PDF-preview

rienvanham · October 25, 2021, 11:09:33 AM

Hi Mario,

All my scanned documents are OCR-ed (with FineReader) and saved as PDF. Very often a preview is white in iMatch (so, no text or pictures are visable) but after changing to another document (or another page then nr. 1) and going back to that document shows the content. I'm wondering what goes wrong. I don't think it's the document itself (BTW this behavior is with many documents) because the second time they show up.

Thanks in advance,

Groeten uit Nederland,
Rien.

Mario · October 25, 2021, 11:35:52 AM

Maybe IMatch was still generating the cache image in the background (assuming you use the on-demand cache setting)?
It can take quite a while to extract a preview, depending on the PDF variant and whether IMatch can use PDFLib or must fall back to the Windows PDF shell thumbnail handler.

rienvanham · October 25, 2021, 12:08:47 PM

I waited minutes long but nothing happened (see attachment)

Mario · October 25, 2021, 12:33:56 PM

This looks like the Quick View panel, right?

IMatch uses the Chromium Browser to display the live content of PDF files. I have no control over how Google implements the PDF support or how Chromium deals with PDF files.
For all my 50+ test PDF files this worked great. But there will always be exceptions. Use Ctrl+Enter to open the PDF file in whatever PDF Viewer software you have installed when Chromium does not handle them.

rienvanham · October 25, 2021, 12:40:03 PM

Mmm, the strange thing is dough that if I click on page 2 and then click page 1 it is showing the page......

Mario · October 25, 2021, 12:58:02 PM

This is something then only the Google/Chromium developers can fix. IMatch only starts Chromium and tells it to open the PDF file.

rienvanham · October 25, 2021, 06:12:49 PM

Thanks Mario!

thrinn · October 25, 2021, 06:14:17 PM

If these PDF files have been imported with an older IMatch version, you could also try to regenerate the preview by using the Rescan > Update cache image only option. If I remember correctly, this helped for some older PDF files in my database.

Mario · October 25, 2021, 06:50:41 PM

The Quick View panel no longer uses cache images for PDF file (the Viewer does).
Instead it hands over the PDF file to an embedded Chromium browser running in the Quick View Panel. This allows for actually paging through PDF files, seeing the table of contents etc. This works well for most PDF files, but Chromium is not Acrobat Reader, so there may be some PDF files which don't render well in Chromium. Or fail to render the first page, for some reason.