Exporting current page from viewer as image

[Toby]

Hi,

I've been struggling to work out how to export the current pdf page as shown in the pdfViewer after it has been rotated using controls in the pdfViewerNavigator. I'm trying to save the image in png format but it seems to export the page in the original orientation ignoring the applied rotation.  

 

Also whilst searching the forum for a solution, I came across the code

this.radPdfViewer1.PdfViewerElement.CurrentPage.PageNo

 

but  it appears that PageNo no longer exists in 2020.3.1020.

Currently i'm using

pdfViewer.ExportPage ( 0, _tempImageFileName, 1.0, true, ImageFormat.Png );

 

which exports the first page as a png, which works, I just need to save the currently selected page that may or may not have been rotated.

Is this possible, if so how ?

[Dess | Tech Support Engineer, Principal]

Hello, Toby,

PageNo is marked as obsolete with the following message: "Use RadFixedDocument.Pages.IndexOf(RadFixedPage) method instead".

RadPdfViewer is intended for visualizing the documents and does not respect changes in its content, including the rotation of the pages, after importing the document. What is allowed to be edited are only the interactive forms inside the document.

Please refer to the following forum post which points to using RadPdfProcessing if you want to change the orientation of a document and preserve these changes: https://www.telerik.com/forums/how-to-rotate-individual-pages#OeIdvbcGW0O0QPgmDRCfJw 

Then, using the API that RadPdfViewer offers you can load the exported pdf document and generate the images for each page in the pdf: https://docs.telerik.com/devtools/winforms/controls/pdfviewer/export-to-image   

I hope this information helps. If you need any further assistance please don't hesitate to contact me. 

Regards,
Dess | Tech Support Engineer, Sr.
Progress Telerik

[Toby]

All sorted now, I think it was the fact that pdfViewer.LoadDocument is asynchronous and returns before the document has actually loaded, hence having to use DpdfViewer.DocumentLoaded event twice

 

The first time to rotate the pages by given amount (noting that Pdf Viewer RotationAngle is 0..3 and RadFixedDocument uses 0, 90, 180 and 270)., and then a second time to export the chosen page after it has been reloaded from the providers memory stream.

 

Regards

Toby

[Dess | Tech Support Engineer, Principal]

Hello, Toby,

Indeed, RadPdfViewer loads the document asynchronously. It is possible to set the PdfViewerElement.AsyncRender property to false and this will disable the async rendering of pages.

However, the DocumentLoaded event is expected to be fired when the worker is completed with the document loading. Then, you can execute the desired action with the exact document.

Should you have further questions please let me know.

Regards,
Dess | Tech Support Engineer, Sr.
Progress Telerik