSetup = new PagesSetup
{
    Pages = pages
};

Sizing and positioning of watermark

Absolute watermark positioning

Using GroupDocs.Watermark, you can also add watermark to some absolute position in the document. Following example shows how to add a text watermark with absolute positioning using properties X, Y, Width and Height. The values of all properties for absolute sizing and positioning are measured in default document units.

// Specify an absolute or relative path to your image. Ex: @"C:\Docs\image.png"
using (Watermarker watermarker = new Watermarker("image.png"))
{
    Font font = new Font("Times New Roman", 8);
    TextWatermark watermark = new TextWatermark("Test watermark", font);

    // Set watermark coordinates
    watermark.X = 10;
    watermark.Y = 20;

    // Set watermark size
    watermark.Width = 100;
    watermark.Height = 40;

    watermarker.Add(watermark);
    watermarker.Save("image.png");
}

Warning
Note that the origin of coordinates may be different for different document types (relative positioning doesn’t have these specifics and can be used as a unified positioning approach).

Following are the origin of the coordinates for different formats of the documents.

Document Format	Unit of Measure	Origin of Coordinates
PDF	Point	Left bottom corner of page
WordProcessing	Point	Left top corner of page
Spreadsheet	Point	Left top corner of worksheet
Presentation	Point	Left top corner of slide
Image	Pixel	Left top corner of image (frame)
Diagram	Point	Left top corner of page

Relative watermark positioning

Instead of exact coordinates, you can also use parent relative alignment. Furthermore, you can also set offset from parent’s borders by using Margins property as shown in below example. Following example shows how to align the watermark vertically and horizontally.

// Specify an absolute or relative path to your image. Ex: @"C:\Docs\image.png"
using (Watermarker watermarker = new Watermarker("image.png"))
{
    Font font = new Font("Calibri", 12);
    TextWatermark watermark = new TextWatermark("Test watermark", font);
    watermark.HorizontalAlignment = HorizontalAlignment.Right;
    watermark.VerticalAlignment = VerticalAlignment.Bottom;

    // Set absolute margins. Values are measured in document units.
    watermark.Margins.Right = 10;
    watermark.Margins.Bottom = 5;

    watermarker.Add(watermark);
    watermarker.Save("image.png");
}

Warning
Excel worksheets don’t have explicit borders, therefore, the most right bottom non-empty cell is used to determine working area size.

Using the MarginType property

In the example above, absolute margin values are used. This means that margins are measured in document units. But you can set relative margins for a watermark as well (as shown in below example), using the MarginType property

// Specify an absolute or relative path to your image. Ex: @"C:\Docs\image.png"
using (Watermarker watermarker = new Watermarker("image.png"))
{
    Font font = new Font("Calibri", 12);
    TextWatermark watermark = new TextWatermark("Test watermark", font);
    watermark.HorizontalAlignment = HorizontalAlignment.Right;
    watermark.VerticalAlignment = VerticalAlignment.Bottom;

    // Set relative margins. Margin value will be interpreted as a portion
    // of appropriate parent dimension. If this type is chosen, margin value
    // must be between 0.0 and 1.0.
    watermark.Margins.MarginType = MarginType.RelativeToParentDimensions;
    watermark.Margins.Right = 0.1;
    watermark.Margins.Bottom = 0.2;

    watermarker.Add(watermark);
    watermarker.Save("image.png");
}

Size types

In most cases, to add a good-looking watermark, you should consider the size of the page/slide/frame on which it will be placed. The SizingType and ScaleFactor properties can be used to scale the watermark depending on the parent size.

// Specify an absolute or relative path to your image. Ex: @"C:\Docs\image.png"
using (Watermarker watermarker = new Watermarker("image.png"))
{
    Font font = new Font("Calibri", 12);
    TextWatermark watermark = new TextWatermark("This is a test watermark", font);

    // Set sizing type
    watermark.SizingType = SizingType.ScaleToParentDimensions;

    // Set watermark scale
    watermark.ScaleFactor = 0.5;

    watermarker.Add(watermark);
    watermarker.Save("image.png");
}

Note
Using of relative size and positioning is the simplest way to add watermark to a document of any type.

Watermark rotation

GroupDocs.Watermark API also supports rotation of the watermark. You can use RotateAngle property to define watermark rotation angle in degrees. A positive value means clockwise rotation.

// Specify an absolute or relative path to your document. Ex: @"C:\Docs\test.docx"
using (Watermarker watermarker = new Watermarker("test.docx"))
{
    Font font = new Font("Calibri", 8);
    TextWatermark watermark = new TextWatermark("Test watermark", font);
    watermark.HorizontalAlignment = HorizontalAlignment.Right;
    watermark.VerticalAlignment = VerticalAlignment.Top;
    watermark.SizingType = SizingType.ScaleToParentDimensions;
    watermark.ScaleFactor = 0.5;

    // Set rotation angle
    watermark.RotateAngle = 45;

    watermarker.Add(watermark);
    watermarker.Save("test.docx");
}

If rotation angle is set, it is assumed that watermark size is equal to axis-aligned bounding box size. The following picture illustrates what is the watermark bounding box and how it is used for sizing and positioning. The picture shows a result of execution of the above code snippet. The actual watermark bounds are colored in blue and the bounding box is colored in red. As you can see, the bounding box size is used to calculate watermark relative size.

adding-text-watermarks

Using custom fonts

GroupDocs.Watermark API provides ability to use custom TrueType fonts. For this you can configure FolderPath property through the Font class constructor with a folder path which contains fonts files.

var fontsFolder = @"c:\CustomFonts\";
using (Watermarker watermarker = new Watermarker("test.pdf"))
{
    // Initialize the font to be used for watermark and a folder which contains that font
    Font font = new Font("CustomFontName", fontsFolder, 36);

    // Create the watermark object
    TextWatermark watermark = new TextWatermark("Test watermark", font);

    // Set watermark properties
    watermark.ForegroundColor = Color.Blue;                
    watermark.Opacity = 0.5;

    watermark.X = 10;
    watermark.Y = 10;

    // Add watermark
    watermarker.Add(watermark);

    watermarker.Save("result.pdf");
}

Considering parent margins

For most document formats you can set page margins when working with a document. By default, GroupDocs.Watermark ignores document margins and uses maximum available space for watermarking as shown in below image.

adding-text-watermarks_1

As you can see, the watermark goes beyond page margins. To change this behavior, set ConsiderParentMargins property to true (as shown in below example).

// Specify an absolute or relative path to your document. Ex: @"C:\Docs\input.vsdx"
using (Watermarker watermarker = new Watermarker("input.vsdx"))
{
    TextWatermark watermark = new TextWatermark("Test watermark", new Font("Arial", 42));
    watermark.HorizontalAlignment = HorizontalAlignment.Right;
    watermark.VerticalAlignment = VerticalAlignment.Top;
    watermark.SizingType = SizingType.ScaleToParentDimensions;
    watermark.ScaleFactor = 1;
    watermark.RotateAngle = 45;
    watermark.ForegroundColor = Color.Red;
    watermark.BackgroundColor = Color.Aqua;

    // Add watermark considering parent margins
    watermark.ConsiderParentMargins = true;

    watermarker.Add(watermark);
    watermarker.Save("input.vsdx");
}

Now, the watermark is aligned with respect to page margins.

adding-text-watermarks_2

Watermark in documents of different types

Watermarks in documents of different types are represented by different objects. Some of these objects do not support some watermark properties. For example, the background color can not be set for WordArt object which is used as text watermark in a Word document. The full list of supported properties for all document types is available at Features Overview.

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