IOException when an object in the cross-reference stream has a negative offset.

"System.IO.IOException: An attempt was made to move the file pointer before the beginning of the file."

Trying to clone the Signature of a SignatureField leads to InvalidOperationException as the FieldName of the cloned signature is already set.
Workaround: Remove the signatures before the merging of the document:
private static void RemoveSignatures(RadFixedDocument document)
{
	List<FormField> signatures = document.AcroForm.FormFields.Where(ff => ff.FieldType == FormFieldType.Signature).ToList();
	if (signatures.Count > 0)
	{
		foreach (FormField signature in signatures)
		{
			document.AcroForm.FormFields.Remove(signature);
		}
	}

	List<SignatureWidget> signatureWidgets = document.Annotations.Where(a => a.Type == AnnotationType.Widget && a.GetType() == typeof(SignatureWidget)).Cast<SignatureWidget>().ToList();
	if (signatureWidgets.Count > 0)
	{
		foreach (var signatureWidget in signatureWidgets)
		{
			foreach (RadFixedPage page in document.Pages)
			{
				if (page.Annotations.Contains(signatureWidget))
				{
					page.Annotations.Remove(signatureWidget);
				}
			}
		}
	}
}

Wrong encoding is used when the PDF file contains font with custom encoding

Workaround:

foreach (var widget in field.Widgets)
{
    widget.TextProperties.Font = FontsRepository.Helvetica;
}

The public API may be implemented as property of PdfExportSettings.

Implementing this feature would help to easily workaround issue with PdfProcessing documents that cannot be opened on devices with iOS version 10.2 (due to the default FlateDecode compression).

According to PDF specification widget's parent field should always be terminal field and should have FieldType specified. However, there are documents which are generated without fulfulling this rule and we need to consider handling this scenario without any exceptions.

The only applied graphics properties are the fill color, the stroke color and the rendering mode (which specifies whether the glyph is filled or/and stroked). Instead, Block and FixedContentEditor classes should apply all other graphics state properties (StrokeThickness, MiterLimit, StrokeDashOffset, StrokeDashArray, StrokeLineJoin, StrokeLineCap).

WORKAROUND: These properties may be applied after the text content is added. For instance, if you require changing the StrokeThickness of the text fragments which are stroked and not filled then you may use code similar to the one below:

foreach (RadFixedPage pages in document.Pages)
{
    foreach (TextFragment textContent in pages.Content.Where(c => c is TextFragment))
    {
        if (textContent.RenderingMode == RenderingMode.Stroke)
        {
            textContent.StrokeThickness = 0.3;
        }
    }
}

When using an ImageSharp version bigger than 2.0 an exception is thrown: "MissingMethodException: 'Method not found: 'SixLabors.ImageSharp.Image SixLabors.ImageSharp.Image.Load(Byte[], SixLabors.ImageSharp.Formats.IImageFormat ByRef)'."

Workaround: Downgrade to a lower ImageSharp version or use a custom implementation of ImagePropertiesResolverBase/JpegImageConverter.