Hi Telerik Support

We use your Telerik PDF-Viewer since your last Version "UI for WPF R1 2021" which supports Type 3 fonts.
Now the version runs productive by our customers. But after a day, they found some special PDFs that doesn't work quite right with your PDF-Viewer.

In the appendix you will find the PDf-Files as samples for the bugs that i'm describing.
Because of data privacy, the PDF-Files are cutted and cropped.
Also a demo project is appended (It could also be reproduced with the demo Progress Telerik WPF UI for th PDF-Viewer).

First Problem: Blank Page

Hint: It seems that only a few PDF-Files from a specific program seems to be a problem.

1. Open Demo "WpfAppPdfViewer.exe"
2. Open the file sample_1_blank_page.pdf(see appendix)
3. You will see only a blank page
4. Open the same PDF-File in another PDF-Reader like Adobe Reader and you will see a scan with an illegible stamp of an address

Second Problem: Displaying data delayed

1. Open Demo "Progress Telerik UI for WPF"
2. Open the file sample_2_delayed_display.pdf (see appendix)
3. You will see only a blank page
4. Wait approx. 5-10 sec. and you will see the content of the PDF-File.

I would be glad for a quick possible solution for our customer.

Best regards

Serge Schoop

Even small documents (~30 kb) containing images encoded with CCITTFaxDecode filter can take about 10 seconds to be opened. In 2014 Q1 SP1 such documents load faster.

This exception seems to be caused because the stream is not decrypted correctly and the stream data is corrupted. For instance when the stream is with FlateDecode filter the exception is InvalidDataException with message "Unknown compression method".

When we render any PDF file with 'x' number of page count and try to enter page 'x+1' in telerik:CurrentPageTextBox and hit enter, it will enable the Previous Page RadButton and if we click Previous Page then it will freeze the application.

System.ArgumentOutOfRangeException: 'pageNo should be greater or equal than 1 and less or equal than 4. (Parameter 'pageNo')'

Workaround: A possible approach could be to attach to the CurrentPageTextBox` KeyDown event in order to restrict the input.

XAML: 

<telerik:CurrentPageTextBox x:Name="PART_CurrentPageNumberTextBox" 
							KeyDown="PART_CurrentPageNumberTextBox_KeyDown"
							Text="{Binding FixedDocumentViewer.CurrentPageNumber, Mode=TwoWay}"/>

private void PART_CurrentPageNumberTextBox_KeyDown(object sender, System.Windows.Input.KeyEventArgs e)
{
	TextBox textBox = sender as TextBox;
	if (textBox != null)
	{
		if (e.Key == System.Windows.Input.Key.Enter)
		{
			int pagesCount = this.pdfViewer.PagesCount;
			int currentPageNumber = this.pdfViewer.CurrentPageNumber;
			if (this.pdfViewer.Document != null && (currentPageNumber < 1 || currentPageNumber > pagesCount))
			{
				RadFixedPage currentPage = this.pdfViewer.CurrentPage;
				int pageNum = this.pdfViewer.Document.Pages.IndexOf(currentPage) + 1;
				this.pdfViewer.CurrentPageNumber = pageNum;
			}
		}
	}
}

When modifying Interactive Forms TextBoxField's value the entered changes are preserved after is clicked out of the TextBoxField's editing area. However the changes are not applied when the click is performed on the save button.

As possible workaround you can raise a MouseLeftButtonDown event on the RadPdfViewer and after this execute the SaveAsCommand. For example:

private void SaveButton_Click(object sender, RoutedEventArgs e)
{
    MouseButtonEventArgs mouseEventArgs = new MouseButtonEventArgs(Mouse.PrimaryDevice, 0, MouseButton.Left)
    {
        RoutedEvent = FrameworkElement.MouseLeftButtonDownEvent
    };
 
    ((FrameworkElement)this.pdfViewer.FixedDocumentPresenter).RaiseEvent(mouseEventArgs);
    this.pdfViewer.CommandDescriptors.SaveAsCommandDescriptor.Command.Execute(null);
}

When importing a PDF document, opening the stream in using statement, and using the default constructor of the PdfDocumentSource class, an exception is thrown:

using (Stream stream = ofd.OpenFile())
{
	this.pdfViewer.DocumentSource = new PdfDocumentSource(stream);
}

using (Stream stream = ofd.OpenFile())
{
	PdfImportSettings importSettings = new PdfImportSettings
	{
		CopyStream = true
	};

	this.pdfViewer.DocumentSource = new PdfDocumentSource(stream, importSettings);
}

This is caused by an incorrect order of applying the TextMatrix and the glyph stroking operation.