Quote:
Originally Posted by CheyenneDonna
I have a curious problem with some scanned in accessible format books. The accessibility center at school scanned several books for me in a format I could reflow, rather than the usual PDF image, however, some of them just show blank pages when I open them on the reader side. I have no trouble if I open them on the LCD with a PDF viewer. Is the reader not able to display all fonts?
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It sounds like they forgot to OCR the scanned book, so it is just a series of page images. Those won't show anything if the reader is in PDF Reflow mode (is the reader in PDF reflow mode? do you see anything when you turn off reflow?). You could open with Adobe Reader to check this, see what happens when you turn on reflow (a View option I think). The Adobe RMSDK that reader uses has a different reflow algorithm than Adobe Reader (RMSDK doesn't pay attention to reading order tags), but they should behave similarly in terms of this.
In general, whatever fonts are needed to render text should be embedded in the PDF. But it is possible to create PDFs without embedded fonts, in which case it tries to find them on the OS. Even then I think it would finally resort to font substitution and display text.
On the other hand if you turn off PDF reflow and still don't see anything, the authoring system is at fault. I sometimes find for example that PDFs I create with Apple's PDF writer cannot be read by Acrobat (no text shows up). The Adobe RMSDK that the eink reader uses is a little more fault tolerant, but it probably shares some of the same properties, if not some of the same code. Adobe has to maintain a very high standard for security, given the ubiquity of Reader, so if some authoring system is doing anything deviant or strange, it's not surprising that Adobe's PDF rendering system is going to ignore it rather than allow potentially malicious code to run. Again a good way to check would be to use Adobe Reader and see how it renders the problem PDFs.