Created attachment 62541 [details]
SVG to reproduce the problem
The attached SVG image looks fine when added to an Impress presentation and exported to PDF (meaning you can zoom on it as much as you like, it's always sharp). But when inserted into a Writer doc and exported to PDF, it looks blurry even at 100% zoom, and it's worse when zooming. It's absolutely not suitable for printing.
I've checked that the "Lossless compression" PDF export option is checked: it has no effect.
Created attachment 62542 [details]
Exported PDF to see the result
Also happens on Windows Vista with LO 126.96.36.199.
*** This bug has been marked as a duplicate of bug 42092 ***