Open Xml Wordprocessing Document Header Pictures Insert Dynamically

9 min read Oct 03, 2024

Open Xml Wordprocessing Document Header Pictures Insert Dynamically

Dynamically Inserting Pictures in WordprocessingML Documents

The ability to dynamically insert pictures into Open XML WordprocessingML documents provides a powerful way to create custom, data-driven reports and documents. Whether you're working with a .docx file generated by Word or crafting documents programmatically, understanding how to manipulate images within the Open XML structure is essential.

Understanding WordprocessingML and Header Pictures

WordprocessingML, the XML-based file format used by Microsoft Word, defines the structure and content of a document. This structure allows developers to interact with the document's content through code, enabling the insertion, modification, and deletion of text, tables, images, and other elements.

When it comes to inserting images into a document, WordprocessingML offers several options, including inserting images directly within the document body or adding them to the document's header or footer.

Inserting Pictures into the Header Dynamically

1. Understanding the Header Structure:

The header of a WordprocessingML document is represented by the <w:hdr> element. Inside the header, we'll use the <w:drawing> element to embed the image.

2. Creating a Drawing Element:

<w:drawing>: The main container for the image.
<wp:inline>: Specifies that the image will be inline within the header.
<wp:extent>: Defines the size of the image in pixels.
<wp:docPr>: Specifies the document properties of the image, such as ID and name.
<a:blipFill>: Specifies the image source, using the r:embed attribute to reference the image data.
<a:stretch>: Defines how the image should be stretched or scaled within the header.

3. Adding the Image Data:

<w:drawing>: The <w:drawing> element should also contain a <w:pict> element. This element is where the actual image data will be stored.
<w:binData>: This element holds the image data in base64-encoded format.

4. Accessing the Image Data:

You'll need to obtain the image data from your preferred source. This could involve reading the image from a file, fetching it from a URL, or generating it dynamically. Once you have the image data, convert it to a base64-encoded string.

5. Assembling the XML Structure:

Once you have all the necessary elements, assemble them into a valid WordprocessingML header structure. This XML can then be written to a file or manipulated in memory.

Example Code (C#):

// Assuming 'imagePath' is the path to the image file
string imagePath = @"C:\MyImages\MyImage.png";
byte[] imageBytes = System.IO.File.ReadAllBytes(imagePath);
string imageBase64 = Convert.ToBase64String(imageBytes);

// Create a WordprocessingDocument object 
using (WordprocessingDocument doc = WordprocessingDocument.Open("MyDocument.docx", true))
{
    // Get the document's header
    HeaderPart headerPart = doc.MainDocumentPart.HeaderParts.FirstOrDefault();
    if (headerPart == null)
    {
        // Create a new header if one doesn't exist
        headerPart = doc.MainDocumentPart.AddNewPart();
        headerPart.Header = new Header();
    }

    // Create a new paragraph for the header
    Paragraph paragraph = new Paragraph();

    // Create the drawing element
    Drawing drawing = new Drawing();

    // Define the inline image properties
    Inline inline = new Inline();
    inline.Extent = new Extent() { Cx = 999990L, Cy = 999990L };
    inline.DocProperties = new DocProperties() { Id = 1, Name = "Image1" };
    inline.BlipFill = new BlipFill();
    inline.BlipFill.Blip = new Blip() { Embed = "rId1" };
    inline.BlipFill.Blip.CompressionState = CompressionStateValues.None;
    inline.BlipFill.Blip.ExtensionList = new ExtensionList() { Extension = new Extension() { Uri = "" } };
    inline.Stretch = new Stretch() { Fill = StretchFillValues.Fill };

    // Add the image data
    Picture picture = new Picture();
    NonVisualDrawingProperties nonVisualDrawingProperties = new NonVisualDrawingProperties() { Id = 1, Name = "Image1" };
    NonVisualPictureProperties nonVisualPictureProperties = new NonVisualPictureProperties() { PictureType = PictureTypeValues.Picture };
    AlternativeText alternativeText = new AlternativeText() { Text = "My Image" };
    ShapeProperties shapeProperties = new ShapeProperties();
    shapeProperties.Transform2D = new Transform2D() { Rot = 0 };
    shapeProperties.BlackWhiteMode = BlackWhiteModeValues.Auto;
    shapeProperties.FillRectangle = new FillRectangle();
    shapeProperties.Stroke = new Stroke();
    shapeProperties.Inline = new Inline();

    // Add the image data to the picture element
    picture.Append(nonVisualDrawingProperties);
    picture.Append(nonVisualPictureProperties);
    picture.Append(alternativeText);
    picture.Append(shapeProperties);
    picture.Append(new ExtensionList() { Extension = new Extension() { Uri = "" } });

    // Set the base64-encoded image data to the picture element
    picture.Append(new BlipFill() { Blip = new Blip() { Embed = "rId1", CompressionState = CompressionStateValues.None, ExtensionList = new ExtensionList() { Extension = new Extension() { Uri = "" } } } });
    picture.Append(new Stretch() { Fill = StretchFillValues.Fill });
    picture.Append(new EffectExtent() { LeftEdge = 0, TopEdge = 0, RightEdge = 0, BottomEdge = 0 });

    // Append the picture to the inline element
    inline.Append(picture);

    // Add the inline image to the drawing element
    drawing.Append(inline);

    // Add the drawing element to the paragraph
    paragraph.Append(drawing);

    // Add the paragraph to the header
    headerPart.Header.Append(paragraph);

    // Add the image data to the document
    headerPart.AddImagePart(ImagePartType.Png, "rId1", new System.IO.MemoryStream(Convert.FromBase64String(imageBase64)));

    // Save the document
    doc.Save();
}

Explanation:

Read Image Data: The code reads the image from the specified path and converts it to base64 encoding.
Open Document: It opens the WordprocessingDocument for editing.
Get/Create Header: It retrieves the header part of the document or creates a new one if it doesn't exist.
Create Drawing Element: It builds the drawing element with necessary properties like Extent, DocProperties, BlipFill, and Stretch.
Add Image Data: It creates a picture element and sets the base64-encoded image data within the binData element.
Append Elements: It assembles the XML structure by appending the created elements to the header.
Add Image Part: It adds the image data as a separate image part to the document, using the rId1 reference to link it to the Blip element in the BlipFill.
Save Document: The changes are saved to the document.

Tips for Success

Validate XML: Use an XML validator to ensure that the generated WordprocessingML is valid.
Image Optimization: Optimize image size for faster document loading.
Error Handling: Implement robust error handling to handle cases where the image cannot be found, loaded, or converted.
Document Generation Libraries: Consider using libraries that simplify working with WordprocessingML, providing methods for creating, manipulating, and saving documents.

Conclusion

Dynamically inserting pictures into WordprocessingML documents offers a powerful way to create customizable and data-driven reports. Understanding the structure of WordprocessingML and the methods for manipulating images within the document allows for the creation of complex and sophisticated documents tailored to specific needs.