Embedding images into RTF document

Aspose.Words Product Family
1

Hi Aspose,

I have had some success with your library so far, but I have run into one specific issue that is blocking progress on a project I am using this for.

We are converting a combination of plain text and RTF data to DOCX files, which by and large has been working. However, there were some modifications to the RTF data I had to make in order for images to be embedded properly. I believe this has to do with the version of RTF being used in my source data.

Image tags are in the following general format:

{\pict\jpegblip\picwX\pichY \binZ <data>}

Where X is the picture width, Y is the picture height, Z is the number of bytes in the raw data, and is the binary data of the embedded image (we are converting the binary data to hex in order to work with it in C#).

There are additional tags based on the image format and if the picture was resized. In our case, we are only working with JPEG (\jpegblip), PNG (\pngblip), WMF (\wmetafile8), and BMP (\dibitmap0) image formats.

I noticed that out of the box, this does not work as intended. However, if we remove the \binZ tag and ensure the <data> is stored as hex, the conversion works for JPEG, PNG, and WMF files. The sticking point is with BMP files. I know from other testing that the BMP <data> is stored with the first 14 bytes (file header) removed, but even if I calculate and add those 14 bytes as hex, it does not get embedded in the word document.

We have a lot of control over the actual content of the RTF source data, so I am curious if there is anything I can do to manipulate the data to allow BMP images to be embedded in the converted word document or if this is functionality that is not possible with the current version of Aspose.Words. Any help would be greatly appreciated. Unfortunately, I am unable to share any actual source data, due to privacy concerns.

Thanks,

Johnny

This Topic is created by alexey.noskov using Email to Topic tool.

2

@alexey.noskov

To embed BMP images into an RTF document using Aspose.Words, you may need to consider a few specific adjustments, especially since BMP images have unique requirements compared to other formats like JPEG and PNG.

  1. Image Format Handling: When embedding BMP images, ensure that the binary data is correctly formatted. As you mentioned, BMP images typically require the first 14 bytes (the file header) to be removed. However, if you are adding those bytes back in hex format, ensure that the total byte count matches the expected size in the RTF format.

  2. RtfSaveOptions Configuration: Utilize the RtfSaveOptions class to control how images are saved in the RTF document. You can set the ExportImagesForOldReaders property to true to ensure compatibility with older RTF readers, which may help with BMP images. This option allows the use of additional keywords that can improve the handling of images in the RTF output.

  3. Example Code: Here’s a simple example of how to set up the RtfSaveOptions for saving images:

    Document doc = new Document("input.docx");
RtfSaveOptions options = new RtfSaveOptions
{
    ExportImagesForOldReaders = true // Ensures compatibility with older readers
};
doc.Save("output.rtf", options);

  4. Testing Different Configurations: Since you have control over the RTF source data, experiment with different configurations of the RTF tags. For BMP images, ensure that the binary data is correctly formatted and that the image dimensions are accurately specified.

If you continue to face issues with BMP images, consider converting them to a different format (like PNG or JPEG) before embedding, as these formats are generally more straightforward to handle in RTF documents.

For further details, you can refer to the Aspose documentation on RTF save options and image handling, which may provide additional insights into managing image formats effectively.

If you have any more specific questions or need further assistance, feel free to ask!

3

@Professionalize.Discourse Aspose.Words does not support direct manipulation of RTF. When you open document using Aspose.Words it is loaded into Aspose.Words Document Object Model. You can manipulate the model through the code. So in your case you can simply insert someplace holder in your template and then insert an image at the placeholder using Aspose.Words.
https://docs.aspose.com/words/net/working-with-images/

You can also consider using LINQ Reporting engine to dynamically insert images into the document:
https://docs.aspose.com/words/net/inserting-images-dynamically/

4

@alexey.noskov Thank you for your input. I tried all of these solutions with no change in the file output. I discovered the RtfSaveOption SaveImagesAsWmf, which failed when I tried using it. The stack trace from this error lead me to discover the libSkiaSharp.dll I had been using was out of date. Upon updating to the latest libSkiaSharp.dll (3.119.0), the SaveImagesAsWmf option started working. Beyond that, using the approach laid out in my initial question (remove the \bin tag and ensure binary data is stored as hex), saving directly to a .docx file was successful in converting BMP images.
It appears this dll was the problem all along, but never threw an error when trying to convert embedded BMPs.

5

@jprevost If possible, could you please attach your problematic input document and code that will allow us to reproduce the problem? We will check the issue and provide you more information. Unfortunately, it is not quite clear from the description how to reproduce the problem.